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Groups > linux.kernel > #1484285

[PATCH v5 4/8] iommu/amd: Add function copy_dev_tables

From Baoquan He <bhe@redhat.com>
Newsgroups linux.kernel
Subject [PATCH v5 4/8] iommu/amd: Add function copy_dev_tables
Date 2016-09-15 17:10 +0200
Message-ID <shGsx-ar-17@gated-at.bofh.it> (permalink)
References <shGsx-ar-11@gated-at.bofh.it>
Organization linux.* mail to news gateway

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Add function copy_dev_tables to copy the old DEV table entry of the panicked
kernel to the new allocated DEV table. Since all iommu share the same DTE table
the copy only need be done once as long as the physical address of old DEV table
is retrieved from iommu reg. Besides the old domain id occupied in 1st kernel
need be reserved to avoid touching the old io-page tables so that on-flight DMA
can continue looking up.

And define MACRO DEV_DOMID_MASK to replace magic number 0xffffULL because
it need be reused in copy_dev_tables.

Signed-off-by: Baoquan He <bhe@redhat.com>
---
 drivers/iommu/amd_iommu.c       |  2 +-
 drivers/iommu/amd_iommu_init.c  | 40 ++++++++++++++++++++++++++++++++++++++++
 drivers/iommu/amd_iommu_types.h |  1 +
 3 files changed, 42 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index 995b050..fcb69ff 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -1747,7 +1747,7 @@ static void set_dte_entry(u16 devid, struct protection_domain *domain, bool ats)
 		flags    |= tmp;
 	}
 
-	flags &= ~(0xffffUL);
+	flags &= ~DEV_DOMID_MASK;
 	flags |= domain->id;
 
 	amd_iommu_dev_table[devid].data[1]  = flags;
diff --git a/drivers/iommu/amd_iommu_init.c b/drivers/iommu/amd_iommu_init.c
index 77c44c8..ce49641 100644
--- a/drivers/iommu/amd_iommu_init.c
+++ b/drivers/iommu/amd_iommu_init.c
@@ -717,6 +717,46 @@ static int get_dev_entry_bit(u16 devid, u8 bit)
 }
 
 
+static int copy_dev_tables(void)
+{
+	u64 entry;
+	u32 lo, hi, devid;
+	phys_addr_t old_devtb_phys;
+	struct dev_table_entry *old_devtb = NULL;
+	u16 dom_id, dte_v;
+	struct amd_iommu *iommu;
+	static int copied;
+
+        for_each_iommu(iommu) {
+		if (!translation_pre_enabled(iommu)) {
+			pr_err("IOMMU:%d is not pre-enabled!/n", iommu->index);
+			return -1;
+		}
+
+		if (copied)
+			continue;
+
+                lo = readl(iommu->mmio_base + MMIO_DEV_TABLE_OFFSET);
+                hi = readl(iommu->mmio_base + MMIO_DEV_TABLE_OFFSET + 4);
+                entry = (((u64) hi) << 32) + lo;
+                old_devtb_phys = entry & PAGE_MASK;
+                old_devtb = memremap(old_devtb_phys, dev_table_size, MEMREMAP_WB);
+		if (!old_devtb)
+			return -1;
+                for (devid = 0; devid <= amd_iommu_last_bdf; ++devid) {
+                        amd_iommu_dev_table[devid] = old_devtb[devid];
+                        dom_id = amd_iommu_dev_table[devid].data[1] & DEV_DOMID_MASK;
+			dte_v = amd_iommu_dev_table[devid].data[0] & DTE_FLAG_V;
+			if (!dte_v || !dom_id)
+				continue;
+                        __set_bit(dom_id, amd_iommu_pd_alloc_bitmap);
+                }
+		memunmap(old_devtb);
+		copied = 1;
+        }
+	return 0;
+}
+
 void amd_iommu_apply_erratum_63(u16 devid)
 {
 	int sysmgt;
diff --git a/drivers/iommu/amd_iommu_types.h b/drivers/iommu/amd_iommu_types.h
index 809944a..a1ccede 100644
--- a/drivers/iommu/amd_iommu_types.h
+++ b/drivers/iommu/amd_iommu_types.h
@@ -310,6 +310,7 @@
 #define DTE_FLAG_MASK	(0x3ffULL << 32)
 #define DTE_GLX_SHIFT	(56)
 #define DTE_GLX_MASK	(3)
+#define DEV_DOMID_MASK 	0xffffULL
 
 #define DTE_GCR3_VAL_A(x)	(((x) >> 12) & 0x00007ULL)
 #define DTE_GCR3_VAL_B(x)	(((x) >> 15) & 0x0ffffULL)
-- 
2.5.5

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Thread

[PATCH v5 0/8] Fix kdump faults on system with amd iommu Baoquan He <bhe@redhat.com> - 2016-09-15 17:10 +0200
  [PATCH v5 4/8] iommu/amd: Add function copy_dev_tables Baoquan He <bhe@redhat.com> - 2016-09-15 17:10 +0200
    Re: [PATCH v5 4/8] iommu/amd: Add function copy_dev_tables Joerg Roedel <joro@8bytes.org> - 2016-09-20 14:00 +0200
      Re: [PATCH v5 4/8] iommu/amd: Add function copy_dev_tables Baoquan He <bhe@redhat.com> - 2016-09-21 12:20 +0200
  [PATCH v5 7/8] iommu/amd: Don't update domain info to dte entry at iommu init stage Baoquan He <bhe@redhat.com> - 2016-09-15 17:10 +0200
    Re: [PATCH v5 7/8] iommu/amd: Don't update domain info to dte entry  at iommu init stage Joerg Roedel <joro@8bytes.org> - 2016-09-20 15:00 +0200
      Re: [PATCH v5 7/8] iommu/amd: Don't update domain info to dte entry  at iommu init stage Baoquan He <bhe@redhat.com> - 2016-09-21 12:30 +0200
        Re: [PATCH v5 7/8] iommu/amd: Don't update domain info to dte entry  at iommu init stage Baoquan He <bhe@redhat.com> - 2016-09-21 15:30 +0200
  [PATCH v5 2/8] iommu/amd: add early_enable_iommu() wrapper function Baoquan He <bhe@redhat.com> - 2016-09-15 17:10 +0200
  [PATCH v5 6/8] iommu/amd: Do not re-enable dev table entries in kdump Baoquan He <bhe@redhat.com> - 2016-09-15 17:10 +0200
    Re: [PATCH v5 6/8] iommu/amd: Do not re-enable dev table entries in  kdump Joerg Roedel <joro@8bytes.org> - 2016-09-20 14:50 +0200
      Re: [PATCH v5 6/8] iommu/amd: Do not re-enable dev table entries in  kdump Baoquan He <bhe@redhat.com> - 2016-09-21 12:30 +0200
  [PATCH v5 5/8] iommu/amd: copy old trans table from old kernel Baoquan He <bhe@redhat.com> - 2016-09-15 17:10 +0200
    Re: [PATCH v5 5/8] iommu/amd: copy old trans table from old kernel Joerg Roedel <joro@8bytes.org> - 2016-09-20 14:50 +0200
      Re: [PATCH v5 5/8] iommu/amd: copy old trans table from old kernel Baoquan He <bhe@redhat.com> - 2016-09-21 12:20 +0200
  [PATCH v5 1/8] iommu/amd: Detect pre enabled translation Baoquan He <bhe@redhat.com> - 2016-09-15 17:10 +0200

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