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@xxxxxxxxxx> --- arch/x86/kvm/vmx.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 23d5aec..7ebcac2 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; -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
