On Mon, Jan 28, 2019 at 03:48:41PM +0100, Christoffer Dall wrote:
> We are currently duplicating the mmu memory cache functionality quite
> heavily between the architectures that support KVM. As a first step,
> move the x86 implementation (which seems to have the most recently
> maintained version of the mmu memory cache) to common code.
>
> We rename the functions and data types to have a kvm_ prefix for
> anything exported as a symbol to the rest of the kernel and take the
> chance to rename memory_cache to memcache to avoid overly long lines.
It'd be helpful to do the rename it a separate patch so that the move
really is a straight move of code.
> This is a bit tedious on the callsites but ends up looking more
> palatable.
>
> We also introduce an arch-specific kvm_types.h which can be used to
> define the architecture-specific GFP flags for allocating memory to the
> memory cache, and to specify how many objects are required in the memory
> cache. These are the two points where the current implementations
> diverge across architectures. Since kvm_host.h defines structures with
> fields of the memcache object, we define the memcache structure in
> kvm_types.h, and we include the architecture-specific kvm_types.h to
> know the size of object in kvm_host.h.
>
> This patch currently only defines the structure and requires valid
> defines in the architecture-specific kvm_types.h when KVM_NR_MEM_OBJS is
> defined. As we move each architecture to the common implementation,
> this condition will eventually go away.
>
> Signed-off-by: Christoffer Dall <christoffer.dall@xxxxxxx>
> ---
> arch/arm/include/asm/kvm_types.h | 5 ++
> arch/arm64/include/asm/kvm_types.h | 6 ++
> arch/mips/include/asm/kvm_types.h | 5 ++
> arch/powerpc/include/asm/kvm_types.h | 5 ++
> arch/s390/include/asm/kvm_types.h | 5 ++
> arch/x86/include/asm/kvm_host.h | 17 +----
> arch/x86/include/asm/kvm_types.h | 10 +++
> arch/x86/kvm/mmu.c | 97 ++++++----------------------
> arch/x86/kvm/paging_tmpl.h | 4 +-
> include/linux/kvm_host.h | 9 +++
> include/linux/kvm_types.h | 12 ++++
> virt/kvm/kvm_main.c | 58 +++++++++++++++++
> 12 files changed, 139 insertions(+), 94 deletions(-)
> create mode 100644 arch/arm/include/asm/kvm_types.h
> create mode 100644 arch/arm64/include/asm/kvm_types.h
> create mode 100644 arch/mips/include/asm/kvm_types.h
> create mode 100644 arch/powerpc/include/asm/kvm_types.h
> create mode 100644 arch/s390/include/asm/kvm_types.h
> create mode 100644 arch/x86/include/asm/kvm_types.h
>
> diff --git a/arch/arm/include/asm/kvm_types.h b/arch/arm/include/asm/kvm_types.h
> new file mode 100644
> index 000000000000..bc389f82e88d
> --- /dev/null
> +++ b/arch/arm/include/asm/kvm_types.h
> @@ -0,0 +1,5 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef _ASM_ARM_KVM_TYPES_H
> +#define _ASM_ARM_KVM_TYPES_H
> +
> +#endif /* _ASM_ARM_KVM_TYPES_H */
> diff --git a/arch/arm64/include/asm/kvm_types.h b/arch/arm64/include/asm/kvm_types.h
> new file mode 100644
> index 000000000000..d0987007d581
> --- /dev/null
> +++ b/arch/arm64/include/asm/kvm_types.h
> @@ -0,0 +1,6 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef _ASM_ARM64_KVM_TYPES_H
> +#define _ASM_ARM64_KVM_TYPES_H
> +
> +#endif /* _ASM_ARM64_KVM_TYPES_H */
> +
> diff --git a/arch/mips/include/asm/kvm_types.h b/arch/mips/include/asm/kvm_types.h
> new file mode 100644
> index 000000000000..5efeb32a5926
> --- /dev/null
> +++ b/arch/mips/include/asm/kvm_types.h
> @@ -0,0 +1,5 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef _ASM_MIPS_KVM_TYPES_H
> +#define _ASM_MIPS_KVM_TYPES_H
> +
> +#endif /* _ASM_MIPS_KVM_TYPES_H */
> diff --git a/arch/powerpc/include/asm/kvm_types.h b/arch/powerpc/include/asm/kvm_types.h
> new file mode 100644
> index 000000000000..f627eceaa314
> --- /dev/null
> +++ b/arch/powerpc/include/asm/kvm_types.h
> @@ -0,0 +1,5 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef _ASM_POWERPC_KVM_TYPES_H
> +#define _ASM_POWERPC_KVM_TYPES_H
> +
> +#endif /* _ASM_POWERPC_KVM_TYPES_H */
> diff --git a/arch/s390/include/asm/kvm_types.h b/arch/s390/include/asm/kvm_types.h
> new file mode 100644
> index 000000000000..b66a81f8a354
> --- /dev/null
> +++ b/arch/s390/include/asm/kvm_types.h
> @@ -0,0 +1,5 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef _ASM_S390_KVM_TYPES_H
> +#define _ASM_S390_KVM_TYPES_H
> +
> +#endif /* _ASM_S390_KVM_TYPES_H */
> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
> index 4660ce90de7f..5c12cba8c2b1 100644
> --- a/arch/x86/include/asm/kvm_host.h
> +++ b/arch/x86/include/asm/kvm_host.h
> @@ -179,8 +179,6 @@ enum {
>
> #include <asm/kvm_emulate.h>
>
> -#define KVM_NR_MEM_OBJS 40
> -
> #define KVM_NR_DB_REGS 4
>
> #define DR6_BD (1 << 13)
> @@ -238,15 +236,6 @@ enum {
>
> struct kvm_kernel_irq_routing_entry;
>
> -/*
> - * We don't want allocation failures within the mmu code, so we preallocate
> - * enough memory for a single page fault in a cache.
> - */
> -struct kvm_mmu_memory_cache {
> - int nobjs;
> - void *objects[KVM_NR_MEM_OBJS];
> -};
> -
> /*
> * the pages used as guest page table on soft mmu are tracked by
> * kvm_memory_slot.arch.gfn_track which is 16 bits, so the role bits used
> @@ -600,9 +589,9 @@ struct kvm_vcpu_arch {
> */
> struct kvm_mmu *walk_mmu;
>
> - struct kvm_mmu_memory_cache mmu_pte_list_desc_cache;
> - struct kvm_mmu_memory_cache mmu_page_cache;
> - struct kvm_mmu_memory_cache mmu_page_header_cache;
> + struct kvm_mmu_memcache mmu_pte_list_desc_cache;
> + struct kvm_mmu_memcache mmu_page_cache;
> + struct kvm_mmu_memcache mmu_page_header_cache;
>
> /*
> * QEMU userspace and the guest each have their own FPU state.
> diff --git a/arch/x86/include/asm/kvm_types.h b/arch/x86/include/asm/kvm_types.h
> new file mode 100644
> index 000000000000..f71fe5556b6f
> --- /dev/null
> +++ b/arch/x86/include/asm/kvm_types.h
> @@ -0,0 +1,10 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef _ASM_X86_KVM_TYPES_H
> +#define _ASM_X86_KVM_TYPES_H
> +
> +#define KVM_NR_MEM_OBJS 40
> +
> +#define KVM_MMU_CACHE_GFP GFP_KERNEL
> +#define KVM_MMU_CACHE_PAGE_GFP GFP_KERNEL_ACCOUNT
> +
> +#endif /* _ASM_X86_KVM_TYPES_H */
> diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
> index ce770b446238..cf0024849404 100644
> --- a/arch/x86/kvm/mmu.c
> +++ b/arch/x86/kvm/mmu.c
> @@ -951,94 +951,35 @@ static void walk_shadow_page_lockless_end(struct kvm_vcpu *vcpu)
> local_irq_enable();
> }
>
> -static int mmu_topup_memory_cache(struct kvm_mmu_memory_cache *cache,
> - struct kmem_cache *base_cache, int min)
> -{
> - void *obj;
> -
> - if (cache->nobjs >= min)
> - return 0;
> - while (cache->nobjs < ARRAY_SIZE(cache->objects)) {
> - obj = kmem_cache_zalloc(base_cache, GFP_KERNEL);
> - if (!obj)
> - return cache->nobjs >= min ? 0 : -ENOMEM;
> - cache->objects[cache->nobjs++] = obj;
> - }
> - return 0;
> -}
> -
> -static int mmu_memory_cache_free_objects(struct kvm_mmu_memory_cache *cache)
> -{
> - return cache->nobjs;
> -}
> -
> -static void mmu_free_memory_cache(struct kvm_mmu_memory_cache *mc,
> - struct kmem_cache *cache)
> -{
> - while (mc->nobjs)
> - kmem_cache_free(cache, mc->objects[--mc->nobjs]);
> -}
> -
> -static int mmu_topup_memory_cache_page(struct kvm_mmu_memory_cache *cache,
> - int min)
> -{
> - void *page;
> -
> - if (cache->nobjs >= min)
> - return 0;
> - while (cache->nobjs < ARRAY_SIZE(cache->objects)) {
> - page = (void *)__get_free_page(GFP_KERNEL_ACCOUNT);
> - if (!page)
> - return cache->nobjs >= min ? 0 : -ENOMEM;
> - cache->objects[cache->nobjs++] = page;
> - }
> - return 0;
> -}
> -
> -static void mmu_free_memory_cache_page(struct kvm_mmu_memory_cache *mc)
> -{
> - while (mc->nobjs)
> - free_page((unsigned long)mc->objects[--mc->nobjs]);
> -}
> -
> -static int mmu_topup_memory_caches(struct kvm_vcpu *vcpu)
> +static int mmu_topup_memcaches(struct kvm_vcpu *vcpu)
> {
> int r;
>
> - r = mmu_topup_memory_cache(&vcpu->arch.mmu_pte_list_desc_cache,
> + r = kvm_mmu_topup_memcache(&vcpu->arch.mmu_pte_list_desc_cache,
> pte_list_desc_cache, 8 + PTE_PREFETCH_NUM);
> if (r)
> goto out;
> - r = mmu_topup_memory_cache_page(&vcpu->arch.mmu_page_cache, 8);
> + r = kvm_mmu_topup_memcache_page(&vcpu->arch.mmu_page_cache, 8);
> if (r)
> goto out;
> - r = mmu_topup_memory_cache(&vcpu->arch.mmu_page_header_cache,
> + r = kvm_mmu_topup_memcache(&vcpu->arch.mmu_page_header_cache,
> mmu_page_header_cache, 4);
> out:
> return r;
> }
>
> -static void mmu_free_memory_caches(struct kvm_vcpu *vcpu)
> +static void mmu_free_memcaches(struct kvm_vcpu *vcpu)
> {
> - mmu_free_memory_cache(&vcpu->arch.mmu_pte_list_desc_cache,
> + kvm_mmu_free_memcache(&vcpu->arch.mmu_pte_list_desc_cache,
> pte_list_desc_cache);
> - mmu_free_memory_cache_page(&vcpu->arch.mmu_page_cache);
> - mmu_free_memory_cache(&vcpu->arch.mmu_page_header_cache,
> + kvm_mmu_free_memcache_page(&vcpu->arch.mmu_page_cache);
> + kvm_mmu_free_memcache(&vcpu->arch.mmu_page_header_cache,
> mmu_page_header_cache);
> }
>
> -static void *mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc)
> -{
> - void *p;
> -
> - BUG_ON(!mc->nobjs);
> - p = mc->objects[--mc->nobjs];
> - return p;
> -}
> -
> static struct pte_list_desc *mmu_alloc_pte_list_desc(struct kvm_vcpu *vcpu)
> {
> - return mmu_memory_cache_alloc(&vcpu->arch.mmu_pte_list_desc_cache);
> + return kvm_mmu_memcache_alloc(&vcpu->arch.mmu_pte_list_desc_cache);
> }
>
> static void mmu_free_pte_list_desc(struct pte_list_desc *pte_list_desc)
> @@ -1358,10 +1299,10 @@ static struct kvm_rmap_head *gfn_to_rmap(struct kvm *kvm, gfn_t gfn,
>
> static bool rmap_can_add(struct kvm_vcpu *vcpu)
> {
> - struct kvm_mmu_memory_cache *cache;
> + struct kvm_mmu_memcache *cache;
>
> cache = &vcpu->arch.mmu_pte_list_desc_cache;
> - return mmu_memory_cache_free_objects(cache);
> + return kvm_mmu_memcache_free_objects(cache);
> }
>
> static int rmap_add(struct kvm_vcpu *vcpu, u64 *spte, gfn_t gfn)
> @@ -2044,10 +1985,10 @@ static struct kvm_mmu_page *kvm_mmu_alloc_page(struct kvm_vcpu *vcpu, int direct
> {
> struct kvm_mmu_page *sp;
>
> - sp = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_header_cache);
> - sp->spt = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_cache);
> + sp = kvm_mmu_memcache_alloc(&vcpu->arch.mmu_page_header_cache);
> + sp->spt = kvm_mmu_memcache_alloc(&vcpu->arch.mmu_page_cache);
> if (!direct)
> - sp->gfns = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_cache);
> + sp->gfns = kvm_mmu_memcache_alloc(&vcpu->arch.mmu_page_cache);
> set_page_private(virt_to_page(sp->spt), (unsigned long)sp);
>
> /*
> @@ -3961,7 +3902,7 @@ static int nonpaging_page_fault(struct kvm_vcpu *vcpu, gva_t gva,
> if (page_fault_handle_page_track(vcpu, error_code, gfn))
> return RET_PF_EMULATE;
>
> - r = mmu_topup_memory_caches(vcpu);
> + r = mmu_topup_memcaches(vcpu);
> if (r)
> return r;
>
> @@ -4090,7 +4031,7 @@ static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa, u32 error_code,
> if (page_fault_handle_page_track(vcpu, error_code, gfn))
> return RET_PF_EMULATE;
>
> - r = mmu_topup_memory_caches(vcpu);
> + r = mmu_topup_memcaches(vcpu);
> if (r)
> return r;
>
> @@ -5062,7 +5003,7 @@ int kvm_mmu_load(struct kvm_vcpu *vcpu)
> {
> int r;
>
> - r = mmu_topup_memory_caches(vcpu);
> + r = mmu_topup_memcaches(vcpu);
> if (r)
> goto out;
> r = mmu_alloc_roots(vcpu);
> @@ -5240,7 +5181,7 @@ static void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
> * or not since pte prefetch is skiped if it does not have
> * enough objects in the cache.
> */
> - mmu_topup_memory_caches(vcpu);
> + mmu_topup_memcaches(vcpu);
>
> spin_lock(&vcpu->kvm->mmu_lock);
>
> @@ -6052,7 +5993,7 @@ void kvm_mmu_destroy(struct kvm_vcpu *vcpu)
> {
> kvm_mmu_unload(vcpu);
> free_mmu_pages(vcpu);
> - mmu_free_memory_caches(vcpu);
> + mmu_free_memcaches(vcpu);
> }
>
> void kvm_mmu_module_exit(void)
> diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
> index 6bdca39829bc..c32b603639a9 100644
> --- a/arch/x86/kvm/paging_tmpl.h
> +++ b/arch/x86/kvm/paging_tmpl.h
> @@ -747,7 +747,7 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr, u32 error_code,
>
> pgprintk("%s: addr %lx err %x\n", __func__, addr, error_code);
>
> - r = mmu_topup_memory_caches(vcpu);
> + r = mmu_topup_memcaches(vcpu);
> if (r)
> return r;
>
> @@ -870,7 +870,7 @@ static void FNAME(invlpg)(struct kvm_vcpu *vcpu, gva_t gva, hpa_t root_hpa)
> * No need to check return value here, rmap_can_add() can
> * help us to skip pte prefetch later.
> */
> - mmu_topup_memory_caches(vcpu);
> + mmu_topup_memcaches(vcpu);
>
> if (!VALID_PAGE(root_hpa)) {
> WARN_ON(1);
> diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
> index c38cc5eb7e73..f5768e5d33f7 100644
> --- a/include/linux/kvm_host.h
> +++ b/include/linux/kvm_host.h
> @@ -739,6 +739,15 @@ 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);
>
> +int kvm_mmu_topup_memcache(struct kvm_mmu_memcache *cache,
> + struct kmem_cache *base_cache, int min);
> +int kvm_mmu_memcache_free_objects(struct kvm_mmu_memcache *cache);
> +void kvm_mmu_free_memcache(struct kvm_mmu_memcache *mc,
> + struct kmem_cache *cache);
> +int kvm_mmu_topup_memcache_page(struct kvm_mmu_memcache *cache, int min);
> +void kvm_mmu_free_memcache_page(struct kvm_mmu_memcache *mc);
> +void *kvm_mmu_memcache_alloc(struct kvm_mmu_memcache *mc);
> +
> bool kvm_make_vcpus_request_mask(struct kvm *kvm, unsigned int req,
> unsigned long *vcpu_bitmap, cpumask_var_t tmp);
> bool kvm_make_all_cpus_request(struct kvm *kvm, unsigned int req);
> diff --git a/include/linux/kvm_types.h b/include/linux/kvm_types.h
> index 8bf259dae9f6..a314f0f08e22 100644
> --- a/include/linux/kvm_types.h
> +++ b/include/linux/kvm_types.h
> @@ -32,6 +32,7 @@ struct kvm_memslots;
>
> enum kvm_mr_change;
>
> +#include <asm/kvm_types.h>
> #include <asm/types.h>
>
> /*
> @@ -63,4 +64,15 @@ struct gfn_to_hva_cache {
> struct kvm_memory_slot *memslot;
> };
>
> +#ifdef KVM_NR_MEM_OBJS
While you're renaming the functions, would it make sense to also rename
the define, e.g. KVM_MMU_NR_MEMCACHE_OBJS, or maybe something a little
less verbose.
> +/*
> + * We don't want allocation failures within the mmu code, so we preallocate
> + * enough memory for a single page fault in a cache.
> + */
> +struct kvm_mmu_memcache {
Wrapping the kvm_mmu_memcache definition in KVM_NR_MEM_OBJS will break
compilation on any arch that doesn't define KVM_NR_MEM_OBJS.
> + int nobjs;
> + void *objects[KVM_NR_MEM_OBJS];
> +};
> +#endif
> +
> #endif /* __KVM_TYPES_H__ */
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index 5ecea812cb6a..ae6454a77aa8 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -285,6 +285,64 @@ void kvm_reload_remote_mmus(struct kvm *kvm)
> kvm_make_all_cpus_request(kvm, KVM_REQ_MMU_RELOAD);
> }
>
> +int kvm_mmu_topup_memcache(struct kvm_mmu_memcache *cache,
> + struct kmem_cache *base_cache, int min)
> +{
> + void *obj;
> +
> + if (cache->nobjs >= min)
> + return 0;
> + while (cache->nobjs < ARRAY_SIZE(cache->objects)) {
> + obj = kmem_cache_zalloc(base_cache, KVM_MMU_CACHE_GFP);
> + if (!obj)
> + return cache->nobjs >= min ? 0 : -ENOMEM;
> + cache->objects[cache->nobjs++] = obj;
> + }
> + return 0;
> +}
> +
> +int kvm_mmu_memcache_free_objects(struct kvm_mmu_memcache *cache)
> +{
> + return cache->nobjs;
> +}
> +
> +void kvm_mmu_free_memcache(struct kvm_mmu_memcache *mc,
> + struct kmem_cache *cache)
> +{
> + while (mc->nobjs)
> + kmem_cache_free(cache, mc->objects[--mc->nobjs]);
> +}
> +
> +int kvm_mmu_topup_memcache_page(struct kvm_mmu_memcache *cache, int min)
> +{
> + void *page;
> +
> + if (cache->nobjs >= min)
> + return 0;
> + while (cache->nobjs < ARRAY_SIZE(cache->objects)) {
> + page = (void *)__get_free_page(KVM_MMU_CACHE_PAGE_GFP);
> + if (!page)
> + return cache->nobjs >= min ? 0 : -ENOMEM;
> + cache->objects[cache->nobjs++] = page;
> + }
> + return 0;
> +}
> +
> +void kvm_mmu_free_memcache_page(struct kvm_mmu_memcache *mc)
> +{
> + while (mc->nobjs)
> + free_page((unsigned long)mc->objects[--mc->nobjs]);
> +}
> +
> +void *kvm_mmu_memcache_alloc(struct kvm_mmu_memcache *mc)
> +{
> + void *p;
> +
> + BUG_ON(!mc->nobjs);
> + p = mc->objects[--mc->nobjs];
> + return p;
> +}
> +
> int kvm_vcpu_init(struct kvm_vcpu *vcpu, struct kvm *kvm, unsigned id)
> {
> struct page *page;
> --
> 2.18.0
>
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