Il 30/05/2013 16:35, Paolo Bonzini ha scritto:
> The x86-64 extended low-byte registers were fetched correctly from reg,
> but not from mod/rm.
>
> This fixes another bug in the boot of RHEL5.9 64-bit, but it is still
> not enough.
Well, it is enough but it takes 2 minutes to reach the point where
hardware virtualization is used. It is doing a lot of stuff in
emulation mode because FS and GS have leftovers from the A20 test:
FS =0000 0000000000000000 0000ffff 00009300 DPL=0 DS16 [-WA]
GS =ffff 00000000000ffff0 0000ffff 00009300 DPL=0 DS16 [-WA]
0x00000000000113be: in $0x92,%al
0x00000000000113c0: or $0x2,%al
0x00000000000113c2: out %al,$0x92
0x00000000000113c4: xor %ax,%ax
0x00000000000113c6: mov %ax,%fs
0x00000000000113c8: dec %ax
0x00000000000113c9: mov %ax,%gs
0x00000000000113cb: inc %ax
0x00000000000113cc: mov %ax,%fs:0x200
0x00000000000113d0: cmp %gs:0x210,%ax
0x00000000000113d5: je 0x113cb
The DPL < RPL test fails. Any ideas? Should we introduce a new
intermediate value for emulate_invalid_guest_state (0=none, 1=some, 2=full)?
Paolo
> Cc: gnatapov@xxxxxxxxxx
> Cc: kvm@xxxxxxxxxxxxxxx
> Cc: <stable@xxxxxxxxxxxxxxx> # 3.9
> Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
> ---
> arch/x86/kvm/emulate.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
> index aa68106..028b34f 100644
> --- a/arch/x86/kvm/emulate.c
> +++ b/arch/x86/kvm/emulate.c
> @@ -1239,9 +1239,12 @@ static int decode_modrm(struct x86_emulate_ctxt *ctxt,
> ctxt->modrm_seg = VCPU_SREG_DS;
>
> if (ctxt->modrm_mod == 3) {
> + int highbyte_regs = ctxt->rex_prefix == 0;
> +
> op->type = OP_REG;
> op->bytes = (ctxt->d & ByteOp) ? 1 : ctxt->op_bytes;
> - op->addr.reg = decode_register(ctxt, ctxt->modrm_rm, ctxt->d & ByteOp);
> + op->addr.reg = decode_register(ctxt, ctxt->modrm_rm,
> + highbyte_regs && (ctxt->d & ByteOp));
> if (ctxt->d & Sse) {
> op->type = OP_XMM;
> op->bytes = 16;
>
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