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| author |   Linus Torvalds <torvalds@linux-foundation.org> | 2022-04-07 06:35:34 -1000 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2022-04-07 06:35:34 -1000 |
| commit | 42e7a03d3badebd4e70aea5362d6914dfc7c220b (patch) | |
| tree | 4024ddc668d571c521becb0a48452a09c020f5bb /drivers/hv/ring_buffer.c | |
| parent | Merge tag 'random-5.18-rc2-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random (diff) | |
| parent | Drivers: hv: vmbus: Replace smp_store_mb() with virt_store_mb() (diff) | |
| download | linux-dev-42e7a03d3badebd4e70aea5362d6914dfc7c220b.tar.xz linux-dev-42e7a03d3badebd4e70aea5362d6914dfc7c220b.zip | |
Merge tag 'hyperv-fixes-signed-20220407' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux
Pull hyperv fixes from Wei Liu:
- Correctly propagate coherence information for VMbus devices (Michael
Kelley)
- Disable balloon and memory hot-add on ARM64 temporarily (Boqun Feng)
- Use barrier to prevent reording when reading ring buffer (Michael
Kelley)
- Use virt_store_mb in favour of smp_store_mb (Andrea Parri)
- Fix VMbus device object initialization (Andrea Parri)
- Deactivate sysctl_record_panic_msg on isolated guest (Andrea Parri)
- Fix a crash when unloading VMbus module (Guilherme G. Piccoli)
* tag 'hyperv-fixes-signed-20220407' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux:
Drivers: hv: vmbus: Replace smp_store_mb() with virt_store_mb()
Drivers: hv: balloon: Disable balloon and hot-add accordingly
Drivers: hv: balloon: Support status report for larger page sizes
Drivers: hv: vmbus: Prevent load re-ordering when reading ring buffer
PCI: hv: Propagate coherence from VMbus device to PCI device
Drivers: hv: vmbus: Propagate VMbus coherence to each VMbus device
Drivers: hv: vmbus: Fix potential crash on module unload
Drivers: hv: vmbus: Fix initialization of device object in vmbus_device_register()
Drivers: hv: vmbus: Deactivate sysctl_record_panic_msg by default in isolated guests
Diffstat (limited to 'drivers/hv/ring_buffer.c')
| -rw-r--r-- | drivers/hv/ring_buffer.c | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/drivers/hv/ring_buffer.c b/drivers/hv/ring_buffer.c index 71efacb90965..3d215d9dec43 100644 --- a/drivers/hv/ring_buffer.c +++ b/drivers/hv/ring_buffer.c @@ -439,7 +439,16 @@ int hv_ringbuffer_read(struct vmbus_channel *channel, static u32 hv_pkt_iter_avail(const struct hv_ring_buffer_info *rbi) { u32 priv_read_loc = rbi->priv_read_index; - u32 write_loc = READ_ONCE(rbi->ring_buffer->write_index); + u32 write_loc; + + /* + * The Hyper-V host writes the packet data, then uses + * store_release() to update the write_index. Use load_acquire() + * here to prevent loads of the packet data from being re-ordered + * before the read of the write_index and potentially getting + * stale data. + */ + write_loc = virt_load_acquire(&rbi->ring_buffer->write_index); if (write_loc >= priv_read_loc) return write_loc - priv_read_loc; |