From 7e66f350cfc853043bfa71b281581dd6f92fa347 Mon Sep 17 00:00:00 2001 From: Avi Kivity Date: Wed, 15 Aug 2007 15:23:34 +0300 Subject: [PATCH] KVM: Close minor race in signal handling We need to check for signals inside the critical section, otherwise a signal can be sent which we will not notice. Also move the check before entry, so that if the signal happens before the first entry, we exit immediately instead of waiting for something to happen to the guest. Signed-off-by: Avi Kivity --- drivers/kvm/svm.c | 19 ++++++++++--------- drivers/kvm/vmx.c | 23 ++++++++++++----------- 2 files changed, 22 insertions(+), 20 deletions(-) diff --git a/drivers/kvm/svm.c b/drivers/kvm/svm.c index e3c6d89..cc674bf 100644 --- a/drivers/kvm/svm.c +++ b/drivers/kvm/svm.c @@ -1398,11 +1398,19 @@ again: if (unlikely(r)) return r; + clgi(); + + if (signal_pending(current)) { + stgi(); + ++vcpu->stat.signal_exits; + post_kvm_run_save(svm, kvm_run); + kvm_run->exit_reason = KVM_EXIT_INTR; + return -EINTR; + } + if (!vcpu->mmio_read_completed) do_interrupt_requests(svm, kvm_run); - clgi(); - vcpu->guest_mode = 1; if (vcpu->requests) if (test_and_clear_bit(KVM_TLB_FLUSH, &vcpu->requests)) @@ -1582,13 +1590,6 @@ again: r = handle_exit(svm, kvm_run); if (r > 0) { - if (signal_pending(current)) { - ++vcpu->stat.signal_exits; - post_kvm_run_save(svm, kvm_run); - kvm_run->exit_reason = KVM_EXIT_INTR; - return -EINTR; - } - if (dm_request_for_irq_injection(svm, kvm_run)) { ++vcpu->stat.request_irq_exits; post_kvm_run_save(svm, kvm_run); diff --git a/drivers/kvm/vmx.c b/drivers/kvm/vmx.c index 906d4fa..a9b4cb5 100644 --- a/drivers/kvm/vmx.c +++ b/drivers/kvm/vmx.c @@ -2066,9 +2066,6 @@ again: preempt_disable(); - if (!vcpu->mmio_read_completed) - do_interrupt_requests(vcpu, kvm_run); - vmx_save_host_state(vmx); kvm_load_guest_fpu(vcpu); @@ -2079,6 +2076,18 @@ again: local_irq_disable(); + if (signal_pending(current)) { + local_irq_enable(); + preempt_enable(); + r = -EINTR; + kvm_run->exit_reason = KVM_EXIT_INTR; + ++vcpu->stat.signal_exits; + goto out; + } + + if (!vcpu->mmio_read_completed) + do_interrupt_requests(vcpu, kvm_run); + vcpu->guest_mode = 1; if (vcpu->requests) if (test_and_clear_bit(KVM_TLB_FLUSH, &vcpu->requests)) @@ -2227,14 +2236,6 @@ again: r = kvm_handle_exit(kvm_run, vcpu); if (r > 0) { - /* Give scheduler a change to reschedule. */ - if (signal_pending(current)) { - r = -EINTR; - kvm_run->exit_reason = KVM_EXIT_INTR; - ++vcpu->stat.signal_exits; - goto out; - } - if (dm_request_for_irq_injection(vcpu, kvm_run)) { r = -EINTR; kvm_run->exit_reason = KVM_EXIT_INTR; -- 2.7.4