Hi Thomas,
Below commit is supposed to fix this issue. It's currently in
x86/vt-d branch of the iommu tree, and will be part of v5.6-rc1.
commit f5a68bb0752e0cf77c06f53f72258e7beb41381b
Author: Barret Rhoden <b...@google.com>
Date: Wed Jan 15 11:03:56 2020 +0800
iommu/vt-d: Mark firmware tainted if RMRR fails sanity check
RMRR entries describe memory regions that are DMA targets for devices
outside the kernel's control.
RMRR entries that fail the sanity check are pointing to regions of
memory that the firmware did not tell the kernel are reserved or
otherwise should not be used.
Instead of aborting DMAR processing, this commit marks the firmware
as tainted. These RMRRs will still be identity mapped, otherwise,
some devices, e.x. graphic devices, will not work during boot.
Signed-off-by: Barret Rhoden <b...@google.com>
Signed-off-by: Lu Baolu <baolu...@linux.intel.com>
Fixes: f036c7fa0ab60 ("iommu/vt-d: Check VT-d RMRR region in BIOS
is reported as reserved")
Signed-off-by: Joerg Roedel <jroe...@suse.de>
Best regards,
baolu
On 2020/2/3 5:06, Thomas G wrote:
Dear all,
Vt-d seems to be broken since I upgraded to kernel 5.5, there is a new
dmesg that was not there in 5.4:
"DMAR: [Firmware Bug]: No firmware reserved region can cover this RMRR
[0x0000000041d92000-0x0000000041d94fff], contact BIOS vendor for fixes"
System motherboard is Asrock X299 Taichi XE, bios 1.70, CPU is Core i9 7920
Vt-d and gpu passthrough was working ok since kernel 4.20 when I
purchased it
I attached the dmesg I get with kernel 5.5.1, and the dmesg from 5.4.17.
Also, I use the following script that displays the IOMMU groups, I found
the script there
https://wiki.archlinux.org/index.php/PCI_passthrough_via_OVMF
#!/bin/bash
shopt -s nullglob
for d in /sys/kernel/iommu_groups/*/devices/*; do
n=${d#*/iommu_groups/*}; n=${n%%/*}
printf 'IOMMU Group %s ' "$n"
lspci -nns "${d##*/}"
done;
The output of this script with kernel 5.4.17 is attached to this email.
The same script with kernel 5.5.1 produces an empty output
Hope it helps narrowing down the problem, please ask additional info if
needed. Sorry if this is not submitted as it should be (then please
advise), first time I report -what apprears to be- a bug.
Best,
Thomas
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