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[Qemu-devel] [PATCH 08/12] vhost: Release memory references on cleanup
From: |
Michael Roth |
Subject: |
[Qemu-devel] [PATCH 08/12] vhost: Release memory references on cleanup |
Date: |
Tue, 19 Sep 2017 19:45:17 -0500 |
From: Alex Williamson <address@hidden>
vhost registers a MemoryListener where it adds and removes references
to MemoryRegions as the MemoryRegionSections pass through. The
region_add callback is invoked for each existing section when the
MemoryListener is registered, but unregistering the MemoryListener
performs no reciprocal region_del callback. It's therefore the
owner of the MemoryListener's responsibility to cleanup any persistent
changes, such as these memory references, after unregistering.
The consequence of this bug is that if we have both a vhost device
and a vfio device, the vhost device will reference any mmap'd MMIO of
the vfio device via this MemoryListener. If the vhost device is then
removed, those references remain outstanding. If we then attempt to
remove the vfio device, it never gets finalized and the only way to
release the kernel file descriptors is to terminate the QEMU process.
Fixes: dfde4e6e1a86 ("memory: add ref/unref calls")
Cc: Michael S. Tsirkin <address@hidden>
Cc: Paolo Bonzini <address@hidden>
Cc: address@hidden # v1.6.0+
Signed-off-by: Alex Williamson <address@hidden>
Reviewed-by: Michael S. Tsirkin <address@hidden>
Signed-off-by: Michael S. Tsirkin <address@hidden>
(cherry picked from commit ee4c112846a0f2ac4fe5601918b0a2642ac8e2ed)
Signed-off-by: Michael Roth <address@hidden>
---
hw/virtio/vhost.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
index 6eddb099b0..b737ca915b 100644
--- a/hw/virtio/vhost.c
+++ b/hw/virtio/vhost.c
@@ -1356,6 +1356,10 @@ void vhost_dev_cleanup(struct vhost_dev *hdev)
if (hdev->mem) {
/* those are only safe after successful init */
memory_listener_unregister(&hdev->memory_listener);
+ for (i = 0; i < hdev->n_mem_sections; ++i) {
+ MemoryRegionSection *section = &hdev->mem_sections[i];
+ memory_region_unref(section->mr);
+ }
QLIST_REMOVE(hdev, entry);
}
if (hdev->migration_blocker) {
--
2.11.0
- [Qemu-devel] [PATCH 10/12] scsi-bus: correct responses for INQUIRY and REQUEST SENSE, (continued)
- [Qemu-devel] [PATCH 10/12] scsi-bus: correct responses for INQUIRY and REQUEST SENSE, Michael Roth, 2017/09/19
- [Qemu-devel] [PATCH 01/12] slirp: fix clearing ifq_so from pending packets, Michael Roth, 2017/09/19
- [Qemu-devel] [PATCH 12/12] vhost-user-bridge: fix resume regression (since 2.9), Michael Roth, 2017/09/19
- [Qemu-devel] [PATCH 05/12] arm_gicv3_kvm: Fix compile warning, Michael Roth, 2017/09/19
- [Qemu-devel] [PATCH 07/12] qcow2: move qcow2_store_persistent_dirty_bitmaps() before cache flushing, Michael Roth, 2017/09/19
- [Qemu-devel] [PATCH 03/12] target/arm: Fix aa64 ldp register writeback, Michael Roth, 2017/09/19
- [Qemu-devel] [PATCH 11/12] libvhost-user: support resuming vq->last_avail_idx based on used_idx, Michael Roth, 2017/09/19
- [Qemu-devel] [PATCH 06/12] hw/arm/allwinner-a10: Mark the allwinner-a10 device with user_creatable = false, Michael Roth, 2017/09/19
- [Qemu-devel] [PATCH 04/12] virtfs: error out gracefully when mandatory suboptions are missing, Michael Roth, 2017/09/19
- [Qemu-devel] [PATCH 02/12] s390-ccw: Fix alignment for CCW1, Michael Roth, 2017/09/19
- [Qemu-devel] [PATCH 08/12] vhost: Release memory references on cleanup,
Michael Roth <=
- Re: [Qemu-devel] [PATCH 00/12] Patch Round-up for stable 2.10.1, freeze on 2017-09-27, Thomas Huth, 2017/09/20
- Re: [Qemu-devel] [PATCH 00/12] Patch Round-up for stable 2.10.1, freeze on 2017-09-27, Greg Kurz, 2017/09/20
- Re: [Qemu-devel] [PATCH 00/12] Patch Round-up for stable 2.10.1, freeze on 2017-09-27, Michael Roth, 2017/09/25
- Re: [Qemu-devel] [PATCH 00/12] Patch Round-up for stable 2.10.1, freeze on 2017-09-27, Anthony PERARD, 2017/09/26
- Re: [Qemu-devel] [PATCH 00/12] Patch Round-up for stable 2.10.1, freeze on 2017-09-27, Eric Blake, 2017/09/26