diff options
| author |   Jim Mattson <jmattson@google.com> | 2018-05-22 09:54:20 -0700 |
|---|---|---|
| committer |   Paolo Bonzini <pbonzini@redhat.com> | 2018-11-27 12:50:42 +0100 |
| commit | fd65d3142f734bc4376053c8d75670041903134d (patch) | |
| tree | cc54b20e91a008463389cb74b4e4dd02252ee29a /arch/x86/kvm | |
| parent | kvm: mmu: Fix race in emulated page table writes (diff) | |
| download | linux-dev-fd65d3142f734bc4376053c8d75670041903134d.tar.xz linux-dev-fd65d3142f734bc4376053c8d75670041903134d.zip | |
kvm: svm: Ensure an IBPB on all affected CPUs when freeing a vmcb
Previously, we only called indirect_branch_prediction_barrier on the
logical CPU that freed a vmcb. This function should be called on all
logical CPUs that last loaded the vmcb in question.
Fixes: 15d45071523d ("KVM/x86: Add IBPB support")
Reported-by: Neel Natu <neelnatu@google.com>
Signed-off-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm')
| -rw-r--r-- | arch/x86/kvm/svm.c | 20 |
1 files changed, 15 insertions, 5 deletions
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index a24733aade4c..cc6467b35a85 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -2193,21 +2193,31 @@ out: return ERR_PTR(err); } +static void svm_clear_current_vmcb(struct vmcb *vmcb) +{ + int i; + + for_each_online_cpu(i) + cmpxchg(&per_cpu(svm_data, i)->current_vmcb, vmcb, NULL); +} + static void svm_free_vcpu(struct kvm_vcpu *vcpu) { struct vcpu_svm *svm = to_svm(vcpu); + /* + * The vmcb page can be recycled, causing a false negative in + * svm_vcpu_load(). So, ensure that no logical CPU has this + * vmcb page recorded as its current vmcb. + */ + svm_clear_current_vmcb(svm->vmcb); + __free_page(pfn_to_page(__sme_clr(svm->vmcb_pa) >> PAGE_SHIFT)); __free_pages(virt_to_page(svm->msrpm), MSRPM_ALLOC_ORDER); __free_page(virt_to_page(svm->nested.hsave)); __free_pages(virt_to_page(svm->nested.msrpm), MSRPM_ALLOC_ORDER); kvm_vcpu_uninit(vcpu); kmem_cache_free(kvm_vcpu_cache, svm); - /* - * The vmcb page can be recycled, causing a false negative in - * svm_vcpu_load(). So do a full IBPB now. - */ - indirect_branch_prediction_barrier(); } static void svm_vcpu_load(struct kvm_vcpu *vcpu, int cpu) |