From e7e1e8dda9c7c571d0e125dad468f673f231ad54 Mon Sep 17 00:00:00 2001 From: Andrea Arcangeli Date: Wed, 20 Dec 2017 08:04:51 -0800 Subject: [PATCH] KVM: x86: add SPEC_CTRL to MSR and CPUID lists Orabug: 27344012 CVE: CVE-2017-5715 Signed-off-by: Andrea Arcangeli Signed-off-by: Konrad Rzeszutek Wilk Reviewed-by: John Haxby Signed-off-by: Kirtikar Kashyap --- arch/x86/kvm/cpuid.c | 17 +++++++++++++++-- arch/x86/kvm/x86.c | 2 +- 2 files changed, 16 insertions(+), 3 deletions(-) diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index 479dd5eb1307..b051031e899a 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -58,6 +58,12 @@ u64 kvm_supported_xcr0(void) #define F(x) bit(X86_FEATURE_##x) +/* These are scattered features in cpufeatures.h. */ +#define KVM_CPUID_BIT_SPEC_CTRL 26 +#define KVM_CPUID_BIT_STIBP 27 + +#define KF(x) bit(KVM_CPUID_BIT_##x) + int kvm_update_cpuid(struct kvm_vcpu *vcpu) { struct kvm_cpuid_entry2 *best; @@ -354,6 +360,7 @@ static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function, const u32 kvm_supported_word10_x86_features = F(XSAVEOPT) | F(XSAVEC) | F(XGETBV1) | f_xsaves; + const u32 kvm_cpuid_7_0_edx_x86_features = KF(SPEC_CTRL) | KF(STIBP); /* all calls to cpuid_count() should be made on the same cpu */ get_cpu(); @@ -425,11 +432,17 @@ static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function, cpuid_mask(&entry->ebx, 9); // TSC_ADJUST is emulated entry->ebx |= F(TSC_ADJUST); - } else + entry->edx &= kvm_cpuid_7_0_edx_x86_features; + if ( !boot_cpu_has(X86_FEATURE_SPEC_CTRL) ) + entry->edx &= !(1u << KVM_CPUID_BIT_SPEC_CTRL); + if ( !boot_cpu_has(X86_FEATURE_STIPB) ) + entry->edx &= !(1u << KVM_CPUID_BIT_STIBP); + } else { entry->ebx = 0; + entry->edx = 0; + } entry->eax = 0; entry->ecx = 0; - entry->edx = 0; break; } case 9: diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index dd6b8ec121ef..a7c32750b4ce 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -941,7 +941,7 @@ static u32 msrs_to_save[] = { MSR_CSTAR, MSR_KERNEL_GS_BASE, MSR_SYSCALL_MASK, MSR_LSTAR, #endif MSR_IA32_TSC, MSR_IA32_CR_PAT, MSR_VM_HSAVE_PA, - MSR_IA32_FEATURE_CONTROL, MSR_IA32_BNDCFGS + MSR_IA32_FEATURE_CONTROL, MSR_IA32_BNDCFGS, MSR_IA32_SPEC_CTRL, }; static unsigned num_msrs_to_save; -- 2.50.1