[PATCH] KVM: emulator: fix error code for __linearize

From: Paolo Bonzini
Date: Mon Oct 27 2014 - 10:32:00 EST


The error code for #GP and #SS is zero when the segment is used to
access an operand or an instruction. It is only non-zero when
a segment register is being loaded; for limit checks this means
cases such as:

* for #GP, when RIP is beyond the limit on a far call (before the first
instruction is executed). We do not implement this check, but it
would be in em_jmp_far/em_call_far.

* for #SS, if the new stack overflows during an inter-privilege-level
call to a non-conforming code segment. We do not implement stack
switching at all.

So use an error code of zero.

Cc: Nadav Amit <namit@xxxxxxxxxxxxxxxxx>
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
---
arch/x86/kvm/emulate.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 749f9fa38254..8aa66068712f 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -711,9 +711,9 @@ static int __linearize(struct x86_emulate_ctxt *ctxt,
return X86EMUL_CONTINUE;
bad:
if (addr.seg == VCPU_SREG_SS)
- return emulate_ss(ctxt, sel);
+ return emulate_ss(ctxt, 0);
else
- return emulate_gp(ctxt, sel);
+ return emulate_gp(ctxt, 0);
}

static int linearize(struct x86_emulate_ctxt *ctxt,
--
1.8.3.1

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