[PATCH v9 02/10] iommu/vt-d: Items required for kdump

Li, Zhen-Hua
2015-03-19T05:37:30Z

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 | 56 +++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 56 insertions(+)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 76674a1..577d5de 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>
@@ -211,6 +212,12 @@ 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
@@ -231,6 +238,32 @@ 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;
@@ -316,6 +349,29 @@ 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.
+ * 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.
+ *
+ */
+
+
+#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