[PATCH v7 04/10] iommu/vt-d: functions to copy data from old mem

From: Li, Zhen-Hua
Date: Tue Jan 06 2015 - 23:06:21 EST


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.

Li, Zhen-hua:
The functions and logics.

Takao Indoh:
Check if pfn is ram:
if (page_is_ram(pfn))

Signed-off-by: Li, Zhen-Hua <zhen-hual@xxxxxx>
Signed-off-by: Takao Indoh <indou.takao@xxxxxxxxxxxxxx>
---
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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