Messages in this thread | | | Subject | Re: [RESEND PATCH v2 0/6] vfio-pci: Add support for mmapping MSI-X table | From | Yongji Xie <> | Date | Wed, 8 Jun 2016 17:56:49 +0800 |
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Hi, Eric
On 2016/6/8 15:41, Auger Eric wrote:
> Hi Yongji, > > Le 02/06/2016 à 08:09, Yongji Xie a écrit : >> Current vfio-pci implementation disallows to mmap the page >> containing MSI-X table in case that users can write directly >> to MSI-X table and generate an incorrect MSIs. >> >> However, this will cause some performance issue when there >> are some critical device registers in the same page as the >> MSI-X table. We have to handle the mmio access to these >> registers in QEMU emulation rather than in guest. >> >> To solve this issue, this series allows to expose MSI-X table >> to userspace when hardware enables the capability of interrupt >> remapping which can ensure that a given PCI device can only >> shoot the MSIs assigned for it. And we introduce a new bus_flags >> PCI_BUS_FLAGS_MSI_REMAP to test this capability on PCI side >> for different archs. >> >> The patch 3 are based on the proposed patchset[1]. > You may have noticed I sent a respin of [1] yesterday: > http://www.gossamer-threads.com/lists/linux/kernel/2455187. > > Unfortunately you will see I removed the patch defining the new > msi_domain_info MSI_FLAG_IRQ_REMAPPING flag you rely on in this series. > I did so because I was not using it anymore. At the beginning this was > used to detect whether the MSI assignment was safe but this > method was covering cases where the MSI controller was > upstream to the IOMMU. So now I rely on a mechanism where MSI controller > are supposed to register their MSI doorbells and tag whether it is safe. > > I don't know yet how this change will be welcomed though. Depending > on reviews/discussions, might happen we revert to the previous flag. > > If you need the feature you can embed the used patches in your series and > follow the review process separately. Sorry for the setback.
Thanks for your notification. I'd better wait until your patches get settled. Then I could exactly know which way we should use to test the capability of interrupt remapping on ARM in my series.
Thanks, Yongji
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