From: Joerg Roedel <[EMAIL PROTECTED]>
In the current inject_page_fault path KVM only checks if there is another PF
pending and injects a DF then. But it has to check for a pending DF too to
detect a shutdown condition in the VCPU. If this is not detected the VCPU goes
to a PF -> DF -> PF loop when it should triple fault. This patch detects this
condition and handles it with an KVM_SHUTDOWN exit to userspace.
Signed-off-by: Joerg Roedel <[EMAIL PROTECTED]>
Signed-off-by: Avi Kivity <[EMAIL PROTECTED]>
---
arch/x86/kvm/x86.c | 20 +++++++++++++++-----
include/linux/kvm_host.h | 1 +
2 files changed, 16 insertions(+), 5 deletions(-)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index dbcff38..491eda3 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -155,11 +155,16 @@ void kvm_inject_page_fault(struct kvm_vcpu *vcpu,
unsigned long addr,
u32 error_code)
{
++vcpu->stat.pf_guest;
- if (vcpu->arch.exception.pending && vcpu->arch.exception.nr ==
PF_VECTOR) {
- printk(KERN_DEBUG "kvm: inject_page_fault:"
- " double fault 0x%lx\n", addr);
- vcpu->arch.exception.nr = DF_VECTOR;
- vcpu->arch.exception.error_code = 0;
+ if (vcpu->arch.exception.pending) {
+ if (vcpu->arch.exception.nr == PF_VECTOR) {
+ printk(KERN_DEBUG "kvm: inject_page_fault:"
+ " double fault 0x%lx\n", addr);
+ vcpu->arch.exception.nr = DF_VECTOR;
+ vcpu->arch.exception.error_code = 0;
+ } else if (vcpu->arch.exception.nr == DF_VECTOR) {
+ /* triple fault -> shutdown */
+ set_bit(KVM_REQ_TRIPLE_FAULT, &vcpu->requests);
+ }
return;
}
vcpu->arch.cr2 = addr;
@@ -2676,6 +2681,11 @@ again:
r = 0;
goto out;
}
+ if (test_and_clear_bit(KVM_REQ_TRIPLE_FAULT, &vcpu->requests)) {
+ kvm_run->exit_reason = KVM_EXIT_SHUTDOWN;
+ r = 0;
+ goto out;
+ }
}
kvm_inject_pending_timer_irqs(vcpu);
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 9750bb3..958e003 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -38,6 +38,7 @@
#define KVM_REQ_MIGRATE_TIMER 1
#define KVM_REQ_REPORT_TPR_ACCESS 2
#define KVM_REQ_MMU_RELOAD 3
+#define KVM_REQ_TRIPLE_FAULT 4
struct kvm_vcpu;
extern struct kmem_cache *kvm_vcpu_cache;
--
1.5.4.5
-------------------------------------------------------------------------
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