From 0647f4aa8c58a7e5adb873b485c83e0c93d9c6d1 Mon Sep 17 00:00:00 2001 From: Gleb Natapov Date: Wed, 12 Dec 2012 19:10:50 +0200 Subject: [PATCH] KVM: VMX: relax check for CS register in rmode_segment_valid() rmode_segment_valid() checks if segment descriptor can be used to enter vm86 mode. VMX spec mandates that in vm86 mode CS register will be of type data, not code. Lets allow guest entry with vm86 mode if the only problem with CS register is incorrect type. Otherwise entire real mode will be emulated. Reviewed-by: Marcelo Tosatti Signed-off-by: Gleb Natapov --- arch/x86/kvm/vmx.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 265fdd3..7c2c054 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -3383,6 +3383,8 @@ static bool rmode_segment_valid(struct kvm_vcpu *vcpu, int 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)) -- 2.7.4