diff options
Diffstat (limited to 'arch/arm64/include/asm/kvm_pgtable.h')
| -rw-r--r-- | arch/arm64/include/asm/kvm_pgtable.h | 558 |
1 files changed, 558 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/kvm_pgtable.h b/arch/arm64/include/asm/kvm_pgtable.h new file mode 100644 index 000000000..3252eb50e --- /dev/null +++ b/arch/arm64/include/asm/kvm_pgtable.h @@ -0,0 +1,558 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2020 Google LLC + * Author: Will Deacon <will@kernel.org> + */ + +#ifndef __ARM64_KVM_PGTABLE_H__ +#define __ARM64_KVM_PGTABLE_H__ + +#include <linux/bits.h> +#include <linux/kvm_host.h> +#include <linux/types.h> + +#define KVM_PGTABLE_MAX_LEVELS 4U + +/* + * The largest supported block sizes for KVM (no 52-bit PA support): + * - 4K (level 1): 1GB + * - 16K (level 2): 32MB + * - 64K (level 2): 512MB + */ +#ifdef CONFIG_ARM64_4K_PAGES +#define KVM_PGTABLE_MIN_BLOCK_LEVEL 1U +#else +#define KVM_PGTABLE_MIN_BLOCK_LEVEL 2U +#endif + +static inline u64 kvm_get_parange(u64 mmfr0) +{ + u64 parange = cpuid_feature_extract_unsigned_field(mmfr0, + ID_AA64MMFR0_EL1_PARANGE_SHIFT); + if (parange > ID_AA64MMFR0_EL1_PARANGE_MAX) + parange = ID_AA64MMFR0_EL1_PARANGE_MAX; + + return parange; +} + +typedef u64 kvm_pte_t; + +#define KVM_PTE_VALID BIT(0) + +#define KVM_PTE_ADDR_MASK GENMASK(47, PAGE_SHIFT) +#define KVM_PTE_ADDR_51_48 GENMASK(15, 12) + +static inline bool kvm_pte_valid(kvm_pte_t pte) +{ + return pte & KVM_PTE_VALID; +} + +static inline u64 kvm_pte_to_phys(kvm_pte_t pte) +{ + u64 pa = pte & KVM_PTE_ADDR_MASK; + + if (PAGE_SHIFT == 16) + pa |= FIELD_GET(KVM_PTE_ADDR_51_48, pte) << 48; + + return pa; +} + +static inline u64 kvm_granule_shift(u32 level) +{ + /* Assumes KVM_PGTABLE_MAX_LEVELS is 4 */ + return ARM64_HW_PGTABLE_LEVEL_SHIFT(level); +} + +static inline u64 kvm_granule_size(u32 level) +{ + return BIT(kvm_granule_shift(level)); +} + +static inline bool kvm_level_supports_block_mapping(u32 level) +{ + return level >= KVM_PGTABLE_MIN_BLOCK_LEVEL; +} + +/** + * struct kvm_pgtable_mm_ops - Memory management callbacks. + * @zalloc_page: Allocate a single zeroed memory page. + * The @arg parameter can be used by the walker + * to pass a memcache. The initial refcount of + * the page is 1. + * @zalloc_pages_exact: Allocate an exact number of zeroed memory pages. + * The @size parameter is in bytes, and is rounded + * up to the next page boundary. The resulting + * allocation is physically contiguous. + * @free_pages_exact: Free an exact number of memory pages previously + * allocated by zalloc_pages_exact. + * @get_page: Increment the refcount on a page. + * @put_page: Decrement the refcount on a page. When the + * refcount reaches 0 the page is automatically + * freed. + * @page_count: Return the refcount of a page. + * @phys_to_virt: Convert a physical address into a virtual + * address mapped in the current context. + * @virt_to_phys: Convert a virtual address mapped in the current + * context into a physical address. + * @dcache_clean_inval_poc: Clean and invalidate the data cache to the PoC + * for the specified memory address range. + * @icache_inval_pou: Invalidate the instruction cache to the PoU + * for the specified memory address range. + */ +struct kvm_pgtable_mm_ops { + void* (*zalloc_page)(void *arg); + void* (*zalloc_pages_exact)(size_t size); + void (*free_pages_exact)(void *addr, size_t size); + void (*get_page)(void *addr); + void (*put_page)(void *addr); + int (*page_count)(void *addr); + void* (*phys_to_virt)(phys_addr_t phys); + phys_addr_t (*virt_to_phys)(void *addr); + void (*dcache_clean_inval_poc)(void *addr, size_t size); + void (*icache_inval_pou)(void *addr, size_t size); +}; + +/** + * enum kvm_pgtable_stage2_flags - Stage-2 page-table flags. + * @KVM_PGTABLE_S2_NOFWB: Don't enforce Normal-WB even if the CPUs have + * ARM64_HAS_STAGE2_FWB. + * @KVM_PGTABLE_S2_IDMAP: Only use identity mappings. + */ +enum kvm_pgtable_stage2_flags { + KVM_PGTABLE_S2_NOFWB = BIT(0), + KVM_PGTABLE_S2_IDMAP = BIT(1), +}; + +/** + * enum kvm_pgtable_prot - Page-table permissions and attributes. + * @KVM_PGTABLE_PROT_X: Execute permission. + * @KVM_PGTABLE_PROT_W: Write permission. + * @KVM_PGTABLE_PROT_R: Read permission. + * @KVM_PGTABLE_PROT_DEVICE: Device attributes. + * @KVM_PGTABLE_PROT_SW0: Software bit 0. + * @KVM_PGTABLE_PROT_SW1: Software bit 1. + * @KVM_PGTABLE_PROT_SW2: Software bit 2. + * @KVM_PGTABLE_PROT_SW3: Software bit 3. + */ +enum kvm_pgtable_prot { + KVM_PGTABLE_PROT_X = BIT(0), + KVM_PGTABLE_PROT_W = BIT(1), + KVM_PGTABLE_PROT_R = BIT(2), + + KVM_PGTABLE_PROT_DEVICE = BIT(3), + + KVM_PGTABLE_PROT_SW0 = BIT(55), + KVM_PGTABLE_PROT_SW1 = BIT(56), + KVM_PGTABLE_PROT_SW2 = BIT(57), + KVM_PGTABLE_PROT_SW3 = BIT(58), +}; + +#define KVM_PGTABLE_PROT_RW (KVM_PGTABLE_PROT_R | KVM_PGTABLE_PROT_W) +#define KVM_PGTABLE_PROT_RWX (KVM_PGTABLE_PROT_RW | KVM_PGTABLE_PROT_X) + +#define PKVM_HOST_MEM_PROT KVM_PGTABLE_PROT_RWX +#define PKVM_HOST_MMIO_PROT KVM_PGTABLE_PROT_RW + +#define PAGE_HYP KVM_PGTABLE_PROT_RW +#define PAGE_HYP_EXEC (KVM_PGTABLE_PROT_R | KVM_PGTABLE_PROT_X) +#define PAGE_HYP_RO (KVM_PGTABLE_PROT_R) +#define PAGE_HYP_DEVICE (PAGE_HYP | KVM_PGTABLE_PROT_DEVICE) + +typedef bool (*kvm_pgtable_force_pte_cb_t)(u64 addr, u64 end, + enum kvm_pgtable_prot prot); + +/** + * struct kvm_pgtable - KVM page-table. + * @ia_bits: Maximum input address size, in bits. + * @start_level: Level at which the page-table walk starts. + * @pgd: Pointer to the first top-level entry of the page-table. + * @mm_ops: Memory management callbacks. + * @mmu: Stage-2 KVM MMU struct. Unused for stage-1 page-tables. + * @flags: Stage-2 page-table flags. + * @force_pte_cb: Function that returns true if page level mappings must + * be used instead of block mappings. + */ +struct kvm_pgtable { + u32 ia_bits; + u32 start_level; + kvm_pte_t *pgd; + struct kvm_pgtable_mm_ops *mm_ops; + + /* Stage-2 only */ + struct kvm_s2_mmu *mmu; + enum kvm_pgtable_stage2_flags flags; + kvm_pgtable_force_pte_cb_t force_pte_cb; +}; + +/** + * enum kvm_pgtable_walk_flags - Flags to control a depth-first page-table walk. + * @KVM_PGTABLE_WALK_LEAF: Visit leaf entries, including invalid + * entries. + * @KVM_PGTABLE_WALK_TABLE_PRE: Visit table entries before their + * children. + * @KVM_PGTABLE_WALK_TABLE_POST: Visit table entries after their + * children. + */ +enum kvm_pgtable_walk_flags { + KVM_PGTABLE_WALK_LEAF = BIT(0), + KVM_PGTABLE_WALK_TABLE_PRE = BIT(1), + KVM_PGTABLE_WALK_TABLE_POST = BIT(2), +}; + +typedef int (*kvm_pgtable_visitor_fn_t)(u64 addr, u64 end, u32 level, + kvm_pte_t *ptep, + enum kvm_pgtable_walk_flags flag, + void * const arg); + +/** + * struct kvm_pgtable_walker - Hook into a page-table walk. + * @cb: Callback function to invoke during the walk. + * @arg: Argument passed to the callback function. + * @flags: Bitwise-OR of flags to identify the entry types on which to + * invoke the callback function. + */ +struct kvm_pgtable_walker { + const kvm_pgtable_visitor_fn_t cb; + void * const arg; + const enum kvm_pgtable_walk_flags flags; +}; + +/** + * kvm_pgtable_hyp_init() - Initialise a hypervisor stage-1 page-table. + * @pgt: Uninitialised page-table structure to initialise. + * @va_bits: Maximum virtual address bits. + * @mm_ops: Memory management callbacks. + * + * Return: 0 on success, negative error code on failure. + */ +int kvm_pgtable_hyp_init(struct kvm_pgtable *pgt, u32 va_bits, + struct kvm_pgtable_mm_ops *mm_ops); + +/** + * kvm_pgtable_hyp_destroy() - Destroy an unused hypervisor stage-1 page-table. + * @pgt: Page-table structure initialised by kvm_pgtable_hyp_init(). + * + * The page-table is assumed to be unreachable by any hardware walkers prior + * to freeing and therefore no TLB invalidation is performed. + */ +void kvm_pgtable_hyp_destroy(struct kvm_pgtable *pgt); + +/** + * kvm_pgtable_hyp_map() - Install a mapping in a hypervisor stage-1 page-table. + * @pgt: Page-table structure initialised by kvm_pgtable_hyp_init(). + * @addr: Virtual address at which to place the mapping. + * @size: Size of the mapping. + * @phys: Physical address of the memory to map. + * @prot: Permissions and attributes for the mapping. + * + * The offset of @addr within a page is ignored, @size is rounded-up to + * the next page boundary and @phys is rounded-down to the previous page + * boundary. + * + * If device attributes are not explicitly requested in @prot, then the + * mapping will be normal, cacheable. Attempts to install a new mapping + * for a virtual address that is already mapped will be rejected with an + * error and a WARN(). + * + * Return: 0 on success, negative error code on failure. + */ +int kvm_pgtable_hyp_map(struct kvm_pgtable *pgt, u64 addr, u64 size, u64 phys, + enum kvm_pgtable_prot prot); + +/** + * kvm_pgtable_hyp_unmap() - Remove a mapping from a hypervisor stage-1 page-table. + * @pgt: Page-table structure initialised by kvm_pgtable_hyp_init(). + * @addr: Virtual address from which to remove the mapping. + * @size: Size of the mapping. + * + * The offset of @addr within a page is ignored, @size is rounded-up to + * the next page boundary and @phys is rounded-down to the previous page + * boundary. + * + * TLB invalidation is performed for each page-table entry cleared during the + * unmapping operation and the reference count for the page-table page + * containing the cleared entry is decremented, with unreferenced pages being + * freed. The unmapping operation will stop early if it encounters either an + * invalid page-table entry or a valid block mapping which maps beyond the range + * being unmapped. + * + * Return: Number of bytes unmapped, which may be 0. + */ +u64 kvm_pgtable_hyp_unmap(struct kvm_pgtable *pgt, u64 addr, u64 size); + +/** + * kvm_get_vtcr() - Helper to construct VTCR_EL2 + * @mmfr0: Sanitized value of SYS_ID_AA64MMFR0_EL1 register. + * @mmfr1: Sanitized value of SYS_ID_AA64MMFR1_EL1 register. + * @phys_shfit: Value to set in VTCR_EL2.T0SZ. + * + * The VTCR value is common across all the physical CPUs on the system. + * We use system wide sanitised values to fill in different fields, + * except for Hardware Management of Access Flags. HA Flag is set + * unconditionally on all CPUs, as it is safe to run with or without + * the feature and the bit is RES0 on CPUs that don't support it. + * + * Return: VTCR_EL2 value + */ +u64 kvm_get_vtcr(u64 mmfr0, u64 mmfr1, u32 phys_shift); + +/** + * __kvm_pgtable_stage2_init() - Initialise a guest stage-2 page-table. + * @pgt: Uninitialised page-table structure to initialise. + * @mmu: S2 MMU context for this S2 translation + * @mm_ops: Memory management callbacks. + * @flags: Stage-2 configuration flags. + * @force_pte_cb: Function that returns true if page level mappings must + * be used instead of block mappings. + * + * Return: 0 on success, negative error code on failure. + */ +int __kvm_pgtable_stage2_init(struct kvm_pgtable *pgt, struct kvm_s2_mmu *mmu, + struct kvm_pgtable_mm_ops *mm_ops, + enum kvm_pgtable_stage2_flags flags, + kvm_pgtable_force_pte_cb_t force_pte_cb); + +#define kvm_pgtable_stage2_init(pgt, mmu, mm_ops) \ + __kvm_pgtable_stage2_init(pgt, mmu, mm_ops, 0, NULL) + +/** + * kvm_pgtable_stage2_destroy() - Destroy an unused guest stage-2 page-table. + * @pgt: Page-table structure initialised by kvm_pgtable_stage2_init*(). + * + * The page-table is assumed to be unreachable by any hardware walkers prior + * to freeing and therefore no TLB invalidation is performed. + */ +void kvm_pgtable_stage2_destroy(struct kvm_pgtable *pgt); + +/** + * kvm_pgtable_stage2_map() - Install a mapping in a guest stage-2 page-table. + * @pgt: Page-table structure initialised by kvm_pgtable_stage2_init*(). + * @addr: Intermediate physical address at which to place the mapping. + * @size: Size of the mapping. + * @phys: Physical address of the memory to map. + * @prot: Permissions and attributes for the mapping. + * @mc: Cache of pre-allocated and zeroed memory from which to allocate + * page-table pages. + * + * The offset of @addr within a page is ignored, @size is rounded-up to + * the next page boundary and @phys is rounded-down to the previous page + * boundary. + * + * If device attributes are not explicitly requested in @prot, then the + * mapping will be normal, cacheable. + * + * Note that the update of a valid leaf PTE in this function will be aborted, + * if it's trying to recreate the exact same mapping or only change the access + * permissions. Instead, the vCPU will exit one more time from guest if still + * needed and then go through the path of relaxing permissions. + * + * Note that this function will both coalesce existing table entries and split + * existing block mappings, relying on page-faults to fault back areas outside + * of the new mapping lazily. + * + * Return: 0 on success, negative error code on failure. + */ +int kvm_pgtable_stage2_map(struct kvm_pgtable *pgt, u64 addr, u64 size, + u64 phys, enum kvm_pgtable_prot prot, + void *mc); + +/** + * kvm_pgtable_stage2_set_owner() - Unmap and annotate pages in the IPA space to + * track ownership. + * @pgt: Page-table structure initialised by kvm_pgtable_stage2_init*(). + * @addr: Base intermediate physical address to annotate. + * @size: Size of the annotated range. + * @mc: Cache of pre-allocated and zeroed memory from which to allocate + * page-table pages. + * @owner_id: Unique identifier for the owner of the page. + * + * By default, all page-tables are owned by identifier 0. This function can be + * used to mark portions of the IPA space as owned by other entities. When a + * stage 2 is used with identity-mappings, these annotations allow to use the + * page-table data structure as a simple rmap. + * + * Return: 0 on success, negative error code on failure. + */ +int kvm_pgtable_stage2_set_owner(struct kvm_pgtable *pgt, u64 addr, u64 size, + void *mc, u8 owner_id); + +/** + * kvm_pgtable_stage2_unmap() - Remove a mapping from a guest stage-2 page-table. + * @pgt: Page-table structure initialised by kvm_pgtable_stage2_init*(). + * @addr: Intermediate physical address from which to remove the mapping. + * @size: Size of the mapping. + * + * The offset of @addr within a page is ignored and @size is rounded-up to + * the next page boundary. + * + * TLB invalidation is performed for each page-table entry cleared during the + * unmapping operation and the reference count for the page-table page + * containing the cleared entry is decremented, with unreferenced pages being + * freed. Unmapping a cacheable page will ensure that it is clean to the PoC if + * FWB is not supported by the CPU. + * + * Return: 0 on success, negative error code on failure. + */ +int kvm_pgtable_stage2_unmap(struct kvm_pgtable *pgt, u64 addr, u64 size); + +/** + * kvm_pgtable_stage2_wrprotect() - Write-protect guest stage-2 address range + * without TLB invalidation. + * @pgt: Page-table structure initialised by kvm_pgtable_stage2_init*(). + * @addr: Intermediate physical address from which to write-protect, + * @size: Size of the range. + * + * The offset of @addr within a page is ignored and @size is rounded-up to + * the next page boundary. + * + * Note that it is the caller's responsibility to invalidate the TLB after + * calling this function to ensure that the updated permissions are visible + * to the CPUs. + * + * Return: 0 on success, negative error code on failure. + */ +int kvm_pgtable_stage2_wrprotect(struct kvm_pgtable *pgt, u64 addr, u64 size); + +/** + * kvm_pgtable_stage2_mkyoung() - Set the access flag in a page-table entry. + * @pgt: Page-table structure initialised by kvm_pgtable_stage2_init*(). + * @addr: Intermediate physical address to identify the page-table entry. + * + * The offset of @addr within a page is ignored. + * + * If there is a valid, leaf page-table entry used to translate @addr, then + * set the access flag in that entry. + * + * Return: The old page-table entry prior to setting the flag, 0 on failure. + */ +kvm_pte_t kvm_pgtable_stage2_mkyoung(struct kvm_pgtable *pgt, u64 addr); + +/** + * kvm_pgtable_stage2_mkold() - Clear the access flag in a page-table entry. + * @pgt: Page-table structure initialised by kvm_pgtable_stage2_init*(). + * @addr: Intermediate physical address to identify the page-table entry. + * + * The offset of @addr within a page is ignored. + * + * If there is a valid, leaf page-table entry used to translate @addr, then + * clear the access flag in that entry. + * + * Note that it is the caller's responsibility to invalidate the TLB after + * calling this function to ensure that the updated permissions are visible + * to the CPUs. + * + * Return: The old page-table entry prior to clearing the flag, 0 on failure. + */ +kvm_pte_t kvm_pgtable_stage2_mkold(struct kvm_pgtable *pgt, u64 addr); + +/** + * kvm_pgtable_stage2_relax_perms() - Relax the permissions enforced by a + * page-table entry. + * @pgt: Page-table structure initialised by kvm_pgtable_stage2_init*(). + * @addr: Intermediate physical address to identify the page-table entry. + * @prot: Additional permissions to grant for the mapping. + * + * The offset of @addr within a page is ignored. + * + * If there is a valid, leaf page-table entry used to translate @addr, then + * relax the permissions in that entry according to the read, write and + * execute permissions specified by @prot. No permissions are removed, and + * TLB invalidation is performed after updating the entry. Software bits cannot + * be set or cleared using kvm_pgtable_stage2_relax_perms(). + * + * Return: 0 on success, negative error code on failure. + */ +int kvm_pgtable_stage2_relax_perms(struct kvm_pgtable *pgt, u64 addr, + enum kvm_pgtable_prot prot); + +/** + * kvm_pgtable_stage2_is_young() - Test whether a page-table entry has the + * access flag set. + * @pgt: Page-table structure initialised by kvm_pgtable_stage2_init*(). + * @addr: Intermediate physical address to identify the page-table entry. + * + * The offset of @addr within a page is ignored. + * + * Return: True if the page-table entry has the access flag set, false otherwise. + */ +bool kvm_pgtable_stage2_is_young(struct kvm_pgtable *pgt, u64 addr); + +/** + * kvm_pgtable_stage2_flush_range() - Clean and invalidate data cache to Point + * of Coherency for guest stage-2 address + * range. + * @pgt: Page-table structure initialised by kvm_pgtable_stage2_init*(). + * @addr: Intermediate physical address from which to flush. + * @size: Size of the range. + * + * The offset of @addr within a page is ignored and @size is rounded-up to + * the next page boundary. + * + * Return: 0 on success, negative error code on failure. + */ +int kvm_pgtable_stage2_flush(struct kvm_pgtable *pgt, u64 addr, u64 size); + +/** + * kvm_pgtable_walk() - Walk a page-table. + * @pgt: Page-table structure initialised by kvm_pgtable_*_init(). + * @addr: Input address for the start of the walk. + * @size: Size of the range to walk. + * @walker: Walker callback description. + * + * The offset of @addr within a page is ignored and @size is rounded-up to + * the next page boundary. + * + * The walker will walk the page-table entries corresponding to the input + * address range specified, visiting entries according to the walker flags. + * Invalid entries are treated as leaf entries. Leaf entries are reloaded + * after invoking the walker callback, allowing the walker to descend into + * a newly installed table. + * + * Returning a negative error code from the walker callback function will + * terminate the walk immediately with the same error code. + * + * Return: 0 on success, negative error code on failure. + */ +int kvm_pgtable_walk(struct kvm_pgtable *pgt, u64 addr, u64 size, + struct kvm_pgtable_walker *walker); + +/** + * kvm_pgtable_get_leaf() - Walk a page-table and retrieve the leaf entry + * with its level. + * @pgt: Page-table structure initialised by kvm_pgtable_*_init() + * or a similar initialiser. + * @addr: Input address for the start of the walk. + * @ptep: Pointer to storage for the retrieved PTE. + * @level: Pointer to storage for the level of the retrieved PTE. + * + * The offset of @addr within a page is ignored. + * + * The walker will walk the page-table entries corresponding to the input + * address specified, retrieving the leaf corresponding to this address. + * Invalid entries are treated as leaf entries. + * + * Return: 0 on success, negative error code on failure. + */ +int kvm_pgtable_get_leaf(struct kvm_pgtable *pgt, u64 addr, + kvm_pte_t *ptep, u32 *level); + +/** + * kvm_pgtable_stage2_pte_prot() - Retrieve the protection attributes of a + * stage-2 Page-Table Entry. + * @pte: Page-table entry + * + * Return: protection attributes of the page-table entry in the enum + * kvm_pgtable_prot format. + */ +enum kvm_pgtable_prot kvm_pgtable_stage2_pte_prot(kvm_pte_t pte); + +/** + * kvm_pgtable_hyp_pte_prot() - Retrieve the protection attributes of a stage-1 + * Page-Table Entry. + * @pte: Page-table entry + * + * Return: protection attributes of the page-table entry in the enum + * kvm_pgtable_prot format. + */ +enum kvm_pgtable_prot kvm_pgtable_hyp_pte_prot(kvm_pte_t pte); +#endif /* __ARM64_KVM_PGTABLE_H__ */ |