Re: [PATCH v2 00/23] MIPS: KVM: Fixes and guest timer rewrite

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Il 29/05/2014 11:16, James Hogan ha scritto:
Here are a range of MIPS KVM T&E fixes, preferably for v3.16 but I know
it's probably a bit late now. Changes are pretty minimal though since
v1 so please consider. They can also be found on my kvm_mips_queue
branch (and the kvm_mips_timer_v2 tag) here:
git://git.kernel.org/pub/scm/linux/kernel/git/jhogan/kvm-mips.git

They originally served to allow it to work better on Ingenic XBurst
cores which have some peculiarities which break non-portable assumptions
in the MIPS KVM implementation (patches 1-4, 13).

Fixing guest CP0_Count emulation to work without a running host
CP0_Count (patch 13) however required a rewrite of the timer emulation
code to use the kernel monotonic time instead, which needed doing anyway
since basing it directly off the host CP0_Count was broken. Various bugs
were fixed in the process (patches 10-12) and improvements made thanks to
valuable feedback from Paolo Bonzini for the last QEMU MIPS/KVM patchset
(patches 5-7, 15-16).

Finally there are some misc cleanups which I did along the way (patches
17-23).

Only the first patch (fixes MIPS KVM with 4K pages) is marked for
stable. For KVM to work on XBurst it needs the timer rework which is a
fairly complex change, so there's little point marking any of the XBurst
specific changes for stable.

All feedback welcome!

Patches 1-4:
	Fix KVM/MIPS with 4K pages, missing RDHWR SYNCI (XBurst),
	unmoving CP0_Random (XBurst).
Patches 5-9:
	Add EPC, Count, Compare, UserLocal, HWREna guest CP0 registers
	to KVM register ioctl interface.
Patches 10-12:
	Fix a few potential races relating to timers.
Patches 13-14:
	Rewrite guest timer emulation to use ktime_get().
Patches 15-16:
	Add KVM virtual registers for controlling guest timer, including
	master timer disable, and timer frequency.
Patches 17-23:
	Cleanups.

Changes in v2 (tag:kvm_mips_timer_v2):
 Patchset:
 - Drop patch 4 "MIPS: KVM: Fix CP0_EBASE KVM register id" (David
   Daney).
 - Drop patch 14 "MIPS: KVM: Add nanosecond count bias KVM register".
   The COUNT_CTL and COUNT_RESUME API is clean and sufficient.
 - Add missing access to UserLocal and HWREna guest CP0 registers
   (patches 15 and 16).
 - Add export of local_flush_icache_range (patch 2).
 Patch 12 MIPS: KVM: Migrate hrtimer to follow VCPU
 - Move kvm_mips_migrate_count() into kvm_tlb.c to fix a link error when
   KVM is built as a module, since kvm_tlb.c is built statically and
   cannot reference symbols in kvm_mips_emul.c.
 Patch 15 MIPS: KVM: Add master disable count interface
 - Make KVM_REG_MIPS_COUNT_RESUME writable too so that userland can
   control timer using master DC and without bias register. New values
   are rejected if they refer to a monotonic time in the future.
 - Expand on description of KVM_REG_MIPS_COUNT_RESUME about the effects
   of the register and that it can be written.

v1 (tag:kvm_mips_timer_v1):
 see http://marc.info/?l=kvm&m=139843936102657&w=2

James Hogan (23):
  MIPS: KVM: Allocate at least 16KB for exception handlers
  MIPS: Export local_flush_icache_range for KVM
  MIPS: KVM: Use local_flush_icache_range to fix RI on XBurst
  MIPS: KVM: Use tlb_write_random
  MIPS: KVM: Add CP0_EPC KVM register access
  MIPS: KVM: Move KVM_{GET,SET}_ONE_REG definitions into kvm_host.h
  MIPS: KVM: Add CP0_Count/Compare KVM register access
  MIPS: KVM: Add CP0_UserLocal KVM register access
  MIPS: KVM: Add CP0_HWREna KVM register access
  MIPS: KVM: Deliver guest interrupts after local_irq_disable()
  MIPS: KVM: Fix timer race modifying guest CP0_Cause
  MIPS: KVM: Migrate hrtimer to follow VCPU
  MIPS: KVM: Rewrite count/compare timer emulation
  MIPS: KVM: Override guest kernel timer frequency directly
  MIPS: KVM: Add master disable count interface
  MIPS: KVM: Add count frequency KVM register
  MIPS: KVM: Make kvm_mips_comparecount_{func,wakeup} static
  MIPS: KVM: Whitespace fixes in kvm_mips_callbacks
  MIPS: KVM: Fix kvm_debug bit-rottage
  MIPS: KVM: Remove ifdef DEBUG around kvm_debug
  MIPS: KVM: Quieten kvm_info() logging
  MIPS: KVM: Remove redundant NULL checks before kfree()
  MIPS: KVM: Remove redundant semicolon

 arch/mips/Kconfig                 |  12 +-
 arch/mips/include/asm/kvm_host.h  | 183 ++++++++++---
 arch/mips/include/uapi/asm/kvm.h  |  35 +++
 arch/mips/kvm/kvm_locore.S        |  32 ---
 arch/mips/kvm/kvm_mips.c          | 140 +++++-----
 arch/mips/kvm/kvm_mips_dyntrans.c |  15 +-
 arch/mips/kvm/kvm_mips_emul.c     | 557 ++++++++++++++++++++++++++++++++++++--
 arch/mips/kvm/kvm_tlb.c           |  77 +++---
 arch/mips/kvm/kvm_trap_emul.c     |  86 +++++-
 arch/mips/mm/cache.c              |   1 +
 arch/mips/mti-malta/malta-time.c  |  14 +-
 11 files changed, 920 insertions(+), 232 deletions(-)

Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Cc: Gleb Natapov <gleb@xxxxxxxxxx>
Cc: kvm@xxxxxxxxxxxxxxx
Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Cc: linux-mips@xxxxxxxxxxxxxx
Cc: David Daney <david.daney@xxxxxxxxxx>
Cc: Andreas Herrmann <andreas.herrmann@xxxxxxxxxxxxxxxxxx>
Cc: Sanjay Lal <sanjayl@xxxxxxxxxxx>


Applied, thanks. I hope you'll get the QEMU patches ready in time for 2.1! :)

Paolo


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