From: Adrian Huang <adrianhuang0701@gmail.com>
Date: Thu, 14 Nov 2019 14:14:47 +0800
Subject: iommu/amd: Treat per-device exclusion ranges as r/w unity-mapped
regions
Git-commit: 387caf0b759ac437a65ad5d59665558025f350fc
References: bsc#1175713
Patch-mainline: v5.6-rc1
Some buggy BIOSes might define multiple exclusion ranges of the
IVMD entries which are associated with the same IOMMU hardware.
This leads to the overwritten exclusion range (exclusion_start
and exclusion_length members) in set_device_exclusion_range().
Here is a real case:
When attaching two Broadcom RAID controllers to a server, the first
one reports the failure during booting (the disks connecting to the
RAID controller cannot be detected).
This patch prevents the issue by treating per-device exclusion
ranges as r/w unity-mapped regions.
Discussion:
* https://lists.linuxfoundation.org/pipermail/iommu/2019-November/040140.html
Suggested-by: Joerg Roedel <joro@8bytes.org>
Signed-off-by: Adrian Huang <ahuang12@lenovo.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
---
drivers/iommu/amd_iommu_init.c | 20 ++++++++++----------
1 file changed, 10 insertions(+), 10 deletions(-)
diff --git a/drivers/iommu/amd_iommu_init.c b/drivers/iommu/amd_iommu_init.c
index 568c52317757..1b65302e07b1 100644
--- a/drivers/iommu/amd_iommu_init.c
+++ b/drivers/iommu/amd_iommu_init.c
@@ -71,6 +71,8 @@
#define IVHD_FLAG_ISOC_EN_MASK 0x08
#define IVMD_FLAG_EXCL_RANGE 0x08
+#define IVMD_FLAG_IW 0x04
+#define IVMD_FLAG_IR 0x02
#define IVMD_FLAG_UNITY_MAP 0x01
#define ACPI_DEVFLAG_INITPASS 0x01
@@ -1121,16 +1123,14 @@ static void __init set_device_exclusion_range(u16 devid, struct ivmd_header *m)
if (!(m->flags & IVMD_FLAG_EXCL_RANGE))
return;
- if (iommu) {
- /*
- * We only can configure exclusion ranges per IOMMU, not
- * per device. But we can enable the exclusion range per
- * device. This is done here
- */
- set_dev_entry_bit(devid, DEV_ENTRY_EX);
- iommu->exclusion_start = m->range_start;
- iommu->exclusion_length = m->range_length;
- }
+ /*
+ * Treat per-device exclusion ranges as r/w unity-mapped regions
+ * since some buggy BIOSes might lead to the overwritten exclusion
+ * range (exclusion_start and exclusion_length members). This
+ * happens when there are multiple exclusion ranges (IVMD entries)
+ * defined in ACPI table.
+ */
+ m->flags = (IVMD_FLAG_IW | IVMD_FLAG_IR | IVMD_FLAG_UNITY_MAP);
}
/*