KVM: x86 emulator: Add flag to check for protected mode instructions

This patch adds a flag for the opcoded to tag instruction
which are only recognized in protected mode. The necessary
check is added too.

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

2 files changed, 11 insertions, 0 deletions

diff --git a/arch/x86/include/asm/kvm_emulate.h b/arch/x86/include/asm/kvm_emulate.h
index 460c2d8964b7..cab841a034f9 100644
--- a/arch/x86/include/asm/kvm_emulate.h
+++ b/arch/x86/include/asm/kvm_emulate.h
@@ -274,6 +274,10 @@ struct x86_emulate_ctxt {
 #define X86EMUL_MODE_PROT32   4 /* 32-bit protected mode. */
 #define X86EMUL_MODE_PROT64   8 /* 64-bit (long) mode.    */
 
+/* any protected mode   */
+#define X86EMUL_MODE_PROT     (X86EMUL_MODE_PROT16|X86EMUL_MODE_PROT32| \
+                               X86EMUL_MODE_PROT64)
+
 enum x86_intercept_stage {
         X86_ICPT_PRE_EXCEPT,
         X86_ICPT_POST_EXCEPT,
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 4822824b608b..3f32a6699fbd 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -78,6 +78,7 @@
 #define Prefix      (1<<16)     /* Instruction varies with 66/f2/f3 prefix */
 #define Sse         (1<<17)     /* SSE Vector instruction */
 /* Misc flags */
+#define Prot        (1<<21) /* instruction generates #UD if not in prot-mode */
 #define VendorSpecific (1<<22) /* Vendor specific instruction */
 #define NoAccess    (1<<23) /* Don't access memory (lea/invlpg/verr etc) */
 #define Op3264      (1<<24) /* Operand is 64b in long mode, 32b otherwise */
@@ -3143,6 +3144,12 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt)
                 goto done;
         }
 
+        /* Instruction can only be executed in protected mode */
+        if ((c->d & Prot) && !(ctxt->mode & X86EMUL_MODE_PROT)) {
+                rc = emulate_ud(ctxt);
+                goto done;
+        }
+
         /* Do instruction specific permission checks */
         if (c->check_perm) {
                 rc = c->check_perm(ctxt);