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Date:	Mon, 22 Dec 2014 17:15:23 +0800
From:	"Li, Zhen-Hua" <zhen-hual@...com>
To:	<dwmw2@...radead.org>, <indou.takao@...fujitsu.com>,
	<bhe@...hat.com>, <joro@...tes.org>, <vgoyal@...hat.com>,
	<dyoung@...hat.com>
Cc:	<iommu@...ts.linux-foundation.org>, <linux-kernel@...r.kernel.org>,
	<linux-pci@...r.kernel.org>, <kexec@...ts.infradead.org>,
	<alex.williamson@...hat.com>, <ddutile@...hat.com>,
	<ishii.hironobu@...fujitsu.com>, <bhelgaas@...gle.com>,
	<doug.hatch@...com>, <jerry.hoemann@...com>, <tom.vaden@...com>,
	<li.zhang6@...com>, <lisa.mitchell@...com>,
	<billsumnerlinux@...il.com>, <zhen-hual@...com>
Subject: [PATCH 04/10] iommu/vt-d: functions to copy data from old mem

Add some functions to copy the data from old kernel.
These functions are used to copy context tables and page tables.

To avoid calling iounmap between spin_lock_irqsave and spin_unlock_irqrestore,
use a link here, store the pointers , and then use iounmap to free them in
another place.

Signed-off-by: Li, Zhen-Hua <zhen-hual@...com>
---
 drivers/iommu/intel-iommu.c | 97 +++++++++++++++++++++++++++++++++++++++++++++
 include/linux/intel-iommu.h |  9 +++++
 2 files changed, 106 insertions(+)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index c0bebd6..8a7ad72 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -388,6 +388,13 @@ static int intel_iommu_get_dids_from_old_kernel(struct intel_iommu *iommu);
 
 static int device_to_domain_id(struct intel_iommu *iommu, u8 bus, u8 devfn);
 
+struct iommu_remapped_entry {
+	struct list_head list;
+	void __iomem *mem;
+};
+static LIST_HEAD(__iommu_remapped_mem);
+static DEFINE_MUTEX(__iommu_mem_list_lock);
+
 #endif /* CONFIG_CRASH_DUMP */
 
 /*
@@ -4843,6 +4850,96 @@ static void __init check_tylersburg_isoch(void)
 #ifdef CONFIG_CRASH_DUMP
 
 /*
+ * Copy memory from a physically-addressed area into a virtually-addressed area
+ */
+int __iommu_load_from_oldmem(void *to, unsigned long from, unsigned long size)
+{
+	unsigned long pfn;		/* Page Frame Number */
+	size_t csize = (size_t)size;	/* Num(bytes to copy) */
+	unsigned long offset;		/* Lower 12 bits of to */
+	void __iomem *virt_mem;
+	struct iommu_remapped_entry *mapped;
+
+	pfn = from >> VTD_PAGE_SHIFT;
+	offset = from & (~VTD_PAGE_MASK);
+
+	if (page_is_ram(pfn)) {
+		memcpy(to, pfn_to_kaddr(pfn) + offset, csize);
+	} else{
+
+		mapped = kzalloc(sizeof(struct iommu_remapped_entry),
+				GFP_KERNEL);
+		if (!mapped)
+			return -ENOMEM;
+
+		virt_mem = ioremap_cache((unsigned long)from, size);
+		if (!virt_mem) {
+			kfree(mapped);
+			return -ENOMEM;
+		}
+		memcpy(to, virt_mem, size);
+
+		mutex_lock(&__iommu_mem_list_lock);
+		mapped->mem = virt_mem;
+		list_add_tail(&mapped->list, &__iommu_remapped_mem);
+		mutex_unlock(&__iommu_mem_list_lock);
+	}
+	return size;
+}
+
+/*
+ * Copy memory from a virtually-addressed area into a physically-addressed area
+ */
+int __iommu_save_to_oldmem(unsigned long to, void *from, unsigned long size)
+{
+	unsigned long pfn;		/* Page Frame Number */
+	size_t csize = (size_t)size;	/* Num(bytes to copy) */
+	unsigned long offset;		/* Lower 12 bits of to */
+	void __iomem *virt_mem;
+	struct iommu_remapped_entry *mapped;
+
+	pfn = to >> VTD_PAGE_SHIFT;
+	offset = to & (~VTD_PAGE_MASK);
+
+	if (page_is_ram(pfn)) {
+		memcpy(pfn_to_kaddr(pfn) + offset, from, csize);
+	} else{
+		mapped = kzalloc(sizeof(struct iommu_remapped_entry),
+				GFP_KERNEL);
+		if (!mapped)
+			return -ENOMEM;
+
+		virt_mem = ioremap_cache((unsigned long)to, size);
+		if (!virt_mem) {
+			kfree(mapped);
+			return -ENOMEM;
+		}
+		memcpy(virt_mem, from, size);
+		mutex_lock(&__iommu_mem_list_lock);
+		mapped->mem = virt_mem;
+		list_add_tail(&mapped->list, &__iommu_remapped_mem);
+		mutex_unlock(&__iommu_mem_list_lock);
+	}
+	return size;
+}
+
+/*
+ * Free the mapped memory for ioremap;
+ */
+int __iommu_free_mapped_mem(void)
+{
+	struct iommu_remapped_entry *mem_entry, *tmp;
+
+	mutex_lock(&__iommu_mem_list_lock);
+	list_for_each_entry_safe(mem_entry, tmp, &__iommu_remapped_mem, list) {
+		iounmap(mem_entry->mem);
+		list_del(&mem_entry->list);
+		kfree(mem_entry);
+	}
+	mutex_unlock(&__iommu_mem_list_lock);
+	return 0;
+}
+/*
  * Interfaces for when a new domain in the crashdump kernel needs some
  * values from the panicked kernel's context entries
  *
diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h
index a65208a..8ffa523 100644
--- a/include/linux/intel-iommu.h
+++ b/include/linux/intel-iommu.h
@@ -26,6 +26,7 @@
 #include <linux/iova.h>
 #include <linux/io.h>
 #include <linux/dma_remapping.h>
+#include <linux/crash_dump.h>
 #include <asm/cacheflush.h>
 #include <asm/iommu.h>
 
@@ -368,4 +369,12 @@ extern int dmar_ir_support(void);
 
 extern const struct attribute_group *intel_iommu_groups[];
 
+#ifdef CONFIG_CRASH_DUMP
+extern int __iommu_load_from_oldmem(void *to, unsigned long from,
+					unsigned long size);
+extern int __iommu_save_to_oldmem(unsigned long to, void *from,
+					unsigned long size);
+extern int __iommu_free_mapped_mem(void);
+#endif /* CONFIG_CRASH_DUMP */
+
 #endif
-- 
2.0.0-rc0

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