5e7d8ddf2a
commit 6941f67ad37d5465b75b9ffc498fcf6897a3c00e upstream.
Current code in netvsc_drv_init() incorrectly assumes that PAGE_SIZE
is 4 Kbytes, which is wrong on ARM64 with 16K or 64K page size. As a
result, the default VMBus ring buffer size on ARM64 with 64K page size
is 8 Mbytes instead of the expected 512 Kbytes. While this doesn't break
anything, a typical VM with 8 vCPUs and 8 netvsc channels wastes 120
Mbytes (8 channels * 2 ring buffers/channel * 7.5 Mbytes/ring buffer).
Unfortunately, the module parameter specifying the ring buffer size
is in units of 4 Kbyte pages. Ideally, it should be in units that
are independent of PAGE_SIZE, but backwards compatibility prevents
changing that now.
Fix this by having netvsc_drv_init() hardcode 4096 instead of using
PAGE_SIZE when calculating the ring buffer size in bytes. Also
use the VMBUS_RING_SIZE macro to ensure proper alignment when running
with page size larger than 4K.
Cc: <stable@vger.kernel.org> # 5.15.x
Fixes:
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||
|---|---|---|
| .. | ||
| hyperv_net.h | ||
| Kconfig | ||
| Makefile | ||
| netvsc_bpf.c | ||
| netvsc_drv.c | ||
| netvsc_trace.c | ||
| netvsc_trace.h | ||
| netvsc.c | ||
| rndis_filter.c | ||