x86/bugs, KVM: Support the combination of guest and host IBRS

[mirror_ubuntu-artful-kernel.git] / arch / x86 / kvm / vmx.c

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 8c638ef4f40917560008ac407becc87c52a2c617..7a7bd88b2e14e01c4fd127d09dfa78d329d61e37 100644 (file)
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -9104,9 +9104,8 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu)
 
        atomic_switch_perf_msrs(vmx);
 
-       if (ibrs_inuse)
-               add_atomic_switch_msr(vmx, MSR_IA32_SPEC_CTRL,
-                       vcpu->arch.spec_ctrl, FEATURE_ENABLE_IBRS);
+       /* SMB: Ignore ibrs_inuse but rely on vcpu value */
+       x86_spec_ctrl_set_guest(vcpu->arch.spec_ctrl);
 
        debugctlmsr = get_debugctlmsr();
 
@@ -9230,6 +9229,8 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu)
 #endif
              );
 
+       x86_spec_ctrl_restore_host(vcpu->arch.spec_ctrl);
+
        /* Eliminate branch target predictions from guest mode */
        vmexit_fill_RSB();