diff options
Diffstat (limited to 'drivers/iommu/amd/io_pgtable.c')
| -rw-r--r-- | drivers/iommu/amd/io_pgtable.c | 558 |
1 files changed, 558 insertions, 0 deletions
diff --git a/drivers/iommu/amd/io_pgtable.c b/drivers/iommu/amd/io_pgtable.c new file mode 100644 index 000000000000..1c4961e05c12 --- /dev/null +++ b/drivers/iommu/amd/io_pgtable.c @@ -0,0 +1,558 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * CPU-agnostic AMD IO page table allocator. + * + * Copyright (C) 2020 Advanced Micro Devices, Inc. + * Author: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com> + */ + +#define pr_fmt(fmt) "AMD-Vi: " fmt +#define dev_fmt(fmt) pr_fmt(fmt) + +#include <linux/atomic.h> +#include <linux/bitops.h> +#include <linux/io-pgtable.h> +#include <linux/kernel.h> +#include <linux/sizes.h> +#include <linux/slab.h> +#include <linux/types.h> +#include <linux/dma-mapping.h> + +#include <asm/barrier.h> + +#include "amd_iommu_types.h" +#include "amd_iommu.h" + +static void v1_tlb_flush_all(void *cookie) +{ +} + +static void v1_tlb_flush_walk(unsigned long iova, size_t size, + size_t granule, void *cookie) +{ +} + +static void v1_tlb_add_page(struct iommu_iotlb_gather *gather, + unsigned long iova, size_t granule, + void *cookie) +{ +} + +static const struct iommu_flush_ops v1_flush_ops = { + .tlb_flush_all = v1_tlb_flush_all, + .tlb_flush_walk = v1_tlb_flush_walk, + .tlb_add_page = v1_tlb_add_page, +}; + +/* + * Helper function to get the first pte of a large mapping + */ +static u64 *first_pte_l7(u64 *pte, unsigned long *page_size, + unsigned long *count) +{ + unsigned long pte_mask, pg_size, cnt; + u64 *fpte; + + pg_size = PTE_PAGE_SIZE(*pte); + cnt = PAGE_SIZE_PTE_COUNT(pg_size); + pte_mask = ~((cnt << 3) - 1); + fpte = (u64 *)(((unsigned long)pte) & pte_mask); + + if (page_size) + *page_size = pg_size; + + if (count) + *count = cnt; + + return fpte; +} + +/**************************************************************************** + * + * The functions below are used the create the page table mappings for + * unity mapped regions. + * + ****************************************************************************/ + +static void free_page_list(struct page *freelist) +{ + while (freelist != NULL) { + unsigned long p = (unsigned long)page_address(freelist); + + freelist = freelist->freelist; + free_page(p); + } +} + +static struct page *free_pt_page(unsigned long pt, struct page *freelist) +{ + struct page *p = virt_to_page((void *)pt); + + p->freelist = freelist; + + return p; +} + +#define DEFINE_FREE_PT_FN(LVL, FN) \ +static struct page *free_pt_##LVL (unsigned long __pt, struct page *freelist) \ +{ \ + unsigned long p; \ + u64 *pt; \ + int i; \ + \ + pt = (u64 *)__pt; \ + \ + for (i = 0; i < 512; ++i) { \ + /* PTE present? */ \ + if (!IOMMU_PTE_PRESENT(pt[i])) \ + continue; \ + \ + /* Large PTE? */ \ + if (PM_PTE_LEVEL(pt[i]) == 0 || \ + PM_PTE_LEVEL(pt[i]) == 7) \ + continue; \ + \ + p = (unsigned long)IOMMU_PTE_PAGE(pt[i]); \ + freelist = FN(p, freelist); \ + } \ + \ + return free_pt_page((unsigned long)pt, freelist); \ +} + +DEFINE_FREE_PT_FN(l2, free_pt_page) +DEFINE_FREE_PT_FN(l3, free_pt_l2) +DEFINE_FREE_PT_FN(l4, free_pt_l3) +DEFINE_FREE_PT_FN(l5, free_pt_l4) +DEFINE_FREE_PT_FN(l6, free_pt_l5) + +static struct page *free_sub_pt(unsigned long root, int mode, + struct page *freelist) +{ + switch (mode) { + case PAGE_MODE_NONE: + case PAGE_MODE_7_LEVEL: + break; + case PAGE_MODE_1_LEVEL: + freelist = free_pt_page(root, freelist); + break; + case PAGE_MODE_2_LEVEL: + freelist = free_pt_l2(root, freelist); + break; + case PAGE_MODE_3_LEVEL: + freelist = free_pt_l3(root, freelist); + break; + case PAGE_MODE_4_LEVEL: + freelist = free_pt_l4(root, freelist); + break; + case PAGE_MODE_5_LEVEL: + freelist = free_pt_l5(root, freelist); + break; + case PAGE_MODE_6_LEVEL: + freelist = free_pt_l6(root, freelist); + break; + default: + BUG(); + } + + return freelist; +} + +void amd_iommu_domain_set_pgtable(struct protection_domain *domain, + u64 *root, int mode) +{ + u64 pt_root; + + /* lowest 3 bits encode pgtable mode */ + pt_root = mode & 7; + pt_root |= (u64)root; + + amd_iommu_domain_set_pt_root(domain, pt_root); +} + +/* + * This function is used to add another level to an IO page table. Adding + * another level increases the size of the address space by 9 bits to a size up + * to 64 bits. + */ +static bool increase_address_space(struct protection_domain *domain, + unsigned long address, + gfp_t gfp) +{ + unsigned long flags; + bool ret = true; + u64 *pte; + + spin_lock_irqsave(&domain->lock, flags); + + if (address <= PM_LEVEL_SIZE(domain->iop.mode)) + goto out; + + ret = false; + if (WARN_ON_ONCE(domain->iop.mode == PAGE_MODE_6_LEVEL)) + goto out; + + pte = (void *)get_zeroed_page(gfp); + if (!pte) + goto out; + + *pte = PM_LEVEL_PDE(domain->iop.mode, iommu_virt_to_phys(domain->iop.root)); + + domain->iop.root = pte; + domain->iop.mode += 1; + amd_iommu_update_and_flush_device_table(domain); + amd_iommu_domain_flush_complete(domain); + + /* + * Device Table needs to be updated and flushed before the new root can + * be published. + */ + amd_iommu_domain_set_pgtable(domain, pte, domain->iop.mode); + + ret = true; + +out: + spin_unlock_irqrestore(&domain->lock, flags); + + return ret; +} + +static u64 *alloc_pte(struct protection_domain *domain, + unsigned long address, + unsigned long page_size, + u64 **pte_page, + gfp_t gfp, + bool *updated) +{ + int level, end_lvl; + u64 *pte, *page; + + BUG_ON(!is_power_of_2(page_size)); + + while (address > PM_LEVEL_SIZE(domain->iop.mode)) { + /* + * Return an error if there is no memory to update the + * page-table. + */ + if (!increase_address_space(domain, address, gfp)) + return NULL; + } + + + level = domain->iop.mode - 1; + pte = &domain->iop.root[PM_LEVEL_INDEX(level, address)]; + address = PAGE_SIZE_ALIGN(address, page_size); + end_lvl = PAGE_SIZE_LEVEL(page_size); + + while (level > end_lvl) { + u64 __pte, __npte; + int pte_level; + + __pte = *pte; + pte_level = PM_PTE_LEVEL(__pte); + + /* + * If we replace a series of large PTEs, we need + * to tear down all of them. + */ + if (IOMMU_PTE_PRESENT(__pte) && + pte_level == PAGE_MODE_7_LEVEL) { + unsigned long count, i; + u64 *lpte; + + lpte = first_pte_l7(pte, NULL, &count); + + /* + * Unmap the replicated PTEs that still match the + * original large mapping + */ + for (i = 0; i < count; ++i) + cmpxchg64(&lpte[i], __pte, 0ULL); + + *updated = true; + continue; + } + + if (!IOMMU_PTE_PRESENT(__pte) || + pte_level == PAGE_MODE_NONE) { + page = (u64 *)get_zeroed_page(gfp); + + if (!page) + return NULL; + + __npte = PM_LEVEL_PDE(level, iommu_virt_to_phys(page)); + + /* pte could have been changed somewhere. */ + if (cmpxchg64(pte, __pte, __npte) != __pte) + free_page((unsigned long)page); + else if (IOMMU_PTE_PRESENT(__pte)) + *updated = true; + + continue; + } + + /* No level skipping support yet */ + if (pte_level != level) + return NULL; + + level -= 1; + + pte = IOMMU_PTE_PAGE(__pte); + + if (pte_page && level == end_lvl) + *pte_page = pte; + + pte = &pte[PM_LEVEL_INDEX(level, address)]; + } + + return pte; +} + +/* + * This function checks if there is a PTE for a given dma address. If + * there is one, it returns the pointer to it. + */ +static u64 *fetch_pte(struct amd_io_pgtable *pgtable, + unsigned long address, + unsigned long *page_size) +{ + int level; + u64 *pte; + + *page_size = 0; + + if (address > PM_LEVEL_SIZE(pgtable->mode)) + return NULL; + + level = pgtable->mode - 1; + pte = &pgtable->root[PM_LEVEL_INDEX(level, address)]; + *page_size = PTE_LEVEL_PAGE_SIZE(level); + + while (level > 0) { + + /* Not Present */ + if (!IOMMU_PTE_PRESENT(*pte)) + return NULL; + + /* Large PTE */ + if (PM_PTE_LEVEL(*pte) == 7 || + PM_PTE_LEVEL(*pte) == 0) + break; + + /* No level skipping support yet */ + if (PM_PTE_LEVEL(*pte) != level) + return NULL; + + level -= 1; + + /* Walk to the next level */ + pte = IOMMU_PTE_PAGE(*pte); + pte = &pte[PM_LEVEL_INDEX(level, address)]; + *page_size = PTE_LEVEL_PAGE_SIZE(level); + } + + /* + * If we have a series of large PTEs, make + * sure to return a pointer to the first one. + */ + if (PM_PTE_LEVEL(*pte) == PAGE_MODE_7_LEVEL) + pte = first_pte_l7(pte, page_size, NULL); + + return pte; +} + +static struct page *free_clear_pte(u64 *pte, u64 pteval, struct page *freelist) +{ + unsigned long pt; + int mode; + + while (cmpxchg64(pte, pteval, 0) != pteval) { + pr_warn("AMD-Vi: IOMMU pte changed since we read it\n"); + pteval = *pte; + } + + if (!IOMMU_PTE_PRESENT(pteval)) + return freelist; + + pt = (unsigned long)IOMMU_PTE_PAGE(pteval); + mode = IOMMU_PTE_MODE(pteval); + + return free_sub_pt(pt, mode, freelist); +} + +/* + * Generic mapping functions. It maps a physical address into a DMA + * address space. It allocates the page table pages if necessary. + * In the future it can be extended to a generic mapping function + * supporting all features of AMD IOMMU page tables like level skipping + * and full 64 bit address spaces. + */ +static int iommu_v1_map_page(struct io_pgtable_ops *ops, unsigned long iova, + phys_addr_t paddr, size_t size, int prot, gfp_t gfp) +{ + struct protection_domain *dom = io_pgtable_ops_to_domain(ops); + struct page *freelist = NULL; + bool updated = false; + u64 __pte, *pte; + int ret, i, count; + + BUG_ON(!IS_ALIGNED(iova, size)); + BUG_ON(!IS_ALIGNED(paddr, size)); + + ret = -EINVAL; + if (!(prot & IOMMU_PROT_MASK)) + goto out; + + count = PAGE_SIZE_PTE_COUNT(size); + pte = alloc_pte(dom, iova, size, NULL, gfp, &updated); + + ret = -ENOMEM; + if (!pte) + goto out; + + for (i = 0; i < count; ++i) + freelist = free_clear_pte(&pte[i], pte[i], freelist); + + if (freelist != NULL) + updated = true; + + if (count > 1) { + __pte = PAGE_SIZE_PTE(__sme_set(paddr), size); + __pte |= PM_LEVEL_ENC(7) | IOMMU_PTE_PR | IOMMU_PTE_FC; + } else + __pte = __sme_set(paddr) | IOMMU_PTE_PR | IOMMU_PTE_FC; + + if (prot & IOMMU_PROT_IR) + __pte |= IOMMU_PTE_IR; + if (prot & IOMMU_PROT_IW) + __pte |= IOMMU_PTE_IW; + + for (i = 0; i < count; ++i) + pte[i] = __pte; + + ret = 0; + +out: + if (updated) { + unsigned long flags; + + spin_lock_irqsave(&dom->lock, flags); + /* + * Flush domain TLB(s) and wait for completion. Any Device-Table + * Updates and flushing already happened in + * increase_address_space(). + */ + amd_iommu_domain_flush_tlb_pde(dom); + amd_iommu_domain_flush_complete(dom); + spin_unlock_irqrestore(&dom->lock, flags); + } + + /* Everything flushed out, free pages now */ + free_page_list(freelist); + + return ret; +} + +static unsigned long iommu_v1_unmap_page(struct io_pgtable_ops *ops, + unsigned long iova, + size_t size, + struct iommu_iotlb_gather *gather) +{ + struct amd_io_pgtable *pgtable = io_pgtable_ops_to_data(ops); + unsigned long long unmapped; + unsigned long unmap_size; + u64 *pte; + + BUG_ON(!is_power_of_2(size)); + + unmapped = 0; + + while (unmapped < size) { + pte = fetch_pte(pgtable, iova, &unmap_size); + if (pte) { + int i, count; + + count = PAGE_SIZE_PTE_COUNT(unmap_size); + for (i = 0; i < count; i++) + pte[i] = 0ULL; + } + + iova = (iova & ~(unmap_size - 1)) + unmap_size; + unmapped += unmap_size; + } + + BUG_ON(unmapped && !is_power_of_2(unmapped)); + + return unmapped; +} + +static phys_addr_t iommu_v1_iova_to_phys(struct io_pgtable_ops *ops, unsigned long iova) +{ + struct amd_io_pgtable *pgtable = io_pgtable_ops_to_data(ops); + unsigned long offset_mask, pte_pgsize; + u64 *pte, __pte; + + if (pgtable->mode == PAGE_MODE_NONE) + return iova; + + pte = fetch_pte(pgtable, iova, &pte_pgsize); + + if (!pte || !IOMMU_PTE_PRESENT(*pte)) + return 0; + + offset_mask = pte_pgsize - 1; + __pte = __sme_clr(*pte & PM_ADDR_MASK); + + return (__pte & ~offset_mask) | (iova & offset_mask); +} + +/* + * ---------------------------------------------------- + */ +static void v1_free_pgtable(struct io_pgtable *iop) +{ + struct amd_io_pgtable *pgtable = container_of(iop, struct amd_io_pgtable, iop); + struct protection_domain *dom; + struct page *freelist = NULL; + unsigned long root; + + if (pgtable->mode == PAGE_MODE_NONE) + return; + + dom = container_of(pgtable, struct protection_domain, iop); + + /* Update data structure */ + amd_iommu_domain_clr_pt_root(dom); + + /* Make changes visible to IOMMUs */ + amd_iommu_domain_update(dom); + + /* Page-table is not visible to IOMMU anymore, so free it */ + BUG_ON(pgtable->mode < PAGE_MODE_NONE || + pgtable->mode > PAGE_MODE_6_LEVEL); + + root = (unsigned long)pgtable->root; + freelist = free_sub_pt(root, pgtable->mode, freelist); + + free_page_list(freelist); +} + +static struct io_pgtable *v1_alloc_pgtable(struct io_pgtable_cfg *cfg, void *cookie) +{ + struct amd_io_pgtable *pgtable = io_pgtable_cfg_to_data(cfg); + + cfg->pgsize_bitmap = AMD_IOMMU_PGSIZES, + cfg->ias = IOMMU_IN_ADDR_BIT_SIZE, + cfg->oas = IOMMU_OUT_ADDR_BIT_SIZE, + cfg->tlb = &v1_flush_ops; + + pgtable->iop.ops.map = iommu_v1_map_page; + pgtable->iop.ops.unmap = iommu_v1_unmap_page; + pgtable->iop.ops.iova_to_phys = iommu_v1_iova_to_phys; + + return &pgtable->iop; +} + +struct io_pgtable_init_fns io_pgtable_amd_iommu_v1_init_fns = { + .alloc = v1_alloc_pgtable, + .free = v1_free_pgtable, +}; |