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

[Wanpeng Li <kernellwp@gmail.com>]

On Fri, 20 Jul 2018 at 16:32, Paolo Bonzini <pbonzini@redhat.com> wrote:
>
> On 20/07/2018 05:58, KY Srinivasan wrote:
> >
> >
> >> -----Original Message-----
> >> From: Tianyu Lan
> >> Sent: Thursday, July 19, 2018 1:40 AM
> >> Cc: Tianyu Lan <Tianyu.Lan@microsoft.com>; devel@linuxdriverproject.org;
> >> Haiyang Zhang <haiyangz@microsoft.com>; hpa@zytor.com;
> >> kvm@vger.kernel.org; KY Srinivasan <kys@microsoft.com>; linux-
> >> kernel@vger.kernel.org; mingo@redhat.com; pbonzini@redhat.com;
> >> rkrcmar@redhat.com; Stephen Hemminger <sthemmin@microsoft.com>;
> >> tglx@linutronix.de; x86@kernel.org; Michael Kelley (EOSG)
> >> <Michael.H.Kelley@microsoft.com>; vkuznets@redhat.com
> >> Subject: [PATCH V3 0/4] KVM/x86/hyper-V: Introduce PV guest address
> >> space mapping flush support
> >>
> >> 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.
> >>
> >> 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
> >
> > Acked-by: K. Y. Srinivasan <kys@microsoft.com>
>
> Queued, thanks!

My CONFIG_HYPERV is disabled, there is a warning when compiling kvm/queue.
warning: ‘hv_remote_flush_tlb’ defined but not used [-Wunused-function]
 static int hv_remote_flush_tlb(struct kvm *kvm)

Regards,
Wanpeng Li