From patchwork Mon Dec 16 10:04:50 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Denis Plotnikov X-Patchwork-Id: 1210207 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=virtuozzo.com Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 47bxl33GjQz9sP6 for ; Mon, 16 Dec 2019 21:06:55 +1100 (AEDT) Received: from localhost ([::1]:49512 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ignHB-0003sJ-A4 for incoming@patchwork.ozlabs.org; Mon, 16 Dec 2019 05:06:53 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:44643) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ignFn-0001xx-Ag for qemu-devel@nongnu.org; Mon, 16 Dec 2019 05:05:28 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ignFl-0007Ao-HR for qemu-devel@nongnu.org; Mon, 16 Dec 2019 05:05:27 -0500 Received: from relay.sw.ru ([185.231.240.75]:55874) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1ignFl-00075G-9e for qemu-devel@nongnu.org; Mon, 16 Dec 2019 05:05:25 -0500 Received: from dptest2.qa.sw.ru ([10.94.4.71]) by relay.sw.ru with esmtp (Exim 4.92.3) (envelope-from ) id 1ignFb-0001Vo-NF; Mon, 16 Dec 2019 13:05:15 +0300 From: Denis Plotnikov To: qemu-devel@nongnu.org Subject: [PATCH v4 1/2] virtio: make seg_max virtqueue size dependent Date: Mon, 16 Dec 2019 13:04:50 +0300 Message-Id: <20191216100451.28060-2-dplotnikov@virtuozzo.com> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20191216100451.28060-1-dplotnikov@virtuozzo.com> References: <20191216100451.28060-1-dplotnikov@virtuozzo.com> X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x [fuzzy] X-Received-From: 185.231.240.75 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kwolf@redhat.com, fam@euphon.net, ehabkost@redhat.com, mst@redhat.com, mreitz@redhat.com, stefanha@redhat.com, pbonzini@redhat.com, den@virtuozzo.com Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" Before the patch, seg_max parameter was immutable and hardcoded to 126 (128 - 2) without respect to queue size. This has two negative effects: 1. when queue size is < 128, we have Virtio 1.1 specfication violation: (2.6.5.3.1 Driver Requirements) seq_max must be <= queue_size. This violation affects the old Linux guests (ver < 4.14). These guests crash on these queue_size setups. 2. when queue_size > 128, as was pointed out by Denis Lunev , seg_max restrics guest's block request length which affects guests' performance making them issues more block request than needed. https://lists.gnu.org/archive/html/qemu-devel/2017-12/msg03721.html To mitigate this two effects, the patch adds the property adjusting seg_max to queue size automaticaly. Since seg_max is a guest visible parameter, the property is machine type managable and allows to choose between old (seg_max = 126 always) and new (seg_max = queue_size - 2) behaviors. Not to change the behavior of the older VMs, prevent setting the default seg_max_adjust value for older machine types. Signed-off-by: Denis Plotnikov --- hw/block/virtio-blk.c | 9 ++++++++- hw/core/machine.c | 3 +++ hw/scsi/vhost-scsi.c | 2 ++ hw/scsi/virtio-scsi.c | 10 +++++++++- include/hw/virtio/virtio-blk.h | 1 + include/hw/virtio/virtio-scsi.h | 1 + 6 files changed, 24 insertions(+), 2 deletions(-) diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c index d62e6377c2..0f6f8113b7 100644 --- a/hw/block/virtio-blk.c +++ b/hw/block/virtio-blk.c @@ -908,7 +908,8 @@ static void virtio_blk_update_config(VirtIODevice *vdev, uint8_t *config) blk_get_geometry(s->blk, &capacity); memset(&blkcfg, 0, sizeof(blkcfg)); virtio_stq_p(vdev, &blkcfg.capacity, capacity); - virtio_stl_p(vdev, &blkcfg.seg_max, 128 - 2); + virtio_stl_p(vdev, &blkcfg.seg_max, + s->conf.seg_max_adjust ? s->conf.queue_size - 2 : 128 - 2); virtio_stw_p(vdev, &blkcfg.geometry.cylinders, conf->cyls); virtio_stl_p(vdev, &blkcfg.blk_size, blk_size); virtio_stw_p(vdev, &blkcfg.min_io_size, conf->min_io_size / blk_size); @@ -1133,6 +1134,11 @@ static void virtio_blk_device_realize(DeviceState *dev, Error **errp) error_setg(errp, "num-queues property must be larger than 0"); return; } + if (conf->queue_size <= 2) { + error_setg(errp, "invalid queue-size property (%" PRIu16 "), " + "must be > 2", conf->queue_size); + return; + } if (!is_power_of_2(conf->queue_size) || conf->queue_size > VIRTQUEUE_MAX_SIZE) { error_setg(errp, "invalid queue-size property (%" PRIu16 "), " @@ -1262,6 +1268,7 @@ static Property virtio_blk_properties[] = { true), DEFINE_PROP_UINT16("num-queues", VirtIOBlock, conf.num_queues, 1), DEFINE_PROP_UINT16("queue-size", VirtIOBlock, conf.queue_size, 128), + DEFINE_PROP_BOOL("seg-max-adjust", VirtIOBlock, conf.seg_max_adjust, true), DEFINE_PROP_LINK("iothread", VirtIOBlock, conf.iothread, TYPE_IOTHREAD, IOThread *), DEFINE_PROP_BIT64("discard", VirtIOBlock, host_features, diff --git a/hw/core/machine.c b/hw/core/machine.c index 023548b4f3..bfa320387e 100644 --- a/hw/core/machine.c +++ b/hw/core/machine.c @@ -29,6 +29,9 @@ GlobalProperty hw_compat_4_2[] = { { "virtio-blk-device", "x-enable-wce-if-config-wce", "off" }, + { "virtio-blk-device", "seg-max-adjust", "off"}, + { "virtio-scsi-device", "seg_max_adjust", "off"}, + { "vhost-blk-device", "seg_max_adjust", "off"}, }; const size_t hw_compat_4_2_len = G_N_ELEMENTS(hw_compat_4_2); diff --git a/hw/scsi/vhost-scsi.c b/hw/scsi/vhost-scsi.c index c693fc748a..26f710d3ec 100644 --- a/hw/scsi/vhost-scsi.c +++ b/hw/scsi/vhost-scsi.c @@ -275,6 +275,8 @@ static Property vhost_scsi_properties[] = { DEFINE_PROP_UINT32("num_queues", VirtIOSCSICommon, conf.num_queues, 1), DEFINE_PROP_UINT32("virtqueue_size", VirtIOSCSICommon, conf.virtqueue_size, 128), + DEFINE_PROP_BOOL("seg_max_adjust", VirtIOSCSICommon, conf.seg_max_adjust, + true), DEFINE_PROP_UINT32("max_sectors", VirtIOSCSICommon, conf.max_sectors, 0xFFFF), DEFINE_PROP_UINT32("cmd_per_lun", VirtIOSCSICommon, conf.cmd_per_lun, 128), diff --git a/hw/scsi/virtio-scsi.c b/hw/scsi/virtio-scsi.c index e8b2b64d09..405cb6c953 100644 --- a/hw/scsi/virtio-scsi.c +++ b/hw/scsi/virtio-scsi.c @@ -654,7 +654,8 @@ static void virtio_scsi_get_config(VirtIODevice *vdev, VirtIOSCSICommon *s = VIRTIO_SCSI_COMMON(vdev); virtio_stl_p(vdev, &scsiconf->num_queues, s->conf.num_queues); - virtio_stl_p(vdev, &scsiconf->seg_max, 128 - 2); + virtio_stl_p(vdev, &scsiconf->seg_max, + s->conf.seg_max_adjust ? s->conf.virtqueue_size - 2 : 128 - 2); virtio_stl_p(vdev, &scsiconf->max_sectors, s->conf.max_sectors); virtio_stl_p(vdev, &scsiconf->cmd_per_lun, s->conf.cmd_per_lun); virtio_stl_p(vdev, &scsiconf->event_info_size, sizeof(VirtIOSCSIEvent)); @@ -893,6 +894,11 @@ void virtio_scsi_common_realize(DeviceState *dev, virtio_cleanup(vdev); return; } + if (s->conf.virtqueue_size <= 2) { + error_setg(errp, "invalid virtqueue_size property (= %" PRIu16 "), " + "must be > 2", s->conf.virtqueue_size); + return; + } s->cmd_vqs = g_new0(VirtQueue *, s->conf.num_queues); s->sense_size = VIRTIO_SCSI_SENSE_DEFAULT_SIZE; s->cdb_size = VIRTIO_SCSI_CDB_DEFAULT_SIZE; @@ -949,6 +955,8 @@ static Property virtio_scsi_properties[] = { DEFINE_PROP_UINT32("num_queues", VirtIOSCSI, parent_obj.conf.num_queues, 1), DEFINE_PROP_UINT32("virtqueue_size", VirtIOSCSI, parent_obj.conf.virtqueue_size, 128), + DEFINE_PROP_BOOL("seg_max_adjust", VirtIOSCSI, + parent_obj.conf.seg_max_adjust, true), DEFINE_PROP_UINT32("max_sectors", VirtIOSCSI, parent_obj.conf.max_sectors, 0xFFFF), DEFINE_PROP_UINT32("cmd_per_lun", VirtIOSCSI, parent_obj.conf.cmd_per_lun, diff --git a/include/hw/virtio/virtio-blk.h b/include/hw/virtio/virtio-blk.h index 9c19f5b634..1e62f869b2 100644 --- a/include/hw/virtio/virtio-blk.h +++ b/include/hw/virtio/virtio-blk.h @@ -38,6 +38,7 @@ struct VirtIOBlkConf uint32_t request_merging; uint16_t num_queues; uint16_t queue_size; + bool seg_max_adjust; uint32_t max_discard_sectors; uint32_t max_write_zeroes_sectors; bool x_enable_wce_if_config_wce; diff --git a/include/hw/virtio/virtio-scsi.h b/include/hw/virtio/virtio-scsi.h index 122f7c4b6f..24e768909d 100644 --- a/include/hw/virtio/virtio-scsi.h +++ b/include/hw/virtio/virtio-scsi.h @@ -48,6 +48,7 @@ typedef struct virtio_scsi_config VirtIOSCSIConfig; struct VirtIOSCSIConf { uint32_t num_queues; uint32_t virtqueue_size; + bool seg_max_adjust; uint32_t max_sectors; uint32_t cmd_per_lun; #ifdef CONFIG_VHOST_SCSI