aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorAvi Kivity <avi@qumranet.com>2007-05-07 10:55:37 +0300
committerAvi Kivity <avi@qumranet.com>2007-07-16 12:05:41 +0300
commit653e3108b7d6097d25089d25ab4e99bc58b28962 (patch)
treeff92977a15ddf12807d3a9f32eb6f5446fb59a79
parenteff708bc2bacd4f22cf844871341bef341bd096a (diff)
KVM: Avoid corrupting tr in real mode
The real mode tr needs to be set to a specific tss so that I/O instructions can function. Divert the new tr values to the real mode save area from where they will be restored on transition to protected mode. This fixes some crashes on reboot when the bios accesses an I/O instruction. Signed-off-by: Avi Kivity <avi@qumranet.com>
-rw-r--r--drivers/kvm/vmx.c45
1 files changed, 31 insertions, 14 deletions
diff --git a/drivers/kvm/vmx.c b/drivers/kvm/vmx.c
index b353eaa0a44..e39ebe0b695 100644
--- a/drivers/kvm/vmx.c
+++ b/drivers/kvm/vmx.c
@@ -1042,23 +1042,11 @@ static void vmx_get_segment(struct kvm_vcpu *vcpu,
var->unusable = (ar >> 16) & 1;
}
-static void vmx_set_segment(struct kvm_vcpu *vcpu,
- struct kvm_segment *var, int seg)
+static u32 vmx_segment_access_rights(struct kvm_segment *var)
{
- struct kvm_vmx_segment_field *sf = &kvm_vmx_segment_fields[seg];
u32 ar;
- vmcs_writel(sf->base, var->base);
- vmcs_write32(sf->limit, var->limit);
- vmcs_write16(sf->selector, var->selector);
- if (vcpu->rmode.active && var->s) {
- /*
- * Hack real-mode segments into vm86 compatibility.
- */
- if (var->base == 0xffff0000 && var->selector == 0xf000)
- vmcs_writel(sf->base, 0xf0000);
- ar = 0xf3;
- } else if (var->unusable)
+ if (var->unusable)
ar = 1 << 16;
else {
ar = var->type & 15;
@@ -1072,6 +1060,35 @@ static void vmx_set_segment(struct kvm_vcpu *vcpu,
}
if (ar == 0) /* a 0 value means unusable */
ar = AR_UNUSABLE_MASK;
+
+ return ar;
+}
+
+static void vmx_set_segment(struct kvm_vcpu *vcpu,
+ struct kvm_segment *var, int seg)
+{
+ struct kvm_vmx_segment_field *sf = &kvm_vmx_segment_fields[seg];
+ u32 ar;
+
+ if (vcpu->rmode.active && seg == VCPU_SREG_TR) {
+ vcpu->rmode.tr.selector = var->selector;
+ vcpu->rmode.tr.base = var->base;
+ vcpu->rmode.tr.limit = var->limit;
+ vcpu->rmode.tr.ar = vmx_segment_access_rights(var);
+ return;
+ }
+ vmcs_writel(sf->base, var->base);
+ vmcs_write32(sf->limit, var->limit);
+ vmcs_write16(sf->selector, var->selector);
+ if (vcpu->rmode.active && var->s) {
+ /*
+ * Hack real-mode segments into vm86 compatibility.
+ */
+ if (var->base == 0xffff0000 && var->selector == 0xf000)
+ vmcs_writel(sf->base, 0xf0000);
+ ar = 0xf3;
+ } else
+ ar = vmx_segment_access_rights(var);
vmcs_write32(sf->ar_bytes, ar);
}