Re: [PATCH v12 0/6] arm/KVM: dirty page logging support for ARMv7 (3.17.0-rc1)

[Wanpeng Li <wanpeng.li@linux.intel.com>]

Hi Mario,
On Wed, Oct 22, 2014 at 03:34:05PM -0700, Mario Smarduch wrote:
>This patch series introduces dirty page logging for ARMv7 and adds some degree 
>of generic dirty logging support for x86, armv7 and later armv8.
>
>I implemented Alex's  suggestion after he took a look at the patches at kvm
>forum to simplify the generic/arch split - leaving mips, powerpc, s390, 
>(ia64 although broken) unchanged. x86/armv7 now share some dirty logging code. 
>armv8 dirty log patches have been posted and tested but for time being armv8
>is non-generic as well.
>
>I briefly spoke to most of you at kvm forum, and this is the patch series
>I was referring to. Implementation changed from previous version (patches
>1 & 2), those who acked previous revision, please review again.
>
>Last 4 patches (ARM) have been rebased for newer kernel, with no signifcant
>changes.
> 
>Testing:
>- Generally live migration + checksumming of source/destination memory regions 
>  is used validate correctness. 

Could you tell me where to get the checksum you are using? In addition,
checksum should be used at which point of live migration?

Regards,
Wanpeng Li 

>- qemu machvirt, VExpress - Exynos 5440, FastModels - lmbench + dirty guest
>  memory cycling.
>- ARMv8 Foundation Model/kvmtool - Due to slight overlap in 2nd stage handlers
>  did a basic bringup using qemu.
>- x86_64 qemu  default machine model, tested migration on HP Z620, tested 
>  convergence for several dirty page rates
>
>See https://github.com/mjsmar/arm-dirtylog-tests
>    - Dirtlogtest-setup.pdf for ARMv7
>    - https://github.com/mjsmar/arm-dirtylog-tests/tree/master/v7 - README
>
>The patch affects armv7,armv8, mips, ia64, powerpc, s390, x86_64. Patch
>series has been compiled for affected architectures:
>
>- x86_64 - defconfig 
>- ia64 - ia64-linux-gcc4.6.3 - defconfig, ia64 Kconfig defines BROKEN worked 
>  around that to make sure new changes don't break build. Eventually build
>  breaks due to other reasons.
>- mips - mips64-linux-gcc4.6.3 - malta_kvm_defconfig
>- ppc - powerpc64-linux-gcc4.6.3 - pseries_defconfig
>- s390 - s390x-linux-gcc4.6.3 - defconfig
>- armv8 - aarch64-linux-gnu-gcc4.8.1 - defconfig
>
>ARMv7 Dirty page logging implementation overivew-
>- initially write protects VM RAM memory region - 2nd stage page tables
>- add support to read dirty page log and again write protect the dirty pages 
>  - second stage page table for next pass.
>- second stage huge page are dissolved into small page tables to keep track of
>  dirty pages at page granularity. Tracking at huge page granularity limits
>  migration to an almost idle system. Small page size logging supports higher 
>  memory dirty rates.
>- In the event migration is canceled, normal behavior is resumed huge pages
>  are rebuilt over time.
>
>Changes since v11:
>- Implemented Alex's comments to simplify generic layer.
>
>Changes since v10:
>- addressed wanghaibin comments 
>- addressed Christoffers comments
>
>Changes since v9:
>- Split patches into generic and architecture specific variants for TLB Flushing
>  and dirty log read (patches 1,2 & 3,4,5,6)
>- rebased to 3.16.0-rc1
>- Applied Christoffers comments.
>
>Mario Smarduch (6):
>  KVM: Add architecture-defined TLB flush support
>  KVM: Add generic support for dirty page logging
>  arm: KVM: Add ARMv7 API to flush TLBs
>  arm: KVM: Add initial dirty page locking infrastructure
>  arm: KVM: dirty log read write protect support
>  arm: KVM: ARMv7 dirty page logging 2nd stage page fault
>
> arch/arm/include/asm/kvm_asm.h        |    1 +
> arch/arm/include/asm/kvm_host.h       |   14 +++
> arch/arm/include/asm/kvm_mmu.h        |   20 ++++
> arch/arm/include/asm/pgtable-3level.h |    1 +
> arch/arm/kvm/Kconfig                  |    2 +
> arch/arm/kvm/Makefile                 |    1 +
> arch/arm/kvm/arm.c                    |    2 +
> arch/arm/kvm/interrupts.S             |   11 ++
> arch/arm/kvm/mmu.c                    |  209 +++++++++++++++++++++++++++++++--
> arch/x86/include/asm/kvm_host.h       |    3 -
> arch/x86/kvm/Kconfig                  |    1 +
> arch/x86/kvm/Makefile                 |    1 +
> arch/x86/kvm/x86.c                    |   86 --------------
> include/linux/kvm_host.h              |    4 +
> virt/kvm/Kconfig                      |    6 +
> virt/kvm/dirtylog.c                   |  112 ++++++++++++++++++
> virt/kvm/kvm_main.c                   |    2 +
> 17 files changed, 380 insertions(+), 96 deletions(-)
> create mode 100644 virt/kvm/dirtylog.c
>
>-- 
>1.7.9.5
>
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