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[Qemu-devel] [PULL v3 12/21] virtio-blk: fix "disabled data plane" mode
From: |
Michael S. Tsirkin |
Subject: |
[Qemu-devel] [PULL v3 12/21] virtio-blk: fix "disabled data plane" mode |
Date: |
Thu, 25 Feb 2016 13:20:59 +0200 |
From: Paolo Bonzini <address@hidden>
In disabled mode, virtio-blk dataplane seems to be enabled, but flow
actually goes through the normal virtio path. This patch simplifies a bit
the handling of disabled mode. In disabled mode, virtio_blk_handle_output
might be called even if s->dataplane is not NULL.
This is a bit tricky, because the current check for s->dataplane will
always trigger, causing a continuous stream of calls to
virtio_blk_data_plane_start. Unfortunately, these calls will not
do anything. To fix this, set the "started" flag even in disabled
mode, and skip virtio_blk_data_plane_start if the started flag is true.
The resulting changes also prepare the code for the next patch, were
virtio-blk dataplane will reuse the same virtio_blk_handle_output function
as "regular" virtio-blk.
Because struct VirtIOBlockDataPlane is opaque in virtio-blk.c, we have
to move s->dataplane->started inside struct VirtIOBlock.
Signed-off-by: Paolo Bonzini <address@hidden>
Reviewed-by: Michael S. Tsirkin <address@hidden>
Signed-off-by: Michael S. Tsirkin <address@hidden>
Reviewed-by: Cornelia Huck <address@hidden>
Reviewed-by: Fam Zheng <address@hidden>
Acked-by: Stefan Hajnoczi <address@hidden>
---
include/hw/virtio/virtio-blk.h | 1 +
hw/block/dataplane/virtio-blk.c | 21 +++++++++------------
hw/block/virtio-blk.c | 2 +-
3 files changed, 11 insertions(+), 13 deletions(-)
diff --git a/include/hw/virtio/virtio-blk.h b/include/hw/virtio/virtio-blk.h
index 199bb0e..781969d 100644
--- a/include/hw/virtio/virtio-blk.h
+++ b/include/hw/virtio/virtio-blk.h
@@ -56,6 +56,7 @@ typedef struct VirtIOBlock {
/* Function to push to vq and notify guest */
void (*complete_request)(struct VirtIOBlockReq *req, unsigned char status);
Notifier migration_state_notifier;
+ bool dataplane_started;
struct VirtIOBlockDataPlane *dataplane;
} VirtIOBlock;
diff --git a/hw/block/dataplane/virtio-blk.c b/hw/block/dataplane/virtio-blk.c
index 03b81bc..cc521c1 100644
--- a/hw/block/dataplane/virtio-blk.c
+++ b/hw/block/dataplane/virtio-blk.c
@@ -28,7 +28,6 @@
#include "qom/object_interfaces.h"
struct VirtIOBlockDataPlane {
- bool started;
bool starting;
bool stopping;
bool disabled;
@@ -264,11 +263,7 @@ void virtio_blk_data_plane_start(VirtIOBlockDataPlane *s)
VirtQueue *vq;
int r;
- if (s->started || s->disabled) {
- return;
- }
-
- if (s->starting) {
+ if (vblk->dataplane_started || s->starting) {
return;
}
@@ -300,7 +295,7 @@ void virtio_blk_data_plane_start(VirtIOBlockDataPlane *s)
vblk->complete_request = complete_request_vring;
s->starting = false;
- s->started = true;
+ vblk->dataplane_started = true;
trace_virtio_blk_data_plane_start(s);
blk_set_aio_context(s->conf->conf.blk, s->ctx);
@@ -319,9 +314,10 @@ void virtio_blk_data_plane_start(VirtIOBlockDataPlane *s)
k->set_guest_notifiers(qbus->parent, 1, false);
fail_guest_notifiers:
vring_teardown(&s->vring, s->vdev, 0);
- s->disabled = true;
fail_vring:
+ s->disabled = true;
s->starting = false;
+ vblk->dataplane_started = true;
}
/* Context: QEMU global mutex held */
@@ -331,13 +327,14 @@ void virtio_blk_data_plane_stop(VirtIOBlockDataPlane *s)
VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
VirtIOBlock *vblk = VIRTIO_BLK(s->vdev);
+ if (!vblk->dataplane_started || s->stopping) {
+ return;
+ }
/* Better luck next time. */
if (s->disabled) {
s->disabled = false;
- return;
- }
- if (!s->started || s->stopping) {
+ vblk->dataplane_started = false;
return;
}
s->stopping = true;
@@ -364,6 +361,6 @@ void virtio_blk_data_plane_stop(VirtIOBlockDataPlane *s)
/* Clean up guest notifier (irq) */
k->set_guest_notifiers(qbus->parent, 1, false);
- s->started = false;
+ vblk->dataplane_started = false;
s->stopping = false;
}
diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
index c427698..e04c8f5 100644
--- a/hw/block/virtio-blk.c
+++ b/hw/block/virtio-blk.c
@@ -589,7 +589,7 @@ static void virtio_blk_handle_output(VirtIODevice *vdev,
VirtQueue *vq)
/* Some guests kick before setting VIRTIO_CONFIG_S_DRIVER_OK so start
* dataplane here instead of waiting for .set_status().
*/
- if (s->dataplane) {
+ if (s->dataplane && !s->dataplane_started) {
virtio_blk_data_plane_start(s->dataplane);
return;
}
--
MST
- [Qemu-devel] [PULL v3 03/21] move get_current_ram_size to virtio-balloon.c, (continued)
- [Qemu-devel] [PULL v3 03/21] move get_current_ram_size to virtio-balloon.c, Michael S. Tsirkin, 2016/02/25
- [Qemu-devel] [PULL v3 01/21] bios-linker-loader: document+validate input, Michael S. Tsirkin, 2016/02/25
- [Qemu-devel] [PULL v3 04/21] virtio-balloon: rewrite get_current_ram_size(), Michael S. Tsirkin, 2016/02/25
- [Qemu-devel] [PULL v3 05/21] balloon: Use only 'pc-dimm' type dimm for ballooning, Michael S. Tsirkin, 2016/02/25
- [Qemu-devel] [PULL v3 06/21] pci core: function pci_host_bus_register() cleanup, Michael S. Tsirkin, 2016/02/25
- [Qemu-devel] [PULL v3 07/21] pci core: function pci_bus_init() cleanup, Michael S. Tsirkin, 2016/02/25
- [Qemu-devel] [PULL v3 10/21] virtio: add AioContext-specific function for host notifiers, Michael S. Tsirkin, 2016/02/25
- [Qemu-devel] [PULL v3 11/21] virtio: export vring_notify as virtio_should_notify, Michael S. Tsirkin, 2016/02/25
- [Qemu-devel] [PULL v3 09/21] vring: make vring_enable_notification return void, Michael S. Tsirkin, 2016/02/25
- [Qemu-devel] [PULL v3 08/21] block-migration: acquire AioContext as necessary, Michael S. Tsirkin, 2016/02/25
- [Qemu-devel] [PULL v3 12/21] virtio-blk: fix "disabled data plane" mode,
Michael S. Tsirkin <=
- [Qemu-devel] [PULL v3 14/21] virtio-scsi: do not use vring in dataplane, Michael S. Tsirkin, 2016/02/25
- [Qemu-devel] [PULL v3 13/21] virtio-blk: do not use vring in dataplane, Michael S. Tsirkin, 2016/02/25
- [Qemu-devel] [PULL v3 15/21] vring: remove, Michael S. Tsirkin, 2016/02/25
- [Qemu-devel] [PULL v3 16/21] tests/vhost-user-bridge: fix build on 32 bit systems, Michael S. Tsirkin, 2016/02/25
- [Qemu-devel] [PULL v3 17/21] q35: Remove old machine versions, Michael S. Tsirkin, 2016/02/25
- [Qemu-devel] [PULL v3 18/21] machine: Remove no_tco field, Michael S. Tsirkin, 2016/02/25
- [Qemu-devel] [PULL v3 19/21] ich9: Remove enable_tco arguments from init functions, Michael S. Tsirkin, 2016/02/25
- [Qemu-devel] [PULL v3 20/21] q35: Remove unused q35-acpi-dsdt.aml file, Michael S. Tsirkin, 2016/02/25
- [Qemu-devel] [PULL v3 21/21] q35: No need to check gigabyte_align, Michael S. Tsirkin, 2016/02/25
- Re: [Qemu-devel] [PULL v3 00/21] vhost, virtio, pci, pc, Peter Maydell, 2016/02/25