From: Boqun Feng <boqun.feng@xxxxxxxxx> Sent: Tuesday, September 15, 2020 8:48 PM
>
> For a Hyper-V vmbus, the size of the ringbuffer has two requirements:
>
> 1) it has to take one PAGE_SIZE for the header
>
> 2) it has to be PAGE_SIZE aligned so that double-mapping can work
>
> VMBUS_RING_SIZE() could calculate a correct ringbuffer size which
> fulfills both requirements, therefore use it to make sure vmbus work
> when PAGE_SIZE != HV_HYP_PAGE_SIZE (4K).
>
> Note that since the argument for VMBUS_RING_SIZE() is the size of
> payload (data part), so it will be minus 4k (the size of header when
> PAGE_SIZE = 4k) than the original value to keep the ringbuffer total
> size unchanged when PAGE_SIZE = 4k.
>
> Signed-off-by: Boqun Feng <boqun.feng@xxxxxxxxx>
> Cc: Michael Kelley <mikelley@xxxxxxxxxxxxx>
>
> ---
> Michael,
>
> I drop your Reviewed-by tag because of the page align issue. Could you
> review this updated version? Thanks!
>
> Regards,
> Boqun
>
>
> drivers/hv/hv_util.c | 11 +++++++----
> 1 file changed, 7 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/hv/hv_util.c b/drivers/hv/hv_util.c
> index a4e8d96513c2..05566ecdbe4b 100644
> --- a/drivers/hv/hv_util.c
> +++ b/drivers/hv/hv_util.c
> @@ -500,6 +500,9 @@ static void heartbeat_onchannelcallback(void *context)
> }
> }
>
> +#define HV_UTIL_RING_SEND_SIZE VMBUS_RING_SIZE(3 * HV_HYP_PAGE_SIZE)
> +#define HV_UTIL_RING_RECV_SIZE VMBUS_RING_SIZE(3 * HV_HYP_PAGE_SIZE)
> +
> static int util_probe(struct hv_device *dev,
> const struct hv_vmbus_device_id *dev_id)
> {
> @@ -530,8 +533,8 @@ static int util_probe(struct hv_device *dev,
>
> hv_set_drvdata(dev, srv);
>
> - ret = vmbus_open(dev->channel, 4 * HV_HYP_PAGE_SIZE,
> - 4 * HV_HYP_PAGE_SIZE, NULL, 0, srv->util_cb,
> + ret = vmbus_open(dev->channel, HV_UTIL_RING_SEND_SIZE,
> + HV_UTIL_RING_RECV_SIZE, NULL, 0, srv->util_cb,
> dev->channel);
> if (ret)
> goto error;
> @@ -590,8 +593,8 @@ static int util_resume(struct hv_device *dev)
> return ret;
> }
>
> - ret = vmbus_open(dev->channel, 4 * HV_HYP_PAGE_SIZE,
> - 4 * HV_HYP_PAGE_SIZE, NULL, 0, srv->util_cb,
> + ret = vmbus_open(dev->channel, HV_UTIL_RING_SEND_SIZE,
> + HV_UTIL_RING_RECV_SIZE, NULL, 0, srv->util_cb,
> dev->channel);
> return ret;
> }
> --
> 2.28.0
Reviewed-by: Michael Kelley <mikelley@xxxxxxxxxxxxx>
