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Subject[PATCH v11 02/10] iommu/vt-d: Items required for kdump
Date
Add context entry functions needed for kdump.

Bill Sumner:
Original version;

Li, Zhenhua:
Changed the name of new functions, make them consistent with current
context get/set functions.
Remove the structure dve which is not used in new version.

Signed-off-by: Bill Sumner <billsumnerlinux@gmail.com>
Signed-off-by: Li, Zhen-Hua <zhen-hual@hp.com>
---
drivers/iommu/intel-iommu.c | 72 +++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 72 insertions(+)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index cb9d6cc..1e7ceb5 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -190,6 +190,31 @@ struct root_entry {
};
#define ROOT_ENTRY_NR (VTD_PAGE_SIZE/sizeof(struct root_entry))

+static inline bool root_present(struct root_entry *root)
+{
+ return (root->lo & 1);
+}
+
+static inline void set_root_value(struct root_entry *root, unsigned long value)
+{
+ root->lo &= ~VTD_PAGE_MASK;
+ root->lo |= value & VTD_PAGE_MASK;
+}
+
+static inline struct context_entry *
+get_context_addr_from_root(struct root_entry *root)
+{
+ return (struct context_entry *)
+ (root_present(root)?phys_to_virt(
+ root->lo & VTD_PAGE_MASK) :
+ NULL);
+}
+
+static inline unsigned long
+get_context_phys_from_root(struct root_entry *root)
+{
+ return root_present(root) ? (root->lo & VTD_PAGE_MASK) : 0;
+}

/*
* low 64 bits:
@@ -211,6 +236,32 @@ static inline bool context_present(struct context_entry *context)
{
return (context->lo & 1);
}
+
+static inline int context_fault_enable(struct context_entry *c)
+{
+ return((c->lo >> 1) & 0x1);
+}
+
+static inline int context_translation_type(struct context_entry *c)
+{
+ return((c->lo >> 2) & 0x3);
+}
+
+static inline u64 context_address_root(struct context_entry *c)
+{
+ return((c->lo >> VTD_PAGE_SHIFT));
+}
+
+static inline int context_address_width(struct context_entry *c)
+{
+ return((c->hi >> 0) & 0x7);
+}
+
+static inline int context_domain_id(struct context_entry *c)
+{
+ return((c->hi >> 8) & 0xffff);
+}
+
static inline void context_set_present(struct context_entry *context)
{
context->lo |= 1;
@@ -296,6 +347,27 @@ static inline int first_pte_in_page(struct dma_pte *pte)
return !((unsigned long)pte & ~VTD_PAGE_MASK);
}

+
+/*
+ * Fix Crashdump failure caused by leftover DMA through a hardware IOMMU
+ *
+ * Fixes the crashdump kernel to deal with an active iommu and legacy
+ * DMA from the (old) panicked kernel in a manner similar to how legacy
+ * DMA is handled when no hardware iommu was in use by the old kernel --
+ * allow the legacy DMA to continue into its current buffers.
+ *
+ * In the crashdump kernel, this code:
+ * 1. skips disabling the IOMMU's translating.
+ * 2. Do not re-enable IOMMU's translating.
+ * 3. In kdump kernel, use the old root entry table.
+ * 4. Allocate pages for new context entry, copy data from old context entries
+ * in the old kernel to the new ones.
+ *
+ * In other kinds of kernel, for example, a kernel started by kexec,
+ * do the same thing as crashdump kernel.
+ */
+
+
/*
* This domain is a statically identity mapping domain.
* 1. This domain creats a static 1:1 mapping to all usable memory.
--
2.0.0-rc0


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