diff options
| author | Nadav Amit <namit@cs.technion.ac.il> | 2014-05-25 23:05:21 +0300 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2014-05-27 10:22:56 +0200 |
| commit | 9b88ae99d2fe11e359b3b3992aff953e28b0b43a (patch) | |
| tree | 11e43ca7db20ad0583755642b384939101938914 /arch | |
| parent | fc57ac2c9ca8109ea97fcc594f4be436944230cc (diff) | |
KVM: x86: MOV CR/DR emulation should ignore mod
MOV CR/DR instructions ignore the mod field (in the ModR/M byte). As the SDM
states: "The 2 bits in the mod field are ignored". Accordingly, the second
operand of these instructions is always a general purpose register.
The current emulator implementation does not do so. If the mod bits do not
equal 3, it expects the second operand to be in memory.
Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kvm/emulate.c | 13 |
1 files changed, 8 insertions, 5 deletions
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 2fa7ab069817..e4e833d3d7d7 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -161,6 +161,7 @@ #define Fastop ((u64)1 << 44) /* Use opcode::u.fastop */ #define NoWrite ((u64)1 << 45) /* No writeback */ #define SrcWrite ((u64)1 << 46) /* Write back src operand */ +#define NoMod ((u64)1 << 47) /* Mod field is ignored */ #define DstXacc (DstAccLo | SrcAccHi | SrcWrite) @@ -1077,7 +1078,7 @@ static int decode_modrm(struct x86_emulate_ctxt *ctxt, ctxt->modrm_rm |= (ctxt->modrm & 0x07); ctxt->modrm_seg = VCPU_SREG_DS; - if (ctxt->modrm_mod == 3) { + if (ctxt->modrm_mod == 3 || (ctxt->d & NoMod)) { op->type = OP_REG; op->bytes = (ctxt->d & ByteOp) ? 1 : ctxt->op_bytes; op->addr.reg = decode_register(ctxt, ctxt->modrm_rm, @@ -3877,10 +3878,12 @@ static const struct opcode twobyte_table[256] = { N, N, N, N, N, N, N, N, D(ImplicitOps | ModRM), N, N, N, N, N, N, D(ImplicitOps | ModRM), /* 0x20 - 0x2F */ - DIP(ModRM | DstMem | Priv | Op3264, cr_read, check_cr_read), - DIP(ModRM | DstMem | Priv | Op3264, dr_read, check_dr_read), - IIP(ModRM | SrcMem | Priv | Op3264, em_cr_write, cr_write, check_cr_write), - IIP(ModRM | SrcMem | Priv | Op3264, em_dr_write, dr_write, check_dr_write), + DIP(ModRM | DstMem | Priv | Op3264 | NoMod, cr_read, check_cr_read), + DIP(ModRM | DstMem | Priv | Op3264 | NoMod, dr_read, check_dr_read), + IIP(ModRM | SrcMem | Priv | Op3264 | NoMod, em_cr_write, cr_write, + check_cr_write), + IIP(ModRM | SrcMem | Priv | Op3264 | NoMod, em_dr_write, dr_write, + check_dr_write), N, N, N, N, GP(ModRM | DstReg | SrcMem | Mov | Sse, &pfx_0f_28_0f_29), GP(ModRM | DstMem | SrcReg | Mov | Sse, &pfx_0f_28_0f_29), |