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Diffstat (limited to 'common/recipes-kernel/linux/linux-yocto-4.9.21/0023-KVM-SVM-Allow-direct-access-to-MSR_IA32_SPEC_CTRL.patch')
-rw-r--r--common/recipes-kernel/linux/linux-yocto-4.9.21/0023-KVM-SVM-Allow-direct-access-to-MSR_IA32_SPEC_CTRL.patch192
1 files changed, 0 insertions, 192 deletions
diff --git a/common/recipes-kernel/linux/linux-yocto-4.9.21/0023-KVM-SVM-Allow-direct-access-to-MSR_IA32_SPEC_CTRL.patch b/common/recipes-kernel/linux/linux-yocto-4.9.21/0023-KVM-SVM-Allow-direct-access-to-MSR_IA32_SPEC_CTRL.patch
deleted file mode 100644
index 905134c7..00000000
--- a/common/recipes-kernel/linux/linux-yocto-4.9.21/0023-KVM-SVM-Allow-direct-access-to-MSR_IA32_SPEC_CTRL.patch
+++ /dev/null
@@ -1,192 +0,0 @@
-From c8b2b4bc3e5eddb48f6eda57e9138a2ea2d39345 Mon Sep 17 00:00:00 2001
-From: KarimAllah Ahmed <karahmed@amazon.de>
-Date: Sat, 3 Feb 2018 15:56:23 +0100
-Subject: [PATCH 23/33] KVM/SVM: Allow direct access to MSR_IA32_SPEC_CTRL
-
-(cherry picked from commit b2ac58f90540e39324e7a29a7ad471407ae0bf48)
-
-[ Based on a patch from Paolo Bonzini <pbonzini@redhat.com> ]
-
-... basically doing exactly what we do for VMX:
-
-- Passthrough SPEC_CTRL to guests (if enabled in guest CPUID)
-- Save and restore SPEC_CTRL around VMExit and VMEntry only if the guest
- actually used it.
-
-Signed-off-by: KarimAllah Ahmed <karahmed@amazon.de>
-Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
-Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
-Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
-Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
-Cc: Andrea Arcangeli <aarcange@redhat.com>
-Cc: Andi Kleen <ak@linux.intel.com>
-Cc: Jun Nakajima <jun.nakajima@intel.com>
-Cc: kvm@vger.kernel.org
-Cc: Dave Hansen <dave.hansen@intel.com>
-Cc: Tim Chen <tim.c.chen@linux.intel.com>
-Cc: Andy Lutomirski <luto@kernel.org>
-Cc: Asit Mallick <asit.k.mallick@intel.com>
-Cc: Arjan Van De Ven <arjan.van.de.ven@intel.com>
-Cc: Greg KH <gregkh@linuxfoundation.org>
-Cc: Paolo Bonzini <pbonzini@redhat.com>
-Cc: Dan Williams <dan.j.williams@intel.com>
-Cc: Linus Torvalds <torvalds@linux-foundation.org>
-Cc: Ashok Raj <ashok.raj@intel.com>
-Link: https://lkml.kernel.org/r/1517669783-20732-1-git-send-email-karahmed@amazon.de
-Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
-Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
----
- arch/x86/kvm/svm.c | 88 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
- 1 file changed, 88 insertions(+)
-
-diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
-index 43e45b9..4a36977 100644
---- a/arch/x86/kvm/svm.c
-+++ b/arch/x86/kvm/svm.c
-@@ -183,6 +183,8 @@ struct vcpu_svm {
- u64 gs_base;
- } host;
-
-+ u64 spec_ctrl;
-+
- u32 *msrpm;
-
- ulong nmi_iret_rip;
-@@ -248,6 +250,7 @@ static const struct svm_direct_access_msrs {
- { .index = MSR_CSTAR, .always = true },
- { .index = MSR_SYSCALL_MASK, .always = true },
- #endif
-+ { .index = MSR_IA32_SPEC_CTRL, .always = false },
- { .index = MSR_IA32_PRED_CMD, .always = false },
- { .index = MSR_IA32_LASTBRANCHFROMIP, .always = false },
- { .index = MSR_IA32_LASTBRANCHTOIP, .always = false },
-@@ -863,6 +866,25 @@ static bool valid_msr_intercept(u32 index)
- return false;
- }
-
-+static bool msr_write_intercepted(struct kvm_vcpu *vcpu, unsigned msr)
-+{
-+ u8 bit_write;
-+ unsigned long tmp;
-+ u32 offset;
-+ u32 *msrpm;
-+
-+ msrpm = is_guest_mode(vcpu) ? to_svm(vcpu)->nested.msrpm:
-+ to_svm(vcpu)->msrpm;
-+
-+ offset = svm_msrpm_offset(msr);
-+ bit_write = 2 * (msr & 0x0f) + 1;
-+ tmp = msrpm[offset];
-+
-+ BUG_ON(offset == MSR_INVALID);
-+
-+ return !!test_bit(bit_write, &tmp);
-+}
-+
- static void set_msr_interception(u32 *msrpm, unsigned msr,
- int read, int write)
- {
-@@ -1534,6 +1556,8 @@ static void svm_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)
- u32 dummy;
- u32 eax = 1;
-
-+ svm->spec_ctrl = 0;
-+
- if (!init_event) {
- svm->vcpu.arch.apic_base = APIC_DEFAULT_PHYS_BASE |
- MSR_IA32_APICBASE_ENABLE;
-@@ -3515,6 +3539,13 @@ static int svm_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
- case MSR_VM_CR:
- msr_info->data = svm->nested.vm_cr_msr;
- break;
-+ case MSR_IA32_SPEC_CTRL:
-+ if (!msr_info->host_initiated &&
-+ !guest_cpuid_has_ibrs(vcpu))
-+ return 1;
-+
-+ msr_info->data = svm->spec_ctrl;
-+ break;
- case MSR_IA32_UCODE_REV:
- msr_info->data = 0x01000065;
- break;
-@@ -3599,6 +3630,33 @@ static int svm_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr)
- case MSR_IA32_TSC:
- kvm_write_tsc(vcpu, msr);
- break;
-+ case MSR_IA32_SPEC_CTRL:
-+ if (!msr->host_initiated &&
-+ !guest_cpuid_has_ibrs(vcpu))
-+ return 1;
-+
-+ /* The STIBP bit doesn't fault even if it's not advertised */
-+ if (data & ~(SPEC_CTRL_IBRS | SPEC_CTRL_STIBP))
-+ return 1;
-+
-+ svm->spec_ctrl = data;
-+
-+ if (!data)
-+ break;
-+
-+ /*
-+ * For non-nested:
-+ * When it's written (to non-zero) for the first time, pass
-+ * it through.
-+ *
-+ * For nested:
-+ * The handling of the MSR bitmap for L2 guests is done in
-+ * nested_svm_vmrun_msrpm.
-+ * We update the L1 MSR bit as well since it will end up
-+ * touching the MSR anyway now.
-+ */
-+ set_msr_interception(svm->msrpm, MSR_IA32_SPEC_CTRL, 1, 1);
-+ break;
- case MSR_IA32_PRED_CMD:
- if (!msr->host_initiated &&
- !guest_cpuid_has_ibpb(vcpu))
-@@ -4842,6 +4900,15 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu)
-
- local_irq_enable();
-
-+ /*
-+ * If this vCPU has touched SPEC_CTRL, restore the guest's value if
-+ * it's non-zero. Since vmentry is serialising on affected CPUs, there
-+ * is no need to worry about the conditional branch over the wrmsr
-+ * being speculatively taken.
-+ */
-+ if (svm->spec_ctrl)
-+ wrmsrl(MSR_IA32_SPEC_CTRL, svm->spec_ctrl);
-+
- asm volatile (
- "push %%" _ASM_BP "; \n\t"
- "mov %c[rbx](%[svm]), %%" _ASM_BX " \n\t"
-@@ -4934,6 +5001,27 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu)
- #endif
- );
-
-+ /*
-+ * We do not use IBRS in the kernel. If this vCPU has used the
-+ * SPEC_CTRL MSR it may have left it on; save the value and
-+ * turn it off. This is much more efficient than blindly adding
-+ * it to the atomic save/restore list. Especially as the former
-+ * (Saving guest MSRs on vmexit) doesn't even exist in KVM.
-+ *
-+ * For non-nested case:
-+ * If the L01 MSR bitmap does not intercept the MSR, then we need to
-+ * save it.
-+ *
-+ * For nested case:
-+ * If the L02 MSR bitmap does not intercept the MSR, then we need to
-+ * save it.
-+ */
-+ if (!msr_write_intercepted(vcpu, MSR_IA32_SPEC_CTRL))
-+ rdmsrl(MSR_IA32_SPEC_CTRL, svm->spec_ctrl);
-+
-+ if (svm->spec_ctrl)
-+ wrmsrl(MSR_IA32_SPEC_CTRL, 0);
-+
- /* Eliminate branch target predictions from guest mode */
- vmexit_fill_RSB();
-
---
-2.7.4
-