Boqun Feng boqun.feng@gmail.com writes:

Baihua reported an error when boot an ARM64 guest with PAGE_SIZE=64k and BALLOON is enabled:

hv_vmbus: registering driver hv_balloon hv_vmbus: probe failed for device 1eccfd72-4b41-45ef-b73a-4a6e44c12924 (-22)

The cause of this is that the ringbuffer size for hv_balloon is not adjusted with VMBUS_RING_SIZE(), which makes the size not large enough for ringbuffers on guest with PAGE_SIZE=64k. Therefore use VMBUS_RING_SIZE() to calculate the ringbuffer size. Note that the old size (20 * 1024) counts a 4k header in the total size, while VMBUS_RING_SIZE() expects the parameter as the payload size, so use 16 * 1024.

Cc: stable@vger.kernel.org # 5.15.x Reported-by: Baihua Lu baihua.lu@microsoft.com Signed-off-by: Boqun Feng boqun.feng@gmail.com

---

drivers/hv/hv_balloon.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/hv/hv_balloon.c b/drivers/hv/hv_balloon.c index 7f11ea07d698..ca873a3b98db 100644 --- a/drivers/hv/hv_balloon.c +++ b/drivers/hv/hv_balloon.c @@ -480,7 +480,7 @@ module_param(pressure_report_delay, uint, (S_IRUGO | S_IWUSR)); MODULE_PARM_DESC(pressure_report_delay, "Delay in secs in reporting pressure"); static atomic_t trans_id = ATOMIC_INIT(0); -static int dm_ring_size = 20 * 1024; +static int dm_ring_size = VMBUS_RING_SIZE(16 * 1024); /*

• Driver specific state.

Tested-by: Vitaly Kuznetsov vkuznets@redhat.com

Thanks!