From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: [PATCHv2 rfc] kvm: get rid of srcu idx Date: Mon, 25 Oct 2010 08:48:05 +0200 Message-ID: <20101025064805.GA4256@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Avi Kivity , Marcelo Tosatti , kvm@vger.kernel.org To: unlisted-recipients:; (no To-header on input) Return-path: Received: from mx1.redhat.com ([209.132.183.28]:57293 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751171Ab0JYGyo (ORCPT ); Mon, 25 Oct 2010 02:54:44 -0400 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) by mx1.redhat.com (8.13.8/8.13.8) with ESMTP id o9P6siIX001137 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Mon, 25 Oct 2010 02:54:44 -0400 Content-Disposition: inline Sender: kvm-owner@vger.kernel.org List-ID: srcu_idx is easy to misuse as it can not be used in nested srcu_read_lock calls. Switch to local index to make correctness easier to verify. Signed-off-by: Michael S. Tsirkin --- This version is rebased to 2.6.36. arch/x86/kvm/x86.c | 26 +++++++++++++------------- 1 files changed, 13 insertions(+), 13 deletions(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 4ca1d7f..fe8960d 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -4672,7 +4672,7 @@ static void kvm_put_guest_xcr0(struct kvm_vcpu *vcpu) } } -static int vcpu_enter_guest(struct kvm_vcpu *vcpu) +static int vcpu_enter_guest(struct kvm_vcpu *vcpu, int *srcu_idx) { int r; bool req_int_win = !irqchip_in_kernel(vcpu->kvm) && @@ -4744,7 +4744,7 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) kvm_lapic_sync_to_vapic(vcpu); } - srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx); + srcu_read_unlock(&vcpu->kvm->srcu, *srcu_idx); kvm_guest_enter(); @@ -4787,7 +4787,7 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) preempt_enable(); - vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu); + *srcu_idx = srcu_read_lock(&vcpu->kvm->srcu); /* * Profile KVM exit RIPs: @@ -4808,7 +4808,7 @@ out: static int __vcpu_run(struct kvm_vcpu *vcpu) { - int r; + int srcu_idx, r; struct kvm *kvm = vcpu->kvm; if (unlikely(vcpu->arch.mp_state == KVM_MP_STATE_SIPI_RECEIVED)) { @@ -4821,17 +4821,17 @@ static int __vcpu_run(struct kvm_vcpu *vcpu) vcpu->arch.mp_state = KVM_MP_STATE_RUNNABLE; } - vcpu->srcu_idx = srcu_read_lock(&kvm->srcu); + srcu_idx = srcu_read_lock(&kvm->srcu); vapic_enter(vcpu); r = 1; while (r > 0) { if (vcpu->arch.mp_state == KVM_MP_STATE_RUNNABLE) - r = vcpu_enter_guest(vcpu); + r = vcpu_enter_guest(vcpu, &srcu_idx); else { - srcu_read_unlock(&kvm->srcu, vcpu->srcu_idx); + srcu_read_unlock(&kvm->srcu, srcu_idx); kvm_vcpu_block(vcpu); - vcpu->srcu_idx = srcu_read_lock(&kvm->srcu); + srcu_idx = srcu_read_lock(&kvm->srcu); if (kvm_check_request(KVM_REQ_UNHALT, vcpu)) { switch(vcpu->arch.mp_state) { @@ -4866,13 +4866,13 @@ static int __vcpu_run(struct kvm_vcpu *vcpu) ++vcpu->stat.signal_exits; } if (need_resched()) { - srcu_read_unlock(&kvm->srcu, vcpu->srcu_idx); + srcu_read_unlock(&kvm->srcu, srcu_idx); kvm_resched(vcpu); - vcpu->srcu_idx = srcu_read_lock(&kvm->srcu); + srcu_idx = srcu_read_lock(&kvm->srcu); } } - srcu_read_unlock(&kvm->srcu, vcpu->srcu_idx); + srcu_read_unlock(&kvm->srcu, srcu_idx); vapic_exit(vcpu); @@ -4905,9 +4905,9 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run) vcpu->mmio_read_completed = 1; vcpu->mmio_needed = 0; } - vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu); + srcu_idx = srcu_read_lock(&vcpu->kvm->srcu); r = emulate_instruction(vcpu, 0, 0, EMULTYPE_NO_DECODE); - srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx); + srcu_read_unlock(&vcpu->kvm->srcu, srcu_idx); if (r != EMULATE_DONE) { r = 0; goto out; -- 1.7.3-rc1