Also Cc Junaid Shahid, Ben Gardon On Wed, 5 Aug 2020 at 22:11, Yulei Zhang <yulei.kernel@xxxxxxxxx> wrote: > > From: Yulei Zhang <yuleixzhang@xxxxxxxxxxx> > > Currently in KVM memory virtulization we relay on mmu_lock to synchronize > the memory mapping update, which make vCPUs work in serialize mode and > slow down the execution, especially after migration to do substantial > memory mapping setup, and performance get worse if increase vCPU numbers > and guest memories. > > The idea we present in this patch set is to mitigate the issue with > pre-constructed memory mapping table. We will fast pin the guest memory > to build up a global memory mapping table according to the guest memslots > changes and apply it to cr3, so that after guest starts up all the vCPUs > would be able to update the memory concurrently, thus the performance > improvement is expected. > > And after test the initial patch with memory dirty pattern workload, we > have seen positive results even with huge page enabled. For example, > guest with 32 vCPUs and 64G memories, in 2M/1G huge page mode we would get > more than 50% improvement. > > > Yulei Zhang (9): > Introduce new fields in kvm_arch/vcpu_arch struct for direct build EPT > support > Introduce page table population function for direct build EPT feature > Introduce page table remove function for direct build EPT feature > Add release function for direct build ept when guest VM exit > Modify the page fault path to meet the direct build EPT requirement > Apply the direct build EPT according to the memory slots change > Add migration support when using direct build EPT > Introduce kvm module parameter global_tdp to turn on the direct build > EPT mode > Handle certain mmu exposed functions properly while turn on direct > build EPT mode > > arch/mips/kvm/mips.c | 13 + > arch/powerpc/kvm/powerpc.c | 13 + > arch/s390/kvm/kvm-s390.c | 13 + > arch/x86/include/asm/kvm_host.h | 13 +- > arch/x86/kvm/mmu/mmu.c | 537 ++++++++++++++++++++++++++++++-- > arch/x86/kvm/svm/svm.c | 2 +- > arch/x86/kvm/vmx/vmx.c | 17 +- > arch/x86/kvm/x86.c | 55 ++-- > include/linux/kvm_host.h | 7 +- > virt/kvm/kvm_main.c | 43 ++- > 10 files changed, 648 insertions(+), 65 deletions(-) > > -- > 2.17.1 >
