[PATCH v2 00/10] Refactor arch specific Hyper-V code

From: Michael Kelley <mikelley@microsoft.com>
To: sthemmin@microsoft.com, kys@microsoft.com, wei.liu@kernel.org,
	tglx@linutronix.de, mingo@redhat.com, bp@alien8.de,
	hpa@zytor.com, daniel.lezcano@linaro.org, arnd@arndb.de,
	linux-hyperv@vger.kernel.org
Cc: mikelley@microsoft.com, linux-kernel@vger.kernel.org,
	x86@kernel.org, linux-arch@vger.kernel.org
Subject: [PATCH v2 00/10] Refactor arch specific Hyper-V code
Date: Sun, 28 Feb 2021 17:15:22 -0800	[thread overview]
Message-ID: <1614561332-2523-1-git-send-email-mikelley@microsoft.com> (raw)

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+_Q04F+g@mail.gmail.com/

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 | 258 ++++++++++++++++++++++++++-----------
 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, 458 insertions(+), 313 deletions(-)

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1.8.3.1