Messages in this thread | | | Date | Tue, 14 Nov 2023 11:22:19 +0800 | Subject | Re: [PATCH 1/1] iommu/vt-d: Make context clearing consistent with context mapping | From | Baolu Lu <> |
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On 11/14/23 11:20 AM, Tian, Kevin wrote: >> From: Lu Baolu <baolu.lu@linux.intel.com> >> Sent: Tuesday, November 14, 2023 9:11 AM >> >> In the iommu probe_device path, domain_context_mapping() allows setting >> up the context entry for a non-PCI device. However, in the iommu >> release_device path, domain_context_clear() only clears context entries >> for PCI devices. >> >> Make domain_context_clear() behave consistently with >> domain_context_mapping() by clearing context entries for both PCI and >> non-PCI devices. >> >> Fixes: 579305f75d34 ("iommu/vt-d: Update to use PCI DMA aliases") >> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com> > > The code before the fix tag also has the same problem. If we really want > backport then let's find out the very first commit which exhibits this > problem.
Commit 579305f75d34 allows non-PCI devices.
+ if (!dev_is_pci(dev)) + return domain_context_mapping_one(domain, iommu, bus, devfn, translation); + + data.domain = domain; + data.iommu = iommu; + data.translation = translation; + + return pci_for_each_dma_alias(to_pci_dev(dev), + &domain_context_mapping_cb, &data);
But it forgot to update the domain_context_clear() helper. So this is actually a fix for that commit.
> > But I wonder the actual impact w/o such fix. If there is no hot-remove > possible for those non-PCI devices the context entry will be leaved > enabled until the machine is off. Then this fix is nice-to-have then > probably no need to backport?
It doesn't cause real issues as far as I can see. So there's no need to back port it to stable kernels. That's the reason I didn't add cc-stable tag. But we still need a fix tag as it's actually a fix.
Best regards, baolu
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