From: Avi Kivity <avi@redhat.com>
Date: Tue, 21 Aug 2012 14:07:01 +0000 (+0300)
Subject: KVM: VMX: Retain limit and attributes when entering protected mode
X-Git-Tag: firefly_0821_release~3680^2~1917^2~36
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=c865c43de66dc973865bda337022f03b6e16c8df;p=firefly-linux-kernel-4.4.55.git

KVM: VMX: Retain limit and attributes when entering protected mode

Real processors don't change segment limits and attributes while in
real mode.  Mimic that behaviour.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
---

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 7e95ff68b9da..88eeb405560f 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -2696,14 +2696,14 @@ static __exit void hardware_unsetup(void)
 static void fix_pmode_dataseg(struct kvm_vcpu *vcpu, int seg, struct kvm_segment *save)
 {
 	struct kvm_vmx_segment_field *sf = &kvm_vmx_segment_fields[seg];
+	struct kvm_segment tmp = *save;
 
-	if (vmcs_readl(sf->base) == save->base && save->s) {
-		vmx_set_segment(vcpu, save, seg);
-	} else {
-		u32 dpl = (vmcs_read16(sf->selector) & SELECTOR_RPL_MASK)
-			<< AR_DPL_SHIFT;
-		vmcs_write32(sf->ar_bytes, 0x93 | dpl);
+	if (!(vmcs_readl(sf->base) == tmp.base && tmp.s)) {
+		tmp.base = vmcs_readl(sf->base);
+		tmp.selector = vmcs_read16(sf->selector);
+		tmp.s = 1;
 	}
+	vmx_set_segment(vcpu, &tmp, seg);
 }
 
 static void enter_pmode(struct kvm_vcpu *vcpu)