[PATCH v6 0/4] live migration dirty bitmap support for ARMv7

[Christoffer Dall]

On Thu, May 15, 2014 at 11:27:27AM -0700, Mario Smarduch wrote:
> This is v6 patcheset of live mgiration support for ARMv7.

migration

This is an extremely terse cover letter.  It would have been nice with a
few sentences of which existing features this leverages, which support
was missing, what the preferred approach is, etc.  Also, links to a wiki
page or just a few notes on how you did the testing below with which
user space tools etc. would also have been great.

> 
> - Tested on two 4-way A15 hardware, QEMU 2-way/4-way SMP guest upto 2GB
> - Various dirty data rates tested - 2GB/1s ... 2048 pgs/5ms
> - validated source/destination memory image integrity
> 
> Changes since v1:
> - add unlock of VM mmu_lock to prevent a deadlock
> - moved migratiion active inside mmu_lock acquire for visibility in 2nd stage
>   data abort handler
> - Added comments
> 
> Changes since v2: 
> - move initial VM write protect to memory region architecture prepare function
>   (needed to make dirty logging function generic) 
> - added stage2_mark_pte_ro() - to mark ptes ro - Marc's comment
> - optimized initial VM memory region write protect to do fewer table lookups -
>   applied Marc's comment for walking dirty bitmap mask
> - added pud_addr_end() for stage2 tables, to make the walk 4-level
> - added kvm_flush_remote_tlbs() to use ARM TLB invalidation, made the generic
>   one weak, Marc's comment to for generic dirty bitmap log function
> - optimized walking dirty bit map mask to skip upper tables - Marc's comment
> - deleted x86,arm kvm_vm_ioctl_get_dirty_log(), moved to kvm_main.c tagged 
>   the function weak - Marc's comment
> - changed Data Abort handler pte index handling - Marc's comment
> 
> Changes since v3:
> - changed pte updates to reset write bit instead of setting default 
>   value for existing pte's - Steve's comment
> - In addition to PUD add 2nd stage >4GB range functions - Steves
>   suggestion
> - Restructured initial memory slot write protect function for PGD, PUD, PMD
>   table walking - Steves suggestion
> - Renamed variable types to resemble their use - Steves suggestions
> - Added couple pte helpers for 2nd stage tables - Steves suggestion
> - Updated unmap_range() that handles 2nd stage tables and identity mappings
>   to handle 2nd stage addresses >4GB. Left ARMv8 unchanged.
> 
> Changes since v4:
> - rebased to 3.15.0-rc1 - 'next' to pickup p*addr_end patches - Gavins comment
> - Update PUD address end function to support 4-level page table walk
> - Elimiated 5th patch of the series that fixed unmap_range(), since it was
>   fixed by Marcs patches.
> 
> Changes since v5:
> - Created seperate entry point for VMID TLB flush with no param - Christoffers
>   comment
> - Update documentation for kvm_flush_remote_tlbs() - Christoffers comment
> - Simplified splitting of huge pages - inittial WP and 2nd stage DABT handler
>   clear the huge page PMD, and use current code to fault in small pages.
>   Removed kvm_split_pmd().
> 
> Mario Smarduch (4):
>   add ARMv7 HYP API to flush VM TLBs without address param
>   live migration support for initial write protect of VM
>   live migration support for VM dirty log management
>   add 2nd stage page fault handling during live migration
> 
>  arch/arm/include/asm/kvm_asm.h  |    1 +
>  arch/arm/include/asm/kvm_host.h |   11 ++
>  arch/arm/include/asm/kvm_mmu.h  |   10 ++
>  arch/arm/kvm/arm.c              |    8 +-
>  arch/arm/kvm/interrupts.S       |   11 ++
>  arch/arm/kvm/mmu.c              |  292 ++++++++++++++++++++++++++++++++++++++-
>  arch/x86/kvm/x86.c              |   86 ------------
>  virt/kvm/kvm_main.c             |   84 ++++++++++-
>  8 files changed, 409 insertions(+), 94 deletions(-)
> 
> -- 
> 1.7.9.5
>