diff options
Diffstat (limited to 'common/recipes-kernel/linux/linux-yocto-4.9.21/0017-KVM-nVMX-Eliminate-vmcs02-pool.patch')
| -rw-r--r-- | common/recipes-kernel/linux/linux-yocto-4.9.21/0017-KVM-nVMX-Eliminate-vmcs02-pool.patch | 295 |
1 files changed, 295 insertions, 0 deletions
diff --git a/common/recipes-kernel/linux/linux-yocto-4.9.21/0017-KVM-nVMX-Eliminate-vmcs02-pool.patch b/common/recipes-kernel/linux/linux-yocto-4.9.21/0017-KVM-nVMX-Eliminate-vmcs02-pool.patch new file mode 100644 index 00000000..96687e49 --- /dev/null +++ b/common/recipes-kernel/linux/linux-yocto-4.9.21/0017-KVM-nVMX-Eliminate-vmcs02-pool.patch @@ -0,0 +1,295 @@ +From 8e52c41b7072930e5951b324964f31ef6991f3af Mon Sep 17 00:00:00 2001 +From: Jim Mattson <jmattson@google.com> +Date: Mon, 27 Nov 2017 17:22:25 -0600 +Subject: [PATCH 17/33] KVM: nVMX: Eliminate vmcs02 pool +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit + +(cherry picked from commit de3a0021a60635de96aa92713c1a31a96747d72c) + +The potential performance advantages of a vmcs02 pool have never been +realized. To simplify the code, eliminate the pool. Instead, a single +vmcs02 is allocated per VCPU when the VCPU enters VMX operation. + +Cc: stable@vger.kernel.org # prereq for Spectre mitigation +Signed-off-by: Jim Mattson <jmattson@google.com> +Signed-off-by: Mark Kanda <mark.kanda@oracle.com> +Reviewed-by: Ameya More <ameya.more@oracle.com> +Reviewed-by: David Hildenbrand <david@redhat.com> +Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> +Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> +Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> +Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> +--- + arch/x86/kvm/vmx.c | 146 +++++++++-------------------------------------------- + 1 file changed, 23 insertions(+), 123 deletions(-) + +diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c +index 2e88fd1..099f221 100644 +--- a/arch/x86/kvm/vmx.c ++++ b/arch/x86/kvm/vmx.c +@@ -174,7 +174,6 @@ module_param(ple_window_max, int, S_IRUGO); + extern const ulong vmx_return; + + #define NR_AUTOLOAD_MSRS 8 +-#define VMCS02_POOL_SIZE 1 + + struct vmcs { + u32 revision_id; +@@ -208,7 +207,7 @@ struct shared_msr_entry { + * stored in guest memory specified by VMPTRLD, but is opaque to the guest, + * which must access it using VMREAD/VMWRITE/VMCLEAR instructions. + * More than one of these structures may exist, if L1 runs multiple L2 guests. +- * nested_vmx_run() will use the data here to build a vmcs02: a VMCS for the ++ * nested_vmx_run() will use the data here to build the vmcs02: a VMCS for the + * underlying hardware which will be used to run L2. + * This structure is packed to ensure that its layout is identical across + * machines (necessary for live migration). +@@ -387,13 +386,6 @@ struct __packed vmcs12 { + */ + #define VMCS12_SIZE 0x1000 + +-/* Used to remember the last vmcs02 used for some recently used vmcs12s */ +-struct vmcs02_list { +- struct list_head list; +- gpa_t vmptr; +- struct loaded_vmcs vmcs02; +-}; +- + /* + * The nested_vmx structure is part of vcpu_vmx, and holds information we need + * for correct emulation of VMX (i.e., nested VMX) on this vcpu. +@@ -420,15 +412,15 @@ struct nested_vmx { + */ + bool sync_shadow_vmcs; + +- /* vmcs02_list cache of VMCSs recently used to run L2 guests */ +- struct list_head vmcs02_pool; +- int vmcs02_num; + bool change_vmcs01_virtual_x2apic_mode; + /* L2 must run next, and mustn't decide to exit to L1. */ + bool nested_run_pending; ++ ++ struct loaded_vmcs vmcs02; ++ + /* +- * Guest pages referred to in vmcs02 with host-physical pointers, so +- * we must keep them pinned while L2 runs. ++ * Guest pages referred to in the vmcs02 with host-physical ++ * pointers, so we must keep them pinned while L2 runs. + */ + struct page *apic_access_page; + struct page *virtual_apic_page; +@@ -6657,94 +6649,6 @@ static int handle_monitor(struct kvm_vcpu *vcpu) + } + + /* +- * To run an L2 guest, we need a vmcs02 based on the L1-specified vmcs12. +- * We could reuse a single VMCS for all the L2 guests, but we also want the +- * option to allocate a separate vmcs02 for each separate loaded vmcs12 - this +- * allows keeping them loaded on the processor, and in the future will allow +- * optimizations where prepare_vmcs02 doesn't need to set all the fields on +- * every entry if they never change. +- * So we keep, in vmx->nested.vmcs02_pool, a cache of size VMCS02_POOL_SIZE +- * (>=0) with a vmcs02 for each recently loaded vmcs12s, most recent first. +- * +- * The following functions allocate and free a vmcs02 in this pool. +- */ +- +-/* Get a VMCS from the pool to use as vmcs02 for the current vmcs12. */ +-static struct loaded_vmcs *nested_get_current_vmcs02(struct vcpu_vmx *vmx) +-{ +- struct vmcs02_list *item; +- list_for_each_entry(item, &vmx->nested.vmcs02_pool, list) +- if (item->vmptr == vmx->nested.current_vmptr) { +- list_move(&item->list, &vmx->nested.vmcs02_pool); +- return &item->vmcs02; +- } +- +- if (vmx->nested.vmcs02_num >= max(VMCS02_POOL_SIZE, 1)) { +- /* Recycle the least recently used VMCS. */ +- item = list_last_entry(&vmx->nested.vmcs02_pool, +- struct vmcs02_list, list); +- item->vmptr = vmx->nested.current_vmptr; +- list_move(&item->list, &vmx->nested.vmcs02_pool); +- return &item->vmcs02; +- } +- +- /* Create a new VMCS */ +- item = kmalloc(sizeof(struct vmcs02_list), GFP_KERNEL); +- if (!item) +- return NULL; +- item->vmcs02.vmcs = alloc_vmcs(); +- item->vmcs02.shadow_vmcs = NULL; +- if (!item->vmcs02.vmcs) { +- kfree(item); +- return NULL; +- } +- loaded_vmcs_init(&item->vmcs02); +- item->vmptr = vmx->nested.current_vmptr; +- list_add(&(item->list), &(vmx->nested.vmcs02_pool)); +- vmx->nested.vmcs02_num++; +- return &item->vmcs02; +-} +- +-/* Free and remove from pool a vmcs02 saved for a vmcs12 (if there is one) */ +-static void nested_free_vmcs02(struct vcpu_vmx *vmx, gpa_t vmptr) +-{ +- struct vmcs02_list *item; +- list_for_each_entry(item, &vmx->nested.vmcs02_pool, list) +- if (item->vmptr == vmptr) { +- free_loaded_vmcs(&item->vmcs02); +- list_del(&item->list); +- kfree(item); +- vmx->nested.vmcs02_num--; +- return; +- } +-} +- +-/* +- * Free all VMCSs saved for this vcpu, except the one pointed by +- * vmx->loaded_vmcs. We must be running L1, so vmx->loaded_vmcs +- * must be &vmx->vmcs01. +- */ +-static void nested_free_all_saved_vmcss(struct vcpu_vmx *vmx) +-{ +- struct vmcs02_list *item, *n; +- +- WARN_ON(vmx->loaded_vmcs != &vmx->vmcs01); +- list_for_each_entry_safe(item, n, &vmx->nested.vmcs02_pool, list) { +- /* +- * Something will leak if the above WARN triggers. Better than +- * a use-after-free. +- */ +- if (vmx->loaded_vmcs == &item->vmcs02) +- continue; +- +- free_loaded_vmcs(&item->vmcs02); +- list_del(&item->list); +- kfree(item); +- vmx->nested.vmcs02_num--; +- } +-} +- +-/* + * The following 3 functions, nested_vmx_succeed()/failValid()/failInvalid(), + * set the success or error code of an emulated VMX instruction, as specified + * by Vol 2B, VMX Instruction Reference, "Conventions". +@@ -7051,6 +6955,12 @@ static int handle_vmon(struct kvm_vcpu *vcpu) + return 1; + } + ++ vmx->nested.vmcs02.vmcs = alloc_vmcs(); ++ vmx->nested.vmcs02.shadow_vmcs = NULL; ++ if (!vmx->nested.vmcs02.vmcs) ++ goto out_vmcs02; ++ loaded_vmcs_init(&vmx->nested.vmcs02); ++ + if (cpu_has_vmx_msr_bitmap()) { + vmx->nested.msr_bitmap = + (unsigned long *)__get_free_page(GFP_KERNEL); +@@ -7073,9 +6983,6 @@ static int handle_vmon(struct kvm_vcpu *vcpu) + vmx->vmcs01.shadow_vmcs = shadow_vmcs; + } + +- INIT_LIST_HEAD(&(vmx->nested.vmcs02_pool)); +- vmx->nested.vmcs02_num = 0; +- + hrtimer_init(&vmx->nested.preemption_timer, CLOCK_MONOTONIC, + HRTIMER_MODE_REL_PINNED); + vmx->nested.preemption_timer.function = vmx_preemption_timer_fn; +@@ -7093,6 +7000,9 @@ static int handle_vmon(struct kvm_vcpu *vcpu) + free_page((unsigned long)vmx->nested.msr_bitmap); + + out_msr_bitmap: ++ free_loaded_vmcs(&vmx->nested.vmcs02); ++ ++out_vmcs02: + return -ENOMEM; + } + +@@ -7178,7 +7088,7 @@ static void free_nested(struct vcpu_vmx *vmx) + vmx->vmcs01.shadow_vmcs = NULL; + } + kfree(vmx->nested.cached_vmcs12); +- /* Unpin physical memory we referred to in current vmcs02 */ ++ /* Unpin physical memory we referred to in the vmcs02 */ + if (vmx->nested.apic_access_page) { + nested_release_page(vmx->nested.apic_access_page); + vmx->nested.apic_access_page = NULL; +@@ -7194,7 +7104,7 @@ static void free_nested(struct vcpu_vmx *vmx) + vmx->nested.pi_desc = NULL; + } + +- nested_free_all_saved_vmcss(vmx); ++ free_loaded_vmcs(&vmx->nested.vmcs02); + } + + /* Emulate the VMXOFF instruction */ +@@ -7242,8 +7152,6 @@ static int handle_vmclear(struct kvm_vcpu *vcpu) + kunmap(page); + nested_release_page(page); + +- nested_free_vmcs02(vmx, vmptr); +- + skip_emulated_instruction(vcpu); + nested_vmx_succeed(vcpu); + return 1; +@@ -8032,10 +7940,11 @@ static bool nested_vmx_exit_handled(struct kvm_vcpu *vcpu) + + /* + * The host physical addresses of some pages of guest memory +- * are loaded into VMCS02 (e.g. L1's Virtual APIC Page). The CPU +- * may write to these pages via their host physical address while +- * L2 is running, bypassing any address-translation-based dirty +- * tracking (e.g. EPT write protection). ++ * are loaded into the vmcs02 (e.g. vmcs12's Virtual APIC ++ * Page). The CPU may write to these pages via their host ++ * physical address while L2 is running, bypassing any ++ * address-translation-based dirty tracking (e.g. EPT write ++ * protection). + * + * Mark them dirty on every exit from L2 to prevent them from + * getting out of sync with dirty tracking. +@@ -10170,7 +10079,6 @@ static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch) + struct vmcs12 *vmcs12; + struct vcpu_vmx *vmx = to_vmx(vcpu); + int cpu; +- struct loaded_vmcs *vmcs02; + bool ia32e; + u32 msr_entry_idx; + +@@ -10310,17 +10218,13 @@ static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch) + * the nested entry. + */ + +- vmcs02 = nested_get_current_vmcs02(vmx); +- if (!vmcs02) +- return -ENOMEM; +- + enter_guest_mode(vcpu); + + if (!(vmcs12->vm_entry_controls & VM_ENTRY_LOAD_DEBUG_CONTROLS)) + vmx->nested.vmcs01_debugctl = vmcs_read64(GUEST_IA32_DEBUGCTL); + + cpu = get_cpu(); +- vmx->loaded_vmcs = vmcs02; ++ vmx->loaded_vmcs = &vmx->nested.vmcs02; + vmx_vcpu_put(vcpu); + vmx_vcpu_load(vcpu, cpu); + vcpu->cpu = cpu; +@@ -10833,10 +10737,6 @@ static void nested_vmx_vmexit(struct kvm_vcpu *vcpu, u32 exit_reason, + vm_exit_controls_reset_shadow(vmx); + vmx_segment_cache_clear(vmx); + +- /* if no vmcs02 cache requested, remove the one we used */ +- if (VMCS02_POOL_SIZE == 0) +- nested_free_vmcs02(vmx, vmx->nested.current_vmptr); +- + load_vmcs12_host_state(vcpu, vmcs12); + + /* Update any VMCS fields that might have changed while L2 ran */ +-- +2.7.4 + |