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Subject[PATCH 02/10] iommu/vt-d: Items required for kdump
Date
Add structure type domain_values_entry used for kdump;
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.

Signed-off-by: Bill Sumner <billsumnerlinux@gmail.com>
Signed-off-by: Li, Zhen-Hua <zhen-hual@hp.com>
---
drivers/iommu/intel-iommu.c | 70 +++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 70 insertions(+)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 2dc6250..5ce2850 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -40,6 +40,7 @@
#include <linux/pci-ats.h>
#include <linux/memblock.h>
#include <linux/dma-contiguous.h>
+#include <linux/crash_dump.h>
#include <asm/irq_remapping.h>
#include <asm/cacheflush.h>
#include <asm/iommu.h>
@@ -208,6 +209,12 @@ get_context_addr_from_root(struct root_entry *root)
NULL);
}

+static inline unsigned long
+get_context_phys_from_root(struct root_entry *root)
+{
+ return root_present(root) ? (root->val & VTD_PAGE_MASK) : 0;
+}
+
/*
* low 64 bits:
* 0: present
@@ -228,6 +235,32 @@ 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;
@@ -313,6 +346,43 @@ static inline int first_pte_in_page(struct dma_pte *pte)
return !((unsigned long)pte & ~VTD_PAGE_MASK);
}

+
+#ifdef CONFIG_CRASH_DUMP
+
+/*
+ * 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 of IO Virtual Addresses (IOVA).
+ * 2. Do not re-enable IOMMU's translating.
+ * 3. In kdump kernel, use the old root entry table.
+ * 4. Leaves the current translations in-place so that legacy DMA will
+ * continue to use its current buffers.
+ * 5. Allocates to the device drivers in the crashdump kernel
+ * portions of the iova address ranges that are different
+ * from the iova address ranges that were being used by the old kernel
+ * at the time of the panic.
+ *
+ */
+
+struct domain_values_entry {
+ struct list_head link; /* link entries into a list */
+ struct iova_domain iovad; /* iova's that belong to this domain */
+ struct dma_pte *pgd; /* virtual address */
+ int did; /* domain id */
+ int gaw; /* max guest address width */
+ int iommu_superpage; /* Level of superpages supported:
+ 0 == 4KiB (no superpages), 1 == 2MiB,
+ 2 == 1GiB, 3 == 512GiB, 4 == 1TiB */
+};
+
+#endif /* CONFIG_CRASH_DUMP */
+
/*
* 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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