Messages in this thread | | | Subject | Re: [PATCH] KVM: X86: Fix the decoding of segment overrides in 64bit mode | From | Paolo Bonzini <> | Date | Thu, 22 Mar 2018 11:07:08 +0100 |
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On 22/03/2018 09:34, Wanpeng Li wrote: > From: Wanpeng Li <wanpengli@tencent.com> > > 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@redhat.com> > Cc: Radim Krčmář <rkrcmar@redhat.com> > Signed-off-by: Wanpeng Li <wanpengli@tencent.com> > --- > 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
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