[PATCH v3 02/11] KVM: x86: tag the instructions which are used to write page table

Xiao Guangrong
2011-08-30T02:32:38Z

The idea is from Avi:
| tag instructions that are typically used to modify the page tables, and
| drop shadow if any other instruction is used.
| The list would include, I'd guess, and, or, bts, btc, mov, xchg, cmpxchg,
| and cmpxchg8b.

This patch is used to tag the instructions and in the later path, shadow page
is dropped if it is written by other instructions

Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
---
arch/x86/kvm/emulate.c | 35 ++++++++++++++++++++---------------
1 files changed, 20 insertions(+), 15 deletions(-)

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 0453c07..e24c269 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -82,6 +82,7 @@
#define RMExt (4<<15) /* Opcode extension in ModRM r/m if mod == 3 */
#define Sse (1<<18) /* SSE Vector instruction */
/* Misc flags */
+#define PageTable (1 << 19) /* instruction used to write page table */
#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) */
@@ -3018,10 +3019,10 @@ static struct opcode group7_rm7[] = {

static struct opcode group1[] = {
I(Lock, em_add),
- I(Lock, em_or),
+ I(Lock | PageTable, em_or),
I(Lock, em_adc),
I(Lock, em_sbb),
- I(Lock, em_and),
+ I(Lock | PageTable, em_and),
I(Lock, em_sub),
I(Lock, em_xor),
I(0, em_cmp),
@@ -3076,18 +3077,21 @@ static struct group_dual group7 = { {

static struct opcode group8[] = {
N, N, N, N,
- D(DstMem | SrcImmByte | ModRM), D(DstMem | SrcImmByte | ModRM | Lock),
- D(DstMem | SrcImmByte | ModRM | Lock), D(DstMem | SrcImmByte | ModRM | Lock),
+ D(DstMem | SrcImmByte | ModRM),
+ D(DstMem | SrcImmByte | ModRM | Lock | PageTable),
+ D(DstMem | SrcImmByte | ModRM | Lock),
+ D(DstMem | SrcImmByte | ModRM | Lock | PageTable),
};

static struct group_dual group9 = { {
- N, D(DstMem64 | ModRM | Lock), N, N, N, N, N, N,
+ N, D(DstMem64 | ModRM | Lock | PageTable), N, N, N, N, N, N,
}, {
N, N, N, N, N, N, N, N,
} };

static struct opcode group11[] = {
- I(DstMem | SrcImm | ModRM | Mov, em_mov), X7(D(Undefined)),
+ I(DstMem | SrcImm | ModRM | Mov | PageTable, em_mov),
+ X7(D(Undefined)),
};

static struct gprefix pfx_0f_6f_0f_7f = {
@@ -3099,7 +3103,7 @@ static struct opcode opcode_table[256] = {
I6ALU(Lock, em_add),
D(ImplicitOps | Stack | No64), D(ImplicitOps | Stack | No64),
/* 0x08 - 0x0F */
- I6ALU(Lock, em_or),
+ I6ALU(Lock | PageTable, em_or),
D(ImplicitOps | Stack | No64), N,
/* 0x10 - 0x17 */
I6ALU(Lock, em_adc),
@@ -3108,7 +3112,7 @@ static struct opcode opcode_table[256] = {
I6ALU(Lock, em_sbb),
D(ImplicitOps | Stack | No64), D(ImplicitOps | Stack | No64),
/* 0x20 - 0x27 */
- I6ALU(Lock, em_and), N, N,
+ I6ALU(Lock | PageTable, em_and), N, N,
/* 0x28 - 0x2F */
I6ALU(Lock, em_sub), N, I(ByteOp | DstAcc | No64, em_das),
/* 0x30 - 0x37 */
@@ -3141,11 +3145,11 @@ static struct opcode opcode_table[256] = {
G(ByteOp | DstMem | SrcImm | ModRM | No64 | Group, group1),
G(DstMem | SrcImmByte | ModRM | Group, group1),
I2bv(DstMem | SrcReg | ModRM, em_test),
- I2bv(DstMem | SrcReg | ModRM | Lock, em_xchg),
+ I2bv(DstMem | SrcReg | ModRM | Lock | PageTable, em_xchg),
/* 0x88 - 0x8F */
- I2bv(DstMem | SrcReg | ModRM | Mov, em_mov),
+ I2bv(DstMem | SrcReg | ModRM | Mov | PageTable, em_mov),
I2bv(DstReg | SrcMem | ModRM | Mov, em_mov),
- I(DstMem | SrcNone | ModRM | Mov, em_mov_rm_sreg),
+ I(DstMem | SrcNone | ModRM | Mov | PageTable, em_mov_rm_sreg),
D(ModRM | SrcMem | NoAccess | DstReg),
I(ImplicitOps | SrcMem16 | ModRM, em_mov_sreg_rm),
G(0, group1A),
@@ -3158,7 +3162,7 @@ static struct opcode opcode_table[256] = {
II(ImplicitOps | Stack, em_popf, popf), N, N,
/* 0xA0 - 0xA7 */
I2bv(DstAcc | SrcMem | Mov | MemAbs, em_mov),
- I2bv(DstMem | SrcAcc | Mov | MemAbs, em_mov),
+ I2bv(DstMem | SrcAcc | Mov | MemAbs | PageTable, em_mov),
I2bv(SrcSI | DstDI | Mov | String, em_mov),
I2bv(SrcSI | DstDI | String, em_cmp),
/* 0xA8 - 0xAF */
@@ -3255,18 +3259,19 @@ static struct opcode twobyte_table[256] = {
D(DstMem | SrcReg | Src2CL | ModRM), N, N,
/* 0xA8 - 0xAF */
D(ImplicitOps | Stack), D(ImplicitOps | Stack),
- DI(ImplicitOps, rsm), D(DstMem | SrcReg | ModRM | BitOp | Lock),
+ DI(ImplicitOps, rsm),
+ D(DstMem | SrcReg | ModRM | BitOp | Lock | PageTable),
D(DstMem | SrcReg | Src2ImmByte | ModRM),
D(DstMem | SrcReg | Src2CL | ModRM),
D(ModRM), I(DstReg | SrcMem | ModRM, em_imul),
/* 0xB0 - 0xB7 */
- D2bv(DstMem | SrcReg | ModRM | Lock),
+ D2bv(DstMem | SrcReg | ModRM | Lock | PageTable),
D(DstReg | SrcMemFAddr | ModRM), D(DstMem | SrcReg | ModRM | BitOp | Lock),
D(DstReg | SrcMemFAddr | ModRM), D(DstReg | SrcMemFAddr | ModRM),
D(ByteOp | DstReg | SrcMem | ModRM | Mov), D(DstReg | SrcMem16 | ModRM | Mov),
/* 0xB8 - 0xBF */
N, N,
- G(BitOp, group8), D(DstMem | SrcReg | ModRM | BitOp | Lock),
+ G(BitOp, group8), D(DstMem | SrcReg | ModRM | BitOp | Lock | PageTable),
D(DstReg | SrcMem | ModRM), D(DstReg | SrcMem | ModRM),
D(ByteOp | DstReg | SrcMem | ModRM | Mov), D(DstReg | SrcMem16 | ModRM | Mov),
/* 0xC0 - 0xCF */
--
1.7.5.4