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From: Boqun Feng <boqun.feng@gmail.com>
To: linux-hyperv@vger.kernel.org, linux-input@vger.kernel.org,
	linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
	linux-scsi@vger.kernel.org
Cc: "K. Y. Srinivasan" <kys@microsoft.com>,
	Haiyang Zhang <haiyangz@microsoft.com>,
	Stephen Hemminger <sthemmin@microsoft.com>,
	Wei Liu <wei.liu@kernel.org>, 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>,
	Boqun Feng <boqun.feng@gmail.com>
Subject: [RFC 00/11] Hyper-V: Support PAGE_SIZE larger than 4K
Date: Tue, 21 Jul 2020 09:41:24 +0800
Message-ID: <20200721014135.84140-1-boqun.feng@gmail.com> (raw)

This patchset add the necessary changes to support guests whose page
size is larger than 4K.

Hyper-V always uses 4K as the page size and expects the same page size
when communicating with guests. That is, all the "pfn"s in the
hypervisor-guest communication protocol are the page numbers in the unit
of HV_HYP_PAGE_SIZE rather than PAGE_SIZE. To support guests with larger
page size, we need to convert between these two page sizes correctly in
the hypervisor-guest communication, which is basically what this
patchset does.

In this conversion, one challenge is how to handle the ringbuffer. A
ringbuffer has two parts: a header and a data part, both of which want
to be PAGE_SIZE aligned in the guest, because we use the "double
mapping" trick to map the data part twice in the guest virtual address
space for faster wrap-around and ease to process data in place. However,
the Hyper-V hypervisor always treats the ringbuffer headers as 4k pages.
To overcome this gap, we enlarge the hv_ring_buffer structure to be
always PAGE_SIZE aligned, and introduce the gpadl type concept to allow
vmbus_establish_gpadl() to handle ringbuffer cases specially. Note that
gpadl type is only meaningful to the guest, there is no such concept in
Hyper-V hypervisor.

This patchset consists of 11 patches:

Patch 1~4: Introduce the types of gpadl, so that we can handle
	   ringbuffer when PAGE_SIZE != HV_HYP_PAGE_SIZE, and also fix
	   a few places where we should use HV_HYP_PAGE_SIZE other than
	   PAGE_SIZE.

Patch 5~6: Add a few helper functions to help calculate the hvpfn (page
	   number in the unit of HV_HYP_PAGE_SIZE) and other related
	   data. So that we can use them in the code of drivers.

Patch 7~11: Use the helpers and change the driver code accordingly to
	    make net/input/util/storage driver work with PAGE_SIZE !=
	    HV_HYP_PAGE_SIZE

I've done some tests with PAGE_SIZE=64k and PAGE_SIZE=16k configurations
on ARM64 guests (with Michael's patchset[1] for ARM64 Hyper-V guest
support), nothing major breaks yet ;-) (I could observe an error caused
by unaligned firmware data, but it's better to have it fixed in the
Hyper-V).

Looking forwards to comments and suggestions!

Regards,
Boqun

[1]: https://lore.kernel.org/lkml/1584200119-18594-1-git-send-email-mikelley@microsoft.com/

Boqun Feng (11):
  Drivers: hv: vmbus: Always use HV_HYP_PAGE_SIZE for gpadl
  Drivers: hv: vmbus: Move __vmbus_open()
  Drivers: hv: vmbus: Introduce types of GPADL
  Drivers: hv: Use HV_HYP_PAGE in hv_synic_enable_regs()
  Drivers: hv: vmbus: Move virt_to_hvpfn() to hyperv header
  hv: hyperv.h: Introduce some hvpfn helper functions
  hv_netvsc: Use HV_HYP_PAGE_SIZE for Hyper-V communication
  Input: hyperv-keyboard: Make ringbuffer at least take two pages
  HID: hyperv: Make ringbuffer at least take two pages
  Driver: hv: util: Make ringbuffer at least take two pages
  scsi: storvsc: Support PAGE_SIZE larger than 4K

 drivers/hid/hid-hyperv.c              |   4 +-
 drivers/hv/channel.c                  | 452 +++++++++++++++-----------
 drivers/hv/hv.c                       |   4 +-
 drivers/hv/hv_util.c                  |  16 +-
 drivers/input/serio/hyperv-keyboard.c |   4 +-
 drivers/net/hyperv/netvsc.c           |   2 +-
 drivers/net/hyperv/netvsc_drv.c       |  46 +--
 drivers/net/hyperv/rndis_filter.c     |  12 +-
 drivers/scsi/storvsc_drv.c            |  27 +-
 include/linux/hyperv.h                |  63 +++-
 10 files changed, 400 insertions(+), 230 deletions(-)

-- 
2.27.0


             reply index

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-21  1:41 Boqun Feng [this message]
2020-07-21  1:41 ` [RFC 01/11] Drivers: hv: vmbus: Always use HV_HYP_PAGE_SIZE for gpadl Boqun Feng
2020-07-21 15:22   ` Wei Liu
2020-07-22 23:20     ` Boqun Feng
2020-07-21  1:41 ` [RFC 02/11] Drivers: hv: vmbus: Move __vmbus_open() Boqun Feng
2020-07-21 15:23   ` Wei Liu
2020-07-21  1:41 ` [RFC 03/11] Drivers: hv: vmbus: Introduce types of GPADL Boqun Feng
2020-07-22 23:25   ` Michael Kelley
2020-07-22 23:43     ` Boqun Feng
2020-07-22 23:56       ` Michael Kelley
2020-07-21  1:41 ` [RFC 04/11] Drivers: hv: Use HV_HYP_PAGE in hv_synic_enable_regs() Boqun Feng
2020-07-21  1:41 ` [RFC 05/11] Drivers: hv: vmbus: Move virt_to_hvpfn() to hyperv header Boqun Feng
2020-07-21  1:41 ` [RFC 06/11] hv: hyperv.h: Introduce some hvpfn helper functions Boqun Feng
2020-07-21  1:41 ` [RFC 07/11] hv_netvsc: Use HV_HYP_PAGE_SIZE for Hyper-V communication Boqun Feng
2020-07-21  1:41 ` [RFC 08/11] Input: hyperv-keyboard: Make ringbuffer at least take two pages Boqun Feng
2020-07-21  1:41 ` [RFC 09/11] HID: hyperv: " Boqun Feng
2020-07-22 23:36   ` Michael Kelley
2020-07-23  1:28     ` boqun.feng
2020-07-21  1:41 ` [RFC 10/11] Driver: hv: util: " Boqun Feng
2020-07-21  1:41 ` [RFC 11/11] scsi: storvsc: Support PAGE_SIZE larger than 4K Boqun Feng
2020-07-23  0:13   ` Michael Kelley
2020-07-23  1:51     ` boqun.feng
2020-07-23  2:26       ` Michael Kelley
2020-07-23  3:12         ` Boqun Feng

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