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authorGleb Natapov <gleb@redhat.com>2012-12-20 16:57:44 +0200
committerMarcelo Tosatti <mtosatti@redhat.com>2013-01-02 19:36:28 -0200
commit89efbed02cfd7e9ce3324de0b44a70ee1c716fac (patch)
tree52e8a8121405ef85d4a8da53b9888a8de9419968
parent045a282ca41505184e8fc805335d1f5aae0c8a03 (diff)
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>
-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;