From 0887561fd28b423a32593367f669ef162cbfa373 Mon Sep 17 00:00:00 2001 From: Andy Whitcroft Date: Wed, 31 Jan 2018 15:38:01 +0000 Subject: [PATCH 012/104] Revert "x86/svm: Set IBPB when running a different VCPU" CVE-2017-5753 (revert embargoed) CVE-2017-5715 (revert embargoed) This reverts commit 0ba3eaabbb6666ebd344ee80534e58c375a00810. Signed-off-by: Andy Whitcroft --- arch/x86/kvm/svm.c | 16 ---------------- 1 file changed, 16 deletions(-) diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index fe90956bdf1b..79ab4d85afe3 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -518,8 +518,6 @@ struct svm_cpu_data { struct kvm_ldttss_desc *tss_desc; struct page *save_area; - - struct vmcb *current_vmcb; }; static DEFINE_PER_CPU(struct svm_cpu_data *, svm_data); @@ -1687,19 +1685,11 @@ static void svm_free_vcpu(struct kvm_vcpu *vcpu) __free_pages(virt_to_page(svm->nested.msrpm), MSRPM_ALLOC_ORDER); kvm_vcpu_uninit(vcpu); kmem_cache_free(kvm_vcpu_cache, svm); - - /* - * The VMCB could be recycled, causing a false negative in svm_vcpu_load; - * block speculative execution. - */ - if (ibpb_inuse) - wrmsrl(MSR_IA32_PRED_CMD, FEATURE_SET_IBPB); } static void svm_vcpu_load(struct kvm_vcpu *vcpu, int cpu) { struct vcpu_svm *svm = to_svm(vcpu); - struct svm_cpu_data *sd = per_cpu(svm_data, cpu); int i; if (unlikely(cpu != vcpu->cpu)) { @@ -1728,12 +1718,6 @@ static void svm_vcpu_load(struct kvm_vcpu *vcpu, int cpu) if (static_cpu_has(X86_FEATURE_RDTSCP)) wrmsrl(MSR_TSC_AUX, svm->tsc_aux); - if (sd->current_vmcb != svm->vmcb) { - sd->current_vmcb = svm->vmcb; - if (ibpb_inuse) - wrmsrl(MSR_IA32_PRED_CMD, FEATURE_SET_IBPB); - } - avic_vcpu_load(vcpu, cpu); } -- 2.15.1