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AJvYcCV+4i0gYtYa107GCuznN24sdfq4yI0rEpX4wbAu3XPDJz3RFw9db3xmYDx6j7ZwPWKSDFvcKGuEjQJFx2ls6Ny3@lists.infradead.org X-Gm-Message-State: AOJu0Yx0h4lzuLJA3w9bDFrNsWOZi0+wgsL0CGeyAr0/CJnhfHR87HPH SmJGQWMtaeMu7KdgDTUiyBU+fp8D++mAeOZ6zJ2U3PVhopxmAC/icgLUJM9j07ny+oVFuqVQ/tE piIMrzMwJ1vXm4IhSxQ== X-Google-Smtp-Source: AGHT+IHEXjKh7uYAxIDUZT7+S3GCsAIurCSRFsj7/bmhTfFhgEBZjfPhhhAzv3sciVIkINBKdc3gwmpKNB2CG4iV X-Received: from wmbeu10.prod.google.com ([2002:a05:600c:81ca:b0:43b:bec3:e552]) (user=vdonnefort job=prod-delivery.src-stubby-dispatcher) by 2002:a05:600c:1c95:b0:439:9b3f:2de1 with SMTP id 5b1f17b1804b1-43bd29ad100mr55221025e9.15.1741258864402; Thu, 06 Mar 2025 03:01:04 -0800 (PST) Date: Thu, 6 Mar 2025 11:00:38 +0000 In-Reply-To: <20250306110038.3733649-1-vdonnefort@google.com> Mime-Version: 1.0 References: <20250306110038.3733649-1-vdonnefort@google.com> X-Mailer: git-send-email 2.48.1.711.g2feabab25a-goog Message-ID: <20250306110038.3733649-10-vdonnefort@google.com> Subject: [PATCH v2 9/9] KVM: arm64: np-guest CMOs with PMD_SIZE fixmap From: Vincent Donnefort To: maz@kernel.org, oliver.upton@linux.dev, joey.gouly@arm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, catalin.marinas@arm.com, will@kernel.org Cc: qperret@google.com, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-kernel@vger.kernel.org, kernel-team@android.com, Vincent Donnefort X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250306_030106_378576_B3B3CFCB X-CRM114-Status: GOOD ( 17.73 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org With the introduction of stage-2 huge mappings in the pKVM hypervisor, guest pages CMO is needed for PMD_SIZE size. Fixmap only supports PAGE_SIZE and iterating over the huge-page is time consuming (mostly due to TLBI on hyp_fixmap_unmap) which is a problem for EL2 latency. Introduce a shared PMD_SIZE fixmap (hyp_fixblock_map/hyp_fixblock_unmap) to improve guest page CMOs when stage-2 huge mappings are installed. On a Pixel6, the iterative solution resulted in a latency of ~700us, while the PMD_SIZE fixmap reduces it to ~100us. Because of the horrendous private range allocation that would be necessary, this is disabled for 64KiB pages systems. Suggested-by: Quentin Perret Signed-off-by: Vincent Donnefort Signed-off-by: Quentin Perret diff --git a/arch/arm64/include/asm/kvm_pgtable.h b/arch/arm64/include/asm/kvm_pgtable.h index 1b43bcd2a679..2888b5d03757 100644 --- a/arch/arm64/include/asm/kvm_pgtable.h +++ b/arch/arm64/include/asm/kvm_pgtable.h @@ -59,6 +59,11 @@ typedef u64 kvm_pte_t; #define KVM_PHYS_INVALID (-1ULL) +#define KVM_PTE_TYPE BIT(1) +#define KVM_PTE_TYPE_BLOCK 0 +#define KVM_PTE_TYPE_PAGE 1 +#define KVM_PTE_TYPE_TABLE 1 + #define KVM_PTE_LEAF_ATTR_LO GENMASK(11, 2) #define KVM_PTE_LEAF_ATTR_LO_S1_ATTRIDX GENMASK(4, 2) diff --git a/arch/arm64/kvm/hyp/include/nvhe/mm.h b/arch/arm64/kvm/hyp/include/nvhe/mm.h index 230e4f2527de..b0c72bc2d5ba 100644 --- a/arch/arm64/kvm/hyp/include/nvhe/mm.h +++ b/arch/arm64/kvm/hyp/include/nvhe/mm.h @@ -13,9 +13,11 @@ extern struct kvm_pgtable pkvm_pgtable; extern hyp_spinlock_t pkvm_pgd_lock; -int hyp_create_pcpu_fixmap(void); +int hyp_create_fixmap(void); void *hyp_fixmap_map(phys_addr_t phys); void hyp_fixmap_unmap(void); +void *hyp_fixblock_map(phys_addr_t phys); +void hyp_fixblock_unmap(void); int hyp_create_idmap(u32 hyp_va_bits); int hyp_map_vectors(void); diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c index b7a995a1d70b..5710c97cafb0 100644 --- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c +++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c @@ -220,17 +220,53 @@ static void guest_s2_put_page(void *addr) hyp_put_page(¤t_vm->pool, addr); } +static void *__fixmap_guest_page(void *va, size_t *size) +{ + if (IS_ALIGNED(*size, PMD_SIZE)) { + void *addr = hyp_fixblock_map(__hyp_pa(va)); + + if (addr) + return addr; + + *size = PAGE_SIZE; + } + + if (IS_ALIGNED(*size, PAGE_SIZE)) + return hyp_fixmap_map(__hyp_pa(va)); + + WARN_ON(1); + + return NULL; +} + +static void __fixunmap_guest_page(size_t size) +{ + switch (size) { + case PAGE_SIZE: + hyp_fixmap_unmap(); + break; + case PMD_SIZE: + hyp_fixblock_unmap(); + break; + default: + WARN_ON(1); + } +} + static void clean_dcache_guest_page(void *va, size_t size) { if (WARN_ON(!PAGE_ALIGNED(size))) return; while (size) { - __clean_dcache_guest_page(hyp_fixmap_map(__hyp_pa(va)), - PAGE_SIZE); - hyp_fixmap_unmap(); - va += PAGE_SIZE; - size -= PAGE_SIZE; + size_t fixmap_size = size == PMD_SIZE ? size : PAGE_SIZE; + void *addr = __fixmap_guest_page(va, &fixmap_size); + + __clean_dcache_guest_page(addr, fixmap_size); + __fixunmap_guest_page(fixmap_size); + + size -= fixmap_size; + va += fixmap_size; } } @@ -240,11 +276,14 @@ static void invalidate_icache_guest_page(void *va, size_t size) return; while (size) { - __invalidate_icache_guest_page(hyp_fixmap_map(__hyp_pa(va)), - PAGE_SIZE); - hyp_fixmap_unmap(); - va += PAGE_SIZE; - size -= PAGE_SIZE; + size_t fixmap_size = size == PMD_SIZE ? size : PAGE_SIZE; + void *addr = __fixmap_guest_page(va, &fixmap_size); + + __invalidate_icache_guest_page(addr, fixmap_size); + __fixunmap_guest_page(fixmap_size); + + size -= fixmap_size; + va += fixmap_size; } } diff --git a/arch/arm64/kvm/hyp/nvhe/mm.c b/arch/arm64/kvm/hyp/nvhe/mm.c index f41c7440b34b..e3b1bece8504 100644 --- a/arch/arm64/kvm/hyp/nvhe/mm.c +++ b/arch/arm64/kvm/hyp/nvhe/mm.c @@ -229,9 +229,8 @@ int hyp_map_vectors(void) return 0; } -void *hyp_fixmap_map(phys_addr_t phys) +static void *fixmap_map_slot(struct hyp_fixmap_slot *slot, phys_addr_t phys) { - struct hyp_fixmap_slot *slot = this_cpu_ptr(&fixmap_slots); kvm_pte_t pte, *ptep = slot->ptep; pte = *ptep; @@ -243,10 +242,21 @@ void *hyp_fixmap_map(phys_addr_t phys) return (void *)slot->addr; } +void *hyp_fixmap_map(phys_addr_t phys) +{ + return fixmap_map_slot(this_cpu_ptr(&fixmap_slots), phys); +} + static void fixmap_clear_slot(struct hyp_fixmap_slot *slot) { kvm_pte_t *ptep = slot->ptep; u64 addr = slot->addr; + u32 level; + + if (FIELD_GET(KVM_PTE_TYPE, *ptep) == KVM_PTE_TYPE_PAGE) + level = KVM_PGTABLE_LAST_LEVEL; + else + level = KVM_PGTABLE_LAST_LEVEL - 1; /* create_fixblock() guarantees PMD level */ WRITE_ONCE(*ptep, *ptep & ~KVM_PTE_VALID); @@ -260,7 +270,7 @@ static void fixmap_clear_slot(struct hyp_fixmap_slot *slot) * https://lore.kernel.org/kvm/20221017115209.2099-1-will@kernel.org/T/#mf10dfbaf1eaef9274c581b81c53758918c1d0f03 */ dsb(ishst); - __tlbi_level(vale2is, __TLBI_VADDR(addr, 0), KVM_PGTABLE_LAST_LEVEL); + __tlbi_level(vale2is, __TLBI_VADDR(addr, 0), level); dsb(ish); isb(); } @@ -273,9 +283,9 @@ void hyp_fixmap_unmap(void) static int __create_fixmap_slot_cb(const struct kvm_pgtable_visit_ctx *ctx, enum kvm_pgtable_walk_flags visit) { - struct hyp_fixmap_slot *slot = per_cpu_ptr(&fixmap_slots, (u64)ctx->arg); + struct hyp_fixmap_slot *slot = (struct hyp_fixmap_slot *)ctx->arg; - if (!kvm_pte_valid(ctx->old) || ctx->level != KVM_PGTABLE_LAST_LEVEL) + if (!kvm_pte_valid(ctx->old) || (ctx->end - ctx->start) != kvm_granule_size(ctx->level)) return -EINVAL; slot->addr = ctx->addr; @@ -296,13 +306,73 @@ static int create_fixmap_slot(u64 addr, u64 cpu) struct kvm_pgtable_walker walker = { .cb = __create_fixmap_slot_cb, .flags = KVM_PGTABLE_WALK_LEAF, - .arg = (void *)cpu, + .arg = (void *)per_cpu_ptr(&fixmap_slots, cpu), }; return kvm_pgtable_walk(&pkvm_pgtable, addr, PAGE_SIZE, &walker); } -int hyp_create_pcpu_fixmap(void) +#ifndef CONFIG_ARM64_64K_PAGES +static struct hyp_fixmap_slot hyp_fixblock_slot; +static DEFINE_HYP_SPINLOCK(hyp_fixblock_lock); + +void *hyp_fixblock_map(phys_addr_t phys) +{ + hyp_spin_lock(&hyp_fixblock_lock); + return fixmap_map_slot(&hyp_fixblock_slot, phys); +} + +void hyp_fixblock_unmap(void) +{ + fixmap_clear_slot(&hyp_fixblock_slot); + hyp_spin_unlock(&hyp_fixblock_lock); +} + +static int create_fixblock(void) +{ + struct kvm_pgtable_walker walker = { + .cb = __create_fixmap_slot_cb, + .flags = KVM_PGTABLE_WALK_LEAF, + .arg = (void *)&hyp_fixblock_slot, + }; + unsigned long addr; + phys_addr_t phys; + int ret, i; + + /* Find a RAM phys address, PMD aligned */ + for (i = 0; i < hyp_memblock_nr; i++) { + phys = ALIGN(hyp_memory[i].base, PMD_SIZE); + if (phys + PMD_SIZE < (hyp_memory[i].base + hyp_memory[i].size)) + break; + } + + if (i >= hyp_memblock_nr) + return -EINVAL; + + hyp_spin_lock(&pkvm_pgd_lock); + addr = ALIGN(__io_map_base, PMD_SIZE); + ret = __pkvm_alloc_private_va_range(addr, PMD_SIZE); + if (ret) + goto unlock; + + ret = kvm_pgtable_hyp_map(&pkvm_pgtable, addr, PMD_SIZE, phys, PAGE_HYP); + if (ret) + goto unlock; + + ret = kvm_pgtable_walk(&pkvm_pgtable, addr, PMD_SIZE, &walker); + +unlock: + hyp_spin_unlock(&pkvm_pgd_lock); + + return ret; +} +#else +void hyp_fixblock_unmap(void) { WARN_ON(1); } +void *hyp_fixblock_map(phys_addr_t phys) { return NULL; } +static int create_fixblock(void) { return 0; } +#endif + +int hyp_create_fixmap(void) { unsigned long addr, i; int ret; @@ -322,7 +392,7 @@ int hyp_create_pcpu_fixmap(void) return ret; } - return 0; + return create_fixblock(); } int hyp_create_idmap(u32 hyp_va_bits) diff --git a/arch/arm64/kvm/hyp/nvhe/setup.c b/arch/arm64/kvm/hyp/nvhe/setup.c index d62bcb5634a2..fb69cf5e6ea8 100644 --- a/arch/arm64/kvm/hyp/nvhe/setup.c +++ b/arch/arm64/kvm/hyp/nvhe/setup.c @@ -295,7 +295,7 @@ void __noreturn __pkvm_init_finalise(void) if (ret) goto out; - ret = hyp_create_pcpu_fixmap(); + ret = hyp_create_fixmap(); if (ret) goto out; diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c index df5cc74a7dd0..c351b4abd5db 100644 --- a/arch/arm64/kvm/hyp/pgtable.c +++ b/arch/arm64/kvm/hyp/pgtable.c @@ -11,12 +11,6 @@ #include #include - -#define KVM_PTE_TYPE BIT(1) -#define KVM_PTE_TYPE_BLOCK 0 -#define KVM_PTE_TYPE_PAGE 1 -#define KVM_PTE_TYPE_TABLE 1 - struct kvm_pgtable_walk_data { struct kvm_pgtable_walker *walker;