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

From: Paolo Bonzini
Date: Thu Jul 19 2018 - 04:57:50 EST


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

> 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
>