During domain reset process vmd_domain_reset() clears PCI
configuration space of VMD root ports. But certain platform
has observed following errors and failed to boot.
...
DMAR: VT-d detected Invalidation Queue Error: Reason f
DMAR: VT-d detected Invalidation Time-out Error: SID ffff
DMAR: VT-d detected Invalidation Completion Error: SID ffff
DMAR: QI HEAD: UNKNOWN qw0 = 0x0, qw1 = 0x0
DMAR: QI PRIOR: UNKNOWN qw0 = 0x0, qw1 = 0x0
DMAR: Invalidation Time-out Error (ITE) cleared
The root cause is that memset_io() clears prefetchable memory base/limit
registers and prefetchable base/limit 32 bits registers sequentially.
This seems to be enabling prefetchable memory if the device disabled
prefetchable memory originally.
Here is an example (before memset_io()):
PCI configuration space for 10000:00:00.0:
86 80 30 20 06 00 10 00 04 00 04 06 00 00 01 00
00 00 00 00 00 00 00 00 00 01 01 00 00 00 00 20
00 00 00 00 01 00 01 00 ff ff ff ff 75 05 00 00
...
So, prefetchable memory is ffffffff00000000-575000fffff, which is
disabled. When memset_io() clears prefetchable base 32 bits register,
the prefetchable memory becomes 0000000000000000-575000fffff, which is
enabled.
This is believed to be the reason for the failure and in addition the
sequence of operation in vmd_domain_reset() is not following the PCIe
specs.
Here is the quote from section 7.5.1.3.9 of PCI Express Base 6.0 spec:
The Prefetchable Memory Limit register must be programmed to a smaller
value than the Prefetchable Memory Base register if there is no
prefetchable memory on the secondary side of the bridg
Disable the bridge window by executing a sequence of operations
borrowed from pci_disable_bridge_window(), that comply with the
PCI specifications.
Signed-off-by: Nirmal Patel <nirmal.patel@xxxxxxxxxxxxxxx>
---
v3->v3: Add more information to commit description.
v1->v2: Follow same chain of operation as pci_disable_bridge_window
and update commit log.
---
drivers/pci/controller/vmd.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/drivers/pci/controller/vmd.c b/drivers/pci/controller/vmd.c
index 769eedeb8802..ca9081be917d 100644
--- a/drivers/pci/controller/vmd.c
+++ b/drivers/pci/controller/vmd.c
@@ -526,8 +526,16 @@ static void vmd_domain_reset(struct vmd_dev *vmd)
PCI_CLASS_BRIDGE_PCI))
continue;
- memset_io(base + PCI_IO_BASE, 0,
- PCI_ROM_ADDRESS1 - PCI_IO_BASE);
+ writel(0, base + PCI_IO_BASE);
+ /* MMIO Base/Limit */
+ writel(0x0000fff0, base + PCI_MEMORY_BASE);
+
+ /* Prefetchable MMIO Base/Limit */
+ writel(0, base + PCI_PREF_LIMIT_UPPER32);
+ writel(0x0000fff0, base + PCI_PREF_MEMORY_BASE);
+ writel(0xffffffff, base + PCI_PREF_BASE_UPPER32);
+ writel(0, base + PCI_IO_BASE_UPPER16);
+ writeb(0, base + PCI_CAPABILITY_LIST);
}
}
}
--
2.31.1
