Mark some instructions as vendor specific, and allow the caller to request
emulation only of vendor specific instructions. This is useful in some
circumstances (responding to a #UD fault).
Signed-off-by: Avi Kivity <avi@xxxxxxxxxx>
---
arch/x86/include/asm/kvm_emulate.h | 1 +
arch/x86/kvm/emulate.c | 12 +++++++++---
2 files changed, 10 insertions(+), 3 deletions(-)
diff --git a/arch/x86/include/asm/kvm_emulate.h b/arch/x86/include/asm/kvm_emulate.h
index 8e37deb..50ebc32 100644
--- a/arch/x86/include/asm/kvm_emulate.h
+++ b/arch/x86/include/asm/kvm_emulate.h
@@ -239,6 +239,7 @@ struct x86_emulate_ctxt {
int interruptibility;
bool perm_ok; /* do not check permissions if true */
+ bool only_vendor_specific_insn;
bool have_exception;
struct x86_exception exception;
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 02a0041..ad46239 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -76,6 +76,7 @@
#define Group (1<<14) /* Bits 3:5 of modrm byte extend opcode */
#define GroupDual (1<<15) /* Alternate decoding of mod == 3 */
/* Misc flags */
+#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 */
#define Undefined (1<<25) /* No Such Instruction */
@@ -2365,7 +2366,8 @@ static struct group_dual group7 = { {
D(SrcMem16 | ModRM | Mov | Priv),
D(SrcMem | ModRM | ByteOp | Priv | NoAccess),
}, {
- D(SrcNone | ModRM | Priv), N, N, D(SrcNone | ModRM | Priv),
+ D(SrcNone | ModRM | Priv | VendorSpecific), N,
+ N, D(SrcNone | ModRM | Priv | VendorSpecific),
D(SrcNone | ModRM | DstMem | Mov), N,
D(SrcMem16 | ModRM | Mov | Priv), N,
} };
@@ -2489,7 +2491,7 @@ static struct opcode opcode_table[256] = {
static struct opcode twobyte_table[256] = {
/* 0x00 - 0x0F */
N, GD(0, &group7), N, N,
- N, D(ImplicitOps), D(ImplicitOps | Priv), N,
+ N, D(ImplicitOps | VendorSpecific), D(ImplicitOps | Priv), N,
D(ImplicitOps | Priv), D(ImplicitOps | Priv), N, N,
N, D(ImplicitOps | ModRM), N, N,
/* 0x10 - 0x1F */
@@ -2502,7 +2504,8 @@ static struct opcode twobyte_table[256] = {
/* 0x30 - 0x3F */
D(ImplicitOps | Priv), I(ImplicitOps, em_rdtsc),
D(ImplicitOps | Priv), N,
- D(ImplicitOps), D(ImplicitOps | Priv), N, N,
+ D(ImplicitOps | VendorSpecific), D(ImplicitOps | Priv | VendorSpecific),
+ N, N,
N, N, N, N, N, N, N, N,
/* 0x40 - 0x4F */
X16(D(DstReg | SrcMem | ModRM | Mov)),
@@ -2741,6 +2744,9 @@ done_prefixes:
if (c->d == 0 || (c->d & Undefined))
return -1;
+ if (!(c->d & VendorSpecific) && ctxt->only_vendor_specific_insn)
+ return -1;
+
if (mode == X86EMUL_MODE_PROT64 && (c->d & Stack))
c->op_bytes = 8;
--
1.7.1
--
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