[PATCH v2 0/3] KVM: emulate AAM, XLAT, SALC

[PATCH v2 0/3] KVM: emulate AAM, XLAT, SALC

[Paolo Bonzini]

These three instructions are not emulated, but can be found in
real mode code.

These are also good for stable, but they conflict before 3.9 and are
not really useful since emulate_invalid_guest_state defaulted to false.
So I'm not marking them for earlier releases.

Paolo Bonzini (3):
  KVM: emulator: emulate AAM
  KVM: emulator: emulate XLAT
  KVM: emulator: emulate SALC

 arch/x86/kvm/emulate.c | 43 ++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 42 insertions(+), 1 deletion(-)

-- 
1.8.1.4

Re: [PATCH v2 2/3] KVM: emulator: emulate XLAT

[Gleb Natapov]

On Thu, May 09, 2013 at 11:32:50AM +0200, Paolo Bonzini wrote:
> This is used by SGABIOS, KVM breaks with emulate_invalid_guest_state=1.
> It is just a MOV in disguise, with a funny source address.
> 
> Reported-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
> Cc: stable@vger.kernel.org # 3.9
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
>  arch/x86/kvm/emulate.c | 16 +++++++++++++++-
>  1 file changed, 15 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
> index 709ba03..210bb4e 100644
> --- a/arch/x86/kvm/emulate.c
> +++ b/arch/x86/kvm/emulate.c
> @@ -60,6 +60,7 @@
>  #define OpGS              25ull  /* GS */
>  #define OpMem8            26ull  /* 8-bit zero extended memory operand */
>  #define OpImm64           27ull  /* Sign extended 16/32/64-bit immediate */
> +#define OpXLat            28ull  /* memory at BX/EBX/RBX + zero-extended AL */
>  
>  #define OpBits             5  /* Width of operand field */
>  #define OpMask             ((1ull << OpBits) - 1)
> @@ -99,6 +100,7 @@
>  #define SrcImmUByte (OpImmUByte << SrcShift)
>  #define SrcImmU     (OpImmU << SrcShift)
>  #define SrcSI       (OpSI << SrcShift)
> +#define SrcXLat     (OpXLat << SrcShift)
>  #define SrcImmFAddr (OpImmFAddr << SrcShift)
>  #define SrcMemFAddr (OpMemFAddr << SrcShift)
>  #define SrcAcc      (OpAcc << SrcShift)
> @@ -3949,7 +3951,8 @@ static const struct opcode opcode_table[256] = {
>  	G(Src2One | ByteOp, group2), G(Src2One, group2),
>  	G(Src2CL | ByteOp, group2), G(Src2CL, group2),
>  	I(DstAcc | SrcImmUByte | No64, em_aam),
> -	I(DstAcc | SrcImmUByte | No64, em_aad), N, N,
> +	I(DstAcc | SrcImmUByte | No64, em_aad), N,
> +	I(DstAcc | SrcXLat | ByteOp, em_mov),
>  	/* 0xD8 - 0xDF */
>  	N, E(0, &escape_d9), N, E(0, &escape_db), N, E(0, &escape_dd), N, N,
>  	/* 0xE0 - 0xE7 */
> @@ -4207,6 +4210,17 @@ static int decode_operand(struct x86_emulate_ctxt *ctxt, struct operand *op,
>  		op->val = 0;
>  		op->count = 1;
>  		break;
> +	case OpXLat:
Sigh, obviously this is not reusable by any other instruction. So many
waisted transistor :(

> +		op->type = OP_MEM;
> +		op->bytes = (ctxt->d & ByteOp) ? 1 : ctxt->op_bytes;
> +		op->addr.mem.ea =
> +			register_address(ctxt,
> +				reg_read(ctxt, VCPU_REGS_RBX) +
> +				(reg_read(ctxt, VCPU_REGS_RAX) & 0xff));
> +		op->addr.mem.seg = seg_override(ctxt);
> +		op->val = 0;
> +		op->count = 1;
The count is set only for decoding that is used by string instructions.
I can drop it while applying.

> +		break;
>  	case OpImmFAddr:
>  		op->type = OP_IMM;
>  		op->addr.mem.ea = ctxt->_eip;
> -- 
> 1.8.1.4
> 

--
			Gleb.

Re: [PATCH v2 2/3] KVM: emulator: emulate XLAT

[Paolo Bonzini]

Il 09/05/2013 12:03, Gleb Natapov ha scritto:
> On Thu, May 09, 2013 at 11:32:50AM +0200, Paolo Bonzini wrote:
>> This is used by SGABIOS, KVM breaks with emulate_invalid_guest_state=1.
>> It is just a MOV in disguise, with a funny source address.
>>
>> Reported-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
>> Cc: stable@vger.kernel.org # 3.9
>> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
>> ---
>>  arch/x86/kvm/emulate.c | 16 +++++++++++++++-
>>  1 file changed, 15 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
>> index 709ba03..210bb4e 100644
>> --- a/arch/x86/kvm/emulate.c
>> +++ b/arch/x86/kvm/emulate.c
>> @@ -60,6 +60,7 @@
>>  #define OpGS              25ull  /* GS */
>>  #define OpMem8            26ull  /* 8-bit zero extended memory operand */
>>  #define OpImm64           27ull  /* Sign extended 16/32/64-bit immediate */
>> +#define OpXLat            28ull  /* memory at BX/EBX/RBX + zero-extended AL */
>>  
>>  #define OpBits             5  /* Width of operand field */
>>  #define OpMask             ((1ull << OpBits) - 1)
>> @@ -99,6 +100,7 @@
>>  #define SrcImmUByte (OpImmUByte << SrcShift)
>>  #define SrcImmU     (OpImmU << SrcShift)
>>  #define SrcSI       (OpSI << SrcShift)
>> +#define SrcXLat     (OpXLat << SrcShift)
>>  #define SrcImmFAddr (OpImmFAddr << SrcShift)
>>  #define SrcMemFAddr (OpMemFAddr << SrcShift)
>>  #define SrcAcc      (OpAcc << SrcShift)
>> @@ -3949,7 +3951,8 @@ static const struct opcode opcode_table[256] = {
>>  	G(Src2One | ByteOp, group2), G(Src2One, group2),
>>  	G(Src2CL | ByteOp, group2), G(Src2CL, group2),
>>  	I(DstAcc | SrcImmUByte | No64, em_aam),
>> -	I(DstAcc | SrcImmUByte | No64, em_aad), N, N,
>> +	I(DstAcc | SrcImmUByte | No64, em_aad), N,
>> +	I(DstAcc | SrcXLat | ByteOp, em_mov),
>>  	/* 0xD8 - 0xDF */
>>  	N, E(0, &escape_d9), N, E(0, &escape_db), N, E(0, &escape_dd), N, N,
>>  	/* 0xE0 - 0xE7 */
>> @@ -4207,6 +4210,17 @@ static int decode_operand(struct x86_emulate_ctxt *ctxt, struct operand *op,
>>  		op->val = 0;
>>  		op->count = 1;
>>  		break;
>> +	case OpXLat:
> Sigh, obviously this is not reusable by any other instruction. So many
> waisted transistor :(

And a precious op value too, we only have 3 left. :/

>> +		op->type = OP_MEM;
>> +		op->bytes = (ctxt->d & ByteOp) ? 1 : ctxt->op_bytes;
>> +		op->addr.mem.ea =
>> +			register_address(ctxt,
>> +				reg_read(ctxt, VCPU_REGS_RBX) +
>> +				(reg_read(ctxt, VCPU_REGS_RAX) & 0xff));
>> +		op->addr.mem.seg = seg_override(ctxt);
>> +		op->val = 0;
>> +		op->count = 1;
> The count is set only for decoding that is used by string instructions.
> I can drop it while applying.

Thanks!

Paolo

>> +		break;
>>  	case OpImmFAddr:
>>  		op->type = OP_IMM;
>>  		op->addr.mem.ea = ctxt->_eip;
>> -- 
>> 1.8.1.4
>>
> 
> --
> 			Gleb.
> 

Re: [PATCH v2 0/3] KVM: emulate AAM, XLAT, SALC

[Gleb Natapov]

On Thu, May 09, 2013 at 11:32:48AM +0200, Paolo Bonzini wrote:
> These three instructions are not emulated, but can be found in
> real mode code.
> 
> These are also good for stable, but they conflict before 3.9 and are
> not really useful since emulate_invalid_guest_state defaulted to false.
> So I'm not marking them for earlier releases.
> 
> Paolo Bonzini (3):
>   KVM: emulator: emulate AAM
>   KVM: emulator: emulate XLAT
>   KVM: emulator: emulate SALC
> 
Applied, thanks.

>  arch/x86/kvm/emulate.c | 43 ++++++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 42 insertions(+), 1 deletion(-)
> 
> -- 
> 1.8.1.4

--
			Gleb.