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* [RFC 00/11] Hyper-V: Support PAGE_SIZE larger than 4K
@ 2020-07-21  1:41 Boqun Feng
  2020-07-21  1:41 ` [RFC 01/11] Drivers: hv: vmbus: Always use HV_HYP_PAGE_SIZE for gpadl Boqun Feng
                   ` (10 more replies)
  0 siblings, 11 replies; 24+ messages in thread
From: Boqun Feng @ 2020-07-21  1:41 UTC (permalink / raw)
  To: linux-hyperv, linux-input, linux-kernel, netdev, linux-scsi
  Cc: K. Y. Srinivasan, Haiyang Zhang, Stephen Hemminger, Wei Liu,
	Jiri Kosina, Benjamin Tissoires, Dmitry Torokhov,
	David S. Miller, Jakub Kicinski, James E.J. Bottomley,
	Martin K. Petersen, Michael Kelley, Boqun Feng

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


^ permalink raw reply	[flat|nested] 24+ messages in thread

end of thread, other threads:[~2020-07-23  3:12 UTC | newest]

Thread overview: 24+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-07-21  1:41 [RFC 00/11] Hyper-V: Support PAGE_SIZE larger than 4K Boqun Feng
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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