On 22/10/19 02:35, Sean Christopherson wrote: > The end goal of this series is to dynamically size the memslot array so > that KVM allocates memory based on the number of memslots in use, as > opposed to unconditionally allocating memory for the maximum number of > memslots. On x86, each memslot consumes 88 bytes, and so with 2 address > spaces of 512 memslots, each VM consumes ~90k bytes for the memslots. > E.g. given a VM that uses a total of 30 memslots, dynamic sizing reduces > the memory footprint from 90k to ~2.6k bytes. > > The changes required to support dynamic sizing are relatively small, > e.g. are essentially contained in patches 12/13 and 13/13. Patches 1-11 > clean up the memslot code, which has gotten quite crusy, especially > __kvm_set_memory_region(). The clean up is likely not strictly necessary > to switch to dynamic sizing, but I didn't have a remotely reasonable > level of confidence in the correctness of the dynamic sizing without first > doing the clean up. > > Testing, especially non-x86 platforms, would be greatly appreciated. The > non-x86 changes are for all intents and purposes untested, e.g. I compile > tested pieces of the code by copying them into x86, but that's it. In > theory, the vast majority of the functional changes are arch agnostic, in > theory... > > v2: > - Split "Drop kvm_arch_create_memslot()" into three patches to move > minor functional changes to standalone patches [Janosch]. > - Rebase to latest kvm/queue (f0574a1cea5b, "KVM: x86: fix ...") > - Collect an Acked-by and a Reviewed-by > > Sean Christopherson (15): > KVM: Reinstall old memslots if arch preparation fails > KVM: Don't free new memslot if allocation of said memslot fails > KVM: PPC: Move memslot memory allocation into prepare_memory_region() > KVM: x86: Allocate memslot resources during prepare_memory_region() > KVM: Drop kvm_arch_create_memslot() > KVM: Explicitly free allocated-but-unused dirty bitmap > KVM: Refactor error handling for setting memory region > KVM: Move setting of memslot into helper routine > KVM: Move memslot deletion to helper function > KVM: Simplify kvm_free_memslot() and all its descendents > KVM: Clean up local variable usage in __kvm_set_memory_region() > KVM: Provide common implementation for generic dirty log functions > KVM: Ensure validity of memslot with respect to kvm_get_dirty_log() > KVM: Terminate memslot walks via used_slots > KVM: Dynamically size memslot array based on number of used slots > > arch/mips/include/asm/kvm_host.h | 2 +- > arch/mips/kvm/mips.c | 68 +--- > arch/powerpc/include/asm/kvm_ppc.h | 14 +- > arch/powerpc/kvm/book3s.c | 22 +- > arch/powerpc/kvm/book3s_hv.c | 36 +- > arch/powerpc/kvm/book3s_pr.c | 20 +- > arch/powerpc/kvm/booke.c | 17 +- > arch/powerpc/kvm/powerpc.c | 13 +- > arch/s390/include/asm/kvm_host.h | 2 +- > arch/s390/kvm/kvm-s390.c | 21 +- > arch/x86/include/asm/kvm_page_track.h | 3 +- > arch/x86/kvm/page_track.c | 15 +- > arch/x86/kvm/x86.c | 100 ++--- > include/linux/kvm_host.h | 48 +-- > virt/kvm/arm/arm.c | 47 +-- > virt/kvm/arm/mmu.c | 18 +- > virt/kvm/kvm_main.c | 546 ++++++++++++++++---------- > 17 files changed, 467 insertions(+), 525 deletions(-) > Christian, Marc, Paul, can you help testing patches 1-13? Thanks,
