iommu/amd: Suppress IO_PAGE_FAULTs in kdump kernel

When booting into a kdump kernel, suppress IO_PAGE_FAULTs by
default for all devices. But allow the faults again when a
domain is assigned to a device.

Signed-off-by: Joerg Roedel <jroedel@suse.de>

3 files changed, 12 insertions, 1 deletions

diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index 6498f5baa7ea..95ee360a5199 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -2078,7 +2078,8 @@ static void set_dte_entry(u16 devid, struct protection_domain *domain, bool ats)
                 flags    |= tmp;
         }
 
-        flags &= ~(0xffffUL);
+
+        flags &= ~(DTE_FLAG_SA | 0xffffULL);
         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 3fa7e3b35507..cf7896550e75 100644
--- a/drivers/iommu/amd_iommu_init.c
+++ b/drivers/iommu/amd_iommu_init.c
@@ -29,6 +29,7 @@
 #include <linux/export.h>
 #include <linux/iommu.h>
 #include <linux/kmemleak.h>
+#include <linux/crash_dump.h>
 #include <asm/pci-direct.h>
 #include <asm/iommu.h>
 #include <asm/gart.h>
@@ -1900,6 +1901,14 @@ static void init_device_table_dma(void)
         for (devid = 0; devid <= amd_iommu_last_bdf; ++devid) {
                 set_dev_entry_bit(devid, DEV_ENTRY_VALID);
                 set_dev_entry_bit(devid, DEV_ENTRY_TRANSLATION);
+                /*
+                 * In kdump kernels in-flight DMA from the old kernel might
+                 * cause IO_PAGE_FAULTs. There are no reports that a kdump
+                 * actually failed because of that, so just disable fault
+                 * reporting in the hardware to get rid of the messages
+                 */
+                if (is_kdump_kernel())
+                        set_dev_entry_bit(devid, DEV_ENTRY_NO_PAGE_FAULT);
         }
 }
 
diff --git a/drivers/iommu/amd_iommu_types.h b/drivers/iommu/amd_iommu_types.h
index 6960d7db2fab..294a409e283b 100644
--- a/drivers/iommu/amd_iommu_types.h
+++ b/drivers/iommu/amd_iommu_types.h
@@ -322,6 +322,7 @@
 #define IOMMU_PTE_IW (1ULL << 62)
 
 #define DTE_FLAG_IOTLB  (1ULL << 32)
+#define DTE_FLAG_SA     (1ULL << 34)
 #define DTE_FLAG_GV     (1ULL << 55)
 #define DTE_FLAG_MASK   (0x3ffULL << 32)
 #define DTE_GLX_SHIFT   (56)