416 lines
9.4 KiB
C
416 lines
9.4 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* CPU-agnostic AMD IO page table v2 allocator.
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*
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* Copyright (C) 2022 Advanced Micro Devices, Inc.
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* Author: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
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* Author: Vasant Hegde <vasant.hegde@amd.com>
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*/
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#define pr_fmt(fmt) "AMD-Vi: " fmt
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#define dev_fmt(fmt) pr_fmt(fmt)
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#include <linux/bitops.h>
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#include <linux/io-pgtable.h>
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#include <linux/kernel.h>
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#include <asm/barrier.h>
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#include "amd_iommu_types.h"
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#include "amd_iommu.h"
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#define IOMMU_PAGE_PRESENT BIT_ULL(0) /* Is present */
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#define IOMMU_PAGE_RW BIT_ULL(1) /* Writeable */
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#define IOMMU_PAGE_USER BIT_ULL(2) /* Userspace addressable */
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#define IOMMU_PAGE_PWT BIT_ULL(3) /* Page write through */
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#define IOMMU_PAGE_PCD BIT_ULL(4) /* Page cache disabled */
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#define IOMMU_PAGE_ACCESS BIT_ULL(5) /* Was accessed (updated by IOMMU) */
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#define IOMMU_PAGE_DIRTY BIT_ULL(6) /* Was written to (updated by IOMMU) */
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#define IOMMU_PAGE_PSE BIT_ULL(7) /* Page Size Extensions */
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#define IOMMU_PAGE_NX BIT_ULL(63) /* No execute */
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#define MAX_PTRS_PER_PAGE 512
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#define IOMMU_PAGE_SIZE_2M BIT_ULL(21)
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#define IOMMU_PAGE_SIZE_1G BIT_ULL(30)
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static inline int get_pgtable_level(void)
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{
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/* 5 level page table is not supported */
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return PAGE_MODE_4_LEVEL;
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}
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static inline bool is_large_pte(u64 pte)
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{
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return (pte & IOMMU_PAGE_PSE);
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}
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static inline void *alloc_pgtable_page(void)
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{
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return (void *)get_zeroed_page(GFP_KERNEL);
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}
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static inline u64 set_pgtable_attr(u64 *page)
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{
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u64 prot;
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prot = IOMMU_PAGE_PRESENT | IOMMU_PAGE_RW | IOMMU_PAGE_USER;
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prot |= IOMMU_PAGE_ACCESS | IOMMU_PAGE_DIRTY;
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return (iommu_virt_to_phys(page) | prot);
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}
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static inline void *get_pgtable_pte(u64 pte)
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{
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return iommu_phys_to_virt(pte & PM_ADDR_MASK);
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}
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static u64 set_pte_attr(u64 paddr, u64 pg_size, int prot)
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{
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u64 pte;
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pte = __sme_set(paddr & PM_ADDR_MASK);
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pte |= IOMMU_PAGE_PRESENT | IOMMU_PAGE_USER;
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pte |= IOMMU_PAGE_ACCESS | IOMMU_PAGE_DIRTY;
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if (prot & IOMMU_PROT_IW)
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pte |= IOMMU_PAGE_RW;
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/* Large page */
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if (pg_size == IOMMU_PAGE_SIZE_1G || pg_size == IOMMU_PAGE_SIZE_2M)
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pte |= IOMMU_PAGE_PSE;
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return pte;
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}
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static inline u64 get_alloc_page_size(u64 size)
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{
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if (size >= IOMMU_PAGE_SIZE_1G)
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return IOMMU_PAGE_SIZE_1G;
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if (size >= IOMMU_PAGE_SIZE_2M)
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return IOMMU_PAGE_SIZE_2M;
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return PAGE_SIZE;
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}
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static inline int page_size_to_level(u64 pg_size)
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{
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if (pg_size == IOMMU_PAGE_SIZE_1G)
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return PAGE_MODE_3_LEVEL;
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if (pg_size == IOMMU_PAGE_SIZE_2M)
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return PAGE_MODE_2_LEVEL;
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return PAGE_MODE_1_LEVEL;
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}
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static inline void free_pgtable_page(u64 *pt)
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{
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free_page((unsigned long)pt);
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}
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static void free_pgtable(u64 *pt, int level)
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{
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u64 *p;
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int i;
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for (i = 0; i < MAX_PTRS_PER_PAGE; i++) {
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/* PTE present? */
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if (!IOMMU_PTE_PRESENT(pt[i]))
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continue;
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if (is_large_pte(pt[i]))
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continue;
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/*
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* Free the next level. No need to look at l1 tables here since
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* they can only contain leaf PTEs; just free them directly.
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*/
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p = get_pgtable_pte(pt[i]);
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if (level > 2)
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free_pgtable(p, level - 1);
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else
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free_pgtable_page(p);
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}
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free_pgtable_page(pt);
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}
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/* Allocate page table */
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static u64 *v2_alloc_pte(u64 *pgd, unsigned long iova,
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unsigned long pg_size, bool *updated)
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{
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u64 *pte, *page;
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int level, end_level;
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level = get_pgtable_level() - 1;
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end_level = page_size_to_level(pg_size);
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pte = &pgd[PM_LEVEL_INDEX(level, iova)];
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iova = PAGE_SIZE_ALIGN(iova, PAGE_SIZE);
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while (level >= end_level) {
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u64 __pte, __npte;
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__pte = *pte;
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if (IOMMU_PTE_PRESENT(__pte) && is_large_pte(__pte)) {
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/* Unmap large pte */
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cmpxchg64(pte, *pte, 0ULL);
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*updated = true;
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continue;
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}
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if (!IOMMU_PTE_PRESENT(__pte)) {
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page = alloc_pgtable_page();
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if (!page)
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return NULL;
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__npte = set_pgtable_attr(page);
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/* pte could have been changed somewhere. */
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if (cmpxchg64(pte, __pte, __npte) != __pte)
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free_pgtable_page(page);
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else if (IOMMU_PTE_PRESENT(__pte))
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*updated = true;
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continue;
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}
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level -= 1;
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pte = get_pgtable_pte(__pte);
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pte = &pte[PM_LEVEL_INDEX(level, iova)];
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}
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/* Tear down existing pte entries */
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if (IOMMU_PTE_PRESENT(*pte)) {
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u64 *__pte;
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*updated = true;
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__pte = get_pgtable_pte(*pte);
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cmpxchg64(pte, *pte, 0ULL);
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if (pg_size == IOMMU_PAGE_SIZE_1G)
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free_pgtable(__pte, end_level - 1);
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else if (pg_size == IOMMU_PAGE_SIZE_2M)
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free_pgtable_page(__pte);
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}
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return pte;
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}
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/*
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* This function checks if there is a PTE for a given dma address.
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* If there is one, it returns the pointer to it.
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*/
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static u64 *fetch_pte(struct amd_io_pgtable *pgtable,
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unsigned long iova, unsigned long *page_size)
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{
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u64 *pte;
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int level;
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level = get_pgtable_level() - 1;
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pte = &pgtable->pgd[PM_LEVEL_INDEX(level, iova)];
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/* Default page size is 4K */
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*page_size = PAGE_SIZE;
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while (level) {
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/* Not present */
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if (!IOMMU_PTE_PRESENT(*pte))
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return NULL;
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/* Walk to the next level */
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pte = get_pgtable_pte(*pte);
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pte = &pte[PM_LEVEL_INDEX(level - 1, iova)];
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/* Large page */
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if (is_large_pte(*pte)) {
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if (level == PAGE_MODE_3_LEVEL)
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*page_size = IOMMU_PAGE_SIZE_1G;
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else if (level == PAGE_MODE_2_LEVEL)
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*page_size = IOMMU_PAGE_SIZE_2M;
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else
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return NULL; /* Wrongly set PSE bit in PTE */
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break;
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}
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level -= 1;
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}
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return pte;
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}
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static int iommu_v2_map_pages(struct io_pgtable_ops *ops, unsigned long iova,
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phys_addr_t paddr, size_t pgsize, size_t pgcount,
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int prot, gfp_t gfp, size_t *mapped)
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{
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struct protection_domain *pdom = io_pgtable_ops_to_domain(ops);
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struct io_pgtable_cfg *cfg = &pdom->iop.iop.cfg;
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u64 *pte;
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unsigned long map_size;
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unsigned long mapped_size = 0;
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unsigned long o_iova = iova;
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size_t size = pgcount << __ffs(pgsize);
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int count = 0;
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int ret = 0;
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bool updated = false;
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if (WARN_ON(!pgsize || (pgsize & cfg->pgsize_bitmap) != pgsize) || !pgcount)
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return -EINVAL;
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if (!(prot & IOMMU_PROT_MASK))
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return -EINVAL;
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while (mapped_size < size) {
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map_size = get_alloc_page_size(pgsize);
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pte = v2_alloc_pte(pdom->iop.pgd, iova, map_size, &updated);
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if (!pte) {
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ret = -EINVAL;
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goto out;
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}
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*pte = set_pte_attr(paddr, map_size, prot);
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count++;
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iova += map_size;
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paddr += map_size;
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mapped_size += map_size;
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}
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out:
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if (updated) {
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if (count > 1)
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amd_iommu_flush_tlb(&pdom->domain, 0);
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else
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amd_iommu_flush_page(&pdom->domain, 0, o_iova);
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}
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if (mapped)
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*mapped += mapped_size;
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return ret;
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}
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static unsigned long iommu_v2_unmap_pages(struct io_pgtable_ops *ops,
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unsigned long iova,
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size_t pgsize, size_t pgcount,
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struct iommu_iotlb_gather *gather)
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{
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struct amd_io_pgtable *pgtable = io_pgtable_ops_to_data(ops);
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struct io_pgtable_cfg *cfg = &pgtable->iop.cfg;
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unsigned long unmap_size;
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unsigned long unmapped = 0;
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size_t size = pgcount << __ffs(pgsize);
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u64 *pte;
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if (WARN_ON(!pgsize || (pgsize & cfg->pgsize_bitmap) != pgsize || !pgcount))
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return 0;
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while (unmapped < size) {
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pte = fetch_pte(pgtable, iova, &unmap_size);
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if (!pte)
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return unmapped;
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*pte = 0ULL;
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iova = (iova & ~(unmap_size - 1)) + unmap_size;
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unmapped += unmap_size;
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}
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return unmapped;
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}
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static phys_addr_t iommu_v2_iova_to_phys(struct io_pgtable_ops *ops, unsigned long iova)
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{
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struct amd_io_pgtable *pgtable = io_pgtable_ops_to_data(ops);
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unsigned long offset_mask, pte_pgsize;
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u64 *pte, __pte;
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pte = fetch_pte(pgtable, iova, &pte_pgsize);
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if (!pte || !IOMMU_PTE_PRESENT(*pte))
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return 0;
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offset_mask = pte_pgsize - 1;
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__pte = __sme_clr(*pte & PM_ADDR_MASK);
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return (__pte & ~offset_mask) | (iova & offset_mask);
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}
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/*
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* ----------------------------------------------------
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*/
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static void v2_tlb_flush_all(void *cookie)
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{
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}
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static void v2_tlb_flush_walk(unsigned long iova, size_t size,
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size_t granule, void *cookie)
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{
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}
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static void v2_tlb_add_page(struct iommu_iotlb_gather *gather,
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unsigned long iova, size_t granule,
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void *cookie)
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{
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}
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static const struct iommu_flush_ops v2_flush_ops = {
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.tlb_flush_all = v2_tlb_flush_all,
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.tlb_flush_walk = v2_tlb_flush_walk,
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.tlb_add_page = v2_tlb_add_page,
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};
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static void v2_free_pgtable(struct io_pgtable *iop)
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{
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struct protection_domain *pdom;
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struct amd_io_pgtable *pgtable = container_of(iop, struct amd_io_pgtable, iop);
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pdom = container_of(pgtable, struct protection_domain, iop);
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if (!(pdom->flags & PD_IOMMUV2_MASK))
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return;
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/*
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* Make changes visible to IOMMUs. No need to clear gcr3 entry
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* as gcr3 table is already freed.
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*/
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amd_iommu_domain_update(pdom);
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/* Free page table */
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free_pgtable(pgtable->pgd, get_pgtable_level());
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}
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static struct io_pgtable *v2_alloc_pgtable(struct io_pgtable_cfg *cfg, void *cookie)
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{
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struct amd_io_pgtable *pgtable = io_pgtable_cfg_to_data(cfg);
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struct protection_domain *pdom = (struct protection_domain *)cookie;
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int ret;
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pgtable->pgd = alloc_pgtable_page();
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if (!pgtable->pgd)
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return NULL;
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ret = amd_iommu_domain_set_gcr3(&pdom->domain, 0, iommu_virt_to_phys(pgtable->pgd));
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if (ret)
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goto err_free_pgd;
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pgtable->iop.ops.map_pages = iommu_v2_map_pages;
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pgtable->iop.ops.unmap_pages = iommu_v2_unmap_pages;
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pgtable->iop.ops.iova_to_phys = iommu_v2_iova_to_phys;
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cfg->pgsize_bitmap = AMD_IOMMU_PGSIZES_V2,
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cfg->ias = IOMMU_IN_ADDR_BIT_SIZE,
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cfg->oas = IOMMU_OUT_ADDR_BIT_SIZE,
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cfg->tlb = &v2_flush_ops;
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return &pgtable->iop;
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err_free_pgd:
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free_pgtable_page(pgtable->pgd);
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return NULL;
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}
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struct io_pgtable_init_fns io_pgtable_amd_iommu_v2_init_fns = {
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.alloc = v2_alloc_pgtable,
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.free = v2_free_pgtable,
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};
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