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authorGleb Natapov2012-12-20 15:57:44 +0100
committerMarcelo Tosatti2013-01-02 22:36:28 +0100
commit89efbed02cfd7e9ce3324de0b44a70ee1c716fac (patch)
tree52e8a8121405ef85d4a8da53b9888a8de9419968 /arch/x86/kvm/vmx.c
parentKVM: emulator: implement fninit, fnstsw, fnstcw (diff)
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KVM: VMX: make rmode_segment_valid() more strict.
Currently it allows entering vm86 mode if segment limit is greater than 0xffff and db bit is set. Both of those can cause incorrect execution of instruction by cpu since in vm86 mode limit will be set to 0xffff and db will be forced to 0. Signed-off-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Diffstat (limited to 'arch/x86/kvm/vmx.c')
-rw-r--r--arch/x86/kvm/vmx.c4
1 files changed, 1 insertions, 3 deletions
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 23d5aec78073..7ebcac25725b 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -3341,15 +3341,13 @@ static bool rmode_segment_valid(struct kvm_vcpu *vcpu, int seg)
vmx_get_segment(vcpu, &var, seg);
var.dpl = 0x3;
- var.g = 0;
- var.db = 0;
if (seg == VCPU_SREG_CS)
var.type = 0x3;
ar = vmx_segment_access_rights(&var);
if (var.base != (var.selector << 4))
return false;
- if (var.limit < 0xffff)
+ if (var.limit != 0xffff)
return false;
if (ar != 0xf3)
return false;