[PATCH 4/6] Crashdump-Accepting-Active-IOMMU-Copy-Translations

[Bill Sumner]

Signed-off-by: Bill Sumner <bill.sumner@xxxxxx>
---
 drivers/iommu/intel-iommu.c | 529 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 529 insertions(+)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index ee68f42..d9a49ad 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -4793,3 +4793,532 @@ static int intel_iommu_get_dids_from_old_kernel(struct intel_iommu *iommu)
 	return 0;
 }
 #endif /* CONFIG_CRASH_DUMP */
+#ifdef CONFIG_CRASH_DUMP
+
+
+
+/* ========================================================================
+ * Copy iommu translation tables from old kernel into new  kernel
+ * Entry to this set of functions is: copy_intel_iommu_translation_tables()
+ * ------------------------------------------------------------------------
+ */
+
+/*
+ * Struct copy_page_addr_parms is used to allow copy_page_addr()
+ * to accumulate values across multiple calls and returns.
+ */
+struct copy_page_addr_parms {
+	u32 first;	/* flag: first-time  */
+	u32 last;	/* flag: last-time */
+	u32 bus;	/* last bus number we saw */
+	u32 devfn;	/* last devfn we saw */
+	u32 shift;	/* last shift we saw */
+	u64 pte;	/* Page Table Entry */
+	u64 next_addr;	/* next-expected page_addr */
+
+	u64 page_addr;	/* page_addr accumulating size */
+	u64 page_size;	/* page_size accumulated */
+
+	struct dmar_domain *domain;	/* to accumulate iova ranges */
+};
+
+/*
+ * constant for initializing instances of copy_page_addr_parms properly.
+ */
+static struct copy_page_addr_parms copy_page_addr_parms_init = {1, 0};
+
+
+
+/*
+ * Lowest-level function in the 'Copy Page Tables' set
+ * Called once for each page_addr present in an iommu page-address table.
+ */
+static int copy_page_addr(u64 page_addr, u32 shift, u32 bus, u32 devfn,
+				u64 pte, struct dmar_domain *domain,
+				void *parms)
+{
+	struct copy_page_addr_parms *ppap = parms;
+
+	u64 page_size = ((u64)1 << shift);	/* page_size */
+	u64 pfn_lo;				/* For reserving IOVA range */
+	u64 pfn_hi;				/* For reserving IOVA range */
+	struct iova *iova_p;			/* For reserving IOVA range */
+
+	if (!ppap) {
+		pr_err("ERROR: ppap is NULL: 0x%3.3x(%3.3d) DevFn: 0x%3.3x(%3.3d) Page: 0x%16.16llx Size: 0x%16.16llx(%lld)\n",
+			bus, bus, devfn, devfn,  page_addr,
+			page_size, page_size);
+		return 0;
+	}
+
+	if (!ppap->last) {			/* If (Not last time) */
+		if (pr_dbg.copy_page_addr)
+			pr_debug("ADDR::B:D:F=%2.2x:%2.2x:%1.1x Addr:0x%12.12llx Size:0x%12.12llx(%lld) Pte:0x%16.16llx\n",
+			bus, devfn >> 3, devfn & 0x7,
+			page_addr, page_size, page_size, pte);
+
+		/* If (only extending current addr range) */
+		if (ppap->first     == 0      &&
+		    ppap->bus       == bus    &&
+		    ppap->devfn     == devfn  &&
+		    ppap->shift     == shift  &&
+		    (ppap->pte & ~VTD_PAGE_MASK) == (pte & ~VTD_PAGE_MASK) &&
+		    ppap->next_addr == page_addr) {
+
+			/* Update page size and next-expected address */
+			ppap->next_addr += page_size;
+			ppap->page_size += page_size;
+			return 0;
+		}
+	}
+
+	if (!ppap->first) {
+		/* Print out the accumulated address range */
+
+		if (pr_dbg.addr_ranges)
+			pr_debug("DATA B:D:F=%2.2x:%2.2x:%1.1x Addr:0x%12.12llx Size:0x%12.12llx(%lld) Pte:0x%16.16llx\n",
+			ppap->bus, ppap->devfn >> 3, ppap->devfn & 0x7,
+			ppap->page_addr,
+			ppap->page_size, ppap->page_size, ppap->pte);
+
+		if (!ppap->domain) {
+			pr_err("%s ERROR: Domain is NULL -- needed to reserve range for B:D:F=%2.2x:%2.2x:%1.1x\n",
+				__func__,
+				ppap->bus, ppap->devfn >> 3, ppap->devfn & 0x7);
+			return 0;
+		}
+		pfn_lo = IOVA_PFN(ppap->page_addr);
+		pfn_hi = IOVA_PFN(ppap->page_addr + ppap->page_size);
+		iova_p = reserve_iova(&ppap->domain->iovad, pfn_lo, pfn_hi);
+
+		if (iova_p)
+			if (pr_dbg.reserved_ranges)
+				pr_debug("RSVD B:D:F=%2.2x:%2.2x:%1.1x (0x%16.16lx, 0x%16.16lx) did=0x%4.4x\n",
+					ppap->bus,
+					ppap->devfn >> 3, ppap->devfn & 0x7,
+					iova_p->pfn_lo, iova_p->pfn_hi,
+					ppap->domain->id);
+	}
+
+	/* Prepare for a new page */
+	ppap->first     = 0;		/* Not first-time anymore */
+	ppap->bus       = bus;
+	ppap->devfn     = devfn;
+	ppap->shift     = shift;
+	ppap->pte       = pte;
+	ppap->next_addr = page_addr + page_size; /* Next-expected page_addr */
+
+	ppap->page_addr = page_addr;	/* Addr(new page) */
+	ppap->page_size = page_size;	/* Size(new page) */
+
+	ppap->domain    = domain;	/* adr(domain for the new range) */
+
+	return 0;
+}
+
+/*
+ * Recursive function to copy the tree of page tables (max 6 recursions)
+ * Parameter 'shift' controls the recursion
+ */
+static int copy_page_table(struct dma_pte **dma_pte_new_p,
+			   struct dma_pte *dma_pte_phys,
+			   u32 shift, u64 page_addr,
+			   struct intel_iommu *iommu,
+			   u32 bus, u32 devfn,
+			   struct dmar_domain *domain, void *ppap)
+{
+	int ret;			/* Integer return code */
+	struct dma_pte *p;		/* Physical adr(each entry) iterator */
+	struct dma_pte *pgt_new_virt;	/* Adr(dma_pte in new kernel) */
+	struct dma_pte *dma_pte_next;	/* Adr(next table down)  */
+	u64 u;				/* index(each entry in page_table) */
+
+	if (pr_dbg.copy_page_table)
+		pr_debug("ENTER %s B:D:F:%2.2x:%2.2x:%1.1x phys:%16.16llx shift:%d addr:%16.16llx\n",
+			__func__, bus, devfn >> 3, devfn & 0x7,
+			(u64)dma_pte_phys, shift, page_addr);
+
+	/* If (already done all levels -- problem) */
+	if (shift < 12) {
+		pr_err("ERROR %s shift < 12 %p\n", __func__, dma_pte_phys);
+		pr_err("shift %d, page_addr %16.16llu bus %3.3u devfn %3.3u\n",
+			shift, page_addr, bus, devfn);
+		return 2;
+	}
+
+	/* allocate a page table in the new kernel
+	 * copy contents from old kernel
+	 * then update each entry in the table in the new kernel
+	 */
+
+	pgt_new_virt = (struct dma_pte *)alloc_pgtable_page(iommu->node);
+	if (!pgt_new_virt)
+		return -ENOMEM;
+
+	ret = oldcopy(pgt_new_virt, dma_pte_phys, VTD_PAGE_SIZE);
+	if (ret <= 0)
+		return ret;
+
+	for (u = 0, p = pgt_new_virt; u < 512; u++, p++) {
+
+		if (((p->val & DMA_PTE_READ) == 0) &&
+		    ((p->val & DMA_PTE_WRITE) == 0))
+			continue;
+
+		if (dma_pte_superpage(p) || (shift == 12)) {
+
+			ret = copy_page_addr(page_addr | (u << shift),
+				shift, bus, devfn, p->val, domain, ppap);
+			if (ret)
+				return ret;
+			continue;
+		}
+
+		ret = copy_page_table(&dma_pte_next,
+				(struct dma_pte *)(p->val & VTD_PAGE_MASK),
+				shift-9, page_addr | (u << shift),
+				iommu, bus, devfn, domain, ppap);
+		if (ret)
+			return ret;
+
+		p->val &= ~VTD_PAGE_MASK;	/* Clear old and set new pgd */
+		p->val |= ((u64)dma_pte_next & VTD_PAGE_MASK);
+	}
+
+	*dma_pte_new_p = (struct dma_pte *)virt_to_phys(pgt_new_virt);
+	__iommu_flush_cache(iommu, pgt_new_virt, VTD_PAGE_SIZE);
+
+	if (pr_dbg.copy_page_table)
+		pr_debug("LEAVE %s new page:%16.16llx(phys) %16.16llx(virt)\n",
+			__func__, (u64)(*dma_pte_new_p), (u64)pgt_new_virt);
+
+	return 0;
+}
+
+
+
+static int copy_context_entry(struct intel_iommu *iommu, u32 bus, u32 devfn,
+			      void *ppap, struct context_entry *ce)
+{
+	int ret = 0;			/* Integer Return Code */
+	u32 shift = 0;			/* bits to shift page_addr  */
+	u64 page_addr = 0;		/* Address of translated page */
+	struct dma_pte *pgt_old_phys;	/* Adr(page_table in the old kernel) */
+	struct dma_pte *pgt_new_phys;	/* Adr(page_table in the new kernel) */
+	unsigned long asr;		/* New asr value for new context */
+	u8  t;				/* Translation-type from context */
+	u8  aw;				/* Address-width from context */
+	u32 aw_shift[8] = {
+		12+9+9,		/* [000b] 30-bit AGAW (2-level page table) */
+		12+9+9+9,	/* [001b] 39-bit AGAW (3-level page table) */
+		12+9+9+9+9,	/* [010b] 48-bit AGAW (4-level page table) */
+		12+9+9+9+9+9,	/* [011b] 57-bit AGAW (5-level page table) */
+		12+9+9+9+9+9+9,	/* [100b] 64-bit AGAW (6-level page table) */
+		0,		/* [111b] Reserved */
+		0,		/* [110b] Reserved */
+		0,		/* [111b] Reserved */
+	};
+
+	struct dmar_domain *domain = NULL;	/* To hold domain & device */
+						/*    values from old kernel */
+	struct device_domain_info *info = NULL;	/* adr(new for this device) */
+	struct device_domain_info *i = NULL;	/* iterator for foreach */
+
+
+	pr_debug("CTXT B:D:F:%2.2x:%2.2x:%1.1x at virt: 0x%16.16llx  hi:%16.16llx lo:%16.16llx\n",
+		bus, devfn >> 3, devfn & 0x7,
+		(u64) ce, ce->hi, ce->lo);
+
+	if (!context_get_p(ce)) {	/* If (context not present) */
+		ret = 0;		/* Skip it */
+		goto exit;
+	}
+
+	pr_debug("CTXT B:D:F:%2.2x:%2.2x:%1.1x p=%d fpd=%d t=%d asr=%16.16llx aw=%d aval=%d did=0x%4.4x\n",
+		bus, devfn >> 3, devfn & 0x7,
+		(int) context_get_p(ce),
+		(int) context_get_fpdi(ce),
+		(int) context_get_t(ce),
+		(u64) context_get_asr(ce),
+		(int) context_get_aw(ce),
+		(int) context_get_aval(ce),
+		(u32) context_get_did(ce));
+
+	info = alloc_devinfo_mem();
+	if (!info) {
+		ret = -ENOMEM;
+		goto exit;
+	}
+	/* info->segment = segment;	 May need this later */
+	info->bus = bus;
+	info->devfn = devfn;
+	info->iommu = iommu;
+
+	list_for_each_entry(i, &device_domain_values_list[iommu->seq_id],
+				global) {
+		if (i->domain->id == (int) context_get_did(ce)) {
+			domain = i->domain;
+			pr_debug("CTXT B:D:F:%2.2x:%2.2x:%1.1x Found did=0x%4.4x\n",
+				bus, devfn >> 3, devfn & 0x7, i->domain->id);
+			break;
+		}
+	}
+
+	if (!domain) {
+		domain = alloc_domain();
+		if (!domain) {
+			ret = -ENOMEM;
+			goto exit;
+		}
+		INIT_LIST_HEAD(&domain->devices);
+		domain->id = (int) context_get_did(ce);
+		domain->agaw = (int) context_get_aw(ce);
+		domain->pgd = NULL;
+
+		pr_debug("CTXT Allocated new list entry, did:%d\n",
+			domain->id);
+	}
+
+	info->domain = domain;
+	list_add(&info->link, &domain->devices);
+	list_add(&info->global, &device_domain_values_list[iommu->seq_id]);
+
+	if (domain->pgd) {
+		asr = virt_to_phys(domain->pgd) >> VTD_PAGE_SHIFT;
+		context_put_asr(ce, asr);
+		ret = 4;
+		goto exit;
+	}
+
+	t = context_get_t(ce);
+
+	if (t == 0 || t == 1) {		/* If (context has page tables) */
+		aw = context_get_aw(ce);
+		shift = aw_shift[aw];
+
+		pgt_old_phys = (struct dma_pte *)(context_get_asr(ce) << 12);
+
+		ret = copy_page_table(&pgt_new_phys, pgt_old_phys,
+			shift-9, page_addr, iommu, bus, devfn, domain, ppap);
+
+		if (ret)		/* if (problem) bail out */
+			goto exit;
+
+		asr = ((unsigned long)(pgt_new_phys)) >> VTD_PAGE_SHIFT;
+		context_put_asr(ce, asr);
+		domain->pgd = phys_to_virt((unsigned long)pgt_new_phys);
+		ret = 1;
+		goto exit;
+	}
+
+	if (t == 2) {		/* If (Identity mapped pass-through) */
+		ret = 2;	/*	REVISIT: Skip for now */
+		goto exit;
+	}
+
+	ret = 3;		/* Else ce->t is a Reserved value */
+
+exit:	/* all returns come through here to insure good clean-up */
+
+	if (ret < 0) {
+		if (info)
+			free_devinfo_mem(info);
+		if (domain)
+			free_domain_mem(domain);
+	}
+	return ret;
+}
+
+
+static int copy_context_entry_table(struct intel_iommu *iommu,
+				    u32 bus, void *ppap,
+				    struct context_entry **context_new_p,
+				    struct context_entry *context_old_phys)
+{
+	int ret = 0;				/* Integer return code */
+	struct context_entry *ce;		/* Iterator */
+	struct context_entry *context_new_phys;	/* adr(table in new kernel) */
+	struct context_entry *context_new_virt;	/* adr(table in new kernel) */
+	u32 devfn = 0;				/* PCI Device & function */
+
+	/* allocate a context-entry table in the new kernel
+	 * copy contents from old kernel
+	 * then update each entry in the table in the new kernel
+	 */
+	context_new_virt =
+		(struct context_entry *)alloc_pgtable_page(iommu->node);
+	if (!context_new_virt)
+		return -ENOMEM;
+
+	context_new_phys =
+		(struct context_entry *)virt_to_phys(context_new_virt);
+
+	oldcopy(context_new_virt, context_old_phys, VTD_PAGE_SIZE);
+
+	for (devfn = 0, ce = context_new_virt; devfn < 256; devfn++, ce++) {
+
+		if (!context_get_p(ce))		/* If (context not present) */
+			continue;		/* Skip it */
+
+		ret = copy_context_entry(iommu, bus, devfn, ppap, ce);
+		if (ret == 0)		/* if (Entry not present) */
+			continue;
+		if (ret == 1)		/* If (Identity mapped pass-through) */
+			continue;	/*    REVISIT -- Skip for now */
+		if (ret == 2)		/* If (ce->t was reserved value) */
+			continue;	/*    REVISIT -- Skip for now */
+		if (ret < 0)		/* if (problem) */
+			return ret;
+	}
+
+	*context_new_p = context_new_phys;
+	__iommu_flush_cache(iommu, context_new_virt, VTD_PAGE_SIZE);
+	return 0;
+}
+
+
+
+static int copy_root_entry_table(struct intel_iommu *iommu, void *ppap,
+				 struct root_entry  **root_new_virt_p,
+				 struct root_entry  *root_old_phys)
+{
+	int ret = 0;				/* Integer return code */
+	u32 bus;				/* Index: root-entry-table */
+	struct root_entry  *re;			/* Virt(iterator: new table) */
+	struct root_entry  *root_new_virt;	/* Virt(table in new kernel) */
+	struct context_entry *context_old_phys;	/* Phys(context table entry) */
+	struct context_entry *context_new_phys;	/* Phys(new context_entry) */
+
+	/*
+	 * allocate a root-entry table in the new kernel
+	 * copy contents from old kernel
+	 * then update each entry in the table in the new kernel
+	 */
+
+	root_new_virt = (struct root_entry *)alloc_pgtable_page(iommu->node);
+	if (!root_new_virt)
+		return -ENOMEM;
+
+	oldcopy(root_new_virt, root_old_phys, VTD_PAGE_SIZE);
+
+	for (bus = 0, re = root_new_virt; bus < 256; bus += 1, re += 1) {
+
+		if (!root_present(re))
+			continue;
+
+		pr_debug("ROOT Bus: %2.2x re->val: %llx rsvd1: %llx\n",
+			bus, re->val, re->rsvd1);
+
+		context_old_phys = get_context_phys_from_root(re);
+
+		if (!context_old_phys)
+			continue;
+
+		ret = copy_context_entry_table(iommu, bus, ppap,
+						&context_new_phys,
+						context_old_phys);
+		if (ret)
+			return ret;
+
+		re->val &= ~VTD_PAGE_MASK;
+		set_root_value(re, (unsigned long)context_new_phys);
+	}
+
+	*root_new_virt_p = root_new_virt;
+	__iommu_flush_cache(iommu, root_new_virt, VTD_PAGE_SIZE);
+	return 0;
+}
+
+/*
+ * Interface to the "copy translation tables" set of functions
+ * from mainline code.
+ */
+static int copy_intel_iommu_translation_tables(struct dmar_drhd_unit *drhd,
+		struct root_entry **root_old_phys_p,
+		struct root_entry **root_new_virt_p)
+{
+	struct intel_iommu *iommu;	/* Virt(iommu hardware registers) */
+	unsigned long long q;		/* quadword scratch */
+	struct root_entry *root_phys;	/* Phys(table in old kernel) */
+	struct root_entry *root_new;	/* Virt(table in new kernel) */
+	int ret = 0;			/* Integer return code */
+	int i = 0;			/* Loop index */
+
+	/* Structure so copy_page_addr() can accumulate things
+	 * over multiple calls and returns
+	 */
+	struct copy_page_addr_parms ppa_parms = copy_page_addr_parms_init;
+	struct copy_page_addr_parms *ppap = &ppa_parms;
+
+
+	pr_debug("ENTER %s\n", __func__);
+
+	iommu = drhd->iommu;
+	q = readq(iommu->reg + DMAR_RTADDR_REG);
+	pr_debug("IOMMU %d: DMAR_RTADDR_REG:0x%16.16llx\n", iommu->seq_id, q);
+
+	if (!q)
+		return -1;
+
+	*root_old_phys_p = (struct root_entry *)q;	/* Returned to caller */
+
+	/* If (list needs initializing) do it here */
+	if (!device_domain_values_list) {
+		device_domain_values_list =
+			 kcalloc(g_num_of_iommus, sizeof(struct list_head),
+					GFP_KERNEL);
+
+		if (!device_domain_values_list) {
+			pr_err("Allocation failed for device_domain_values_list array\n");
+			return -ENOMEM;
+		}
+		for (i = 0; i < g_num_of_iommus; i++)
+			INIT_LIST_HEAD(&device_domain_values_list[i]);
+	}
+
+	/* Copy the root-entry table from the old kernel
+	 * foreach context_entry_table in root_entry
+	 *    foreach context_entry in context_entry_table
+	 *       foreach level-1 page_table_entry in context_entry
+	 *          foreach level-2 page_table_entry in level 1 page_table_entry
+	 *             Above pattern continues up to 6 levels of page tables
+	 *                Sanity-check the entry
+	 *                Process the bus, devfn, page_address, page_size
+	 */
+
+	root_phys = (struct root_entry *)q;
+	ret = copy_root_entry_table(iommu, ppap, &root_new, root_phys);
+	if (ret)
+		return ret;
+
+
+	ppa_parms.last = 1;
+	copy_page_addr(0, 0, 0, 0, 0, NULL, ppap);
+	*root_new_virt_p = root_new;			/* Returned to caller */
+
+	/* The translation tables in the new kernel should now contain
+	 * the same translations as the tables in the old kernel.
+	 * This will allow us to update the iommu hdw to use the new tables.
+	 *
+	 * NOTE: Neither the iommu hardware nor the iommu->root_entry
+	 *       struct-value is updated herein.
+	 *       These are left for the caller to do.
+	 */
+
+	{	/* Dump the new root-entry table on the console */
+		u64 *p;
+		int  i;
+
+		pr_debug("ROOT_ENTRY TABLE (NEW) START\n");
+
+		for (p = (void *)root_new, i = 0; i < 256; p += 2, i++)
+			if (p[1] != 0 || p[0] != 0 || i == 255)
+				pr_debug("i:%3.3d, p:0x%12.12llx %16.16llx %16.16llx\n",
+					i, (u64)p, p[1], p[0]);
+
+		pr_debug("ROOT_ENTRY TABLE (NEW) END\n");
+	}
+	pr_debug("LEAVE %s\n", __func__);
+	return 0;
+}
+#endif /* CONFIG_CRASH_DUMP */
-- 
Bill Sumner <bill.sumner@xxxxxx>

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