Messages in this thread | | | Subject | Re: [PATCH v3 2/3] uio_pci_generic: add MSI/MSI-X support | From | Vlad Zolotarov <> | Date | Wed, 7 Oct 2015 11:00:16 +0300 |
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On 10/07/15 09:53, Avi Kivity wrote: > On 10/07/2015 12:58 AM, Stephen Hemminger wrote: >> Go ahead and submit a seperate taint bit for UIO as a patch. >> > > Taint should only be applied if bus mastering is enabled (to avoid > annoying the users of the original uio use case)
Pls., note that this series would enable the legacy INT#X mode if possible and this, of course, without enabling bus mastering and without tainting the kernel. This means that the current users of uio_pci_generic won't feel/get any difference after/if these patches are applied since before these patches it could only be used with the devices that do have INT#X capability.
> >> >> On Tue, Oct 6, 2015 at 10:41 PM, Alex Williamson >> <alex.williamson@redhat.com <mailto:alex.williamson@redhat.com>> wrote: >> >> On Tue, 2015-10-06 at 22:32 +0100, Stephen Hemminger wrote: >> > On Tue, 06 Oct 2015 12:51:20 -0600 >> > Alex Williamson <alex.williamson@redhat.com >> <mailto:alex.williamson@redhat.com>> wrote: >> > >> > > Of course this is entirely unsafe and this no-iommu driver >> should taint >> > > the kernel, but it at least standardizes on one userspace API >> and you're >> > > already doing completely unsafe things with uio. vfio should be >> > > enlightened at least to the point that it allows only >> privileged users >> > > access to devices under such a (lack of) iommu >> > >> > I agree with the design, but not with the taint argument. >> > (Unless you want to taint any and all use of UIO drivers which can >> > already do this). >> >> Yes, actually, if the bus master bit gets enabled all bets are >> off. I >> don't see how that leaves a supportable kernel, so we might as well >> taint it. Isn't this exactly why we taint for proprietary >> drivers, we >> have no idea what it has mucked with in kernel space. This just moves >> the proprietary driver out to userspace without an iommu to >> protect the >> host. Thanks, >> >> Alex >> >> >
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