From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:45568) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WYHs7-0001lP-Et for qemu-devel@nongnu.org; Thu, 10 Apr 2014 12:30:44 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WYHry-0000XT-Nu for qemu-devel@nongnu.org; Thu, 10 Apr 2014 12:30:39 -0400 Received: from isrv.corpit.ru ([86.62.121.231]:38212) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WYHry-0000WY-8J for qemu-devel@nongnu.org; Thu, 10 Apr 2014 12:30:30 -0400 Message-ID: <5346C71D.6070606@msgid.tls.msk.ru> Date: Thu, 10 Apr 2014 20:30:21 +0400 From: Michael Tokarev MIME-Version: 1.0 References: <20140409032106.GA5163@sergelap> In-Reply-To: <20140409032106.GA5163@sergelap> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 1/1] kvm_physical_sync_dirty_bitmap: ignore ENOENT from kvm_vm_ioctl List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Serge Hallyn Cc: qemu-devel@nongnu.org, 1303926@bugs.launchpad.net, Mario Smarduch 09.04.2014 07:21, Serge Hallyn wrote: > ENOENT (iiuc) means the kernel has an empty dirty bitmap for this > slot. Don't abort in that case. This appears to solve the bug > reported at > > https://bugs.launchpad.net/ubuntu/+source/qemu/+bug/1303926 > > which first showed up with commit b533f658a98325d: fix return check for > KVM_GET_DIRTY_LOG ioctl > > Signed-off-by: Serge Hallyn > --- > kvm-all.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/kvm-all.c b/kvm-all.c > index 82a9119..7b7ea8d 100644 > --- a/kvm-all.c > +++ b/kvm-all.c > @@ -441,10 +441,13 @@ static int kvm_physical_sync_dirty_bitmap(MemoryRegionSection *section) > > d.slot = mem->slot; > > - if (kvm_vm_ioctl(s, KVM_GET_DIRTY_LOG, &d) == -1) { > + ret = kvm_vm_ioctl(s, KVM_GET_DIRTY_LOG, &d); > + if (ret < 0 && ret != -ENOENT) { > DPRINTF("ioctl failed %d\n", errno); > ret = -1; > break; > + } else if (ret < 0) { > + ret = 0; > } > > kvm_get_dirty_pages_log_range(section, d.dirty_bitmap); Should we omit calling kvm_get_dirty_pages_log_range() if there's no bitmap from kernel? In particular, do we trust kernel to not touch d.dirty_bitmap when it returns ENOENT? Thanks, /mjt