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iommu/amd: Treat per-device exclusion ranges as r/w unity-mapped regions 

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>
This commit is contained in:
Adrian Huang 2019-11-14 14:14:47 +08:00 committed by Joerg Roedel
parent 46cf053efe
commit 387caf0b75
1 changed files with 10 additions and 10 deletions
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20
drivers/iommu/amd_iommu_init.c
View File

@ -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);
}
/*