Messages in this thread Patch in this message | | | From | Wanpeng Li <> | Subject | [PATCH] KVM: X86: Fix the decoding of segment overrides in 64bit mode | Date | Thu, 22 Mar 2018 16:34:11 +0800 |
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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 */ -- 2.7.4
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