* [PATCH v2 0/3] virtio-balloon: free page hinting fixes
@ 2020-05-20 10:04 David Hildenbrand
2020-05-20 10:04 ` [PATCH v2 1/3] virtio-balloon: fix free page hinting without an iothread David Hildenbrand
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: David Hildenbrand @ 2020-05-20 10:04 UTC (permalink / raw)
To: qemu-devel
Cc: Michael S. Tsirkin, David Hildenbrand, Alexander Duyck,
Alexander Bulekov, Wei Wang, Alexander Duyck,
Philippe Mathieu-Daudé
Some fixes for VIRTIO_BALLOON_F_FREE_PAGE_HINT. First issue was reported by
Alexander Bulekov [1], the other ones were discovered by me when digging
into the details.
We keep finding more issues, let's see how we'll proceed with this feature
long-term. These patches can be backported to stable QEMU.
[1] https://lkml.kernel.org/r/20200511044121.eihns2tdimdzgi4i@mozz.bu.edu
v1 -> v2:
- "virtio-balloon: fix free page hinting without an iothread"
-- Drop initialization to 0/false
-- Reformat one condition
- cc stable
David Hildenbrand (3):
virtio-balloon: fix free page hinting without an iothread
virtio-balloon: fix free page hinting check on unrealize
virtio-balloon: unref the iothread when unrealizing
hw/virtio/virtio-balloon.c | 36 ++++++++++++++++++------------------
1 file changed, 18 insertions(+), 18 deletions(-)
--
2.25.4
^ permalink raw reply [flat|nested] 4+ messages in thread
* [PATCH v2 1/3] virtio-balloon: fix free page hinting without an iothread
2020-05-20 10:04 [PATCH v2 0/3] virtio-balloon: free page hinting fixes David Hildenbrand
@ 2020-05-20 10:04 ` David Hildenbrand
2020-05-20 10:04 ` [PATCH v2 2/3] virtio-balloon: fix free page hinting check on unrealize David Hildenbrand
2020-05-20 10:04 ` [PATCH v2 3/3] virtio-balloon: unref the iothread when unrealizing David Hildenbrand
2 siblings, 0 replies; 4+ messages in thread
From: David Hildenbrand @ 2020-05-20 10:04 UTC (permalink / raw)
To: qemu-devel
Cc: David Hildenbrand, Michael S . Tsirkin, qemu-stable,
Alexander Duyck, Alexander Bulekov, Wei Wang, Alexander Duyck,
Philippe Mathieu-Daudé
In case we don't have an iothread, we mark the feature as abscent but
still add the queue. 'free_page_bh' remains set to NULL.
qemu-system-i386 \
-M microvm \
-nographic \
-device virtio-balloon-device,free-page-hint=true \
-nographic \
-display none \
-monitor none \
-serial none \
-qtest stdio
Doing a "write 0xc0000e30 0x24
0x030000000300000003000000030000000300000003000000030000000300000003000000"
We will trigger a SEGFAULT. Let's move the check and bail out.
While at it, move the static initializations to instance_init().
free_page_report_status and block_iothread are implicitly set to the
right values (0/false) already, so drop the initialization.
Reviewed-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Fixes: c13c4153f76d ("virtio-balloon: VIRTIO_BALLOON_F_FREE_PAGE_HINT")
Reported-by: Alexander Bulekov <alxndr@bu.edu>
Cc: qemu-stable@nongnu.org
Cc: Wei Wang <wei.w.wang@intel.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Philippe Mathieu-Daudé <philmd@redhat.com>
Cc: Alexander Duyck <alexander.duyck@gmail.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
hw/virtio/virtio-balloon.c | 33 ++++++++++++++++-----------------
1 file changed, 16 insertions(+), 17 deletions(-)
diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c
index 065cd450f1..7ff6a7aa7c 100644
--- a/hw/virtio/virtio-balloon.c
+++ b/hw/virtio/virtio-balloon.c
@@ -789,6 +789,13 @@ static void virtio_balloon_device_realize(DeviceState *dev, Error **errp)
return;
}
+ if (virtio_has_feature(s->host_features, VIRTIO_BALLOON_F_FREE_PAGE_HINT) &&
+ !s->iothread) {
+ error_setg(errp, "'free-page-hint' requires 'iothread' to be set");
+ virtio_cleanup(vdev);
+ return;
+ }
+
s->ivq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output);
s->dvq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output);
s->svq = virtio_add_queue(vdev, 128, virtio_balloon_receive_stats);
@@ -797,24 +804,11 @@ static void virtio_balloon_device_realize(DeviceState *dev, Error **errp)
VIRTIO_BALLOON_F_FREE_PAGE_HINT)) {
s->free_page_vq = virtio_add_queue(vdev, VIRTQUEUE_MAX_SIZE,
virtio_balloon_handle_free_page_vq);
- s->free_page_report_status = FREE_PAGE_REPORT_S_STOP;
- s->free_page_report_cmd_id =
- VIRTIO_BALLOON_FREE_PAGE_REPORT_CMD_ID_MIN;
- s->free_page_report_notify.notify =
- virtio_balloon_free_page_report_notify;
precopy_add_notifier(&s->free_page_report_notify);
- if (s->iothread) {
- object_ref(OBJECT(s->iothread));
- s->free_page_bh = aio_bh_new(iothread_get_aio_context(s->iothread),
- virtio_ballloon_get_free_page_hints, s);
- qemu_mutex_init(&s->free_page_lock);
- qemu_cond_init(&s->free_page_cond);
- s->block_iothread = false;
- } else {
- /* Simply disable this feature if the iothread wasn't created. */
- s->host_features &= ~(1 << VIRTIO_BALLOON_F_FREE_PAGE_HINT);
- virtio_error(vdev, "iothread is missing");
- }
+
+ object_ref(OBJECT(s->iothread));
+ s->free_page_bh = aio_bh_new(iothread_get_aio_context(s->iothread),
+ virtio_ballloon_get_free_page_hints, s);
}
reset_stats(s);
}
@@ -892,6 +886,11 @@ static void virtio_balloon_instance_init(Object *obj)
{
VirtIOBalloon *s = VIRTIO_BALLOON(obj);
+ qemu_mutex_init(&s->free_page_lock);
+ qemu_cond_init(&s->free_page_cond);
+ s->free_page_report_cmd_id = VIRTIO_BALLOON_FREE_PAGE_REPORT_CMD_ID_MIN;
+ s->free_page_report_notify.notify = virtio_balloon_free_page_report_notify;
+
object_property_add(obj, "guest-stats", "guest statistics",
balloon_stats_get_all, NULL, NULL, s);
--
2.25.4
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH v2 2/3] virtio-balloon: fix free page hinting check on unrealize
2020-05-20 10:04 [PATCH v2 0/3] virtio-balloon: free page hinting fixes David Hildenbrand
2020-05-20 10:04 ` [PATCH v2 1/3] virtio-balloon: fix free page hinting without an iothread David Hildenbrand
@ 2020-05-20 10:04 ` David Hildenbrand
2020-05-20 10:04 ` [PATCH v2 3/3] virtio-balloon: unref the iothread when unrealizing David Hildenbrand
2 siblings, 0 replies; 4+ messages in thread
From: David Hildenbrand @ 2020-05-20 10:04 UTC (permalink / raw)
To: qemu-devel
Cc: Michael S . Tsirkin, David Hildenbrand, qemu-stable,
Alexander Duyck, Wei Wang, Alexander Duyck,
Philippe Mathieu-Daudé
Checking against guest features is wrong. We allocated data structures
based on host features. We can rely on "free_page_bh" as an indicator
whether to un-do stuff instead.
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Fixes: c13c4153f76d ("virtio-balloon: VIRTIO_BALLOON_F_FREE_PAGE_HINT")
Cc: qemu-stable@nongnu.org
Cc: Wei Wang <wei.w.wang@intel.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Philippe Mathieu-Daudé <philmd@redhat.com>
Cc: Alexander Duyck <alexander.duyck@gmail.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
hw/virtio/virtio-balloon.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c
index 7ff6a7aa7c..32e9fe3f64 100644
--- a/hw/virtio/virtio-balloon.c
+++ b/hw/virtio/virtio-balloon.c
@@ -818,7 +818,7 @@ static void virtio_balloon_device_unrealize(DeviceState *dev)
VirtIODevice *vdev = VIRTIO_DEVICE(dev);
VirtIOBalloon *s = VIRTIO_BALLOON(dev);
- if (virtio_balloon_free_page_support(s)) {
+ if (s->free_page_bh) {
qemu_bh_delete(s->free_page_bh);
virtio_balloon_free_page_stop(s);
precopy_remove_notifier(&s->free_page_report_notify);
--
2.25.4
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH v2 3/3] virtio-balloon: unref the iothread when unrealizing
2020-05-20 10:04 [PATCH v2 0/3] virtio-balloon: free page hinting fixes David Hildenbrand
2020-05-20 10:04 ` [PATCH v2 1/3] virtio-balloon: fix free page hinting without an iothread David Hildenbrand
2020-05-20 10:04 ` [PATCH v2 2/3] virtio-balloon: fix free page hinting check on unrealize David Hildenbrand
@ 2020-05-20 10:04 ` David Hildenbrand
2 siblings, 0 replies; 4+ messages in thread
From: David Hildenbrand @ 2020-05-20 10:04 UTC (permalink / raw)
To: qemu-devel
Cc: David Hildenbrand, Michael S . Tsirkin, qemu-stable,
Alexander Duyck, Wei Wang, Alexander Duyck,
Philippe Mathieu-Daudé
We took a reference when realizing, so let's drop that reference when
unrealizing.
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Fixes: c13c4153f76d ("virtio-balloon: VIRTIO_BALLOON_F_FREE_PAGE_HINT")
Cc: qemu-stable@nongnu.org
Cc: Wei Wang <wei.w.wang@intel.com>
Cc: Alexander Duyck <alexander.duyck@gmail.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
hw/virtio/virtio-balloon.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c
index 32e9fe3f64..cff8eab6a1 100644
--- a/hw/virtio/virtio-balloon.c
+++ b/hw/virtio/virtio-balloon.c
@@ -820,6 +820,7 @@ static void virtio_balloon_device_unrealize(DeviceState *dev)
if (s->free_page_bh) {
qemu_bh_delete(s->free_page_bh);
+ object_unref(OBJECT(s->iothread));
virtio_balloon_free_page_stop(s);
precopy_remove_notifier(&s->free_page_report_notify);
}
--
2.25.4
^ permalink raw reply related [flat|nested] 4+ messages in thread
end of thread, other threads:[~2020-05-20 10:07 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2020-05-20 10:04 [PATCH v2 0/3] virtio-balloon: free page hinting fixes David Hildenbrand
2020-05-20 10:04 ` [PATCH v2 1/3] virtio-balloon: fix free page hinting without an iothread David Hildenbrand
2020-05-20 10:04 ` [PATCH v2 2/3] virtio-balloon: fix free page hinting check on unrealize David Hildenbrand
2020-05-20 10:04 ` [PATCH v2 3/3] virtio-balloon: unref the iothread when unrealizing David Hildenbrand
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