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.
Signed-off-by: Marcelo Tosatti <[EMAIL PROTECTED]>
Index: kvm/arch/x86/kvm/x86.c
===================================================================
--- kvm.orig/arch/x86/kvm/x86.c
+++ kvm/arch/x86/kvm/x86.c
@@ -2798,6 +2798,8 @@ 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;
@@ -2820,21 +2822,13 @@ 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();
@@ -2864,9 +2858,6 @@ 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);
--
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