Re: [PATCH V3 0/4] KVM/x86/hyper-V: Introduce PV guest address space mapping flush support

From: Tianyu Lan
Date: Thu Jul 19 2018 - 05:31:48 EST


On 7/19/2018 4:57 PM, Paolo Bonzini wrote:
> On 19/07/2018 10:39, Tianyu Lan wrote:
>> Hyper-V provides a para-virtualization hypercall HvFlushGuestPhysicalAddressSpace
>> to flush nested VM address space mapping in l1 hypervisor and it's to reduce overhead
>> of flushing ept tlb among vcpus. The tradition way is to send IPIs to all affected
>> vcpus and executes INVEPT on each vcpus. It will trigger several vmexits for IPI and
>> INVEPT emulation. The pv hypercall can help to flush specified ept table on all vcpus
>> via one single hypercall.
>
> Thanks, this looks good apart from a global replace of EFAULT with
> ENOTSUP (which can be done when applying). Can I have an explicit ack
> for patches 1 and 2 from the Hyper-V people?

Thanks, Paolo. I will try to hyper-V people's ack.

>
> Thanks,
>
> Paolo
>
>> Change since v2:
>> - Make ept_pointers_match as tristate "check", "match" and "mismatch".
>> Set "check" in vmx_set_cr3(), check all ept table pointers in hv_remote_flush_tlb()
>> and call hypercall when all ept pointers are same.
>> - Rename kvm_arch_hv_flush_remote_tlb with kvm_arch_flush_remote_tlb and
>> Rename kvm_x86_ops->hv_tlb_remote_flush with kvm_x86_ops->tlb_remote_flush
>> - Fix issue that ignore updating tlbs_dirty during calling kvm_arch_flush_remote_tlbs()
>> - Merge patch "KVM/VMX: Add identical ept table pointer check" and
>> patch "KVM/x86: Add tlb_remote_flush callback support for vmx"
>>
>> Change since v1:
>> - Fix compilation error for non-x86 platform.
>> - Use ept_pointers_match to check condition of identical ept
>> table pointer and get ept pointer from struct vcpu_vmx->ept_pointer.
>> - Add hyperv_nested_flush_guest_mapping ftrace support
>>
>>
>>
>> Lan Tianyu (4):
>> X86/Hyper-V: Add flush HvFlushGuestPhysicalAddressSpace hypercall
>> support
>> X86/Hyper-V: Add hyperv_nested_flush_guest_mapping ftrace support
>> KVM: Add tlb remote flush callback in kvm_x86_ops.
>> KVM/x86: Add tlb_remote_flush callback support for vmx
>>
>> arch/x86/hyperv/Makefile | 2 +-
>> arch/x86/hyperv/nested.c | 67 ++++++++++++++++++++++++++++++++++
>> arch/x86/include/asm/hyperv-tlfs.h | 8 +++++
>> arch/x86/include/asm/kvm_host.h | 11 ++++++
>> arch/x86/include/asm/mshyperv.h | 2 ++
>> arch/x86/include/asm/trace/hyperv.h | 14 ++++++++
>> arch/x86/kvm/vmx.c | 72 ++++++++++++++++++++++++++++++++++++-
>> include/linux/kvm_host.h | 7 ++++
>> virt/kvm/kvm_main.c | 3 +-
>> 9 files changed, 183 insertions(+), 3 deletions(-)
>> create mode 100644 arch/x86/hyperv/nested.c
>>
>