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@xxxxxxxxxx>
Signed-off-by: Jim Mattson <jmattson@xxxxxxxxxx>
---
arch/x86/kvm/svm.c | 20 +++++++++++++++-----
1 file changed, 15 insertions(+), 5 deletions(-)
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 220e5a89465a..ffa27f75e323 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -2172,21 +2172,31 @@ static struct kvm_vcpu *svm_create_vcpu(struct kvm *kvm, unsigned int id)
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)
--
2.17.0.441.gb46fe60e1d-goog
