From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:52162) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1c7Q0r-0007nd-0P for qemu-devel@nongnu.org; Thu, 17 Nov 2016 11:58:13 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1c7Q0m-00034E-5b for qemu-devel@nongnu.org; Thu, 17 Nov 2016 11:58:13 -0500 Received: from mail.kernel.org ([198.145.29.136]:41532) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1c7Q0m-00033j-0P for qemu-devel@nongnu.org; Thu, 17 Nov 2016 11:58:08 -0500 Date: Thu, 17 Nov 2016 18:58:01 +0200 From: "Michael S. Tsirkin" Message-ID: <20161117184955-mutt-send-email-mst@kernel.org> References: <20161116180551.9611-1-pbonzini@redhat.com> <20161116180551.9611-4-pbonzini@redhat.com> <20161116220123-mutt-send-email-mst@kernel.org> <195787138.13215853.1479328691064.JavaMail.zimbra@redhat.com> <20161116223848-mutt-send-email-mst@kernel.org> <1250949559.13223324.1479330331523.JavaMail.zimbra@redhat.com> <20161116232008-mutt-send-email-mst@kernel.org> <1913696176.64577.1479373466625.JavaMail.zimbra@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1913696176.64577.1479373466625.JavaMail.zimbra@redhat.com> Subject: Re: [Qemu-devel] [PATCH 3/3] virtio: set ISR on dataplane notifications List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Paolo Bonzini Cc: qemu-devel@nongnu.org, alex williamson , borntraeger@de.ibm.com, felipe@nutanix.com On Thu, Nov 17, 2016 at 04:04:26AM -0500, Paolo Bonzini wrote: > > > > > > /* > > > > > > * virtio spec 1.0 says ISR bit 0 should be ignored with MSI, but > > > > > > * windows drivers included in virtio-win 1.8.0 (circa 2015) > > > > > > * for Windows 8.1 only are incorrectly polling this bit during > > > > > > shutdown > > > > > ^^^^^^^^^^^^^^^^ > > > > > > > > > > Not sure it's only for Windows 8.1, in fact probably not. > > > > > > > > 8.1 on shutdown and others on crashdump or hibernation? > > > > > > Even 8.1 is really a hibernation hidden behind a "Shut down" menu item. > > > > > > Paolo > > > > what does "hang during shutdown" in your commit log refer to then? > > The full text from the commit log is: > > recent releases of > Windows do not really shut down, but rather log out and hibernate to > make the next startup faster. Hence, this manifested as a more serious > hang during shutdown with e.g. Windows 8.1 and virtio-win 1.8.0 RPMs. > > Shutdown in the commit log just means "clicking Shut down". The previous > sentence explains why. Also note the "e.g.", I've not tested other versions > of Windows. > > Paolo AFAIK the specific version of drivers did not support windows 10, and IIRC windows 7 does shutdown normally. So that only leaves windows 8 and 8.1. > > > > > Looks good if you replace this line with > > > > > > > > > > "are incorrectly polling this bit during crashdump or hibernation" ... which on windows 8 and 8.1 is activated by default through the shutdown menu > > > > > Paolo > > > > > > > > > > > * in MSI mode, causing a hang if this bit is never updated. > > > > > > * Next driver release from 2016 fixed this problem, so working > > > > > > around it > > > > > > * is not a must, but it's easy to do so let's do it here. > > > > > > * > > > > > > * Note: it's safe to update ISR from any thread as it was switched > > > > > > * to an atomic operation. > > > > > > */ > > > > >