Expose IA32_FLUSH_CMD to the guest if the guest CPUID enumerates
support for this MSR. As with IA32_PRED_CMD, permission for
unintercepted writes to this MSR will be granted to the guest after
the first non-zero write.
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@xxxxxxxxxx>
---
arch/x86/kvm/svm/svm.c | 44 +++++++++++++++++++++++++++++-------------
1 file changed, 31 insertions(+), 13 deletions(-)
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index d13cf53e7390..8a4fa8edf6ee 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -2866,6 +2866,28 @@ static int svm_set_vm_cr(struct kvm_vcpu *vcpu, u64 data)
return 0;
}
+static int svm_set_msr_ia32_cmd(struct kvm_vcpu *vcpu, struct msr_data *msr,
+ bool guest_has_feat, u64 cmd,
+ int x86_feature_bit)
+{
+ struct vcpu_svm *svm = to_svm(vcpu);
+
+ if (!msr->host_initiated && !guest_has_feat)
+ return 1;
+
+ if (!(msr->data & ~cmd))
+ return 1;
+ if (!boot_cpu_has(x86_feature_bit))
+ return 1;
+ if (!msr->data)
+ return 0;
+
+ wrmsrl(msr->index, cmd);
+ set_msr_interception(vcpu, svm->msrpm, msr->index, 0, 1);
+
+ return 0;
+}
+
static int svm_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr)
{
struct vcpu_svm *svm = to_svm(vcpu);
@@ -2940,19 +2962,15 @@ static int svm_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr)
set_msr_interception(vcpu, svm->msrpm, MSR_IA32_SPEC_CTRL, 1, 1);
break;
case MSR_IA32_PRED_CMD:
- if (!msr->host_initiated &&
- !guest_has_pred_cmd_msr(vcpu))
- return 1;
-
- if (data & ~PRED_CMD_IBPB)
- return 1;
- if (!boot_cpu_has(X86_FEATURE_IBPB))
- return 1;
- if (!data)
- break;
-
- wrmsrl(MSR_IA32_PRED_CMD, PRED_CMD_IBPB);
- set_msr_interception(vcpu, svm->msrpm, MSR_IA32_PRED_CMD, 0, 1);
+ r = svm_set_msr_ia32_cmd(vcpu, msr,
+ guest_has_pred_cmd_msr(vcpu),
+ PRED_CMD_IBPB, X86_FEATURE_IBPB);
+ break;
+ case MSR_IA32_FLUSH_CMD:
+ bool guest_flush_l1d = guest_cpuid_has(vcpu,
+ X86_FEATURE_FLUSH_L1D);
+ r = svm_set_msr_ia32_cmd(vcpu, msr, guest_flush_l1d,
+ L1D_FLUSH, X86_FEATURE_FLUSH_L1D);
break;
case MSR_AMD64_VIRT_SPEC_CTRL:
if (!msr->host_initiated &&
--
2.39.1
