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

[James Hogan <james.hogan@imgtec.com>]

On Friday 30 May 2014 13:07:13 Paolo Bonzini wrote:
> 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@redhat.com>
> > Cc: Gleb Natapov <gleb@kernel.org>
> > Cc: kvm@vger.kernel.org
> > Cc: Ralf Baechle <ralf@linux-mips.org>
> > Cc: linux-mips@linux-mips.org
> > Cc: David Daney <david.daney@cavium.com>
> > Cc: Andreas Herrmann <andreas.herrmann@caviumnetworks.com>
> > Cc: Sanjay Lal <sanjayl@kymasys.com>
> 
> Applied, thanks.

Thanks Paolo & Ralf!

> I hope you'll get the QEMU patches ready in time for
> 2.1! :)

Me too, 2.1 is the plan.

Cheers
James