From: Baolu Lu <baolu.lu@linux.intel.com>
To: Jason Gunthorpe <jgg@nvidia.com>, Vasant Hegde <vasant.hegde@amd.com>
Cc: baolu.lu@linux.intel.com, Matt Fagnani <matt.fagnani@bell.net>,
Thorsten Leemhuis <regressions@leemhuis.info>,
Joerg Roedel <jroedel@suse.de>,
"iommu@lists.linux.dev" <iommu@lists.linux.dev>,
LKML <linux-kernel@vger.kernel.org>,
"regressions@lists.linux.dev" <regressions@lists.linux.dev>,
Linux PCI <linux-pci@vger.kernel.org>,
Bjorn Helgaas <bhelgaas@google.com>
Subject: Re: [regression, bisected, pci/iommu] Bug 216865 - Black screen when amdgpu started during 6.2-rc1 boot with AMD IOMMU enabled
Date: Tue, 10 Jan 2023 13:48:39 +0800 [thread overview]
Message-ID: <f96b1cf3-6865-663d-f1cd-466a71519b08@linux.intel.com> (raw)
In-Reply-To: <Y7gs0zYKp/VXACBi@nvidia.com>
On 2023/1/6 22:14, Jason Gunthorpe wrote:
> On Thu, Jan 05, 2023 at 03:57:28PM +0530, Vasant Hegde wrote:
>> Matt,
>>
>> On 1/5/2023 6:39 AM, Matt Fagnani wrote:
>>> I built 6.2-rc2 with the patch applied. The same black screen problem happened
>>> with 6.2-rc2 with the patch. I tried to use early kdump with 6.2-rc2 with the
>>> patch twice by panicking the kernel with sysrq+alt+c after the black screen
>>> happened. The system rebooted after about 10-20 seconds both times, but no kdump
>>> and dmesg files were saved in /var/crash. I'm attaching the lspci -vvv output as
>>> requested.
>>>
>> Thanks for testing. As mentioned earlier I was not expecting this patch to fix
>> the black screen issue. It should fix kernel warnings and IOMMU page fault
>> related call traces. By any chance do you have the kernel boot logs?
>>
>>
>> @Baolu,
>> Looking into lspci output, it doesn't list ACS feature for Graphics card. So
>> with your fix it didn't enable PASID and hence it failed to boot.
> The ACS checks being done are feature of the path not the end point or
> root port.
>
> If we are expecting ACS on the end port then it is just a bug in how
> the test was written.. The test should be a NOP because there are no
> switches in this topology.
>
> Looking at it, this seems to just be because pci_enable_pasid is
> calling pci_acs_path_enabled wrong, the only other user is here:
>
> for (bus = pdev->bus; !pci_is_root_bus(bus); bus = bus->parent) {
> if (!bus->self)
> continue;
>
> if (pci_acs_path_enabled(bus->self, NULL, REQ_ACS_FLAGS))
> break;
>
> pdev = bus->self;
>
> group = iommu_group_get(&pdev->dev);
> if (group)
> return group;
> }
>
> And notice it is calling it on pdev->bus not on pdev itself which
> naturally excludes the end point from the ACS validation.
>
> So try something like:
>
> if (!pci_acs_path_enabled(pdev->bus->self, NULL, PCI_ACS_RR | PCI_ACS_UF))
>
> (and probably need to check for null ?)
Hi Matt,
Do you mind helping to test below change? No other change needed.
diff --git a/drivers/pci/ats.c b/drivers/pci/ats.c
index f9cc2e10b676..48f34cc996e4 100644
--- a/drivers/pci/ats.c
+++ b/drivers/pci/ats.c
@@ -382,8 +382,15 @@ int pci_enable_pasid(struct pci_dev *pdev, int
features)
if (!pasid)
return -EINVAL;
- if (!pci_acs_path_enabled(pdev, NULL, PCI_ACS_RR | PCI_ACS_UF))
- return -EINVAL;
+ if (pdev->multifunction) {
+ if (!pci_acs_path_enabled(pdev, NULL, PCI_ACS_RR |
PCI_ACS_UF))
+ return -EINVAL;
+ } else {
+ if (!pdev->bus->self ||
+ !pci_acs_path_enabled(pdev->bus->self, NULL,
+ PCI_ACS_RR | PCI_ACS_UF))
+ return -EINVAL;
+ }
pci_read_config_word(pdev, pasid + PCI_PASID_CAP, &supported);
supported &= PCI_PASID_CAP_EXEC | PCI_PASID_CAP_PRIV;
--
Best regards,
baolu
next prev parent reply other threads:[~2023-01-10 5:48 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-12-30 8:18 [regression, bisected, pci/iommu] Bug 216865 - Black screen when amdgpu started during 6.2-rc1 boot with AMD IOMMU enabled Thorsten Leemhuis
2023-01-03 10:30 ` Joerg Roedel
2023-01-03 19:06 ` Matt Fagnani
[not found] ` <5aa0e698-f715-0481-36e5-46505024ebc1@bell.net>
2023-01-04 6:54 ` Baolu Lu
2023-01-04 15:50 ` Vasant Hegde
2023-01-05 1:09 ` Matt Fagnani
2023-01-05 10:27 ` Vasant Hegde
2023-01-05 10:37 ` Baolu Lu
2023-01-05 10:46 ` Vasant Hegde
2023-01-05 14:46 ` Deucher, Alexander
2023-01-05 15:27 ` Felix Kuehling
2023-01-06 5:48 ` Baolu Lu
2023-02-15 15:39 ` Bjorn Helgaas
2023-02-16 0:35 ` Felix Kuehling
2023-02-16 0:44 ` Jason Gunthorpe
2023-02-16 5:37 ` Vasant Hegde
2023-02-16 14:55 ` Felix Kuehling
2023-02-16 14:53 ` Felix Kuehling
2023-02-16 5:25 ` Vasant Hegde
2023-02-16 18:59 ` Matt Fagnani
2023-02-16 19:59 ` Felix Kuehling
2023-02-17 5:36 ` Vasant Hegde
2023-02-17 5:23 ` Vasant Hegde
2023-01-05 19:51 ` Matt Fagnani
2023-01-06 7:28 ` Matt Fagnani
2023-01-10 16:08 ` Vasant Hegde
2023-01-10 16:12 ` Vasant Hegde
2023-01-06 14:14 ` Jason Gunthorpe
2023-01-07 2:44 ` Baolu Lu
2023-01-09 13:43 ` Jason Gunthorpe
2023-01-10 5:28 ` Baolu Lu
2023-01-10 5:48 ` Baolu Lu [this message]
2023-01-10 8:06 ` Matt Fagnani
[not found] ` <bb3d5d1a-c222-9270-60fa-7d0b74bebd1a@linux.intel.com>
2023-01-10 22:12 ` Matt Fagnani
2023-01-10 13:25 ` Jason Gunthorpe
2023-01-10 13:45 ` Christian König
2023-01-10 13:51 ` Jason Gunthorpe
2023-01-10 13:56 ` Christian König
2023-01-10 20:51 ` Matt Fagnani
2023-01-11 8:35 ` Christian König
2023-01-10 15:05 ` Felix Kuehling
2023-01-10 15:19 ` Jason Gunthorpe
2023-01-10 15:21 ` Felix Kuehling
2023-01-11 3:16 ` Baolu Lu
2023-01-11 13:08 ` Jason Gunthorpe
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