| Message ID | 1412099359-5316-7-git-send-email-namit@cs.technion.ac.il (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
2014-09-30 20:49+0300, Nadav Amit: > In long-mode, when the address size is 4 bytes, the linear address is not > truncated as the emulator mistakenly does. Instead, the offset within the > segment (the ea field) should be truncated according to the address size. > > As Intel SDM says: "In 64-bit mode, the effective address components are added > and the effective address is truncated ... before adding the full 64-bit > segment base." > > Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> > --- Reviewed-by: Radim Kr?má? <rkrcmar@redhat.com> -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 4b687ff..755d703 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -624,7 +624,8 @@ static int __linearize(struct x86_emulate_ctxt *ctxt, u16 sel, error_code = 0; unsigned cpl; - la = seg_base(ctxt, addr.seg) + addr.ea; + la = seg_base(ctxt, addr.seg) + + (fetch || ctxt->ad_bytes == 8 ? addr.ea : (u32)addr.ea); switch (ctxt->mode) { case X86EMUL_MODE_PROT64: if (((signed long)la << 16) >> 16 != la) @@ -676,7 +677,7 @@ static int __linearize(struct x86_emulate_ctxt *ctxt, } break; } - if (fetch ? ctxt->mode != X86EMUL_MODE_PROT64 : ctxt->ad_bytes != 8) + if (ctxt->mode != X86EMUL_MODE_PROT64) la &= (u32)-1; if (insn_aligned(ctxt, size) && ((la & (size - 1)) != 0)) return emulate_gp(ctxt, 0);
In long-mode, when the address size is 4 bytes, the linear address is not truncated as the emulator mistakenly does. Instead, the offset within the segment (the ea field) should be truncated according to the address size. As Intel SDM says: "In 64-bit mode, the effective address components are added and the effective address is truncated ... before adding the full 64-bit segment base." Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> --- arch/x86/kvm/emulate.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)