From 58b7075d059f7d37ca86c76fb1446fa3447b9f4f Mon Sep 17 00:00:00 2001 From: Nadav Amit Date: Fri, 24 Oct 2014 11:35:09 +0300 Subject: [PATCH] KVM: x86: Distinguish between stack operation and near branches In 64-bit, stack operations default to 64-bits, but can be overriden (to 16-bit) using opsize override prefix. In contrast, near-branches are always 64-bit. This patch distinguish between the different behaviors. Signed-off-by: Nadav Amit Signed-off-by: Paolo Bonzini --- arch/x86/kvm/emulate.c | 32 +++++++++++++++++++------------- 1 file changed, 19 insertions(+), 13 deletions(-) diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 147f3fdfb5c..a90fa188aee 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -166,6 +166,7 @@ #define CheckPerm ((u64)1 << 49) /* Has valid check_perm field */ #define NoBigReal ((u64)1 << 50) /* No big real mode */ #define PrivUD ((u64)1 << 51) /* #UD instead of #GP on CPL > 0 */ +#define NearBranch ((u64)1 << 52) /* Near branches */ #define DstXacc (DstAccLo | SrcAccHi | SrcWrite) @@ -3771,9 +3772,9 @@ static const struct opcode group4[] = { static const struct opcode group5[] = { F(DstMem | SrcNone | Lock, em_inc), F(DstMem | SrcNone | Lock, em_dec), - I(SrcMem | Stack, em_call_near_abs), + I(SrcMem | NearBranch, em_call_near_abs), I(SrcMemFAddr | ImplicitOps | Stack, em_call_far), - I(SrcMem | Stack, em_jmp_abs), + I(SrcMem | NearBranch, em_jmp_abs), I(SrcMemFAddr | ImplicitOps, em_jmp_far), I(SrcMem | Stack, em_push), D(Undefined), }; @@ -3955,7 +3956,7 @@ static const struct opcode opcode_table[256] = { I2bvIP(DstDI | SrcDX | Mov | String | Unaligned, em_in, ins, check_perm_in), /* insb, insw/insd */ I2bvIP(SrcSI | DstDX | String, em_out, outs, check_perm_out), /* outsb, outsw/outsd */ /* 0x70 - 0x7F */ - X16(D(SrcImmByte)), + X16(D(SrcImmByte | NearBranch)), /* 0x80 - 0x87 */ G(ByteOp | DstMem | SrcImm, group1), G(DstMem | SrcImm, group1), @@ -3994,8 +3995,8 @@ static const struct opcode opcode_table[256] = { X8(I(DstReg | SrcImm64 | Mov, em_mov)), /* 0xC0 - 0xC7 */ G(ByteOp | Src2ImmByte, group2), G(Src2ImmByte, group2), - I(ImplicitOps | Stack | SrcImmU16, em_ret_near_imm), - I(ImplicitOps | Stack, em_ret), + I(ImplicitOps | NearBranch | SrcImmU16, em_ret_near_imm), + I(ImplicitOps | NearBranch, em_ret), I(DstReg | SrcMemFAddr | ModRM | No64 | Src2ES, em_lseg), I(DstReg | SrcMemFAddr | ModRM | No64 | Src2DS, em_lseg), G(ByteOp, group11), G(0, group11), @@ -4015,13 +4016,14 @@ static const struct opcode opcode_table[256] = { /* 0xD8 - 0xDF */ N, E(0, &escape_d9), N, E(0, &escape_db), N, E(0, &escape_dd), N, N, /* 0xE0 - 0xE7 */ - X3(I(SrcImmByte, em_loop)), - I(SrcImmByte, em_jcxz), + X3(I(SrcImmByte | NearBranch, em_loop)), + I(SrcImmByte | NearBranch, em_jcxz), I2bvIP(SrcImmUByte | DstAcc, em_in, in, check_perm_in), I2bvIP(SrcAcc | DstImmUByte, em_out, out, check_perm_out), /* 0xE8 - 0xEF */ - I(SrcImm | Stack, em_call), D(SrcImm | ImplicitOps), - I(SrcImmFAddr | No64, em_jmp_far), D(SrcImmByte | ImplicitOps), + I(SrcImm | NearBranch, em_call), D(SrcImm | ImplicitOps | NearBranch), + I(SrcImmFAddr | No64, em_jmp_far), + D(SrcImmByte | ImplicitOps | NearBranch), I2bvIP(SrcDX | DstAcc, em_in, in, check_perm_in), I2bvIP(SrcAcc | DstDX, em_out, out, check_perm_out), /* 0xF0 - 0xF7 */ @@ -4081,7 +4083,7 @@ static const struct opcode twobyte_table[256] = { N, N, N, N, N, N, N, GP(SrcReg | DstMem | ModRM | Mov, &pfx_0f_6f_0f_7f), /* 0x80 - 0x8F */ - X16(D(SrcImm)), + X16(D(SrcImm | NearBranch)), /* 0x90 - 0x9F */ X16(D(ByteOp | DstMem | SrcNone | ModRM| Mov)), /* 0xA0 - 0xA7 */ @@ -4550,7 +4552,7 @@ done_prefixes: return EMULATION_FAILED; if (unlikely(ctxt->d & - (NotImpl|Stack|Op3264|Sse|Mmx|Intercept|CheckPerm))) { + (NotImpl|Stack|Op3264|Sse|Mmx|Intercept|CheckPerm|NearBranch))) { /* * These are copied unconditionally here, and checked unconditionally * in x86_emulate_insn. @@ -4561,8 +4563,12 @@ done_prefixes: if (ctxt->d & NotImpl) return EMULATION_FAILED; - if (mode == X86EMUL_MODE_PROT64 && (ctxt->d & Stack)) - ctxt->op_bytes = 8; + if (mode == X86EMUL_MODE_PROT64) { + if (ctxt->op_bytes == 4 && (ctxt->d & Stack)) + ctxt->op_bytes = 8; + else if (ctxt->d & NearBranch) + ctxt->op_bytes = 8; + } if (ctxt->d & Op3264) { if (mode == X86EMUL_MODE_PROT64) -- 2.41.0