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

[Tianyu Lan <Tianyu.Lan@microsoft.com>]

On 7/23/2018 3:39 PM, Wanpeng Li wrote:
> 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)

Thanks. Wanpeng! Just send a fix patch.

> 
> Regards,
> Wanpeng Li
>