Re: [PATCH 15/21] KVM: Move x86's MMU memory cache helpers to common KVM code

Ben Gardon
2020-06-10T20:24:37Z

On Fri, Jun 5, 2020 at 2:39 PM Sean Christopherson
<sean.j.christopherson@intel.com> wrote:
>
> Move x86's memory cache helpers to common KVM code so that they can be
> reused by arm64 and MIPS in future patches.
>
> Suggested-by: Christoffer Dall <christoffer.dall@arm.com>
> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Ben Gardon <bgardon@google.com>
> ---
> arch/x86/kvm/mmu/mmu.c | 53 --------------------------------------
> include/linux/kvm_host.h | 7 +++++
> virt/kvm/kvm_main.c | 55 ++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 62 insertions(+), 53 deletions(-)
>
> diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
> index b85d3e8e8403..a627437f73fd 100644
> --- a/arch/x86/kvm/mmu/mmu.c
> +++ b/arch/x86/kvm/mmu/mmu.c
> @@ -1060,47 +1060,6 @@ static void walk_shadow_page_lockless_end(struct kvm_vcpu *vcpu)
> local_irq_enable();
> }
>
> -static inline void *mmu_memory_cache_alloc_obj(struct kvm_mmu_memory_cache *mc,
> - gfp_t gfp_flags)
> -{
> - gfp_flags |= mc->gfp_zero;
> -
> - if (mc->kmem_cache)
> - return kmem_cache_alloc(mc->kmem_cache, gfp_flags);
> - else
> - return (void *)__get_free_page(gfp_flags);
> -}
> -
> -static int kvm_mmu_topup_memory_cache(struct kvm_mmu_memory_cache *mc, int min)
> -{
> - void *obj;
> -
> - if (mc->nobjs >= min)
> - return 0;
> - while (mc->nobjs < ARRAY_SIZE(mc->objects)) {
> - obj = mmu_memory_cache_alloc_obj(mc, GFP_KERNEL_ACCOUNT);
> - if (!obj)
> - return mc->nobjs >= min ? 0 : -ENOMEM;
> - mc->objects[mc->nobjs++] = obj;
> - }
> - return 0;
> -}
> -
> -static int kvm_mmu_memory_cache_nr_free_objects(struct kvm_mmu_memory_cache *mc)
> -{
> - return mc->nobjs;
> -}
> -
> -static void kvm_mmu_free_memory_cache(struct kvm_mmu_memory_cache *mc)
> -{
> - while (mc->nobjs) {
> - if (mc->kmem_cache)
> - kmem_cache_free(mc->kmem_cache, mc->objects[--mc->nobjs]);
> - else
> - free_page((unsigned long)mc->objects[--mc->nobjs]);
> - }
> -}
> -
> static int mmu_topup_memory_caches(struct kvm_vcpu *vcpu, bool maybe_indirect)
> {
> int r;
> @@ -1132,18 +1091,6 @@ static void mmu_free_memory_caches(struct kvm_vcpu *vcpu)
> kvm_mmu_free_memory_cache(&vcpu->arch.mmu_page_header_cache);
> }
>
> -static void *kvm_mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc)
> -{
> - void *p;
> -
> - if (WARN_ON(!mc->nobjs))
> - p = mmu_memory_cache_alloc_obj(mc, GFP_ATOMIC | __GFP_ACCOUNT);
> - else
> - p = mc->objects[--mc->nobjs];
> - BUG_ON(!p);
> - return p;
> -}
> -
> static struct pte_list_desc *mmu_alloc_pte_list_desc(struct kvm_vcpu *vcpu)
> {
> return kvm_mmu_memory_cache_alloc(&vcpu->arch.mmu_pte_list_desc_cache);
> diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
> index d38d6b9c24be..802b9e2306f0 100644
> --- a/include/linux/kvm_host.h
> +++ b/include/linux/kvm_host.h
> @@ -815,6 +815,13 @@ void kvm_vcpu_on_spin(struct kvm_vcpu *vcpu, bool usermode_vcpu_not_eligible);
> void kvm_flush_remote_tlbs(struct kvm *kvm);
> void kvm_reload_remote_mmus(struct kvm *kvm);
>
> +#ifdef KVM_ARCH_NR_OBJS_PER_MEMORY_CACHE
> +int kvm_mmu_topup_memory_cache(struct kvm_mmu_memory_cache *mc, int min);
> +int kvm_mmu_memory_cache_nr_free_objects(struct kvm_mmu_memory_cache *mc);
> +void kvm_mmu_free_memory_cache(struct kvm_mmu_memory_cache *mc);
> +void *kvm_mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc);
> +#endif
> +
> bool kvm_make_vcpus_request_mask(struct kvm *kvm, unsigned int req,
> struct kvm_vcpu *except,
> unsigned long *vcpu_bitmap, cpumask_var_t tmp);
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index 4db151f6101e..fead5f1d5594 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -342,6 +342,61 @@ void kvm_reload_remote_mmus(struct kvm *kvm)
> kvm_make_all_cpus_request(kvm, KVM_REQ_MMU_RELOAD);
> }
>
> +#ifdef KVM_ARCH_NR_OBJS_PER_MEMORY_CACHE
> +static inline void *mmu_memory_cache_alloc_obj(struct kvm_mmu_memory_cache *mc,
> + gfp_t gfp_flags)
> +{
> + gfp_flags |= mc->gfp_zero;
> +
> + if (mc->kmem_cache)
> + return kmem_cache_alloc(mc->kmem_cache, gfp_flags);
> + else
> + return (void *)__get_free_page(gfp_flags);
> +}
> +
> +int kvm_mmu_topup_memory_cache(struct kvm_mmu_memory_cache *mc, int min)
> +{
> + void *obj;
> +
> + if (mc->nobjs >= min)
> + return 0;
> + while (mc->nobjs < ARRAY_SIZE(mc->objects)) {
> + obj = mmu_memory_cache_alloc_obj(mc, GFP_KERNEL_ACCOUNT);
> + if (!obj)
> + return mc->nobjs >= min ? 0 : -ENOMEM;
> + mc->objects[mc->nobjs++] = obj;
> + }
> + return 0;
> +}
> +
> +int kvm_mmu_memory_cache_nr_free_objects(struct kvm_mmu_memory_cache *mc)
> +{
> + return mc->nobjs;
> +}
> +
> +void kvm_mmu_free_memory_cache(struct kvm_mmu_memory_cache *mc)
> +{
> + while (mc->nobjs) {
> + if (mc->kmem_cache)
> + kmem_cache_free(mc->kmem_cache, mc->objects[--mc->nobjs]);
> + else
> + free_page((unsigned long)mc->objects[--mc->nobjs]);
> + }
> +}
> +
> +void *kvm_mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc)
> +{
> + void *p;
> +
> + if (WARN_ON(!mc->nobjs))
> + p = mmu_memory_cache_alloc_obj(mc, GFP_ATOMIC | __GFP_ACCOUNT);
> + else
> + p = mc->objects[--mc->nobjs];
> + BUG_ON(!p);
> + return p;
> +}
> +#endif
> +
> static void kvm_vcpu_init(struct kvm_vcpu *vcpu, struct kvm *kvm, unsigned id)
> {
> mutex_init(&vcpu->mutex);
> --
> 2.26.0
>