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authorAkihiko Odaki <akihiko.odaki@gmail.com>2021-02-25 09:12:39 +0900
committerStefan Hajnoczi <stefanha@redhat.com>2021-03-15 09:48:53 +0000
commitfb0b154c801e3447e505de420195fb7038695941 (patch)
treea060af2e30b44fddad72be77331c4dad8ca12b61
parent6157b0e19721aadb4c7fdcfe57b2924af6144b14 (diff)
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virtio-blk: Respect discard granularity
Report the configured granularity for discard operation to the guest. If this is not set use the block size. Since until now we have ignored the configured discard granularity and always reported the block size, let's add 'report-discard-granularity' property and disable it for older machine types to avoid migration issues. Signed-off-by: Akihiko Odaki <akihiko.odaki@gmail.com> Reviewed-by: Stefano Garzarella <sgarzare@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Message-Id: <20210225001239.47046-1-akihiko.odaki@gmail.com>
-rw-r--r--hw/block/virtio-blk.c8
-rw-r--r--hw/core/machine.c1
-rw-r--r--include/hw/virtio/virtio-blk.h1
3 files changed, 9 insertions, 1 deletions
diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
index 3d2072c..d28979e 100644
--- a/hw/block/virtio-blk.c
+++ b/hw/block/virtio-blk.c
@@ -962,10 +962,14 @@ static void virtio_blk_update_config(VirtIODevice *vdev, uint8_t *config)
blkcfg.wce = blk_enable_write_cache(s->blk);
virtio_stw_p(vdev, &blkcfg.num_queues, s->conf.num_queues);
if (virtio_has_feature(s->host_features, VIRTIO_BLK_F_DISCARD)) {
+ uint32_t discard_granularity = conf->discard_granularity;
+ if (discard_granularity == -1 || !s->conf.report_discard_granularity) {
+ discard_granularity = blk_size;
+ }
virtio_stl_p(vdev, &blkcfg.max_discard_sectors,
s->conf.max_discard_sectors);
virtio_stl_p(vdev, &blkcfg.discard_sector_alignment,
- blk_size >> BDRV_SECTOR_BITS);
+ discard_granularity >> BDRV_SECTOR_BITS);
/*
* We support only one segment per request since multiple segments
* are not widely used and there are no userspace APIs that allow
@@ -1299,6 +1303,8 @@ static Property virtio_blk_properties[] = {
IOThread *),
DEFINE_PROP_BIT64("discard", VirtIOBlock, host_features,
VIRTIO_BLK_F_DISCARD, true),
+ DEFINE_PROP_BOOL("report-discard-granularity", VirtIOBlock,
+ conf.report_discard_granularity, true),
DEFINE_PROP_BIT64("write-zeroes", VirtIOBlock, host_features,
VIRTIO_BLK_F_WRITE_ZEROES, true),
DEFINE_PROP_UINT32("max-discard-sectors", VirtIOBlock,
diff --git a/hw/core/machine.c b/hw/core/machine.c
index 4386f57..4c1a4a4 100644
--- a/hw/core/machine.c
+++ b/hw/core/machine.c
@@ -39,6 +39,7 @@
GlobalProperty hw_compat_5_2[] = {
{ "ICH9-LPC", "smm-compat", "on"},
{ "PIIX4_PM", "smm-compat", "on"},
+ { "virtio-blk-device", "report-discard-granularity", "off" },
};
const size_t hw_compat_5_2_len = G_N_ELEMENTS(hw_compat_5_2);
diff --git a/include/hw/virtio/virtio-blk.h b/include/hw/virtio/virtio-blk.h
index 214ab74..29655a4 100644
--- a/include/hw/virtio/virtio-blk.h
+++ b/include/hw/virtio/virtio-blk.h
@@ -41,6 +41,7 @@ struct VirtIOBlkConf
uint16_t num_queues;
uint16_t queue_size;
bool seg_max_adjust;
+ bool report_discard_granularity;
uint32_t max_discard_sectors;
uint32_t max_write_zeroes_sectors;
bool x_enable_wce_if_config_wce;