From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:43269) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dmiHO-00030D-69 for qemu-devel@nongnu.org; Tue, 29 Aug 2017 11:18:15 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dmiHN-0006HZ-6Q for qemu-devel@nongnu.org; Tue, 29 Aug 2017 11:18:14 -0400 Received: from mail-vk0-x241.google.com ([2607:f8b0:400c:c05::241]:37638) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1dmiHN-0006HR-0Z for qemu-devel@nongnu.org; Tue, 29 Aug 2017 11:18:13 -0400 Received: by mail-vk0-x241.google.com with SMTP id z187so1436693vkd.4 for ; Tue, 29 Aug 2017 08:18:12 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <20170829180900-mutt-send-email-mst@kernel.org> References: <20170829144805.28872-1-marcandre.lureau@redhat.com> <20170829144805.28872-2-marcandre.lureau@redhat.com> <20170829175820-mutt-send-email-mst@kernel.org> <20170829180900-mutt-send-email-mst@kernel.org> From: =?UTF-8?B?TWFyYy1BbmRyw6kgTHVyZWF1?= Date: Tue, 29 Aug 2017 17:18:11 +0200 Message-ID: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [PATCH 1/2] libvhost-user: support resuming vq->last_avail_idx based on used_idx List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Michael S. Tsirkin" Cc: Victor Kaplansky , QEMU Hi On Tue, Aug 29, 2017 at 5:09 PM, Michael S. Tsirkin wrote: > On Tue, Aug 29, 2017 at 05:04:34PM +0200, Marc-Andr=C3=A9 Lureau wrote: >> Hi >> >> On Tue, Aug 29, 2017 at 5:01 PM, Michael S. Tsirkin wro= te: >> > On Tue, Aug 29, 2017 at 04:48:04PM +0200, Marc-Andr=C3=A9 Lureau wrote= : >> >> This is the same workaround as commit 523b018dde3b765, which was lost >> >> with libvhost-user transition in commit e10e798c85c2331. >> >> >> >> Signed-off-by: Marc-Andr=C3=A9 Lureau >> >> --- >> >> contrib/libvhost-user/libvhost-user.h | 5 +++++ >> >> contrib/libvhost-user/libvhost-user.c | 13 +++++++++++++ >> >> 2 files changed, 18 insertions(+) >> >> >> >> diff --git a/contrib/libvhost-user/libvhost-user.h b/contrib/libvhost= -user/libvhost-user.h >> >> index 53ef222c0b..aca71717c1 100644 >> >> --- a/contrib/libvhost-user/libvhost-user.h >> >> +++ b/contrib/libvhost-user/libvhost-user.h >> >> @@ -132,6 +132,7 @@ typedef void (*vu_set_features_cb) (VuDev *dev, u= int64_t features); >> >> typedef int (*vu_process_msg_cb) (VuDev *dev, VhostUserMsg *vmsg, >> >> int *do_reply); >> >> typedef void (*vu_queue_set_started_cb) (VuDev *dev, int qidx, bool = started); >> >> +typedef bool (*vu_queue_resume_to_used_cb) (VuDev *dev, int qidx); >> >> >> >> typedef struct VuDevIface { >> >> /* called by VHOST_USER_GET_FEATURES to get the features bitmask= */ >> >> @@ -148,6 +149,10 @@ typedef struct VuDevIface { >> >> vu_process_msg_cb process_msg; >> >> /* tells when queues can be processed */ >> >> vu_queue_set_started_cb queue_set_started; >> >> + /* If the queue must be resumed to vring.used->idx. */ >> >> + /* This can help to support resuming on unmanaged exit/crash whe= n >> >> + * the slave/driver processes elements in order. */ >> >> + vu_queue_resume_to_used_cb queue_resume_to_used; >> >> } VuDevIface; >> >> >> >> typedef void (*vu_queue_handler_cb) (VuDev *dev, int qidx); >> > >> > Let's consider: this is only safe if queue is processed in order. >> > So I think that would be a better name for the field. >> > >> That's what the comment say already :) >> >> Which name do you suggest? vu_queue_is_processed_in_order? > > Something like this. > >> Does that >> imply it should always resume? > > Not sure I understand the question. If a "queue_is_processed_in_order", does that imply libvhost-user should always resume it based on used_idx? I think it does, but the correlation is less obvious than explicitly saying "resume_to_used". --=20 Marc-Andr=C3=A9 Lureau