linux-kernel - Re: [PATCH v4 12/29] KVM: x86/mmu: Move kvm_arch_flush_shadow

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Message-ID: <20230803235017.GA2257301@ls.amr.corp.intel.com>
Date:   Thu, 3 Aug 2023 16:50:17 -0700
From:   Isaku Yamahata <isaku.yamahata@...il.com>
To:     Sean Christopherson <seanjc@...gle.com>
Cc:     Paolo Bonzini <pbonzini@...hat.com>,
        Zhenyu Wang <zhenyuw@...ux.intel.com>,
        Zhi Wang <zhi.a.wang@...el.com>, kvm@...r.kernel.org,
        intel-gvt-dev@...ts.freedesktop.org,
        intel-gfx@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
        Yan Zhao <yan.y.zhao@...el.com>,
        Yongwei Ma <yongwei.ma@...el.com>,
        Ben Gardon <bgardon@...gle.com>, isaku.yamahata@...il.com
Subject: Re: [PATCH v4 12/29] KVM: x86/mmu: Move
 kvm_arch_flush_shadow_{all,memslot}() to mmu.c

On Fri, Jul 28, 2023 at 06:35:18PM -0700,
Sean Christopherson <seanjc@...gle.com> wrote:

> Move x86's implementation of kvm_arch_flush_shadow_{all,memslot}() into
> mmu.c, and make kvm_mmu_zap_all() static as it was globally visible only
> for kvm_arch_flush_shadow_all().  This will allow refactoring
> kvm_arch_flush_shadow_memslot() to call kvm_mmu_zap_all() directly without
> having to expose kvm_mmu_zap_all_fast() outside of mmu.c.  Keeping
> everything in mmu.c will also likely simplify supporting TDX, which
> intends to do zap only relevant SPTEs on memslot updates.

Yes, it helps TDX code cleaner to move mmu related function under mmu.c.
Reviewed-by: Isaku Yamahata <isaku.yamahata@...el.com>

Thanks,

> 
> No functional change intended.
> 
> Suggested-by: Yan Zhao <yan.y.zhao@...el.com>
> Tested-by: Yongwei Ma <yongwei.ma@...el.com>
> Signed-off-by: Sean Christopherson <seanjc@...gle.com>
> ---
>  arch/x86/include/asm/kvm_host.h |  1 -
>  arch/x86/kvm/mmu/mmu.c          | 13 ++++++++++++-
>  arch/x86/kvm/x86.c              | 11 -----------
>  3 files changed, 12 insertions(+), 13 deletions(-)
> 
> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
> index 28bd38303d70..856ec22aceb6 100644
> --- a/arch/x86/include/asm/kvm_host.h
> +++ b/arch/x86/include/asm/kvm_host.h
> @@ -1832,7 +1832,6 @@ void kvm_mmu_zap_collapsible_sptes(struct kvm *kvm,
>  				   const struct kvm_memory_slot *memslot);
>  void kvm_mmu_slot_leaf_clear_dirty(struct kvm *kvm,
>  				   const struct kvm_memory_slot *memslot);
> -void kvm_mmu_zap_all(struct kvm *kvm);
>  void kvm_mmu_invalidate_mmio_sptes(struct kvm *kvm, u64 gen);
>  void kvm_mmu_change_mmu_pages(struct kvm *kvm, unsigned long kvm_nr_mmu_pages);
>  
> diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
> index ec169f5c7dce..c6dee659d592 100644
> --- a/arch/x86/kvm/mmu/mmu.c
> +++ b/arch/x86/kvm/mmu/mmu.c
> @@ -6732,7 +6732,7 @@ void kvm_mmu_slot_leaf_clear_dirty(struct kvm *kvm,
>  	 */
>  }
>  
> -void kvm_mmu_zap_all(struct kvm *kvm)
> +static void kvm_mmu_zap_all(struct kvm *kvm)
>  {
>  	struct kvm_mmu_page *sp, *node;
>  	LIST_HEAD(invalid_list);
> @@ -6757,6 +6757,17 @@ void kvm_mmu_zap_all(struct kvm *kvm)
>  	write_unlock(&kvm->mmu_lock);
>  }
>  
> +void kvm_arch_flush_shadow_all(struct kvm *kvm)
> +{
> +	kvm_mmu_zap_all(kvm);
> +}
> +
> +void kvm_arch_flush_shadow_memslot(struct kvm *kvm,
> +				   struct kvm_memory_slot *slot)
> +{
> +	kvm_page_track_flush_slot(kvm, slot);
> +}
> +
>  void kvm_mmu_invalidate_mmio_sptes(struct kvm *kvm, u64 gen)
>  {
>  	WARN_ON(gen & KVM_MEMSLOT_GEN_UPDATE_IN_PROGRESS);
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index a6b9bea62fb8..059571d5abed 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -12776,17 +12776,6 @@ void kvm_arch_commit_memory_region(struct kvm *kvm,
>  		kvm_arch_free_memslot(kvm, old);
>  }
>  
> -void kvm_arch_flush_shadow_all(struct kvm *kvm)
> -{
> -	kvm_mmu_zap_all(kvm);
> -}
> -
> -void kvm_arch_flush_shadow_memslot(struct kvm *kvm,
> -				   struct kvm_memory_slot *slot)
> -{
> -	kvm_page_track_flush_slot(kvm, slot);
> -}
> -
>  static inline bool kvm_guest_apic_has_interrupt(struct kvm_vcpu *vcpu)
>  {
>  	return (is_guest_mode(vcpu) &&
> -- 
> 2.41.0.487.g6d72f3e995-goog
> 

-- 
Isaku Yamahata <isaku.yamahata@...il.com>