| From 13e457e0eebf0a0c82c38ceb890d93eb826d62a6 Mon Sep 17 00:00:00 2001 |
| From: Nadav Amit <namit@cs.technion.ac.il> |
| Date: Mon, 13 Oct 2014 13:04:13 +0300 |
| Subject: KVM: x86: Emulator does not decode clflush well |
| |
| From: Nadav Amit <namit@cs.technion.ac.il> |
| |
| commit 13e457e0eebf0a0c82c38ceb890d93eb826d62a6 upstream. |
| |
| 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 |
| Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> |
| Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| arch/x86/kvm/emulate.c | 20 +++++++++++++++++--- |
| 1 file changed, 17 insertions(+), 3 deletions(-) |
| |
| --- a/arch/x86/kvm/emulate.c |
| +++ b/arch/x86/kvm/emulate.c |
| @@ -3376,6 +3376,12 @@ static int em_bswap(struct x86_emulate_c |
| 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) { |
| @@ -3708,6 +3714,16 @@ 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), |
| }; |
| @@ -3967,7 +3983,7 @@ static const struct opcode twobyte_table |
| 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), |
| @@ -4894,8 +4910,6 @@ 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 |