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authorAvi Kivity <avi@redhat.com>2012-06-07 17:03:42 +0300
committerAvi Kivity <avi@redhat.com>2012-07-09 14:19:01 +0300
commit79d5b4c3cd809c770d4bf9812635647016c56011 (patch)
tree4d79b468cc6316529e7d3753edc872c1d1cf9aec /arch/x86/kvm
parent6d6eede4a0492c7478d44d7c8fae80c3bcf529d9 (diff)
KVM: x86 emulator: allow loading null SS in long mode
Null SS is valid in long mode; allow loading it. Signed-off-by: Avi Kivity <avi@redhat.com>
Diffstat (limited to 'arch/x86/kvm')
-rw-r--r--arch/x86/kvm/emulate.c12
1 files changed, 8 insertions, 4 deletions
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index db95a55d5936..fe4340f62137 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -1324,8 +1324,14 @@ static int load_segment_descriptor(struct x86_emulate_ctxt *ctxt,
goto load;
}
- /* NULL selector is not valid for TR, CS and SS */
- if ((seg == VCPU_SREG_CS || seg == VCPU_SREG_SS || seg == VCPU_SREG_TR)
+ rpl = selector & 3;
+ cpl = ctxt->ops->cpl(ctxt);
+
+ /* NULL selector is not valid for TR, CS and SS (except for long mode) */
+ if ((seg == VCPU_SREG_CS
+ || (seg == VCPU_SREG_SS
+ && (ctxt->mode != X86EMUL_MODE_PROT64 || rpl != cpl))
+ || seg == VCPU_SREG_TR)
&& null_selector)
goto exception;
@@ -1352,9 +1358,7 @@ static int load_segment_descriptor(struct x86_emulate_ctxt *ctxt,
goto exception;
}
- rpl = selector & 3;
dpl = seg_desc.dpl;
- cpl = ctxt->ops->cpl(ctxt);
switch (seg) {
case VCPU_SREG_SS: