iommu/amd: Move IO page table related functions

Preparing to migrate to use IO page table framework.
There is no functional change.

Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Link: https://lore.kernel.org/r/20201215073705.123786-7-suravee.suthikulpanit@amd.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>

1 files changed, 473 insertions, 0 deletions

diff --git a/drivers/iommu/amd/io_pgtable.c b/drivers/iommu/amd/io_pgtable.c
index cf2cd2d2e43e..dbc0ad775d5e 100644
--- a/drivers/iommu/amd/io_pgtable.c
+++ b/drivers/iommu/amd/io_pgtable.c
@@ -45,6 +45,479 @@ static const struct iommu_flush_ops v1_flush_ops = {
 };
 
 /*
+ * 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 free_pagetable(struct domain_pgtable *pgtable)
+{
+	struct page *freelist = NULL;
+	unsigned long root;
+
+	if (pgtable->mode == PAGE_MODE_NONE)
+		return;
+
+	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);
+}
+
+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)
+{
+	struct domain_pgtable pgtable;
+	unsigned long flags;
+	bool ret = true;
+	u64 *pte;
+
+	spin_lock_irqsave(&domain->lock, flags);
+
+	amd_iommu_domain_get_pgtable(domain, &pgtable);
+
+	if (address <= PM_LEVEL_SIZE(pgtable.mode))
+		goto out;
+
+	ret = false;
+	if (WARN_ON_ONCE(pgtable.mode == PAGE_MODE_6_LEVEL))
+		goto out;
+
+	pte = (void *)get_zeroed_page(gfp);
+	if (!pte)
+		goto out;
+
+	*pte = PM_LEVEL_PDE(pgtable.mode, iommu_virt_to_phys(pgtable.root));
+
+	pgtable.root  = pte;
+	pgtable.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, pgtable.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)
+{
+	struct domain_pgtable pgtable;
+	int level, end_lvl;
+	u64 *pte, *page;
+
+	BUG_ON(!is_power_of_2(page_size));
+
+	amd_iommu_domain_get_pgtable(domain, &pgtable);
+
+	while (address > PM_LEVEL_SIZE(pgtable.mode)) {
+		/*
+		 * Return an error if there is no memory to update the
+		 * page-table.
+		 */
+		if (!increase_address_space(domain, address, gfp))
+			return NULL;
+
+		/* Read new values to check if update was successful */
+		amd_iommu_domain_get_pgtable(domain, &pgtable);
+	}
+
+
+	level   = pgtable.mode - 1;
+	pte     = &pgtable.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.
+ */
+u64 *fetch_pte(struct protection_domain *domain,
+	       unsigned long address,
+	       unsigned long *page_size)
+{
+	struct domain_pgtable pgtable;
+	int level;
+	u64 *pte;
+
+	*page_size = 0;
+
+	amd_iommu_domain_get_pgtable(domain, &pgtable);
+
+	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.
+ */
+int iommu_map_page(struct protection_domain *dom,
+		   unsigned long bus_addr,
+		   unsigned long phys_addr,
+		   unsigned long page_size,
+		   int prot,
+		   gfp_t gfp)
+{
+	struct page *freelist = NULL;
+	bool updated = false;
+	u64 __pte, *pte;
+	int ret, i, count;
+
+	BUG_ON(!IS_ALIGNED(bus_addr, page_size));
+	BUG_ON(!IS_ALIGNED(phys_addr, page_size));
+
+	ret = -EINVAL;
+	if (!(prot & IOMMU_PROT_MASK))
+		goto out;
+
+	count = PAGE_SIZE_PTE_COUNT(page_size);
+	pte   = alloc_pte(dom, bus_addr, page_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(phys_addr), page_size);
+		__pte |= PM_LEVEL_ENC(7) | IOMMU_PTE_PR | IOMMU_PTE_FC;
+	} else
+		__pte = __sme_set(phys_addr) | 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;
+}
+
+unsigned long iommu_unmap_page(struct protection_domain *dom,
+			       unsigned long bus_addr,
+			       unsigned long page_size)
+{
+	unsigned long long unmapped;
+	unsigned long unmap_size;
+	u64 *pte;
+
+	BUG_ON(!is_power_of_2(page_size));
+
+	unmapped = 0;
+
+	while (unmapped < page_size) {
+
+		pte = fetch_pte(dom, bus_addr, &unmap_size);
+
+		if (pte) {
+			int i, count;
+
+			count = PAGE_SIZE_PTE_COUNT(unmap_size);
+			for (i = 0; i < count; i++)
+				pte[i] = 0ULL;
+		}
+
+		bus_addr  = (bus_addr & ~(unmap_size - 1)) + unmap_size;
+		unmapped += unmap_size;
+	}
+
+	BUG_ON(unmapped && !is_power_of_2(unmapped));
+
+	return unmapped;
+}
+
+/*
  * ----------------------------------------------------
  */
 static void v1_free_pgtable(struct io_pgtable *iop)