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commit 49de6749baa8d0addc3048defd4ef3e85cb135e9
Author: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
AuthorDate: Thu Mar 23 09:16:41 2023 +0100
Commit: Jan Beulich <jbeulich@suse.com>
CommitDate: Thu Mar 23 09:16:41 2023 +0100

VT-d: fix iommu=no-igfx if the IOMMU scope contains fake device(s)

If the scope for IGD's IOMMU contains additional device that doesn't
actually exist, iommu=no-igfx would not disable that IOMMU. In this
particular case (Thinkpad x230) it included 00:02.1, but there is no
such device on this platform. Consider only existing devices for the
"gfx only" check as well as the establishing of IGD DRHD address
(underlying is_igd_drhd(), which is used to determine applicability of
two workarounds).

Fixes: 2d7f191b392e ("VT-d: generalize and correct "iommu=no-igfx" handling")
Signed-off-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
---
xen/drivers/passthrough/vtd/dmar.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/xen/drivers/passthrough/vtd/dmar.c b/xen/drivers/passthrough/vtd/dmar.c
index 78d4526446..4936c20952 100644
--- a/xen/drivers/passthrough/vtd/dmar.c
+++ b/xen/drivers/passthrough/vtd/dmar.c
@@ -389,7 +389,7 @@ static int __init acpi_parse_dev_scope(
printk(VTDPREFIX " endpoint: %pp\n",
&PCI_SBDF(seg, bus, path->dev, path->fn));

- if ( drhd )
+ if ( drhd && pci_device_detect(seg, bus, path->dev, path->fn) )
{
if ( pci_conf_read8(PCI_SBDF(seg, bus, path->dev, path->fn),
PCI_CLASS_DEVICE + 1) != 0x03
--
generated by git-patchbot for /home/xen/git/xen.git#master