From 5f2585772fff7ada93cb6691c51603451228a09c Mon Sep 17 00:00:00 2001 From: Evgeny Yakovlev Date: Tue, 5 Nov 2019 21:22:17 +0300 Subject: virtio-blk: advertise F_WCE (F_FLUSH) if F_CONFIG_WCE is advertised Virtio spec 1.1 (and earlier), 5.2.5.2 Driver Requirements: Device Initialization: "Devices SHOULD always offer VIRTIO_BLK_F_FLUSH, and MUST offer it if they offer VIRTIO_BLK_F_CONFIG_WCE" Currently F_CONFIG_WCE and F_WCE are not connected to each other. Qemu will advertise F_CONFIG_WCE if config-wce argument is set for virtio-blk device. And F_WCE is advertised only if underlying block backend actually has it's caching enabled. Fix this by advertising F_WCE if F_CONFIG_WCE is also advertised. To preserve backwards compatibility with newer machine types make this behaviour governed by "x-enable-wce-if-config-wce" virtio-blk-device property and introduce hw_compat_4_2 with new property being off by default for all machine types <= 4.2 (but don't introduce 4.3 machine type itself yet). Signed-off-by: Evgeny Yakovlev Message-Id: <1572978137-189218-1-git-send-email-wrfsh@yandex-team.ru> Signed-off-by: Stefan Hajnoczi --- hw/block/virtio-blk.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'hw/block/virtio-blk.c') diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c index 4c357d2928..d62e6377c2 100644 --- a/hw/block/virtio-blk.c +++ b/hw/block/virtio-blk.c @@ -991,7 +991,9 @@ static uint64_t virtio_blk_get_features(VirtIODevice *vdev, uint64_t features, virtio_add_feature(&features, VIRTIO_BLK_F_SCSI); } - if (blk_enable_write_cache(s->blk)) { + if (blk_enable_write_cache(s->blk) || + (s->conf.x_enable_wce_if_config_wce && + virtio_has_feature(features, VIRTIO_BLK_F_CONFIG_WCE))) { virtio_add_feature(&features, VIRTIO_BLK_F_WCE); } if (blk_is_read_only(s->blk)) { @@ -1270,6 +1272,8 @@ static Property virtio_blk_properties[] = { conf.max_discard_sectors, BDRV_REQUEST_MAX_SECTORS), DEFINE_PROP_UINT32("max-write-zeroes-sectors", VirtIOBlock, conf.max_write_zeroes_sectors, BDRV_REQUEST_MAX_SECTORS), + DEFINE_PROP_BOOL("x-enable-wce-if-config-wce", VirtIOBlock, + conf.x_enable_wce_if_config_wce, true), DEFINE_PROP_END_OF_LIST(), }; -- cgit v1.2.3