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-rw-r--r--arch/x86/Kconfig45
-rw-r--r--arch/x86/events/amd/ibs.c8
-rw-r--r--arch/x86/include/asm/cpufeatures.h2
-rw-r--r--arch/x86/include/asm/kvm_host.h6
-rw-r--r--arch/x86/include/asm/msr-index.h16
-rw-r--r--arch/x86/include/asm/nospec-branch.h4
-rw-r--r--arch/x86/include/asm/processor.h7
-rw-r--r--arch/x86/include/asm/smp.h10
-rw-r--r--arch/x86/kernel/apic/apic.c122
-rw-r--r--arch/x86/kernel/cpu/Makefile2
-rw-r--r--arch/x86/kernel/cpu/bugs.c161
-rw-r--r--arch/x86/kernel/cpu/common.c94
-rw-r--r--arch/x86/kernel/cpu/cpu.h18
-rw-r--r--arch/x86/kernel/cpu/intel.c5
-rw-r--r--arch/x86/kernel/cpu/tsx.c140
-rw-r--r--arch/x86/kvm/cpuid.c8
-rw-r--r--arch/x86/kvm/mmu.c374
-rw-r--r--arch/x86/kvm/mmu.h4
-rw-r--r--arch/x86/kvm/mmutrace.h59
-rw-r--r--arch/x86/kvm/paging_tmpl.h65
-rw-r--r--arch/x86/kvm/svm.c10
-rw-r--r--arch/x86/kvm/vmx.c14
-rw-r--r--arch/x86/kvm/x86.c63
23 files changed, 1024 insertions, 213 deletions
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 8fec1585ac7a..b58daecc591e 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1853,6 +1853,51 @@ config X86_INTEL_MEMORY_PROTECTION_KEYS
If unsure, say y.
+choice
+ prompt "TSX enable mode"
+ depends on CPU_SUP_INTEL
+ default X86_INTEL_TSX_MODE_OFF
+ help
+ Intel's TSX (Transactional Synchronization Extensions) feature
+ allows to optimize locking protocols through lock elision which
+ can lead to a noticeable performance boost.
+
+ On the other hand it has been shown that TSX can be exploited
+ to form side channel attacks (e.g. TAA) and chances are there
+ will be more of those attacks discovered in the future.
+
+ Therefore TSX is not enabled by default (aka tsx=off). An admin
+ might override this decision by tsx=on the command line parameter.
+ Even with TSX enabled, the kernel will attempt to enable the best
+ possible TAA mitigation setting depending on the microcode available
+ for the particular machine.
+
+ This option allows to set the default tsx mode between tsx=on, =off
+ and =auto. See Documentation/admin-guide/kernel-parameters.txt for more
+ details.
+
+ Say off if not sure, auto if TSX is in use but it should be used on safe
+ platforms or on if TSX is in use and the security aspect of tsx is not
+ relevant.
+
+config X86_INTEL_TSX_MODE_OFF
+ bool "off"
+ help
+ TSX is disabled if possible - equals to tsx=off command line parameter.
+
+config X86_INTEL_TSX_MODE_ON
+ bool "on"
+ help
+ TSX is always enabled on TSX capable HW - equals the tsx=on command
+ line parameter.
+
+config X86_INTEL_TSX_MODE_AUTO
+ bool "auto"
+ help
+ TSX is enabled on TSX capable HW that is believed to be safe against
+ side channel attacks- equals the tsx=auto command line parameter.
+endchoice
+
config EFI
bool "EFI runtime service support"
depends on ACPI
diff --git a/arch/x86/events/amd/ibs.c b/arch/x86/events/amd/ibs.c
index 7a86fbc07ddc..f24e9adaa316 100644
--- a/arch/x86/events/amd/ibs.c
+++ b/arch/x86/events/amd/ibs.c
@@ -389,7 +389,8 @@ static inline void perf_ibs_disable_event(struct perf_ibs *perf_ibs,
struct hw_perf_event *hwc, u64 config)
{
config &= ~perf_ibs->cnt_mask;
- wrmsrl(hwc->config_base, config);
+ if (boot_cpu_data.x86 == 0x10)
+ wrmsrl(hwc->config_base, config);
config &= ~perf_ibs->enable_mask;
wrmsrl(hwc->config_base, config);
}
@@ -564,7 +565,8 @@ static struct perf_ibs perf_ibs_op = {
},
.msr = MSR_AMD64_IBSOPCTL,
.config_mask = IBS_OP_CONFIG_MASK,
- .cnt_mask = IBS_OP_MAX_CNT,
+ .cnt_mask = IBS_OP_MAX_CNT | IBS_OP_CUR_CNT |
+ IBS_OP_CUR_CNT_RAND,
.enable_mask = IBS_OP_ENABLE,
.valid_mask = IBS_OP_VAL,
.max_period = IBS_OP_MAX_CNT << 4,
@@ -625,7 +627,7 @@ fail:
if (event->attr.sample_type & PERF_SAMPLE_RAW)
offset_max = perf_ibs->offset_max;
else if (check_rip)
- offset_max = 2;
+ offset_max = 3;
else
offset_max = 1;
do {
diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index 14357354cd28..b4bef819d5d5 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -388,5 +388,7 @@
#define X86_BUG_MDS X86_BUG(19) /* CPU is affected by Microarchitectural data sampling */
#define X86_BUG_MSBDS_ONLY X86_BUG(20) /* CPU is only affected by the MSDBS variant of BUG_MDS */
#define X86_BUG_SWAPGS X86_BUG(21) /* CPU is affected by speculation through SWAPGS */
+#define X86_BUG_TAA X86_BUG(22) /* CPU is affected by TSX Async Abort(TAA) */
+#define X86_BUG_ITLB_MULTIHIT X86_BUG(23) /* CPU may incur MCE during certain page attribute changes */
#endif /* _ASM_X86_CPUFEATURES_H */
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 00c12158a5dc..d0e17813a9b0 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -277,6 +277,7 @@ struct kvm_rmap_head {
struct kvm_mmu_page {
struct list_head link;
struct hlist_node hash_link;
+ struct list_head lpage_disallowed_link;
/*
* The following two entries are used to key the shadow page in the
@@ -289,6 +290,7 @@ struct kvm_mmu_page {
/* hold the gfn of each spte inside spt */
gfn_t *gfns;
bool unsync;
+ bool lpage_disallowed; /* Can't be replaced by an equiv large page */
int root_count; /* Currently serving as active root */
unsigned int unsync_children;
struct kvm_rmap_head parent_ptes; /* rmap pointers to parent sptes */
@@ -779,6 +781,7 @@ struct kvm_arch {
*/
struct list_head active_mmu_pages;
struct list_head zapped_obsolete_pages;
+ struct list_head lpage_disallowed_mmu_pages;
struct kvm_page_track_notifier_node mmu_sp_tracker;
struct kvm_page_track_notifier_head track_notifier_head;
@@ -854,6 +857,8 @@ struct kvm_arch {
bool x2apic_format;
bool x2apic_broadcast_quirk_disabled;
+
+ struct task_struct *nx_lpage_recovery_thread;
};
struct kvm_vm_stat {
@@ -867,6 +872,7 @@ struct kvm_vm_stat {
ulong mmu_unsync;
ulong remote_tlb_flush;
ulong lpages;
+ ulong nx_lpage_splits;
ulong max_mmu_page_hash_collisions;
};
diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h
index fda3bf75de6c..5761a86b88e0 100644
--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h
@@ -84,6 +84,18 @@
* Microarchitectural Data
* Sampling (MDS) vulnerabilities.
*/
+#define ARCH_CAP_PSCHANGE_MC_NO BIT(6) /*
+ * The processor is not susceptible to a
+ * machine check error due to modifying the
+ * code page size along with either the
+ * physical address or cache type
+ * without TLB invalidation.
+ */
+#define ARCH_CAP_TSX_CTRL_MSR BIT(7) /* MSR for TSX control is available. */
+#define ARCH_CAP_TAA_NO BIT(8) /*
+ * Not susceptible to
+ * TSX Async Abort (TAA) vulnerabilities.
+ */
#define MSR_IA32_FLUSH_CMD 0x0000010b
#define L1D_FLUSH BIT(0) /*
@@ -94,6 +106,10 @@
#define MSR_IA32_BBL_CR_CTL 0x00000119
#define MSR_IA32_BBL_CR_CTL3 0x0000011e
+#define MSR_IA32_TSX_CTRL 0x00000122
+#define TSX_CTRL_RTM_DISABLE BIT(0) /* Disable RTM feature */
+#define TSX_CTRL_CPUID_CLEAR BIT(1) /* Disable TSX enumeration */
+
#define MSR_IA32_SYSENTER_CS 0x00000174
#define MSR_IA32_SYSENTER_ESP 0x00000175
#define MSR_IA32_SYSENTER_EIP 0x00000176
diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h
index f6b496d11097..b73a16a56e4f 100644
--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -323,7 +323,7 @@ DECLARE_STATIC_KEY_FALSE(mds_idle_clear);
#include <asm/segment.h>
/**
- * mds_clear_cpu_buffers - Mitigation for MDS vulnerability
+ * mds_clear_cpu_buffers - Mitigation for MDS and TAA vulnerability
*
* This uses the otherwise unused and obsolete VERW instruction in
* combination with microcode which triggers a CPU buffer flush when the
@@ -346,7 +346,7 @@ static inline void mds_clear_cpu_buffers(void)
}
/**
- * mds_user_clear_cpu_buffers - Mitigation for MDS vulnerability
+ * mds_user_clear_cpu_buffers - Mitigation for MDS and TAA vulnerability
*
* Clear CPU buffers if the corresponding static key is enabled
*/
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index d55a0adbcf27..6a87eda9691e 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -994,4 +994,11 @@ enum mds_mitigations {
MDS_MITIGATION_VMWERV,
};
+enum taa_mitigations {
+ TAA_MITIGATION_OFF,
+ TAA_MITIGATION_UCODE_NEEDED,
+ TAA_MITIGATION_VERW,
+ TAA_MITIGATION_TSX_DISABLED,
+};
+
#endif /* _ASM_X86_PROCESSOR_H */
diff --git a/arch/x86/include/asm/smp.h b/arch/x86/include/asm/smp.h
index fe2ee61880a8..a14730ca9d1e 100644
--- a/arch/x86/include/asm/smp.h
+++ b/arch/x86/include/asm/smp.h
@@ -175,16 +175,6 @@ static inline int wbinvd_on_all_cpus(void)
extern unsigned disabled_cpus;
#ifdef CONFIG_X86_LOCAL_APIC
-
-#ifndef CONFIG_X86_64
-static inline int logical_smp_processor_id(void)
-{
- /* we don't want to mark this access volatile - bad code generation */
- return GET_APIC_LOGICAL_ID(apic_read(APIC_LDR));
-}
-
-#endif
-
extern int hard_smp_processor_id(void);
#else /* CONFIG_X86_LOCAL_APIC */
diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index ea2de324ab02..6415b4aead54 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -1362,6 +1362,56 @@ static void lapic_setup_esr(void)
oldvalue, value);
}
+static void apic_pending_intr_clear(void)
+{
+ long long max_loops = cpu_khz ? cpu_khz : 1000000;
+ unsigned long long tsc = 0, ntsc;
+ unsigned int value, queued;
+ int i, j, acked = 0;
+
+ if (boot_cpu_has(X86_FEATURE_TSC))
+ tsc = rdtsc();
+ /*
+ * After a crash, we no longer service the interrupts and a pending
+ * interrupt from previous kernel might still have ISR bit set.
+ *
+ * Most probably by now CPU has serviced that pending interrupt and
+ * it might not have done the ack_APIC_irq() because it thought,
+ * interrupt came from i8259 as ExtInt. LAPIC did not get EOI so it
+ * does not clear the ISR bit and cpu thinks it has already serivced
+ * the interrupt. Hence a vector might get locked. It was noticed
+ * for timer irq (vector 0x31). Issue an extra EOI to clear ISR.
+ */
+ do {
+ queued = 0;
+ for (i = APIC_ISR_NR - 1; i >= 0; i--)
+ queued |= apic_read(APIC_IRR + i*0x10);
+
+ for (i = APIC_ISR_NR - 1; i >= 0; i--) {
+ value = apic_read(APIC_ISR + i*0x10);
+ for (j = 31; j >= 0; j--) {
+ if (value & (1<<j)) {
+ ack_APIC_irq();
+ acked++;
+ }
+ }
+ }
+ if (acked > 256) {
+ printk(KERN_ERR "LAPIC pending interrupts after %d EOI\n",
+ acked);
+ break;
+ }
+ if (queued) {
+ if (boot_cpu_has(X86_FEATURE_TSC) && cpu_khz) {
+ ntsc = rdtsc();
+ max_loops = (cpu_khz << 10) - (ntsc - tsc);
+ } else
+ max_loops--;
+ }
+ } while (queued && max_loops > 0);
+ WARN_ON(max_loops <= 0);
+}
+
/**
* setup_local_APIC - setup the local APIC
*
@@ -1371,13 +1421,8 @@ static void lapic_setup_esr(void)
void setup_local_APIC(void)
{
int cpu = smp_processor_id();
- unsigned int value, queued;
- int i, j, acked = 0;
- unsigned long long tsc = 0, ntsc;
- long long max_loops = cpu_khz ? cpu_khz : 1000000;
+ unsigned int value;
- if (boot_cpu_has(X86_FEATURE_TSC))
- tsc = rdtsc();
if (disable_apic) {
disable_ioapic_support();
@@ -1417,16 +1462,21 @@ void setup_local_APIC(void)
apic->init_apic_ldr();
#ifdef CONFIG_X86_32
- /*
- * APIC LDR is initialized. If logical_apicid mapping was
- * initialized during get_smp_config(), make sure it matches the
- * actual value.
- */
- i = early_per_cpu(x86_cpu_to_logical_apicid, cpu);
- WARN_ON(i != BAD_APICID && i != logical_smp_processor_id());
- /* always use the value from LDR */
- early_per_cpu(x86_cpu_to_logical_apicid, cpu) =
- logical_smp_processor_id();
+ if (apic->dest_logical) {
+ int logical_apicid, ldr_apicid;
+
+ /*
+ * APIC LDR is initialized. If logical_apicid mapping was
+ * initialized during get_smp_config(), make sure it matches
+ * the actual value.
+ */
+ logical_apicid = early_per_cpu(x86_cpu_to_logical_apicid, cpu);
+ ldr_apicid = GET_APIC_LOGICAL_ID(apic_read(APIC_LDR));
+ if (logical_apicid != BAD_APICID)
+ WARN_ON(logical_apicid != ldr_apicid);
+ /* Always use the value from LDR. */
+ early_per_cpu(x86_cpu_to_logical_apicid, cpu) = ldr_apicid;
+ }
#endif
/*
@@ -1437,45 +1487,7 @@ void setup_local_APIC(void)
value &= ~APIC_TPRI_MASK;
apic_write(APIC_TASKPRI, value);
- /*
- * After a crash, we no longer service the interrupts and a pending
- * interrupt from previous kernel might still have ISR bit set.
- *
- * Most probably by now CPU has serviced that pending interrupt and
- * it might not have done the ack_APIC_irq() because it thought,
- * interrupt came from i8259 as ExtInt. LAPIC did not get EOI so it
- * does not clear the ISR bit and cpu thinks it has already serivced
- * the interrupt. Hence a vector might get locked. It was noticed
- * for timer irq (vector 0x31). Issue an extra EOI to clear ISR.
- */
- do {
- queued = 0;
- for (i = APIC_ISR_NR - 1; i >= 0; i--)
- queued |= apic_read(APIC_IRR + i*0x10);
-
- for (i = APIC_ISR_NR - 1; i >= 0; i--) {
- value = apic_read(APIC_ISR + i*0x10);
- for (j = 31; j >= 0; j--) {
- if (value & (1<<j)) {
- ack_APIC_irq();
- acked++;
- }
- }
- }
- if (acked > 256) {
- printk(KERN_ERR "LAPIC pending interrupts after %d EOI\n",
- acked);
- break;
- }
- if (queued) {
- if (boot_cpu_has(X86_FEATURE_TSC) && cpu_khz) {
- ntsc = rdtsc();
- max_loops = (cpu_khz << 10) - (ntsc - tsc);
- } else
- max_loops--;
- }
- } while (queued && max_loops > 0);
- WARN_ON(max_loops <= 0);
+ apic_pending_intr_clear();
/*
* Now that we are all set up, enable the APIC
diff --git a/arch/x86/kernel/cpu/Makefile b/arch/x86/kernel/cpu/Makefile
index 570e8bb1f386..e13ddd19a76c 100644
--- a/arch/x86/kernel/cpu/Makefile
+++ b/arch/x86/kernel/cpu/Makefile
@@ -28,7 +28,7 @@ obj-y += cpuid-deps.o
obj-$(CONFIG_PROC_FS) += proc.o
obj-$(CONFIG_X86_FEATURE_NAMES) += capflags.o powerflags.o
-obj-$(CONFIG_CPU_SUP_INTEL) += intel.o
+obj-$(CONFIG_CPU_SUP_INTEL) += intel.o tsx.o
obj-$(CONFIG_CPU_SUP_AMD) += amd.o
obj-$(CONFIG_CPU_SUP_CYRIX_32) += cyrix.o
obj-$(CONFIG_CPU_SUP_CENTAUR) += centaur.o
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index 8bf21bc7a190..8596811843cc 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -32,11 +32,14 @@
#include <asm/intel-family.h>
#include <asm/e820/api.h>
+#include "cpu.h"
+
static void __init spectre_v1_select_mitigation(void);
static void __init spectre_v2_select_mitigation(void);
static void __init ssb_select_mitigation(void);
static void __init l1tf_select_mitigation(void);
static void __init mds_select_mitigation(void);
+static void __init taa_select_mitigation(void);
/* The base value of the SPEC_CTRL MSR that always has to be preserved. */
u64 x86_spec_ctrl_base;
@@ -103,6 +106,7 @@ void __init check_bugs(void)
ssb_select_mitigation();
l1tf_select_mitigation();
mds_select_mitigation();
+ taa_select_mitigation();
arch_smt_update();
@@ -267,6 +271,100 @@ static int __init mds_cmdline(char *str)
early_param("mds", mds_cmdline);
#undef pr_fmt
+#define pr_fmt(fmt) "TAA: " fmt
+
+/* Default mitigation for TAA-affected CPUs */
+static enum taa_mitigations taa_mitigation __ro_after_init = TAA_MITIGATION_VERW;
+static bool taa_nosmt __ro_after_init;
+
+static const char * const taa_strings[] = {
+ [TAA_MITIGATION_OFF] = "Vulnerable",
+ [TAA_MITIGATION_UCODE_NEEDED] = "Vulnerable: Clear CPU buffers attempted, no microcode",
+ [TAA_MITIGATION_VERW] = "Mitigation: Clear CPU buffers",
+ [TAA_MITIGATION_TSX_DISABLED] = "Mitigation: TSX disabled",
+};
+
+static void __init taa_select_mitigation(void)
+{
+ u64 ia32_cap;
+
+ if (!boot_cpu_has_bug(X86_BUG_TAA)) {
+ taa_mitigation = TAA_MITIGATION_OFF;
+ return;
+ }
+
+ /* TSX previously disabled by tsx=off */
+ if (!boot_cpu_has(X86_FEATURE_RTM)) {
+ taa_mitigation = TAA_MITIGATION_TSX_DISABLED;
+ goto out;
+ }
+
+ if (cpu_mitigations_off()) {
+ taa_mitigation = TAA_MITIGATION_OFF;
+ return;
+ }
+
+ /* TAA mitigation is turned off on the cmdline (tsx_async_abort=off) */
+ if (taa_mitigation == TAA_MITIGATION_OFF)
+ goto out;
+
+ if (boot_cpu_has(X86_FEATURE_MD_CLEAR))
+ taa_mitigation = TAA_MITIGATION_VERW;
+ else
+ taa_mitigation = TAA_MITIGATION_UCODE_NEEDED;
+
+ /*
+ * VERW doesn't clear the CPU buffers when MD_CLEAR=1 and MDS_NO=1.
+ * A microcode update fixes this behavior to clear CPU buffers. It also
+ * adds support for MSR_IA32_TSX_CTRL which is enumerated by the
+ * ARCH_CAP_TSX_CTRL_MSR bit.
+ *
+ * On MDS_NO=1 CPUs if ARCH_CAP_TSX_CTRL_MSR is not set, microcode
+ * update is required.
+ */
+ ia32_cap = x86_read_arch_cap_msr();
+ if ( (ia32_cap & ARCH_CAP_MDS_NO) &&
+ !(ia32_cap & ARCH_CAP_TSX_CTRL_MSR))
+ taa_mitigation = TAA_MITIGATION_UCODE_NEEDED;
+
+ /*
+ * TSX is enabled, select alternate mitigation for TAA which is
+ * the same as MDS. Enable MDS static branch to clear CPU buffers.
+ *
+ * For guests that can't determine whether the correct microcode is
+ * present on host, enable the mitigation for UCODE_NEEDED as well.
+ */
+ static_branch_enable(&mds_user_clear);
+
+ if (taa_nosmt || cpu_mitigations_auto_nosmt())
+ cpu_smt_disable(false);
+
+out:
+ pr_info("%s\n", taa_strings[taa_mitigation]);
+}
+
+static int __init tsx_async_abort_parse_cmdline(char *str)
+{
+ if (!boot_cpu_has_bug(X86_BUG_TAA))
+ return 0;
+
+ if (!str)
+ return -EINVAL;
+
+ if (!strcmp(str, "off")) {
+ taa_mitigation = TAA_MITIGATION_OFF;
+ } else if (!strcmp(str, "full")) {
+ taa_mitigation = TAA_MITIGATION_VERW;
+ } else if (!strcmp(str, "full,nosmt")) {
+ taa_mitigation = TAA_MITIGATION_VERW;
+ taa_nosmt = true;
+ }
+
+ return 0;
+}
+early_param("tsx_async_abort", tsx_async_abort_parse_cmdline);
+
+#undef pr_fmt
#define pr_fmt(fmt) "Spectre V1 : " fmt
enum spectre_v1_mitigation {
@@ -772,13 +870,10 @@ static void update_mds_branch_idle(void)
}
#define MDS_MSG_SMT "MDS CPU bug present and SMT on, data leak possible. See https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/mds.html for more details.\n"
+#define TAA_MSG_SMT "TAA CPU bug present and SMT on, data leak possible. See https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/tsx_async_abort.html for more details.\n"
void arch_smt_update(void)
{
- /* Enhanced IBRS implies STIBP. No update required. */
- if (spectre_v2_enabled == SPECTRE_V2_IBRS_ENHANCED)
- return;
-
mutex_lock(&spec_ctrl_mutex);
switch (spectre_v2_user) {
@@ -804,6 +899,17 @@ void arch_smt_update(void)
break;
}
+ switch (taa_mitigation) {
+ case TAA_MITIGATION_VERW:
+ case TAA_MITIGATION_UCODE_NEEDED:
+ if (sched_smt_active())
+ pr_warn_once(TAA_MSG_SMT);
+ break;
+ case TAA_MITIGATION_TSX_DISABLED:
+ case TAA_MITIGATION_OFF:
+ break;
+ }
+
mutex_unlock(&spec_ctrl_mutex);
}
@@ -1119,6 +1225,9 @@ void x86_spec_ctrl_setup_ap(void)
x86_amd_ssb_disable();
}
+bool itlb_multihit_kvm_mitigation;
+EXPORT_SYMBOL_GPL(itlb_multihit_kvm_mitigation);
+
#undef pr_fmt
#define pr_fmt(fmt) "L1TF: " fmt
@@ -1274,11 +1383,24 @@ static ssize_t l1tf_show_state(char *buf)
l1tf_vmx_states[l1tf_vmx_mitigation],
sched_smt_active() ? "vulnerable" : "disabled");
}
+
+static ssize_t itlb_multihit_show_state(char *buf)
+{
+ if (itlb_multihit_kvm_mitigation)
+ return sprintf(buf, "KVM: Mitigation: Split huge pages\n");
+ else
+ return sprintf(buf, "KVM: Vulnerable\n");
+}
#else
static ssize_t l1tf_show_state(char *buf)
{
return sprintf(buf, "%s\n", L1TF_DEFAULT_MSG);
}
+
+static ssize_t itlb_multihit_show_state(char *buf)
+{
+ return sprintf(buf, "Processor vulnerable\n");
+}
#endif
static ssize_t mds_show_state(char *buf)
@@ -1298,6 +1420,21 @@ static ssize_t mds_show_state(char *buf)
sched_smt_active() ? "vulnerable" : "disabled");
}
+static ssize_t tsx_async_abort_show_state(char *buf)
+{
+ if ((taa_mitigation == TAA_MITIGATION_TSX_DISABLED) ||
+ (taa_mitigation == TAA_MITIGATION_OFF))
+ return sprintf(buf, "%s\n", taa_strings[taa_mitigation]);
+
+ if (boot_cpu_has(X86_FEATURE_HYPERVISOR)) {
+ return sprintf(buf, "%s; SMT Host state unknown\n",
+ taa_strings[taa_mitigation]);
+ }
+
+ return sprintf(buf, "%s; SMT %s\n", taa_strings[taa_mitigation],
+ sched_smt_active() ? "vulnerable" : "disabled");
+}
+
static char *stibp_state(void)
{
if (spectre_v2_enabled == SPECTRE_V2_IBRS_ENHANCED)
@@ -1363,6 +1500,12 @@ static ssize_t cpu_show_common(struct device *dev, struct device_attribute *attr
case X86_BUG_MDS:
return mds_show_state(buf);
+ case X86_BUG_TAA:
+ return tsx_async_abort_show_state(buf);
+
+ case X86_BUG_ITLB_MULTIHIT:
+ return itlb_multihit_show_state(buf);
+
default:
break;
}
@@ -1399,4 +1542,14 @@ ssize_t cpu_show_mds(struct device *dev, struct device_attribute *attr, char *bu
{
return cpu_show_common(dev, attr, buf, X86_BUG_MDS);
}
+
+ssize_t cpu_show_tsx_async_abort(struct device *dev, struct device_attribute *attr, char *buf)
+{
+ return cpu_show_common(dev, attr, buf, X86_BUG_TAA);
+}
+
+ssize_t cpu_show_itlb_multihit(struct device *dev, struct device_attribute *attr, char *buf)
+{
+ return cpu_show_common(dev, attr, buf, X86_BUG_ITLB_MULTIHIT);
+}
#endif
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 551c6bed7c8c..c0c9c5a44e82 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -897,13 +897,14 @@ static void identify_cpu_without_cpuid(struct cpuinfo_x86 *c)
c->x86_cache_bits = c->x86_phys_bits;
}
-#define NO_SPECULATION BIT(0)
-#define NO_MELTDOWN BIT(1)
-#define NO_SSB BIT(2)
-#define NO_L1TF BIT(3)
-#define NO_MDS BIT(4)
-#define MSBDS_ONLY BIT(5)
-#define NO_SWAPGS BIT(6)
+#define NO_SPECULATION BIT(0)
+#define NO_MELTDOWN BIT(1)
+#define NO_SSB BIT(2)
+#define NO_L1TF BIT(3)
+#define NO_MDS BIT(4)
+#define MSBDS_ONLY BIT(5)
+#define NO_SWAPGS BIT(6)
+#define NO_ITLB_MULTIHIT BIT(7)
#define VULNWL(_vendor, _family, _model, _whitelist) \
{ X86_VENDOR_##_vendor, _family, _model, X86_FEATURE_ANY, _whitelist }
@@ -921,26 +922,26 @@ static const __initconst struct x86_cpu_id cpu_vuln_whitelist[] = {
VULNWL(NSC, 5, X86_MODEL_ANY, NO_SPECULATION),
/* Intel Family 6 */
- VULNWL_INTEL(ATOM_SALTWELL, NO_SPECULATION),
- VULNWL_INTEL(ATOM_SALTWELL_TABLET, NO_SPECULATION),
- VULNWL_INTEL(ATOM_SALTWELL_MID, NO_SPECULATION),
- VULNWL_INTEL(ATOM_BONNELL, NO_SPECULATION),
- VULNWL_INTEL(ATOM_BONNELL_MID, NO_SPECULATION),
-
- VULNWL_INTEL(ATOM_SILVERMONT, NO_SSB | NO_L1TF | MSBDS_ONLY | NO_SWAPGS),
- VULNWL_INTEL(ATOM_SILVERMONT_X, NO_SSB | NO_L1TF | MSBDS_ONLY | NO_SWAPGS),
- VULNWL_INTEL(ATOM_SILVERMONT_MID, NO_SSB | NO_L1TF | MSBDS_ONLY | NO_SWAPGS),
- VULNWL_INTEL(ATOM_AIRMONT, NO_SSB | NO_L1TF | MSBDS_ONLY | NO_SWAPGS),
- VULNWL_INTEL(XEON_PHI_KNL, NO_SSB | NO_L1TF | MSBDS_ONLY | NO_SWAPGS),
- VULNWL_INTEL(XEON_PHI_KNM, NO_SSB | NO_L1TF | MSBDS_ONLY | NO_SWAPGS),
+ VULNWL_INTEL(ATOM_SALTWELL, NO_SPECULATION | NO_ITLB_MULTIHIT),
+ VULNWL_INTEL(ATOM_SALTWELL_TABLET, NO_SPECULATION | NO_ITLB_MULTIHIT),
+ VULNWL_INTEL(ATOM_SALTWELL_MID, NO_SPECULATION | NO_ITLB_MULTIHIT),
+ VULNWL_INTEL(ATOM_BONNELL, NO_SPECULATION | NO_ITLB_MULTIHIT),
+ VULNWL_INTEL(ATOM_BONNELL_MID, NO_SPECULATION | NO_ITLB_MULTIHIT),
+
+ VULNWL_INTEL(ATOM_SILVERMONT, NO_SSB | NO_L1TF | MSBDS_ONLY | NO_SWAPGS | NO_ITLB_MULTIHIT),
+ VULNWL_INTEL(ATOM_SILVERMONT_X, NO_SSB | NO_L1TF | MSBDS_ONLY | NO_SWAPGS | NO_ITLB_MULTIHIT),
+ VULNWL_INTEL(ATOM_SILVERMONT_MID, NO_SSB | NO_L1TF | MSBDS_ONLY | NO_SWAPGS | NO_ITLB_MULTIHIT),
+ VULNWL_INTEL(ATOM_AIRMONT, NO_SSB | NO_L1TF | MSBDS_ONLY | NO_SWAPGS | NO_ITLB_MULTIHIT),
+ VULNWL_INTEL(XEON_PHI_KNL, NO_SSB | NO_L1TF | MSBDS_ONLY | NO_SWAPGS | NO_ITLB_MULTIHIT),
+ VULNWL_INTEL(XEON_PHI_KNM, NO_SSB | NO_L1TF | MSBDS_ONLY | NO_SWAPGS | NO_ITLB_MULTIHIT),
VULNWL_INTEL(CORE_YONAH, NO_SSB),
- VULNWL_INTEL(ATOM_AIRMONT_MID, NO_L1TF | MSBDS_ONLY | NO_SWAPGS),
+ VULNWL_INTEL(ATOM_AIRMONT_MID, NO_L1TF | MSBDS_ONLY | NO_SWAPGS | NO_ITLB_MULTIHIT),
- VULNWL_INTEL(ATOM_GOLDMONT, NO_MDS | NO_L1TF | NO_SWAPGS),
- VULNWL_INTEL(ATOM_GOLDMONT_X, NO_MDS | NO_L1TF | NO_SWAPGS),
- VULNWL_INTEL(ATOM_GOLDMONT_PLUS, NO_MDS | NO_L1TF | NO_SWAPGS),
+ VULNWL_INTEL(ATOM_GOLDMONT, NO_MDS | NO_L1TF | NO_SWAPGS | NO_ITLB_MULTIHIT),
+ VULNWL_INTEL(ATOM_GOLDMONT_X, NO_MDS | NO_L1TF | NO_SWAPGS | NO_ITLB_MULTIHIT),
+ VULNWL_INTEL(ATOM_GOLDMONT_PLUS, NO_MDS | NO_L1TF | NO_SWAPGS | NO_ITLB_MULTIHIT),
/*
* Technically, swapgs isn't serializing on AMD (despite it previously
@@ -950,14 +951,16 @@ static const __initconst struct x86_cpu_id cpu_vuln_whitelist[] = {
* good enough for our purposes.
*/
+ VULNWL_INTEL(ATOM_TREMONT_X, NO_ITLB_MULTIHIT),
+
/* AMD Family 0xf - 0x12 */
- VULNWL_AMD(0x0f, NO_MELTDOWN | NO_SSB | NO_L1TF | NO_MDS | NO_SWAPGS),
- VULNWL_AMD(0x10, NO_MELTDOWN | NO_SSB | NO_L1TF | NO_MDS | NO_SWAPGS),
- VULNWL_AMD(0x11, NO_MELTDOWN | NO_SSB | NO_L1TF | NO_MDS | NO_SWAPGS),
- VULNWL_AMD(0x12, NO_MELTDOWN | NO_SSB | NO_L1TF | NO_MDS | NO_SWAPGS),
+ VULNWL_AMD(0x0f, NO_MELTDOWN | NO_SSB | NO_L1TF | NO_MDS | NO_SWAPGS | NO_ITLB_MULTIHIT),
+ VULNWL_AMD(0x10, NO_MELTDOWN | NO_SSB | NO_L1TF | NO_MDS | NO_SWAPGS | NO_ITLB_MULTIHIT),
+ VULNWL_AMD(0x11, NO_MELTDOWN | NO_SSB | NO_L1TF | NO_MDS | NO_SWAPGS | NO_ITLB_MULTIHIT),
+ VULNWL_AMD(0x12, NO_MELTDOWN | NO_SSB | NO_L1TF | NO_MDS | NO_SWAPGS | NO_ITLB_MULTIHIT),
/* FAMILY_ANY must be last, otherwise 0x0f - 0x12 matches won't work */
- VULNWL_AMD(X86_FAMILY_ANY, NO_MELTDOWN | NO_L1TF | NO_MDS | NO_SWAPGS),
+ VULNWL_AMD(X86_FAMILY_ANY, NO_MELTDOWN | NO_L1TF | NO_MDS | NO_SWAPGS | NO_ITLB_MULTIHIT),
{}
};
@@ -968,19 +971,30 @@ static bool __init cpu_matches(unsigned long which)
return m && !!(m->driver_data & which);
}
-static void __init cpu_set_bug_bits(struct cpuinfo_x86 *c)
+u64 x86_read_arch_cap_msr(void)
{
u64 ia32_cap = 0;
+ if (boot_cpu_has(X86_FEATURE_ARCH_CAPABILITIES))
+ rdmsrl(MSR_IA32_ARCH_CAPABILITIES, ia32_cap);
+
+ return ia32_cap;
+}
+
+static void __init cpu_set_bug_bits(struct cpuinfo_x86 *c)
+{
+ u64 ia32_cap = x86_read_arch_cap_msr();
+
+ /* Set ITLB_MULTIHIT bug if cpu is not in the whitelist and not mitigated */
+ if (!cpu_matches(NO_ITLB_MULTIHIT) && !(ia32_cap & ARCH_CAP_PSCHANGE_MC_NO))
+ setup_force_cpu_bug(X86_BUG_ITLB_MULTIHIT);
+
if (cpu_matches(NO_SPECULATION))
return;
setup_force_cpu_bug(X86_BUG_SPECTRE_V1);
setup_force_cpu_bug(X86_BUG_SPECTRE_V2);
- if (cpu_has(c, X86_FEATURE_ARCH_CAPABILITIES))
- rdmsrl(MSR_IA32_ARCH_CAPABILITIES, ia32_cap);
-
if (!cpu_matches(NO_SSB) && !(ia32_cap & ARCH_CAP_SSB_NO) &&
!cpu_has(c, X86_FEATURE_AMD_SSB_NO))
setup_force_cpu_bug(X86_BUG_SPEC_STORE_BYPASS);
@@ -997,6 +1011,21 @@ static void __init cpu_set_bug_bits(struct cpuinfo_x86 *c)
if (!cpu_matches(NO_SWAPGS))
setup_force_cpu_bug(X86_BUG_SWAPGS);
+ /*
+ * When the CPU is not mitigated for TAA (TAA_NO=0) set TAA bug when:
+ * - TSX is supported or
+ * - TSX_CTRL is present
+ *
+ * TSX_CTRL check is needed for cases when TSX could be disabled before
+ * the kernel boot e.g. kexec.
+ * TSX_CTRL check alone is not sufficient for cases when the microcode
+ * update is not present or running as guest that don't get TSX_CTRL.
+ */
+ if (!(ia32_cap & ARCH_CAP_TAA_NO) &&
+ (cpu_has(c, X86_FEATURE_RTM) ||
+ (ia32_cap & ARCH_CAP_TSX_CTRL_MSR)))
+ setup_force_cpu_bug(X86_BUG_TAA);
+
if (cpu_matches(NO_MELTDOWN))
return;
@@ -1407,6 +1436,7 @@ void __init identify_boot_cpu(void)
enable_sep_cpu();
#endif
cpu_detect_tlb(&boot_cpu_data);
+ tsx_init();
}
void identify_secondary_cpu(struct cpuinfo_x86 *c)
diff --git a/arch/x86/kernel/cpu/cpu.h b/arch/x86/kernel/cpu/cpu.h
index cca588407dca..db10a63687d3 100644
--- a/arch/x86/kernel/cpu/cpu.h
+++ b/arch/x86/kernel/cpu/cpu.h
@@ -45,6 +45,22 @@ struct _tlb_table {
extern const struct cpu_dev *const __x86_cpu_dev_start[],
*const __x86_cpu_dev_end[];
+#ifdef CONFIG_CPU_SUP_INTEL
+enum tsx_ctrl_states {
+ TSX_CTRL_ENABLE,
+ TSX_CTRL_DISABLE,
+ TSX_CTRL_NOT_SUPPORTED,
+};
+
+extern __ro_after_init enum tsx_ctrl_states tsx_ctrl_state;
+
+extern void __init tsx_init(void);
+extern void tsx_enable(void);
+extern void tsx_disable(void);
+#else
+static inline void tsx_init(void) { }
+#endif /* CONFIG_CPU_SUP_INTEL */
+
extern void get_cpu_cap(struct cpuinfo_x86 *c);
extern void cpu_detect_cache_sizes(struct cpuinfo_x86 *c);
extern int detect_extended_topology_early(struct cpuinfo_x86 *c);
@@ -54,4 +70,6 @@ unsigned int aperfmperf_get_khz(int cpu);
extern void x86_spec_ctrl_setup_ap(void);
+extern u64 x86_read_arch_cap_msr(void);
+
#endif /* ARCH_X86_CPU_H */
diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index 574dcdc092ab..3a5ea741701b 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -695,6 +695,11 @@ static void init_intel(struct cpuinfo_x86 *c)
init_intel_energy_perf(c);
init_intel_misc_features(c);
+
+ if (tsx_ctrl_state == TSX_CTRL_ENABLE)
+ tsx_enable();
+ if (tsx_ctrl_state == TSX_CTRL_DISABLE)
+ tsx_disable();
}
#ifdef CONFIG_X86_32
diff --git a/arch/x86/kernel/cpu/tsx.c b/arch/x86/kernel/cpu/tsx.c
new file mode 100644
index 000000000000..3e20d322bc98
--- /dev/null
+++ b/arch/x86/kernel/cpu/tsx.c
@@ -0,0 +1,140 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Intel Transactional Synchronization Extensions (TSX) control.
+ *
+ * Copyright (C) 2019 Intel Corporation
+ *
+ * Author:
+ * Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
+ */
+
+#include <linux/cpufeature.h>
+
+#include <asm/cmdline.h>
+
+#include "cpu.h"
+
+enum tsx_ctrl_states tsx_ctrl_state __ro_after_init = TSX_CTRL_NOT_SUPPORTED;
+
+void tsx_disable(void)
+{
+ u64 tsx;
+
+ rdmsrl(MSR_IA32_TSX_CTRL, tsx);
+
+ /* Force all transactions to immediately abort */
+ tsx |= TSX_CTRL_RTM_DISABLE;
+
+ /*
+ * Ensure TSX support is not enumerated in CPUID.
+ * This is visible to userspace and will ensure they
+ * do not waste resources trying TSX transactions that
+ * will always abort.
+ */
+ tsx |= TSX_CTRL_CPUID_CLEAR;
+
+ wrmsrl(MSR_IA32_TSX_CTRL, tsx);
+}
+
+void tsx_enable(void)
+{
+ u64 tsx;
+
+ rdmsrl(MSR_IA32_TSX_CTRL, tsx);
+
+ /* Enable the RTM feature in the cpu */
+ tsx &= ~TSX_CTRL_RTM_DISABLE;
+
+ /*
+ * Ensure TSX support is enumerated in CPUID.
+ * This is visible to userspace and will ensure they
+ * can enumerate and use the TSX feature.
+ */
+ tsx &= ~TSX_CTRL_CPUID_CLEAR;
+
+ wrmsrl(MSR_IA32_TSX_CTRL, tsx);
+}
+
+static bool __init tsx_ctrl_is_supported(void)
+{
+ u64 ia32_cap = x86_read_arch_cap_msr();
+
+ /*
+ * TSX is controlled via MSR_IA32_TSX_CTRL. However, support for this
+ * MSR is enumerated by ARCH_CAP_TSX_MSR bit in MSR_IA32_ARCH_CAPABILITIES.
+ *
+ * TSX control (aka MSR_IA32_TSX_CTRL) is only available after a
+ * microcode update on CPUs that have their MSR_IA32_ARCH_CAPABILITIES
+ * bit MDS_NO=1. CPUs with MDS_NO=0 are not planned to get
+ * MSR_IA32_TSX_CTRL support even after a microcode update. Thus,
+ * tsx= cmdline requests will do nothing on CPUs without
+ * MSR_IA32_TSX_CTRL support.
+ */
+ return !!(ia32_cap & ARCH_CAP_TSX_CTRL_MSR);
+}
+
+static enum tsx_ctrl_states x86_get_tsx_auto_mode(void)
+{
+ if (boot_cpu_has_bug(X86_BUG_TAA))
+ return TSX_CTRL_DISABLE;
+
+ return TSX_CTRL_ENABLE;
+}
+
+void __init tsx_init(void)
+{
+ char arg[5] = {};
+ int ret;
+
+ if (!tsx_ctrl_is_supported())
+ return;
+
+ ret = cmdline_find_option(boot_command_line, "tsx", arg, sizeof(arg));
+ if (ret >= 0) {
+ if (!strcmp(arg, "on")) {
+ tsx_ctrl_state = TSX_CTRL_ENABLE;
+ } else if (!strcmp(arg, "off")) {
+ tsx_ctrl_state = TSX_CTRL_DISABLE;
+ } else if (!strcmp(arg, "auto")) {
+ tsx_ctrl_state = x86_get_tsx_auto_mode();
+ } else {
+ tsx_ctrl_state = TSX_CTRL_DISABLE;
+ pr_err("tsx: invalid option, defaulting to off\n");
+ }
+ } else {
+ /* tsx= not provided */
+ if (IS_ENABLED(CONFIG_X86_INTEL_TSX_MODE_AUTO))
+ tsx_ctrl_state = x86_get_tsx_auto_mode();
+ else if (IS_ENABLED(CONFIG_X86_INTEL_TSX_MODE_OFF))
+ tsx_ctrl_state = TSX_CTRL_DISABLE;
+ else
+ tsx_ctrl_state = TSX_CTRL_ENABLE;
+ }
+
+ if (tsx_ctrl_state == TSX_CTRL_DISABLE) {
+ tsx_disable();
+
+ /*
+ * tsx_disable() will change the state of the
+ * RTM CPUID bit. Clear it here since it is now
+ * expected to be not set.
+ */
+ setup_clear_cpu_cap(X86_FEATURE_RTM);
+ } else if (tsx_ctrl_state == TSX_CTRL_ENABLE) {
+
+ /*
+ * HW defaults TSX to be enabled at bootup.
+ * We may still need the TSX enable support
+ * during init for special cases like
+ * kexec after TSX is disabled.
+ */
+ tsx_enable();
+
+ /*
+ * tsx_enable() will change the state of the
+ * RTM CPUID bit. Force it here since it is now
+ * expected to be set.
+ */
+ setup_force_cpu_cap(X86_FEATURE_RTM);
+ }
+}
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 5c82b4bc4a68..33f87b696487 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -481,8 +481,16 @@ static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
/* PKU is not yet implemented for shadow paging. */
if (!tdp_enabled || !boot_cpu_has(X86_FEATURE_OSPKE))
entry->ecx &= ~F(PKU);
+
entry->edx &= kvm_cpuid_7_0_edx_x86_features;
cpuid_mask(&entry->edx, CPUID_7_EDX);
+ if (boot_cpu_has(X86_FEATURE_IBPB) &&
+ boot_cpu_has(X86_FEATURE_IBRS))
+ entry->edx |= F(SPEC_CTRL);
+ if (boot_cpu_has(X86_FEATURE_STIBP))
+ entry->edx |= F(INTEL_STIBP);
+ if (boot_cpu_has(X86_FEATURE_SSBD))
+ entry->edx |= F(SPEC_CTRL_SSBD);
/*
* We emulate ARCH_CAPABILITIES in software even
* if the host doesn't support it.
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 87a0601b1c20..8cd26e50d41c 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -40,6 +40,7 @@
#include <linux/uaccess.h>
#include <linux/hash.h>
#include <linux/kern_levels.h>
+#include <linux/kthread.h>
#include <asm/page.h>
#include <asm/cmpxchg.h>
@@ -48,6 +49,30 @@
#include <asm/kvm_page_track.h>
#include "trace.h"
+extern bool itlb_multihit_kvm_mitigation;
+
+static int __read_mostly nx_huge_pages = -1;
+static uint __read_mostly nx_huge_pages_recovery_ratio = 60;
+
+static int set_nx_huge_pages(const char *val, const struct kernel_param *kp);
+static int set_nx_huge_pages_recovery_ratio(const char *val, const struct kernel_param *kp);
+
+static struct kernel_param_ops nx_huge_pages_ops = {
+ .set = set_nx_huge_pages,
+ .get = param_get_bool,
+};
+
+static struct kernel_param_ops nx_huge_pages_recovery_ratio_ops = {
+ .set = set_nx_huge_pages_recovery_ratio,
+ .get = param_get_uint,
+};
+
+module_param_cb(nx_huge_pages, &nx_huge_pages_ops, &nx_huge_pages, 0644);
+__MODULE_PARM_TYPE(nx_huge_pages, "bool");
+module_param_cb(nx_huge_pages_recovery_ratio, &nx_huge_pages_recovery_ratio_ops,
+ &nx_huge_pages_recovery_ratio, 0644);
+__MODULE_PARM_TYPE(nx_huge_pages_recovery_ratio, "uint");
+
/*
* When setting this variable to true it enables Two-Dimensional-Paging
* where the hardware walks 2 page tables:
@@ -139,9 +164,6 @@ module_param(dbg, bool, 0644);
#include <trace/events/kvm.h>
-#define CREATE_TRACE_POINTS
-#include "mmutrace.h"
-
#define SPTE_HOST_WRITEABLE (1ULL << PT_FIRST_AVAIL_BITS_SHIFT)
#define SPTE_MMU_WRITEABLE (1ULL << (PT_FIRST_AVAIL_BITS_SHIFT + 1))
@@ -244,6 +266,11 @@ static u64 __read_mostly shadow_nonpresent_or_rsvd_lower_gfn_mask;
static void mmu_spte_set(u64 *sptep, u64 spte);
static void mmu_free_roots(struct kvm_vcpu *vcpu);
+static bool is_executable_pte(u64 spte);
+
+#define CREATE_TRACE_POINTS
+#include "mmutrace.h"
+
void kvm_mmu_set_mmio_spte_mask(u64 mmio_mask, u64 mmio_value)
{
@@ -264,6 +291,11 @@ static inline bool spte_ad_enabled(u64 spte)
return !(spte & shadow_acc_track_value);
}
+static bool is_nx_huge_page_enabled(void)
+{
+ return READ_ONCE(nx_huge_pages);
+}
+
static inline u64 spte_shadow_accessed_mask(u64 spte)
{
MMU_WARN_ON((spte & shadow_mmio_mask) == shadow_mmio_value);
@@ -1008,10 +1040,16 @@ static gfn_t kvm_mmu_page_get_gfn(struct kvm_mmu_page *sp, int index)
static void kvm_mmu_page_set_gfn(struct kvm_mmu_page *sp, int index, gfn_t gfn)
{
- if (sp->role.direct)
- BUG_ON(gfn != kvm_mmu_page_get_gfn(sp, index));
- else
+ if (!sp->role.direct) {
sp->gfns[index] = gfn;
+ return;
+ }
+
+ if (WARN_ON(gfn != kvm_mmu_page_get_gfn(sp, index)))
+ pr_err_ratelimited("gfn mismatch under direct page %llx "
+ "(expected %llx, got %llx)\n",
+ sp->gfn,
+ kvm_mmu_page_get_gfn(sp, index), gfn);
}
/*
@@ -1070,6 +1108,17 @@ static void account_shadowed(struct kvm *kvm, struct kvm_mmu_page *sp)
kvm_mmu_gfn_disallow_lpage(slot, gfn);
}
+static void account_huge_nx_page(struct kvm *kvm, struct kvm_mmu_page *sp)
+{
+ if (sp->lpage_disallowed)
+ return;
+
+ ++kvm->stat.nx_lpage_splits;
+ list_add_tail(&sp->lpage_disallowed_link,
+ &kvm->arch.lpage_disallowed_mmu_pages);
+ sp->lpage_disallowed = true;
+}
+
static void unaccount_shadowed(struct kvm *kvm, struct kvm_mmu_page *sp)
{
struct kvm_memslots *slots;
@@ -1087,6 +1136,13 @@ static void unaccount_shadowed(struct kvm *kvm, struct kvm_mmu_page *sp)
kvm_mmu_gfn_allow_lpage(slot, gfn);
}
+static void unaccount_huge_nx_page(struct kvm *kvm, struct kvm_mmu_page *sp)
+{
+ --kvm->stat.nx_lpage_splits;
+ sp->lpage_disallowed = false;
+ list_del(&sp->lpage_disallowed_link);
+}
+
static bool __mmu_gfn_lpage_is_disallowed(gfn_t gfn, int level,
struct kvm_memory_slot *slot)
{
@@ -2634,6 +2690,9 @@ static int kvm_mmu_prepare_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp,
kvm_reload_remote_mmus(kvm);
}
+ if (sp->lpage_disallowed)
+ unaccount_huge_nx_page(kvm, sp);
+
sp->role.invalid = 1;
return ret;
}
@@ -2788,6 +2847,11 @@ static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
if (!speculative)
spte |= spte_shadow_accessed_mask(spte);
+ if (level > PT_PAGE_TABLE_LEVEL && (pte_access & ACC_EXEC_MASK) &&
+ is_nx_huge_page_enabled()) {
+ pte_access &= ~ACC_EXEC_MASK;
+ }
+
if (pte_access & ACC_EXEC_MASK)
spte |= shadow_x_mask;
else
@@ -2903,10 +2967,7 @@ static int mmu_set_spte(struct kvm_vcpu *vcpu, u64 *sptep, unsigned pte_access,
ret = RET_PF_EMULATE;
pgprintk("%s: setting spte %llx\n", __func__, *sptep);
- pgprintk("instantiating %s PTE (%s) at %llx (%llx) addr %p\n",
- is_large_pte(*sptep)? "2MB" : "4kB",
- *sptep & PT_WRITABLE_MASK ? "RW" : "R", gfn,
- *sptep, sptep);
+ trace_kvm_mmu_set_spte(level, gfn, sptep);
if (!was_rmapped && is_large_pte(*sptep))
++vcpu->kvm->stat.lpages;
@@ -2918,8 +2979,6 @@ static int mmu_set_spte(struct kvm_vcpu *vcpu, u64 *sptep, unsigned pte_access,
}
}
- kvm_release_pfn_clean(pfn);
-
return ret;
}
@@ -2954,9 +3013,11 @@ static int direct_pte_prefetch_many(struct kvm_vcpu *vcpu,
if (ret <= 0)
return -1;
- for (i = 0; i < ret; i++, gfn++, start++)
+ for (i = 0; i < ret; i++, gfn++, start++) {
mmu_set_spte(vcpu, start, access, 0, sp->role.level, gfn,
page_to_pfn(pages[i]), true, true);
+ put_page(pages[i]);
+ }
return 0;
}
@@ -3004,40 +3065,71 @@ static void direct_pte_prefetch(struct kvm_vcpu *vcpu, u64 *sptep)
__direct_pte_prefetch(vcpu, sp, sptep);
}
-static int __direct_map(struct kvm_vcpu *vcpu, int write, int map_writable,
- int level, gfn_t gfn, kvm_pfn_t pfn, bool prefault)
+static void disallowed_hugepage_adjust(struct kvm_shadow_walk_iterator it,
+ gfn_t gfn, kvm_pfn_t *pfnp, int *levelp)
{
- struct kvm_shadow_walk_iterator iterator;
+ int level = *levelp;
+ u64 spte = *it.sptep;
+
+ if (it.level == level && level > PT_PAGE_TABLE_LEVEL &&
+ is_nx_huge_page_enabled() &&
+ is_shadow_present_pte(spte) &&
+ !is_large_pte(spte)) {
+ /*
+ * A small SPTE exists for this pfn, but FNAME(fetch)
+ * and __direct_map would like to create a large PTE
+ * instead: just force them to go down another level,
+ * patching back for them into pfn the next 9 bits of
+ * the address.
+ */
+ u64 page_mask = KVM_PAGES_PER_HPAGE(level) - KVM_PAGES_PER_HPAGE(level - 1);
+ *pfnp |= gfn & page_mask;
+ (*levelp)--;
+ }
+}
+
+static int __direct_map(struct kvm_vcpu *vcpu, gpa_t gpa, int write,
+ int map_writable, int level, kvm_pfn_t pfn,
+ bool prefault, bool lpage_disallowed)
+{
+ struct kvm_shadow_walk_iterator it;
struct kvm_mmu_page *sp;
- int emulate = 0;
- gfn_t pseudo_gfn;
+ int ret;
+ gfn_t gfn = gpa >> PAGE_SHIFT;
+ gfn_t base_gfn = gfn;
if (!VALID_PAGE(vcpu->arch.mmu.root_hpa))
- return 0;
+ return RET_PF_RETRY;
- for_each_shadow_entry(vcpu, (u64)gfn << PAGE_SHIFT, iterator) {
- if (iterator.level == level) {
- emulate = mmu_set_spte(vcpu, iterator.sptep, ACC_ALL,
- write, level, gfn, pfn, prefault,
- map_writable);
- direct_pte_prefetch(vcpu, iterator.sptep);
- ++vcpu->stat.pf_fixed;
- break;
- }
+ trace_kvm_mmu_spte_requested(gpa, level, pfn);
+ for_each_shadow_entry(vcpu, gpa, it) {
+ /*
+ * We cannot overwrite existing page tables with an NX
+ * large page, as the leaf could be executable.
+ */
+ disallowed_hugepage_adjust(it, gfn, &pfn, &level);
- drop_large_spte(vcpu, iterator.sptep);
- if (!is_shadow_present_pte(*iterator.sptep)) {
- u64 base_addr = iterator.addr;
+ base_gfn = gfn & ~(KVM_PAGES_PER_HPAGE(it.level) - 1);
+ if (it.level == level)
+ break;
- base_addr &= PT64_LVL_ADDR_MASK(iterator.level);
- pseudo_gfn = base_addr >> PAGE_SHIFT;
- sp = kvm_mmu_get_page(vcpu, pseudo_gfn, iterator.addr,
- iterator.level - 1, 1, ACC_ALL);
+ drop_large_spte(vcpu, it.sptep);
+ if (!is_shadow_present_pte(*it.sptep)) {
+ sp = kvm_mmu_get_page(vcpu, base_gfn, it.addr,
+ it.level - 1, true, ACC_ALL);
- link_shadow_page(vcpu, iterator.sptep, sp);
+ link_shadow_page(vcpu, it.sptep, sp);
+ if (lpage_disallowed)
+ account_huge_nx_page(vcpu->kvm, sp);
}
}
- return emulate;
+
+ ret = mmu_set_spte(vcpu, it.sptep, ACC_ALL,
+ write, level, base_gfn, pfn, prefault,
+ map_writable);
+ direct_pte_prefetch(vcpu, it.sptep);
+ ++vcpu->stat.pf_fixed;
+ return ret;
}
static void kvm_send_hwpoison_signal(unsigned long address, struct task_struct *tsk)
@@ -3072,11 +3164,10 @@ static int kvm_handle_bad_page(struct kvm_vcpu *vcpu, gfn_t gfn, kvm_pfn_t pfn)
}
static void transparent_hugepage_adjust(struct kvm_vcpu *vcpu,
- gfn_t *gfnp, kvm_pfn_t *pfnp,
+ gfn_t gfn, kvm_pfn_t *pfnp,
int *levelp)
{
kvm_pfn_t pfn = *pfnp;
- gfn_t gfn = *gfnp;
int level = *levelp;
/*
@@ -3103,8 +3194,6 @@ static void transparent_hugepage_adjust(struct kvm_vcpu *vcpu,
mask = KVM_PAGES_PER_HPAGE(level) - 1;
VM_BUG_ON((gfn & mask) != (pfn & mask));
if (pfn & mask) {
- gfn &= ~mask;
- *gfnp = gfn;
kvm_release_pfn_clean(pfn);
pfn &= ~mask;
kvm_get_pfn(pfn);
@@ -3331,11 +3420,14 @@ static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, u32 error_code,
{
int r;
int level;
- bool force_pt_level = false;
+ bool force_pt_level;
kvm_pfn_t pfn;
unsigned long mmu_seq;
bool map_writable, write = error_code & PFERR_WRITE_MASK;
+ bool lpage_disallowed = (error_code & PFERR_FETCH_MASK) &&
+ is_nx_huge_page_enabled();
+ force_pt_level = lpage_disallowed;
level = mapping_level(vcpu, gfn, &force_pt_level);
if (likely(!force_pt_level)) {
/*
@@ -3361,22 +3453,20 @@ static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, u32 error_code,
if (handle_abnormal_pfn(vcpu, v, gfn, pfn, ACC_ALL, &r))
return r;
+ r = RET_PF_RETRY;
spin_lock(&vcpu->kvm->mmu_lock);
if (mmu_notifier_retry(vcpu->kvm, mmu_seq))
goto out_unlock;
if (make_mmu_pages_available(vcpu) < 0)
goto out_unlock;
if (likely(!force_pt_level))
- transparent_hugepage_adjust(vcpu, &gfn, &pfn, &level);
- r = __direct_map(vcpu, write, map_writable, level, gfn, pfn, prefault);
- spin_unlock(&vcpu->kvm->mmu_lock);
-
- return r;
-
+ transparent_hugepage_adjust(vcpu, gfn, &pfn, &level);
+ r = __direct_map(vcpu, v, write, map_writable, level, pfn,
+ prefault, false);
out_unlock:
spin_unlock(&vcpu->kvm->mmu_lock);
kvm_release_pfn_clean(pfn);
- return RET_PF_RETRY;
+ return r;
}
@@ -3922,6 +4012,8 @@ static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa, u32 error_code,
unsigned long mmu_seq;
int write = error_code & PFERR_WRITE_MASK;
bool map_writable;
+ bool lpage_disallowed = (error_code & PFERR_FETCH_MASK) &&
+ is_nx_huge_page_enabled();
MMU_WARN_ON(!VALID_PAGE(vcpu->arch.mmu.root_hpa));
@@ -3932,8 +4024,9 @@ static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa, u32 error_code,
if (r)
return r;
- force_pt_level = !check_hugepage_cache_consistency(vcpu, gfn,
- PT_DIRECTORY_LEVEL);
+ force_pt_level =
+ lpage_disallowed ||
+ !check_hugepage_cache_consistency(vcpu, gfn, PT_DIRECTORY_LEVEL);
level = mapping_level(vcpu, gfn, &force_pt_level);
if (likely(!force_pt_level)) {
if (level > PT_DIRECTORY_LEVEL &&
@@ -3954,22 +4047,20 @@ static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa, u32 error_code,
if (handle_abnormal_pfn(vcpu, 0, gfn, pfn, ACC_ALL, &r))
return r;
+ r = RET_PF_RETRY;
spin_lock(&vcpu->kvm->mmu_lock);
if (mmu_notifier_retry(vcpu->kvm, mmu_seq))
goto out_unlock;
if (make_mmu_pages_available(vcpu) < 0)
goto out_unlock;
if (likely(!force_pt_level))
- transparent_hugepage_adjust(vcpu, &gfn, &pfn, &level);
- r = __direct_map(vcpu, write, map_writable, level, gfn, pfn, prefault);
- spin_unlock(&vcpu->kvm->mmu_lock);
-
- return r;
-
+ transparent_hugepage_adjust(vcpu, gfn, &pfn, &level);
+ r = __direct_map(vcpu, gpa, write, map_writable, level, pfn,
+ prefault, lpage_disallowed);
out_unlock:
spin_unlock(&vcpu->kvm->mmu_lock);
kvm_release_pfn_clean(pfn);
- return RET_PF_RETRY;
+ return r;
}
static void nonpaging_init_context(struct kvm_vcpu *vcpu,
@@ -5454,7 +5545,7 @@ mmu_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
int nr_to_scan = sc->nr_to_scan;
unsigned long freed = 0;
- spin_lock(&kvm_lock);
+ mutex_lock(&kvm_lock);
list_for_each_entry(kvm, &vm_list, vm_list) {
int idx;
@@ -5504,7 +5595,7 @@ unlock:
break;
}
- spin_unlock(&kvm_lock);
+ mutex_unlock(&kvm_lock);
return freed;
}
@@ -5528,8 +5619,58 @@ static void mmu_destroy_caches(void)
kmem_cache_destroy(mmu_page_header_cache);
}
+static bool get_nx_auto_mode(void)
+{
+ /* Return true when CPU has the bug, and mitigations are ON */
+ return boot_cpu_has_bug(X86_BUG_ITLB_MULTIHIT) && !cpu_mitigations_off();
+}
+
+static void __set_nx_huge_pages(bool val)
+{
+ nx_huge_pages = itlb_multihit_kvm_mitigation = val;
+}
+
+static int set_nx_huge_pages(const char *val, const struct kernel_param *kp)
+{
+ bool old_val = nx_huge_pages;
+ bool new_val;
+
+ /* In "auto" mode deploy workaround only if CPU has the bug. */
+ if (sysfs_streq(val, "off"))
+ new_val = 0;
+ else if (sysfs_streq(val, "force"))
+ new_val = 1;
+ else if (sysfs_streq(val, "auto"))
+ new_val = get_nx_auto_mode();
+ else if (strtobool(val, &new_val) < 0)
+ return -EINVAL;
+
+ __set_nx_huge_pages(new_val);
+
+ if (new_val != old_val) {
+ struct kvm *kvm;
+ int idx;
+
+ mutex_lock(&kvm_lock);
+
+ list_for_each_entry(kvm, &vm_list, vm_list) {
+ idx = srcu_read_lock(&kvm->srcu);
+ kvm_mmu_invalidate_zap_all_pages(kvm);
+ srcu_read_unlock(&kvm->srcu, idx);
+
+ wake_up_process(kvm->arch.nx_lpage_recovery_thread);
+ }
+ mutex_unlock(&kvm_lock);
+ }
+
+ return 0;
+}
+
int kvm_mmu_module_init(void)
{
+ if (nx_huge_pages == -1)
+ __set_nx_huge_pages(get_nx_auto_mode());
+
kvm_mmu_reset_all_pte_masks();
pte_list_desc_cache = kmem_cache_create("pte_list_desc",
@@ -5595,3 +5736,116 @@ void kvm_mmu_module_exit(void)
unregister_shrinker(&mmu_shrinker);
mmu_audit_disable();
}
+
+static int set_nx_huge_pages_recovery_ratio(const char *val, const struct kernel_param *kp)
+{
+ unsigned int old_val;
+ int err;
+
+ old_val = nx_huge_pages_recovery_ratio;
+ err = param_set_uint(val, kp);
+ if (err)
+ return err;
+
+ if (READ_ONCE(nx_huge_pages) &&
+ !old_val && nx_huge_pages_recovery_ratio) {
+ struct kvm *kvm;
+
+ mutex_lock(&kvm_lock);
+
+ list_for_each_entry(kvm, &vm_list, vm_list)
+ wake_up_process(kvm->arch.nx_lpage_recovery_thread);
+
+ mutex_unlock(&kvm_lock);
+ }
+
+ return err;
+}
+
+static void kvm_recover_nx_lpages(struct kvm *kvm)
+{
+ int rcu_idx;
+ struct kvm_mmu_page *sp;
+ unsigned int ratio;
+ LIST_HEAD(invalid_list);
+ ulong to_zap;
+
+ rcu_idx = srcu_read_lock(&kvm->srcu);
+ spin_lock(&kvm->mmu_lock);
+
+ ratio = READ_ONCE(nx_huge_pages_recovery_ratio);
+ to_zap = ratio ? DIV_ROUND_UP(kvm->stat.nx_lpage_splits, ratio) : 0;
+ while (to_zap && !list_empty(&kvm->arch.lpage_disallowed_mmu_pages)) {
+ /*
+ * We use a separate list instead of just using active_mmu_pages
+ * because the number of lpage_disallowed pages is expected to
+ * be relatively small compared to the total.
+ */
+ sp = list_first_entry(&kvm->arch.lpage_disallowed_mmu_pages,
+ struct kvm_mmu_page,
+ lpage_disallowed_link);
+ WARN_ON_ONCE(!sp->lpage_disallowed);
+ kvm_mmu_prepare_zap_page(kvm, sp, &invalid_list);
+ WARN_ON_ONCE(sp->lpage_disallowed);
+
+ if (!--to_zap || need_resched() || spin_needbreak(&kvm->mmu_lock)) {
+ kvm_mmu_commit_zap_page(kvm, &invalid_list);
+ if (to_zap)
+ cond_resched_lock(&kvm->mmu_lock);
+ }
+ }
+
+ spin_unlock(&kvm->mmu_lock);
+ srcu_read_unlock(&kvm->srcu, rcu_idx);
+}
+
+static long get_nx_lpage_recovery_timeout(u64 start_time)
+{
+ return READ_ONCE(nx_huge_pages) && READ_ONCE(nx_huge_pages_recovery_ratio)
+ ? start_time + 60 * HZ - get_jiffies_64()
+ : MAX_SCHEDULE_TIMEOUT;
+}
+
+static int kvm_nx_lpage_recovery_worker(struct kvm *kvm, uintptr_t data)
+{
+ u64 start_time;
+ long remaining_time;
+
+ while (true) {
+ start_time = get_jiffies_64();
+ remaining_time = get_nx_lpage_recovery_timeout(start_time);
+
+ set_current_state(TASK_INTERRUPTIBLE);
+ while (!kthread_should_stop() && remaining_time > 0) {
+ schedule_timeout(remaining_time);
+ remaining_time = get_nx_lpage_recovery_timeout(start_time);
+ set_current_state(TASK_INTERRUPTIBLE);
+ }
+
+ set_current_state(TASK_RUNNING);
+
+ if (kthread_should_stop())
+ return 0;
+
+ kvm_recover_nx_lpages(kvm);
+ }
+}
+
+int kvm_mmu_post_init_vm(struct kvm *kvm)
+{
+ int err;
+
+ err = kvm_vm_create_worker_thread(kvm, kvm_nx_lpage_recovery_worker, 0,
+ "kvm-nx-lpage-recovery",
+ &kvm->arch.nx_lpage_recovery_thread);
+ if (!err)
+ kthread_unpark(kvm->arch.nx_lpage_recovery_thread);
+
+ return err;
+}
+
+void kvm_mmu_pre_destroy_vm(struct kvm *kvm)
+{
+ if (kvm->arch.nx_lpage_recovery_thread)
+ kthread_stop(kvm->arch.nx_lpage_recovery_thread);
+}
diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h
index efc857615d8e..068feab64acf 100644
--- a/arch/x86/kvm/mmu.h
+++ b/arch/x86/kvm/mmu.h
@@ -195,4 +195,8 @@ void kvm_mmu_gfn_allow_lpage(struct kvm_memory_slot *slot, gfn_t gfn);
bool kvm_mmu_slot_gfn_write_protect(struct kvm *kvm,
struct kvm_memory_slot *slot, u64 gfn);
int kvm_arch_write_log_dirty(struct kvm_vcpu *vcpu);
+
+int kvm_mmu_post_init_vm(struct kvm *kvm);
+void kvm_mmu_pre_destroy_vm(struct kvm *kvm);
+
#endif
diff --git a/arch/x86/kvm/mmutrace.h b/arch/x86/kvm/mmutrace.h
index c73bf4e4988c..918b0d5bf272 100644
--- a/arch/x86/kvm/mmutrace.h
+++ b/arch/x86/kvm/mmutrace.h
@@ -325,6 +325,65 @@ TRACE_EVENT(
__entry->kvm_gen == __entry->spte_gen
)
);
+
+TRACE_EVENT(
+ kvm_mmu_set_spte,
+ TP_PROTO(int level, gfn_t gfn, u64 *sptep),
+ TP_ARGS(level, gfn, sptep),
+
+ TP_STRUCT__entry(
+ __field(u64, gfn)
+ __field(u64, spte)
+ __field(u64, sptep)
+ __field(u8, level)
+ /* These depend on page entry type, so compute them now. */
+ __field(bool, r)
+ __field(bool, x)
+ __field(u8, u)
+ ),
+
+ TP_fast_assign(
+ __entry->gfn = gfn;
+ __entry->spte = *sptep;
+ __entry->sptep = virt_to_phys(sptep);
+ __entry->level = level;
+ __entry->r = shadow_present_mask || (__entry->spte & PT_PRESENT_MASK);
+ __entry->x = is_executable_pte(__entry->spte);
+ __entry->u = shadow_user_mask ? !!(__entry->spte & shadow_user_mask) : -1;
+ ),
+
+ TP_printk("gfn %llx spte %llx (%s%s%s%s) level %d at %llx",
+ __entry->gfn, __entry->spte,
+ __entry->r ? "r" : "-",
+ __entry->spte & PT_WRITABLE_MASK ? "w" : "-",
+ __entry->x ? "x" : "-",
+ __entry->u == -1 ? "" : (__entry->u ? "u" : "-"),
+ __entry->level, __entry->sptep
+ )
+);
+
+TRACE_EVENT(
+ kvm_mmu_spte_requested,
+ TP_PROTO(gpa_t addr, int level, kvm_pfn_t pfn),
+ TP_ARGS(addr, level, pfn),
+
+ TP_STRUCT__entry(
+ __field(u64, gfn)
+ __field(u64, pfn)
+ __field(u8, level)
+ ),
+
+ TP_fast_assign(
+ __entry->gfn = addr >> PAGE_SHIFT;
+ __entry->pfn = pfn | (__entry->gfn & (KVM_PAGES_PER_HPAGE(level) - 1));
+ __entry->level = level;
+ ),
+
+ TP_printk("gfn %llx pfn %llx level %d",
+ __entry->gfn, __entry->pfn, __entry->level
+ )
+);
+
#endif /* _TRACE_KVMMMU_H */
#undef TRACE_INCLUDE_PATH
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index 6288e9d7068e..8cf7a09bdd73 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -522,6 +522,7 @@ FNAME(prefetch_gpte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
mmu_set_spte(vcpu, spte, pte_access, 0, PT_PAGE_TABLE_LEVEL, gfn, pfn,
true, true);
+ kvm_release_pfn_clean(pfn);
return true;
}
@@ -595,12 +596,14 @@ static void FNAME(pte_prefetch)(struct kvm_vcpu *vcpu, struct guest_walker *gw,
static int FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr,
struct guest_walker *gw,
int write_fault, int hlevel,
- kvm_pfn_t pfn, bool map_writable, bool prefault)
+ kvm_pfn_t pfn, bool map_writable, bool prefault,
+ bool lpage_disallowed)
{
struct kvm_mmu_page *sp = NULL;
struct kvm_shadow_walk_iterator it;
unsigned direct_access, access = gw->pt_access;
int top_level, ret;
+ gfn_t gfn, base_gfn;
direct_access = gw->pte_access;
@@ -645,35 +648,48 @@ static int FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr,
link_shadow_page(vcpu, it.sptep, sp);
}
- for (;
- shadow_walk_okay(&it) && it.level > hlevel;
- shadow_walk_next(&it)) {
- gfn_t direct_gfn;
+ /*
+ * FNAME(page_fault) might have clobbered the bottom bits of
+ * gw->gfn, restore them from the virtual address.
+ */
+ gfn = gw->gfn | ((addr & PT_LVL_OFFSET_MASK(gw->level)) >> PAGE_SHIFT);
+ base_gfn = gfn;
+ trace_kvm_mmu_spte_requested(addr, gw->level, pfn);
+
+ for (; shadow_walk_okay(&it); shadow_walk_next(&it)) {
clear_sp_write_flooding_count(it.sptep);
- validate_direct_spte(vcpu, it.sptep, direct_access);
- drop_large_spte(vcpu, it.sptep);
+ /*
+ * We cannot overwrite existing page tables with an NX
+ * large page, as the leaf could be executable.
+ */
+ disallowed_hugepage_adjust(it, gfn, &pfn, &hlevel);
- if (is_shadow_present_pte(*it.sptep))
- continue;
+ base_gfn = gfn & ~(KVM_PAGES_PER_HPAGE(it.level) - 1);
+ if (it.level == hlevel)
+ break;
+
+ validate_direct_spte(vcpu, it.sptep, direct_access);
- direct_gfn = gw->gfn & ~(KVM_PAGES_PER_HPAGE(it.level) - 1);
+ drop_large_spte(vcpu, it.sptep);
- sp = kvm_mmu_get_page(vcpu, direct_gfn, addr, it.level-1,
- true, direct_access);
- link_shadow_page(vcpu, it.sptep, sp);
+ if (!is_shadow_present_pte(*it.sptep)) {
+ sp = kvm_mmu_get_page(vcpu, base_gfn, addr,
+ it.level - 1, true, direct_access);
+ link_shadow_page(vcpu, it.sptep, sp);
+ if (lpage_disallowed)
+ account_huge_nx_page(vcpu->kvm, sp);
+ }
}
- clear_sp_write_flooding_count(it.sptep);
ret = mmu_set_spte(vcpu, it.sptep, gw->pte_access, write_fault,
- it.level, gw->gfn, pfn, prefault, map_writable);
+ it.level, base_gfn, pfn, prefault, map_writable);
FNAME(pte_prefetch)(vcpu, gw, it.sptep);
-
+ ++vcpu->stat.pf_fixed;
return ret;
out_gpte_changed:
- kvm_release_pfn_clean(pfn);
return RET_PF_RETRY;
}
@@ -740,9 +756,11 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr, u32 error_code,
int r;
kvm_pfn_t pfn;
int level = PT_PAGE_TABLE_LEVEL;
- bool force_pt_level = false;
unsigned long mmu_seq;
bool map_writable, is_self_change_mapping;
+ bool lpage_disallowed = (error_code & PFERR_FETCH_MASK) &&
+ is_nx_huge_page_enabled();
+ bool force_pt_level = lpage_disallowed;
pgprintk("%s: addr %lx err %x\n", __func__, addr, error_code);
@@ -821,6 +839,7 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr, u32 error_code,
walker.pte_access &= ~ACC_EXEC_MASK;
}
+ r = RET_PF_RETRY;
spin_lock(&vcpu->kvm->mmu_lock);
if (mmu_notifier_retry(vcpu->kvm, mmu_seq))
goto out_unlock;
@@ -829,19 +848,15 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr, u32 error_code,
if (make_mmu_pages_available(vcpu) < 0)
goto out_unlock;
if (!force_pt_level)
- transparent_hugepage_adjust(vcpu, &walker.gfn, &pfn, &level);
+ transparent_hugepage_adjust(vcpu, walker.gfn, &pfn, &level);
r = FNAME(fetch)(vcpu, addr, &walker, write_fault,
- level, pfn, map_writable, prefault);
- ++vcpu->stat.pf_fixed;
+ level, pfn, map_writable, prefault, lpage_disallowed);
kvm_mmu_audit(vcpu, AUDIT_POST_PAGE_FAULT);
- spin_unlock(&vcpu->kvm->mmu_lock);
-
- return r;
out_unlock:
spin_unlock(&vcpu->kvm->mmu_lock);
kvm_release_pfn_clean(pfn);
- return RET_PF_RETRY;
+ return r;
}
static gpa_t FNAME(get_level1_sp_gpa)(struct kvm_mmu_page *sp)
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index f6adc8db0e32..52edb8cf1c40 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -608,8 +608,14 @@ static int get_npt_level(struct kvm_vcpu *vcpu)
static void svm_set_efer(struct kvm_vcpu *vcpu, u64 efer)
{
vcpu->arch.efer = efer;
- if (!npt_enabled && !(efer & EFER_LMA))
- efer &= ~EFER_LME;
+
+ if (!npt_enabled) {
+ /* Shadow paging assumes NX to be available. */
+ efer |= EFER_NX;
+
+ if (!(efer & EFER_LMA))
+ efer &= ~EFER_LME;
+ }
to_svm(vcpu)->vmcb->save.efer = efer | EFER_SVME;
mark_dirty(to_svm(vcpu)->vmcb, VMCB_CR);
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 02c0326dc259..cd5a8e888eb6 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -2259,17 +2259,9 @@ static bool update_transition_efer(struct vcpu_vmx *vmx, int efer_offset)
u64 guest_efer = vmx->vcpu.arch.efer;
u64 ignore_bits = 0;
- if (!enable_ept) {
- /*
- * NX is needed to handle CR0.WP=1, CR4.SMEP=1. Testing
- * host CPUID is more efficient than testing guest CPUID
- * or CR4. Host SMEP is anyway a requirement for guest SMEP.
- */
- if (boot_cpu_has(X86_FEATURE_SMEP))
- guest_efer |= EFER_NX;
- else if (!(guest_efer & EFER_NX))
- ignore_bits |= EFER_NX;
- }
+ /* Shadow paging assumes NX to be available. */
+ if (!enable_ept)
+ guest_efer |= EFER_NX;
/*
* LMA and LME handled by hardware; SCE meaningless outside long mode.
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 4927d0f5be13..dcee3282112d 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -90,8 +90,8 @@ u64 __read_mostly efer_reserved_bits = ~((u64)(EFER_SCE | EFER_LME | EFER_LMA));
static u64 __read_mostly efer_reserved_bits = ~((u64)EFER_SCE);
#endif
-#define VM_STAT(x) offsetof(struct kvm, stat.x), KVM_STAT_VM
-#define VCPU_STAT(x) offsetof(struct kvm_vcpu, stat.x), KVM_STAT_VCPU
+#define VM_STAT(x, ...) offsetof(struct kvm, stat.x), KVM_STAT_VM, ## __VA_ARGS__
+#define VCPU_STAT(x, ...) offsetof(struct kvm_vcpu, stat.x), KVM_STAT_VCPU, ## __VA_ARGS__
#define KVM_X2APIC_API_VALID_FLAGS (KVM_X2APIC_API_USE_32BIT_IDS | \
KVM_X2APIC_API_DISABLE_BROADCAST_QUIRK)
@@ -191,7 +191,8 @@ struct kvm_stats_debugfs_item debugfs_entries[] = {
{ "mmu_cache_miss", VM_STAT(mmu_cache_miss) },
{ "mmu_unsync", VM_STAT(mmu_unsync) },
{ "remote_tlb_flush", VM_STAT(remote_tlb_flush) },
- { "largepages", VM_STAT(lpages) },
+ { "largepages", VM_STAT(lpages, .mode = 0444) },
+ { "nx_largepages_splitted", VM_STAT(nx_lpage_splits, .mode = 0444) },
{ "max_mmu_page_hash_collisions",
VM_STAT(max_mmu_page_hash_collisions) },
{ NULL }
@@ -1070,6 +1071,14 @@ u64 kvm_get_arch_capabilities(void)
rdmsrl_safe(MSR_IA32_ARCH_CAPABILITIES, &data);
/*
+ * If nx_huge_pages is enabled, KVM's shadow paging will ensure that
+ * the nested hypervisor runs with NX huge pages. If it is not,
+ * L1 is anyway vulnerable to ITLB_MULTIHIT explots from other
+ * L1 guests, so it need not worry about its own (L2) guests.
+ */
+ data |= ARCH_CAP_PSCHANGE_MC_NO;
+
+ /*
* If we're doing cache flushes (either "always" or "cond")
* we will do one whenever the guest does a vmlaunch/vmresume.
* If an outer hypervisor is doing the cache flush for us
@@ -1081,8 +1090,35 @@ u64 kvm_get_arch_capabilities(void)
if (l1tf_vmx_mitigation != VMENTER_L1D_FLUSH_NEVER)
data |= ARCH_CAP_SKIP_VMENTRY_L1DFLUSH;
+ if (!boot_cpu_has_bug(X86_BUG_CPU_MELTDOWN))
+ data |= ARCH_CAP_RDCL_NO;
+ if (!boot_cpu_has_bug(X86_BUG_SPEC_STORE_BYPASS))
+ data |= ARCH_CAP_SSB_NO;
+ if (!boot_cpu_has_bug(X86_BUG_MDS))
+ data |= ARCH_CAP_MDS_NO;
+
+ /*
+ * On TAA affected systems, export MDS_NO=0 when:
+ * - TSX is enabled on the host, i.e. X86_FEATURE_RTM=1.
+ * - Updated microcode is present. This is detected by
+ * the presence of ARCH_CAP_TSX_CTRL_MSR and ensures
+ * that VERW clears CPU buffers.
+ *
+ * When MDS_NO=0 is exported, guests deploy clear CPU buffer
+ * mitigation and don't complain:
+ *
+ * "Vulnerable: Clear CPU buffers attempted, no microcode"
+ *
+ * If TSX is disabled on the system, guests are also mitigated against
+ * TAA and clear CPU buffer mitigation is not required for guests.
+ */
+ if (boot_cpu_has_bug(X86_BUG_TAA) && boot_cpu_has(X86_FEATURE_RTM) &&
+ (data & ARCH_CAP_TSX_CTRL_MSR))
+ data &= ~ARCH_CAP_MDS_NO;
+
return data;
}
+
EXPORT_SYMBOL_GPL(kvm_get_arch_capabilities);
static int kvm_get_msr_feature(struct kvm_msr_entry *msr)
@@ -6129,17 +6165,17 @@ static int kvmclock_cpufreq_notifier(struct notifier_block *nb, unsigned long va
smp_call_function_single(freq->cpu, tsc_khz_changed, freq, 1);
- spin_lock(&kvm_lock);
+ mutex_lock(&kvm_lock);
list_for_each_entry(kvm, &vm_list, vm_list) {
kvm_for_each_vcpu(i, vcpu, kvm) {
if (vcpu->cpu != freq->cpu)
continue;
kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu);
- if (vcpu->cpu != smp_processor_id())
+ if (vcpu->cpu != raw_smp_processor_id())
send_ipi = 1;
}
}
- spin_unlock(&kvm_lock);
+ mutex_unlock(&kvm_lock);
if (freq->old < freq->new && send_ipi) {
/*
@@ -6276,12 +6312,12 @@ static void pvclock_gtod_update_fn(struct work_struct *work)
struct kvm_vcpu *vcpu;
int i;
- spin_lock(&kvm_lock);
+ mutex_lock(&kvm_lock);
list_for_each_entry(kvm, &vm_list, vm_list)
kvm_for_each_vcpu(i, vcpu, kvm)
kvm_make_request(KVM_REQ_MASTERCLOCK_UPDATE, vcpu);
atomic_set(&kvm_guest_has_master_clock, 0);
- spin_unlock(&kvm_lock);
+ mutex_unlock(&kvm_lock);
}
static DECLARE_WORK(pvclock_gtod_work, pvclock_gtod_update_fn);
@@ -8334,6 +8370,7 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
INIT_HLIST_HEAD(&kvm->arch.mask_notifier_list);
INIT_LIST_HEAD(&kvm->arch.active_mmu_pages);
INIT_LIST_HEAD(&kvm->arch.zapped_obsolete_pages);
+ INIT_LIST_HEAD(&kvm->arch.lpage_disallowed_mmu_pages);
INIT_LIST_HEAD(&kvm->arch.assigned_dev_head);
atomic_set(&kvm->arch.noncoherent_dma_count, 0);
@@ -8363,6 +8400,11 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
return 0;
}
+int kvm_arch_post_init_vm(struct kvm *kvm)
+{
+ return kvm_mmu_post_init_vm(kvm);
+}
+
static void kvm_unload_vcpu_mmu(struct kvm_vcpu *vcpu)
{
int r;
@@ -8466,6 +8508,11 @@ int x86_set_memory_region(struct kvm *kvm, int id, gpa_t gpa, u32 size)
}
EXPORT_SYMBOL_GPL(x86_set_memory_region);
+void kvm_arch_pre_destroy_vm(struct kvm *kvm)
+{
+ kvm_mmu_pre_destroy_vm(kvm);
+}
+
void kvm_arch_destroy_vm(struct kvm *kvm)
{
if (current->mm == kvm->mm) {
generated by cgit 1.2.3-korg (git 2.39.0) at 2024-05-22 08:58:02 +0000