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> Cc: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx> --- Michael and Dmitry, I change the code because of a problem I found: https://lore.kernel.org/lkml/20200914084600.GA45838@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/ , so I drop your Reviewed-by or Acked-by tag. If the update version looks good to you, may I add your tag again? Thanks in advance, and apologies for the inconvenience. Regards, Boqun drivers/input/serio/hyperv-keyboard.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/input/serio/hyperv-keyboard.c b/drivers/input/serio/hyperv-keyboard.c index df4e9f6f4529..1a7b72a9016d 100644 --- a/drivers/input/serio/hyperv-keyboard.c +++ b/drivers/input/serio/hyperv-keyboard.c @@ -75,8 +75,8 @@ struct synth_kbd_keystroke { #define HK_MAXIMUM_MESSAGE_SIZE 256 -#define KBD_VSC_SEND_RING_BUFFER_SIZE (40 * 1024) -#define KBD_VSC_RECV_RING_BUFFER_SIZE (40 * 1024) +#define KBD_VSC_SEND_RING_BUFFER_SIZE VMBUS_RING_SIZE(36 * 1024) +#define KBD_VSC_RECV_RING_BUFFER_SIZE VMBUS_RING_SIZE(36 * 1024) #define XTKBD_EMUL0 0xe0 #define XTKBD_EMUL1 0xe1 -- 2.28.0
