To support Linux guests on Hyper-V on multiple architectures, the original approach factored out all differences between Hyper-V on x86/x64 and Hyper-V on ARM64 into functions or #defines under arch/x86 and arch/arm64. Some of these differences are truly related to the architecture, but others are more properly treated as Linux OS differences or just quirks in Hyper-V. Feedback from Arnd Bergmann[1] recommended that differences other than architecture should be incorporated into the architecture independent Hyper-V code. Each difference can be handled with conditions specific to the difference instead of tying it to the broader x86/x64 vs. ARM64. This approach reduces the amount of code under arch/x86 and arch/arm64 and keeps the non-architectural differences localized and more easily understood.
This patch set implements the new approach by changing the interface between the architecture independent code and the architecture dependent code for x86/x64. The patches move code from arch/x86 to the architecture independent Hyper-V code whenever possible, and add architecture independent support needed by other architectures like ARM64. No functionality is changed for x86/x64. A subsequent patch set will provide the Hyper-V support code under arch/arm64. This patch set results in an increase in lines of code (though some of the increase is additional comments). But the lines needed under arch/arm64 in the upcoming patch set is significantly reduced, resulting in a net decrease of about 125 lines. [1] https://lore.kernel.org/lkml/CAK8P3a1hDBVembCd+6=ENUWYFz=72jbtfmrkyz2afd+_q04...@mail.gmail.com/ Change in v3: * In patch 7/10, tweak the #ifdefs [Daniel Lezcano] * In patch 8/10, tweak the #ifdefs to be around entire functions [Daniel Lezcano] * In patch 10/10, use DEFINE_PER_CPU for stimer0_evt instead of dynamically allocating per-cpu memory [Daniel Lezcano] Changes in v2: * In patch 9/10, for consistency change the rating on hyperv_cs_msr along with the rating on hyperv_cs_tsc [Boqun Feng] * In patch 10/10, add missing call to hv_remove_stimer0_handler() [Boqun Feng] * In patch 10/10, add clarifying comment that hv_setup_stimer0_irq() is not used on x86/x64 [Wei Liu] Michael Kelley (10): Drivers: hv: vmbus: Move Hyper-V page allocator to arch neutral code x86/hyper-v: Move hv_message_type to architecture neutral module Drivers: hv: Redo Hyper-V synthetic MSR get/set functions Drivers: hv: vmbus: Move hyperv_report_panic_msg to arch neutral code Drivers: hv: vmbus: Handle auto EOI quirk inline Drivers: hv: vmbus: Move handling of VMbus interrupts clocksource/drivers/hyper-v: Handle vDSO differences inline clocksource/drivers/hyper-v: Handle sched_clock differences inline clocksource/drivers/hyper-v: Set clocksource rating based on Hyper-V feature clocksource/drivers/hyper-v: Move handling of STIMER0 interrupts arch/x86/hyperv/hv_init.c | 53 +------- arch/x86/include/asm/hyperv-tlfs.h | 131 ++++++++++--------- arch/x86/include/asm/mshyperv.h | 67 ++-------- arch/x86/kernel/cpu/mshyperv.c | 23 ++-- drivers/clocksource/hyperv_timer.c | 249 +++++++++++++++++++++++++------------ drivers/hv/hv.c | 93 +++++++++++--- drivers/hv/vmbus_drv.c | 89 +++++++++++-- include/asm-generic/hyperv-tlfs.h | 35 ++++++ include/asm-generic/mshyperv.h | 19 ++- include/clocksource/hyperv_timer.h | 3 +- 10 files changed, 449 insertions(+), 313 deletions(-) -- 1.8.3.1
