KVM: SVM: add intercept for machine check exception

To properly forward a MCE occured while the guest is running to the host, we
have to intercept this exception and call the host handler by hand. This is
implemented by this patch.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

2 files changed, 17 insertions, 1 deletions

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 8af463b91526..da3ddef47605 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -507,7 +507,8 @@ static void init_vmcb(struct vcpu_svm *svm)
                                         INTERCEPT_DR7_MASK;
 
         control->intercept_exceptions = (1 << PF_VECTOR) |
-                                        (1 << UD_VECTOR);
+                                        (1 << UD_VECTOR) |
+                                        (1 << MC_VECTOR);
 
 
         control->intercept =    (1ULL << INTERCEPT_INTR) |
@@ -1044,6 +1045,19 @@ static int nm_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
         return 1;
 }
 
+static int mc_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
+{
+        /*
+         * On an #MC intercept the MCE handler is not called automatically in
+         * the host. So do it by hand here.
+         */
+        asm volatile (
+                "int $0x12\n");
+        /* not sure if we ever come back to this point */
+
+        return 1;
+}
+
 static int shutdown_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
 {
         /*
@@ -1367,6 +1381,7 @@ static int (*svm_exit_handlers[])(struct vcpu_svm *svm,
         [SVM_EXIT_EXCP_BASE + UD_VECTOR]        = ud_interception,
         [SVM_EXIT_EXCP_BASE + PF_VECTOR]        = pf_interception,
         [SVM_EXIT_EXCP_BASE + NM_VECTOR]        = nm_interception,
+        [SVM_EXIT_EXCP_BASE + MC_VECTOR]        = mc_interception,
         [SVM_EXIT_INTR]                         = nop_on_interception,
         [SVM_EXIT_NMI]                          = nop_on_interception,
         [SVM_EXIT_SMI]                          = nop_on_interception,
diff --git a/include/asm-x86/kvm_host.h b/include/asm-x86/kvm_host.h
index de3eccfb767c..286117878ce2 100644
--- a/include/asm-x86/kvm_host.h
+++ b/include/asm-x86/kvm_host.h
@@ -62,6 +62,7 @@
 #define SS_VECTOR 12
 #define GP_VECTOR 13
 #define PF_VECTOR 14
+#define MC_VECTOR 18
 
 #define SELECTOR_TI_MASK (1 << 2)
 #define SELECTOR_RPL_MASK 0x03