Hi,
On 2019/12/23 15:59, Jim,Yan wrote:
-----邮件原件-----
发件人: Jerry Snitselaar [mailto:jsnit...@redhat.com]
发送时间: 2019年12月20日 17:23
收件人: Jim,Yan <jim...@baidu.com>
抄送: j...@8bytes.org; iommu@lists.linux-foundation.org;
linux-ker...@vger.kernel.org
主题: Re: [PATCH] iommu/vt-d: Don't reject nvme host due to scope mismatch
On Fri Dec 20 19, jimyan wrote:
On a system with an Intel PCIe port configured as a nvme host device,
iommu initialization fails with
DMAR: Device scope type does not match for 0000:80:00.0
This is because the DMAR table reports this device as having scope 2
(ACPI_DMAR_SCOPE_TYPE_BRIDGE):
Isn't that a problem to be fixed in the DMAR table then?
but the device has a type 0 PCI header:
80:00.0 Class 0600: Device 8086:2020 (rev 06)
00: 86 80 20 20 47 05 10 00 06 00 00 06 10 00 00 00
10: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
20: 00 00 00 00 00 00 00 00 00 00 00 00 86 80 00 00
30: 00 00 00 00 90 00 00 00 00 00 00 00 00 01 00 00
VT-d works perfectly on this system, so there's no reason to bail out
on initialization due to this apparent scope mismatch. Add the class
0x600 ("PCI_CLASS_BRIDGE_HOST") as a heuristic for allowing DMAR
initialization for non-bridge PCI devices listed with scope bridge.
Signed-off-by: jimyan <jim...@baidu.com>
---
drivers/iommu/dmar.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/iommu/dmar.c b/drivers/iommu/dmar.c index
eecd6a421667..9faf2f0e0237 100644
--- a/drivers/iommu/dmar.c
+++ b/drivers/iommu/dmar.c
@@ -244,6 +244,7 @@ int dmar_insert_dev_scope(struct
dmar_pci_notify_info *info,
info->dev->hdr_type != PCI_HEADER_TYPE_NORMAL) ||
(scope->entry_type == ACPI_DMAR_SCOPE_TYPE_BRIDGE &&
(info->dev->hdr_type == PCI_HEADER_TYPE_NORMAL &&
+ info->dev->class >> 8 != PCI_CLASS_BRIDGE_HOST &&
info->dev->class >> 8 != PCI_CLASS_BRIDGE_OTHER))) {
pr_warn("Device scope type does not match for %s\n",
pci_name(info->dev));
--
2.11.0
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Actually this patch is similar to the commit: ffb2d1eb88c3("iommu/vt-d: Don't reject
NTB devices due to scope mismatch"). Besides, modifying DMAR table need OEM update
BIOS. It is hard to implement.
For both cases, a quirk flag seems to be more reasonable, so that
unrelated devices will not be impacted.
Best regards,
baolu
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