From: Nadav Amit <namit@xxxxxxxxxxxxxxxxx>
Currently, all group15 instructions are decoded as clflush (e.g., mfence,
xsave). In addition, the clflush instruction requires no prefix (66/f2/f3)
would exist. If prefix exists it may encode a different instruction (e.g.,
clflushopt).
Creating a group for clflush, and different group for each prefix.
This has been the case forever, but the next patch needs the cflush group
in order to fix a bug introduced in 3.17.
Fixes: 41061cdb98a0bec464278b4db8e894a3121671f5
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Nadav Amit <namit@xxxxxxxxxxxxxxxxx>
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
---
arch/x86/kvm/emulate.c | 20 +++++++++++++++++---
1 file changed, 17 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index eb3b1c46f995..97da5034d812 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -3462,6 +3462,12 @@ static int em_bswap(struct x86_emulate_ctxt *ctxt)
return X86EMUL_CONTINUE;
}
+static int em_clflush(struct x86_emulate_ctxt *ctxt)
+{
+ /* emulating clflush regardless of cpuid */
+ return X86EMUL_CONTINUE;
+}
+
static bool valid_cr(int nr)
{
switch (nr) {
@@ -3800,6 +3806,16 @@ static const struct opcode group11[] = {
X7(D(Undefined)),
};
+static const struct gprefix pfx_0f_ae_7 = {
+ I(0, em_clflush), N, N, N,
+};
+
+static const struct group_dual group15 = { {
+ N, N, N, N, N, N, N, GP(0, &pfx_0f_ae_7),
+}, {
+ N, N, N, N, N, N, N, N,
+} };
+
static const struct gprefix pfx_0f_6f_0f_7f = {
I(Mmx, em_mov), I(Sse | Aligned, em_mov), N, I(Sse | Unaligned, em_mov),
};
@@ -4063,7 +4079,7 @@ static const struct opcode twobyte_table[256] = {
F(DstMem | SrcReg | ModRM | BitOp | Lock | PageTable, em_bts),
F(DstMem | SrcReg | Src2ImmByte | ModRM, em_shrd),
F(DstMem | SrcReg | Src2CL | ModRM, em_shrd),
- D(ModRM), F(DstReg | SrcMem | ModRM, em_imul),
+ GD(0, &group15), F(DstReg | SrcMem | ModRM, em_imul),
/* 0xB0 - 0xB7 */
I2bv(DstMem | SrcReg | ModRM | Lock | PageTable, em_cmpxchg),
I(DstReg | SrcMemFAddr | ModRM | Src2SS, em_lseg),
@@ -4993,8 +5009,6 @@ twobyte_insn:
case 0x90 ... 0x9f: /* setcc r/m8 */
ctxt->dst.val = test_cc(ctxt->b, ctxt->eflags);
break;
- case 0xae: /* clflush */
- break;
case 0xb6 ... 0xb7: /* movzx */
ctxt->dst.bytes = ctxt->op_bytes;
ctxt->dst.val = (ctxt->src.bytes == 1) ? (u8) ctxt->src.val
--
1.8.3.1
--
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