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KVM: detect if VCPU triple faults

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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 <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
This commit is contained in:
Joerg Roedel 2008-02-26 16:49:16 +01:00 committed by Avi Kivity
parent 3e4bb3ac9e
commit 71c4dfafc0
2 changed files with 16 additions and 5 deletions
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20
arch/x86/kvm/x86.c
View File

@ -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);

1
include/linux/kvm_host.h
View File

@ -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;