From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH] KVM: Add reading critical region for kvm_io_bus_read/write Date: Mon, 06 Dec 2010 14:58:10 +0200 Message-ID: <4CFCDDE2.4040709@redhat.com> References: <1291625099-29152-1-git-send-email-sheng@linux.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Marcelo Tosatti , kvm@vger.kernel.org To: Sheng Yang Return-path: Received: from mx1.redhat.com ([209.132.183.28]:42492 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751254Ab0LFM6O (ORCPT ); Mon, 6 Dec 2010 07:58:14 -0500 In-Reply-To: <1291625099-29152-1-git-send-email-sheng@linux.intel.com> Sender: kvm-owner@vger.kernel.org List-ID: On 12/06/2010 10:44 AM, Sheng Yang wrote: > Seems we missed it. > > Signed-off-by: Sheng Yang > --- > Do we need this, or slot_lock covered this? > > virt/kvm/kvm_main.c | 24 ++++++++++++++++-------- > 1 files changed, 16 insertions(+), 8 deletions(-) > > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c > index c4ee364..3e71b91 100644 > --- a/virt/kvm/kvm_main.c > +++ b/virt/kvm/kvm_main.c > @@ -2228,28 +2228,36 @@ static void kvm_io_bus_destroy(struct kvm_io_bus *bus) > int kvm_io_bus_write(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr, > int len, const void *val) > { > - int i; > + int i, idx, r = -EOPNOTSUPP; > struct kvm_io_bus *bus; > > + idx = srcu_read_lock(&kvm->srcu); > bus = srcu_dereference(kvm->buses[bus_idx],&kvm->srcu); > for (i = 0; i< bus->dev_count; i++) > - if (!kvm_iodevice_write(bus->devs[i], addr, len, val)) > - return 0; > - return -EOPNOTSUPP; > + if (!kvm_iodevice_write(bus->devs[i], addr, len, val)) { > + r = 0; > + break; > + } > + srcu_read_unlock(&kvm->srcu, idx); > + return r; > } Isn't this already taken care of by srcu_read_lock() in vcpu_enter_guest(), just before calling ->handle_exit()? -- error compiling committee.c: too many arguments to function