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| author | Marcelo Tosatti <mtosatti@redhat.com> | 2008-06-06 16:37:35 -0300 |
|---|---|---|
| committer | Avi Kivity <avi@qumranet.com> | 2008-06-24 12:16:52 +0300 |
| commit | d4acf7e7abe45457e751525a2a4d5b693dfdd597 (patch) | |
| tree | 2ff1cf6f59b0591ea39c0457705188d5f46cb118 | |
| parent | 62786b9e81a2dbe9c073a2ade52d33a2627d6d85 (diff) | |
| download | linux-d4acf7e7abe45457e751525a2a4d5b693dfdd597.tar.gz linux-d4acf7e7abe45457e751525a2a4d5b693dfdd597.tar.bz2 linux-d4acf7e7abe45457e751525a2a4d5b693dfdd597.zip | |
KVM: Fix race between timer migration and vcpu migration
A guest vcpu instance can be scheduled to a different physical CPU
between the test for KVM_REQ_MIGRATE_TIMER and local_irq_disable().
If that happens, the timer will only be migrated to the current pCPU on
the next exit, meaning that guest LAPIC timer event can be delayed until
a host interrupt is triggered.
Fix it by cancelling guest entry if any vcpu request is pending. This
has the side effect of nicely consolidating vcpu->requests checks.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
| -rw-r--r-- | arch/x86/kvm/x86.c | 15 |
1 files changed, 3 insertions, 12 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 00acf1301a15..b90744a1dc3a 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -2759,6 +2759,8 @@ again: if (vcpu->requests) { if (test_and_clear_bit(KVM_REQ_MIGRATE_TIMER, &vcpu->requests)) __kvm_migrate_timers(vcpu); + if (test_and_clear_bit(KVM_REQ_TLB_FLUSH, &vcpu->requests)) + kvm_x86_ops->tlb_flush(vcpu); if (test_and_clear_bit(KVM_REQ_REPORT_TPR_ACCESS, &vcpu->requests)) { kvm_run->exit_reason = KVM_EXIT_TPR_ACCESS; @@ -2781,21 +2783,13 @@ again: local_irq_disable(); - if (need_resched()) { + if (vcpu->requests || need_resched()) { local_irq_enable(); preempt_enable(); r = 1; goto out; } - if (vcpu->requests) - if (test_bit(KVM_REQ_MMU_RELOAD, &vcpu->requests)) { - local_irq_enable(); - preempt_enable(); - r = 1; - goto out; - } - if (signal_pending(current)) { local_irq_enable(); preempt_enable(); @@ -2825,9 +2819,6 @@ again: kvm_guest_enter(); - if (vcpu->requests) - if (test_and_clear_bit(KVM_REQ_TLB_FLUSH, &vcpu->requests)) - kvm_x86_ops->tlb_flush(vcpu); KVMTRACE_0D(VMENTRY, vcpu, entryexit); kvm_x86_ops->run(vcpu, kvm_run); |