From: Boqun Feng <boqun.feng@gmail.com>
To: Wei Liu <wei.liu@kernel.org>
Cc: linux-hyperv@vger.kernel.org, linux-input@vger.kernel.org,
linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
linux-scsi@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
"K. Y. Srinivasan" <kys@microsoft.com>,
Haiyang Zhang <haiyangz@microsoft.com>,
Stephen Hemminger <sthemmin@microsoft.com>,
Jiri Kosina <jikos@kernel.org>,
Benjamin Tissoires <benjamin.tissoires@redhat.com>,
Dmitry Torokhov <dmitry.torokhov@gmail.com>,
"David S. Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
"James E.J. Bottomley" <jejb@linux.ibm.com>,
"Martin K. Petersen" <martin.petersen@oracle.com>,
Michael Kelley <mikelley@microsoft.com>,
will@kernel.org, ardb@kernel.org, arnd@arndb.de,
catalin.marinas@arm.com, mark.rutland@arm.com, maz@kernel.org
Subject: Re: [PATCH v3 08/11] Input: hyperv-keyboard: Make ringbuffer at least take two pages
Date: Mon, 14 Sep 2020 18:22:39 +0800 [thread overview]
Message-ID: <20200914102239.GB45838@debian-boqun.qqnc3lrjykvubdpftowmye0fmh.lx.internal.cloudapp.net> (raw)
In-Reply-To: <20200914093016.lsfrfk4c7kyj6tn3@liuwe-devbox-debian-v2>
On Mon, Sep 14, 2020 at 09:30:16AM +0000, Wei Liu wrote:
> On Mon, Sep 14, 2020 at 04:46:00PM +0800, Boqun Feng wrote:
> > On Thu, Sep 10, 2020 at 10:34:52PM +0800, Boqun Feng wrote:
> > > When PAGE_SIZE > HV_HYP_PAGE_SIZE, we need the ringbuffer size to be at
> > > least 2 * PAGE_SIZE: one page for the header and at least one page of
> > > the data part (because of the alignment requirement for double mapping).
> > >
> > > So make sure the ringbuffer sizes to be at least 2 * PAGE_SIZE when
> > > using vmbus_open() to establish the vmbus connection.
> > >
> > > Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
> > > ---
> > > 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..6ebc61e2db3f 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 max(40 * 1024, (int)(2 * PAGE_SIZE))
> > > +#define KBD_VSC_RECV_RING_BUFFER_SIZE max(40 * 1024, (int)(2 * PAGE_SIZE))
> > >
> >
> > Hmm.. just realized there is a problem here, if PAGE_SIZE = 16k, then
> > 40 * 1024 > 2 * PAGE_SIZE, however in the ring buffer size should also
> > be page aligned, otherwise vmbus_open() will fail.
> >
> > I plan to modify this as
> >
> > in linux/hyperv.h:
> >
> > #define VMBUS_RING_SIZE(payload_sz) PAGE_ALIGN(sizeof(struct hv_ring_buffer) + (playload_sz))
> >
> > and here:
> >
> > #define KBD_VSC_SEND_RING_BUFFER_SIZE VMBUS_RING_SIZE(36 * 1024)
> > #define KBD_VSC_RECV_RING_BUFFER_SIZE VMBUS_RING_SIZE(36 * 1024)
> >
> > and the similar change for patch #9.
>
> OOI why do you reduce the size by 4k here?
>
To keep the total ring buffer size unchanged (still 40k) when
PAGE_SIZE=4k. Because in VMBUS_RING_SIZE() (which I plan to rename as
HV_RING_SIZE()), the hv_ring_buffer size is already added.
Regards,
Boqun
> Wei.
>
> >
> > Thoughts?
> >
> > Regards,
> > Boqun
> >
> > > #define XTKBD_EMUL0 0xe0
> > > #define XTKBD_EMUL1 0xe1
> > > --
> > > 2.28.0
> > >
next prev parent reply other threads:[~2020-09-14 10:23 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-10 14:34 [PATCH v3 00/11] Hyper-V: Support PAGE_SIZE larger than 4K Boqun Feng
2020-09-10 14:34 ` [PATCH v3 01/11] Drivers: hv: vmbus: Always use HV_HYP_PAGE_SIZE for gpadl Boqun Feng
2020-09-12 19:23 ` Michael Kelley
2020-09-10 14:34 ` [PATCH v3 02/11] Drivers: hv: vmbus: Move __vmbus_open() Boqun Feng
2020-09-12 19:24 ` Michael Kelley
2020-09-10 14:34 ` [PATCH v3 03/11] Drivers: hv: vmbus: Introduce types of GPADL Boqun Feng
2020-09-12 19:29 ` Michael Kelley
2020-09-10 14:34 ` [PATCH v3 04/11] Drivers: hv: Use HV_HYP_PAGE in hv_synic_enable_regs() Boqun Feng
2020-09-12 19:30 ` Michael Kelley
2020-09-10 14:34 ` [PATCH v3 05/11] Drivers: hv: vmbus: Move virt_to_hvpfn() to hyperv header Boqun Feng
2020-09-12 19:32 ` Michael Kelley
2020-09-10 14:34 ` [PATCH v3 06/11] hv: hyperv.h: Introduce some hvpfn helper functions Boqun Feng
2020-09-12 19:33 ` Michael Kelley
2020-09-10 14:34 ` [PATCH v3 07/11] hv_netvsc: Use HV_HYP_PAGE_SIZE for Hyper-V communication Boqun Feng
2020-09-12 19:36 ` Michael Kelley
2020-09-10 14:34 ` [PATCH v3 08/11] Input: hyperv-keyboard: Make ringbuffer at least take two pages Boqun Feng
2020-09-12 19:37 ` Michael Kelley
2020-09-13 16:59 ` Dmitry Torokhov
2020-09-14 8:46 ` Boqun Feng
2020-09-14 9:30 ` Wei Liu
2020-09-14 10:22 ` Boqun Feng [this message]
2020-09-10 14:34 ` [PATCH v3 09/11] HID: hyperv: " Boqun Feng
2020-09-12 19:38 ` Michael Kelley
2020-09-10 14:34 ` [PATCH v3 10/11] Driver: hv: util: " Boqun Feng
2020-09-12 19:40 ` Michael Kelley
2020-09-10 14:34 ` [PATCH v3 11/11] scsi: storvsc: Support PAGE_SIZE larger than 4K Boqun Feng
2020-09-12 19:55 ` Michael Kelley
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