The Linux guest page size and hypervisor page size concepts are different, even though they happen to be the same value on x86. Hyper-V code mixes up the two, so this patchset begins to address that by creating and using a set of Hyper-V specific page definitions.
A major benefit of those new definitions is that they support non-x86 architectures, such as ARM64, that use different page sizes. On ARM64, the guest page size may not be 4096, and Hyper-V always runs with a page size of 4096. In this patchset, the first two patches lay the foundation for the others, creating definitions and preparing for allocation of memory with the size and alignment that Hyper-V expects as a page. Patch 3 applies the page size definition where the guest VM and Hyper-V communicate, and where the code intends to use the Hyper-V page size. The last two patches set the ring buffer size to a fixed value, removing the dependency on the guest page size. This is the initial set of changes to the Hyper-V code, and future patches will make additional changes using the same foundation, for example, replace __vmalloc() and related functions when Hyper-V pages are intended. Changes in v4 (all apply to patch 2 only): - Remove file name from the subject. - Include prototypes of two new functions. - Add another Link tag. Changes in v3: - Simplify expression for BUILD_BUG_ON() in patch 2. - Add Link and Reviewed-by tags. Change in v2: - Replace patch 2 with a new one. Maya Nakamura (5): x86: hv: hyperv-tlfs.h: Create and use Hyper-V page definitions x86: hv: Add functions to allocate/deallocate page for Hyper-V hv: vmbus: Replace page definition with Hyper-V specific one HID: hv: Remove dependencies on PAGE_SIZE for ring buffer Input: hv: Remove dependencies on PAGE_SIZE for ring buffer arch/x86/hyperv/hv_init.c | 14 ++++++++++++++ arch/x86/include/asm/hyperv-tlfs.h | 12 +++++++++++- arch/x86/include/asm/mshyperv.h | 5 ++++- drivers/hid/hid-hyperv.c | 4 ++-- drivers/hv/hyperv_vmbus.h | 8 ++++---- drivers/input/serio/hyperv-keyboard.c | 4 ++-- 6 files changed, 37 insertions(+), 10 deletions(-) -- 2.17.1