On 22/03/2018 09:34, Wanpeng Li wrote:
> From: Wanpeng Li <wanpengli@xxxxxxxxxxx>
>
> Explicit segment overides other than %fs and %gs are documented as ignored by
> both Intel and AMD.
>
> In practice, this means that:
>
> * Explicit uses of %ss don't actually yield #SS[0] for non-canonical
> memory references.
> * Explicit uses of %{e,c,d}s don't override %rbp/%rsp-based memory references
> to yield #GP[0] for non-canonical memory references.
>
> Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
> Cc: Radim Krčmář <rkrcmar@xxxxxxxxxx>
> Signed-off-by: Wanpeng Li <wanpengli@xxxxxxxxxxx>
> ---
> arch/x86/kvm/emulate.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
> index dd88158..5091255 100644
> --- a/arch/x86/kvm/emulate.c
> +++ b/arch/x86/kvm/emulate.c
> @@ -5148,8 +5148,10 @@ int x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len)
> case 0x2e: /* CS override */
> case 0x36: /* SS override */
> case 0x3e: /* DS override */
> - has_seg_override = true;
> - ctxt->seg_override = (ctxt->b >> 3) & 3;
> + if (mode != X86EMUL_MODE_PROT64) {
> + has_seg_override = true;
> + ctxt->seg_override = (ctxt->b >> 3) & 3;
> + }
> break;
> case 0x64: /* FS override */
> case 0x65: /* GS override */
>
Testcase, please...
Paolo
