From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joerg Roedel Subject: [PATCH] kvm/x86: check KVM_REQ_TLB_FLUSH with irqs disabled Date: Mon, 16 Mar 2009 14:03:45 +0100 Message-ID: <1237208625-2657-1-git-send-email-joerg.roedel@amd.com> Mime-Version: 1.0 Content-Type: text/plain Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Joerg Roedel To: Avi Kivity , Marcelo Tosatti Return-path: Received: from va3ehsobe003.messaging.microsoft.com ([216.32.180.13]:34434 "EHLO VA3EHSOBE003.bigfish.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1756566AbZCPNEI (ORCPT ); Mon, 16 Mar 2009 09:04:08 -0400 Sender: kvm-owner@vger.kernel.org List-ID: For KVM remote TLB flushes we need to check the KVM_REQ_TLB_FLUSH request flag when the irqs are already disabled. Otherwise there is a small window of time for a race condition where we may enter a guest without doing a requested TLB flush. Signed-off-by: Joerg Roedel --- arch/x86/kvm/x86.c | 5 +++-- 1 files changed, 3 insertions(+), 2 deletions(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index b556b6a..301660a 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -3108,8 +3108,6 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run) kvm_write_guest_time(vcpu); if (test_and_clear_bit(KVM_REQ_MMU_SYNC, &vcpu->requests)) kvm_mmu_sync_roots(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; @@ -3133,6 +3131,9 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run) local_irq_disable(); + if (test_and_clear_bit(KVM_REQ_TLB_FLUSH, &vcpu->requests)) + kvm_x86_ops->tlb_flush(vcpu); + if (vcpu->requests || need_resched() || signal_pending(current)) { local_irq_enable(); preempt_enable(); -- 1.5.6.4