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

James Hogan
2014-05-29T09:16:22Z

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>