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[Qemu-devel] [PATCH v4] virtio-blk: set correct config size for the host
From: |
Changpeng Liu |
Subject: |
[Qemu-devel] [PATCH v4] virtio-blk: set correct config size for the host driver |
Date: |
Wed, 13 Feb 2019 09:48:57 +0800 |
Commit caa1ee43 "vhost-user-blk: add discard/write zeroes features
support" added fields to struct virtio_blk_config. This changes
the size of the config space and breaks migration from QEMU 3.1
and older:
qemu-system-ppc64: get_pci_config_device: Bad config data: i=0x10 read: 41
device: 1 cmask: ff wmask: 80 w1cmask:0
qemu-system-ppc64: Failed to load PCIDevice:config
qemu-system-ppc64: Failed to load virtio-blk:virtio
qemu-system-ppc64: error while loading state for instance 0x0 of device
'address@hidden:01.0/virtio-blk'
qemu-system-ppc64: load of migration failed: Invalid argument
Since virtio-blk doesn't support the "discard" and "write zeroes"
features, it shouldn't even expose the associated fields in the
config space actually. Just include all fields up to num_queues to
match QEMU 3.1 and older.
Signed-off-by: Changpeng Liu <address@hidden>
---
hw/block/virtio-blk.c | 13 +++++++++----
1 file changed, 9 insertions(+), 4 deletions(-)
diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
index 9a87b3b..6fce9c7 100644
--- a/hw/block/virtio-blk.c
+++ b/hw/block/virtio-blk.c
@@ -28,6 +28,10 @@
#include "hw/virtio/virtio-bus.h"
#include "hw/virtio/virtio-access.h"
+/* We don't support discard yet, hide associated config fields. */
+#define VIRTIO_BLK_CFG_SIZE offsetof(struct virtio_blk_config, \
+ max_discard_sectors)
+
static void virtio_blk_init_request(VirtIOBlock *s, VirtQueue *vq,
VirtIOBlockReq *req)
{
@@ -761,7 +765,8 @@ static void virtio_blk_update_config(VirtIODevice *vdev,
uint8_t *config)
blkcfg.alignment_offset = 0;
blkcfg.wce = blk_enable_write_cache(s->blk);
virtio_stw_p(vdev, &blkcfg.num_queues, s->conf.num_queues);
- memcpy(config, &blkcfg, sizeof(struct virtio_blk_config));
+ memcpy(config, &blkcfg, VIRTIO_BLK_CFG_SIZE);
+ QEMU_BUILD_BUG_ON(VIRTIO_BLK_CFG_SIZE > sizeof(blkcfg));
}
static void virtio_blk_set_config(VirtIODevice *vdev, const uint8_t *config)
@@ -769,7 +774,8 @@ static void virtio_blk_set_config(VirtIODevice *vdev, const
uint8_t *config)
VirtIOBlock *s = VIRTIO_BLK(vdev);
struct virtio_blk_config blkcfg;
- memcpy(&blkcfg, config, sizeof(blkcfg));
+ memcpy(&blkcfg, config, VIRTIO_BLK_CFG_SIZE);
+ QEMU_BUILD_BUG_ON(VIRTIO_BLK_CFG_SIZE > sizeof(blkcfg));
aio_context_acquire(blk_get_aio_context(s->blk));
blk_set_enable_write_cache(s->blk, blkcfg.wce != 0);
@@ -952,8 +958,7 @@ static void virtio_blk_device_realize(DeviceState *dev,
Error **errp)
return;
}
- virtio_init(vdev, "virtio-blk", VIRTIO_ID_BLOCK,
- sizeof(struct virtio_blk_config));
+ virtio_init(vdev, "virtio-blk", VIRTIO_ID_BLOCK, VIRTIO_BLK_CFG_SIZE);
s->blk = conf->conf.blk;
s->rq = NULL;
--
1.9.3
- [Qemu-devel] [PATCH v4] virtio-blk: set correct config size for the host driver,
Changpeng Liu <=
Re: [Qemu-devel] [PATCH v4] virtio-blk: set correct config size for the host driver, Greg Kurz, 2019/02/13