This patchset add the necessary changes to support guests whose page size is larger than 4K. And the main architecture which we develop this for is ARM64 (also it's the architecture that I use to test this feature). Now as the patchset has been deeply reviewed, I change it from "RFC" to "PATCH", and also add ARM64 people Cced for broader insights (although the code is arch-independent). Previous version: v1: https://lore.kernel.org/lkml/20200721014135.84140-1-boqun.feng@xxxxxxxxx/ v2: https://lore.kernel.org/lkml/20200902030107.33380-1-boqun.feng@xxxxxxxxx Changes since v2: * Use a simpler and straight-forwards method to set up the payload array for storvsc thanks to the inspiration from Michael Kelley. * Some typo fixes as per suggestion from Michael Kelley. * Fixes compiler warnings due to the different types of two operands for max(). 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), everything worked fine ;-) (I could observe an error caused by unaligned firmware data, but it's better to have it fixed in the Hyper-V). I also have done a build and boot test on x86, everything worked well. Looking forwards to comments and suggestions! Regards, Boqun [1]: https://lore.kernel.org/lkml/1598287583-71762-1-git-send-email-mikelley@xxxxxxxxxxxxx/ 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 | 461 ++++++++++++++++---------- 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 | 13 +- drivers/scsi/storvsc_drv.c | 54 ++- include/linux/hyperv.h | 64 +++- 10 files changed, 441 insertions(+), 227 deletions(-) -- 2.28.0
