linux-kernel - Re: [Patch v4 13/18] KVM: mmu: Add common initialization logic for struct kvm_mmu_memory

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Date:   Tue, 28 Mar 2023 10:16:40 -0700
From:   Vipin Sharma <vipinsh@...gle.com>
To:     David Matlack <dmatlack@...gle.com>
Cc:     seanjc@...gle.com, pbonzini@...hat.com, bgardon@...gle.com,
        jmattson@...gle.com, mizhang@...gle.com, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [Patch v4 13/18] KVM: mmu: Add common initialization logic for
 struct kvm_mmu_memory_cache{}

On Thu, Mar 23, 2023 at 3:23 PM David Matlack <dmatlack@...gle.com> wrote:
>
> On Mon, Mar 06, 2023 at 02:41:22PM -0800, Vipin Sharma wrote:
> > Add macros and function to make common logic for struct
> > kvm_mmu_memory_cache{} declaration and initialization.
> >
> > Any user which wants different values in struct kvm_mmu_memory_cache{}
> > will overwrite the default values explicitly after the initialization.
> >
> > Suggested-by: David Matlack <dmatlack@...gle.com>
> > Signed-off-by: Vipin Sharma <vipinsh@...gle.com>
> > ---
> >  arch/arm64/kvm/arm.c      |  1 +
> >  arch/arm64/kvm/mmu.c      |  3 ++-
> >  arch/riscv/kvm/mmu.c      |  9 +++++----
> >  arch/riscv/kvm/vcpu.c     |  1 +
>
> MIPS also has cache (git grep "struct kvm_mmu_memory_cache").
>

I will respond in Patch 15 where I added stuff for MIPS.

> >  arch/x86/kvm/mmu/mmu.c    |  8 ++++++++
> >  include/linux/kvm_types.h | 10 ++++++++++
> >  6 files changed, 27 insertions(+), 5 deletions(-)
> >
> > diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
> > index 3bd732eaf087..2b3d88e4ace8 100644
> > --- a/arch/arm64/kvm/arm.c
> > +++ b/arch/arm64/kvm/arm.c
> > @@ -330,6 +330,7 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu)
> >       vcpu->arch.target = -1;
> >       bitmap_zero(vcpu->arch.features, KVM_VCPU_MAX_FEATURES);
> >
> > +     INIT_KVM_MMU_MEMORY_CACHE(&vcpu->arch.mmu_page_cache);
> >       vcpu->arch.mmu_page_cache.gfp_zero = __GFP_ZERO;
> >
> >       /*
> > diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
> > index 7113587222ff..8a56f071ca66 100644
> > --- a/arch/arm64/kvm/mmu.c
> > +++ b/arch/arm64/kvm/mmu.c
> > @@ -895,7 +895,7 @@ int kvm_phys_addr_ioremap(struct kvm *kvm, phys_addr_t guest_ipa,
> >  {
> >       phys_addr_t addr;
> >       int ret = 0;
> > -     struct kvm_mmu_memory_cache cache = { .gfp_zero = __GFP_ZERO };
> > +     KVM_MMU_MEMORY_CACHE(cache);
>
> nit: DEFINE_KVM_MMU_MEMORY_CACHE()
>
> (Based on similar existing macros in the kernel, e.g. DEFINE_MUTEX(),
> DEFINE_TIMER().)
>

I will update in v5.

> >       struct kvm_pgtable *pgt = kvm->arch.mmu.pgt;
> >       enum kvm_pgtable_prot prot = KVM_PGTABLE_PROT_DEVICE |
> >                                    KVM_PGTABLE_PROT_R |
> > @@ -904,6 +904,7 @@ int kvm_phys_addr_ioremap(struct kvm *kvm, phys_addr_t guest_ipa,
> >       if (is_protected_kvm_enabled())
> >               return -EPERM;
> >
> > +     cache.gfp_zero = __GFP_ZERO;
> >       size += offset_in_page(guest_ipa);
> >       guest_ipa &= PAGE_MASK;
> >
> > diff --git a/arch/riscv/kvm/mmu.c b/arch/riscv/kvm/mmu.c
> > index 78211aed36fa..bdd8c17958dd 100644
> > --- a/arch/riscv/kvm/mmu.c
> > +++ b/arch/riscv/kvm/mmu.c
> > @@ -351,10 +351,11 @@ int kvm_riscv_gstage_ioremap(struct kvm *kvm, gpa_t gpa,
> >       int ret = 0;
> >       unsigned long pfn;
> >       phys_addr_t addr, end;
> > -     struct kvm_mmu_memory_cache pcache = {
> > -             .gfp_custom = (in_atomic) ? GFP_ATOMIC | __GFP_ACCOUNT : 0,
> > -             .gfp_zero = __GFP_ZERO,
> > -     };
> > +     KVM_MMU_MEMORY_CACHE(pcache);
> > +
> > +     pcache.gfp_zero = __GFP_ZERO;
> > +     if (in_atomic)
> > +             pcache.gfp_custom = GFP_ATOMIC | __GFP_ACCOUNT;
> >
> >       end = (gpa + size + PAGE_SIZE - 1) & PAGE_MASK;
> >       pfn = __phys_to_pfn(hpa);
> > diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c
> > index 7d010b0be54e..bc743e9122d1 100644
> > --- a/arch/riscv/kvm/vcpu.c
> > +++ b/arch/riscv/kvm/vcpu.c
> > @@ -163,6 +163,7 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu)
> >
> >       /* Mark this VCPU never ran */
> >       vcpu->arch.ran_atleast_once = false;
> > +     INIT_KVM_MMU_MEMORY_CACHE(&vcpu->arch.mmu_page_cache);
> >       vcpu->arch.mmu_page_cache.gfp_zero = __GFP_ZERO;
> >       bitmap_zero(vcpu->arch.isa, RISCV_ISA_EXT_MAX);
> >
> > diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
> > index a4bf2e433030..b706087ef74e 100644
> > --- a/arch/x86/kvm/mmu/mmu.c
> > +++ b/arch/x86/kvm/mmu/mmu.c
> > @@ -5961,15 +5961,20 @@ int kvm_mmu_create(struct kvm_vcpu *vcpu)
> >  {
> >       int ret;
> >
> > +     INIT_KVM_MMU_MEMORY_CACHE(&vcpu->arch.mmu_pte_list_desc_cache);
> >       vcpu->arch.mmu_pte_list_desc_cache.kmem_cache = pte_list_desc_cache;
> >       vcpu->arch.mmu_pte_list_desc_cache.gfp_zero = __GFP_ZERO;
> >
> > +     INIT_KVM_MMU_MEMORY_CACHE(&vcpu->arch.mmu_page_header_cache);
> >       vcpu->arch.mmu_page_header_cache.kmem_cache = mmu_page_header_cache;
> >       vcpu->arch.mmu_page_header_cache.gfp_zero = __GFP_ZERO;
> >
> > +     INIT_KVM_MMU_MEMORY_CACHE(&vcpu->arch.mmu_shadow_page_cache);
> >       vcpu->arch.mmu_shadow_page_cache.gfp_zero = __GFP_ZERO;
> >       mutex_init(&vcpu->arch.mmu_shadow_page_cache_lock);
> >
> > +     INIT_KVM_MMU_MEMORY_CACHE(&vcpu->arch.mmu_shadowed_info_cache);
> > +
> >       vcpu->arch.mmu = &vcpu->arch.root_mmu;
> >       vcpu->arch.walk_mmu = &vcpu->arch.root_mmu;
> >
> > @@ -6131,11 +6136,14 @@ int kvm_mmu_init_vm(struct kvm *kvm)
> >       node->track_flush_slot = kvm_mmu_invalidate_zap_pages_in_memslot;
> >       kvm_page_track_register_notifier(kvm, node);
> >
> > +     INIT_KVM_MMU_MEMORY_CACHE(&kvm->arch.split_page_header_cache);
> >       kvm->arch.split_page_header_cache.kmem_cache = mmu_page_header_cache;
> >       kvm->arch.split_page_header_cache.gfp_zero = __GFP_ZERO;
> >
> > +     INIT_KVM_MMU_MEMORY_CACHE(&kvm->arch.split_shadow_page_cache);
> >       kvm->arch.split_shadow_page_cache.gfp_zero = __GFP_ZERO;
> >
> > +     INIT_KVM_MMU_MEMORY_CACHE(&kvm->arch.split_desc_cache);
> >       kvm->arch.split_desc_cache.kmem_cache = pte_list_desc_cache;
> >       kvm->arch.split_desc_cache.gfp_zero = __GFP_ZERO;
> >
> > diff --git a/include/linux/kvm_types.h b/include/linux/kvm_types.h
> > index 2728d49bbdf6..192516eeccac 100644
> > --- a/include/linux/kvm_types.h
> > +++ b/include/linux/kvm_types.h
> > @@ -98,6 +98,16 @@ struct kvm_mmu_memory_cache {
> >       int capacity;
> >       void **objects;
> >  };
> > +
> > +#define KVM_MMU_MEMORY_CACHE_INIT() { }
> > +
> > +#define KVM_MMU_MEMORY_CACHE(_name) \
> > +             struct kvm_mmu_memory_cache _name = KVM_MMU_MEMORY_CACHE_INIT()
>
> nit: There's an extra tab here.
>

Auto formatting is happy with two tabs only. I will update in the next
version. Thanks for catching it.

> > +
> > +static inline void INIT_KVM_MMU_MEMORY_CACHE(struct kvm_mmu_memory_cache *cache)
> > +{
> > +     *cache = (struct kvm_mmu_memory_cache)KVM_MMU_MEMORY_CACHE_INIT();
> > +}
> >  #endif
> >
> >  #define HALT_POLL_HIST_COUNT                 32
> > --
> > 2.40.0.rc0.216.gc4246ad0f0-goog
> >