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authorCathy Avery <cavery@redhat.com>2021-01-12 11:43:12 -0500
committerPaolo Bonzini <pbonzini@redhat.com>2021-03-15 04:42:29 -0400
commitaf18fa775d07aeb92d4598df5364a21489aa4141 (patch)
tree0a63abc5f4414f89725839d5f6bc4dae4b6e75e6 /arch/x86/kvm/svm/svm.c
parent4995a3685f1b768648187ed20bea3366f5f76228 (diff)
downloadlwn-af18fa775d07aeb92d4598df5364a21489aa4141.tar.gz
lwn-af18fa775d07aeb92d4598df5364a21489aa4141.zip
KVM: nSVM: Track the physical cpu of the vmcb vmrun through the vmcb
This patch moves the physical cpu tracking from the vcpu to the vmcb in svm_switch_vmcb. If either vmcb01 or vmcb02 change physical cpus from one vmrun to the next the vmcb's previous cpu is preserved for comparison with the current cpu and the vmcb is marked dirty if different. This prevents the processor from using old cached data for a vmcb that may have been updated on a prior run on a different processor. It also moves the physical cpu check from svm_vcpu_load to pre_svm_run as the check only needs to be done at run. Suggested-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Cathy Avery <cavery@redhat.com> Message-Id: <20210112164313.4204-2-cavery@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/svm/svm.c')
-rw-r--r--arch/x86/kvm/svm/svm.c23
1 files changed, 15 insertions, 8 deletions
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index aa7f6aee1d69..a6b02f6241a7 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -1319,11 +1319,12 @@ void svm_switch_vmcb(struct vcpu_svm *svm, struct kvm_vmcb_info *target_vmcb)
svm->asid_generation = 0;
/*
- * Workaround: we don't yet track the physical CPU that
- * target_vmcb has run on.
+ * Track the physical CPU the target_vmcb is running on
+ * in order to mark the VMCB dirty if the cpu changes at
+ * its next vmrun.
*/
- vmcb_mark_all_dirty(svm->vmcb);
+ svm->current_vmcb->cpu = svm->vcpu.cpu;
}
static int svm_create_vcpu(struct kvm_vcpu *vcpu)
@@ -1499,11 +1500,6 @@ 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);
- if (unlikely(cpu != vcpu->cpu)) {
- svm->asid_generation = 0;
- vmcb_mark_all_dirty(svm->vmcb);
- }
-
if (sd->current_vmcb != svm->vmcb) {
sd->current_vmcb = svm->vmcb;
indirect_branch_prediction_barrier();
@@ -3435,6 +3431,17 @@ static void pre_svm_run(struct vcpu_svm *svm)
{
struct svm_cpu_data *sd = per_cpu(svm_data, svm->vcpu.cpu);
+ /*
+ * If the previous vmrun of the vmcb occurred on
+ * a different physical cpu then we must mark the vmcb dirty.
+ */
+
+ if (unlikely(svm->current_vmcb->cpu != svm->vcpu.cpu)) {
+ svm->asid_generation = 0;
+ vmcb_mark_all_dirty(svm->vmcb);
+ svm->current_vmcb->cpu = svm->vcpu.cpu;
+ }
+
if (sev_guest(svm->vcpu.kvm))
return pre_sev_run(svm, svm->vcpu.cpu);