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RE: [PATCH 5/5] vfio-pci: Allow to mmap MSI-X table if interrupt remapping is supported

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> From: Tian, Kevin
> Sent: Friday, May 13, 2016 10:33 AM
> 
> > means.  The MSI-X vector table of a device is always considered
> > untrusted which is why we require user opt-ins to subvert that
> > protection.  Thanks,
> >
> 
> I only partially agree with this statement since there is different
> trust level for kernel space driver and user space driver.
> 
> OS may choose to trust kernel space driver then it can enable IRQ
> remapping only for load balance purpose w/o source id verfification.
> In such case MSI-X vector table is trusted and fully under kernel
> control. Allowing to mmap MSI-X table in user space definitely
> breaks that boundary.
> 
> Anyway my point is simple. Let's ignore how Linux kernel implements
> IRQ remapping on x86 (which may change time to time), and just
> focus on architectural possibility. Non-x86 platform may implement
> IRQ remapping completely separate from device side, then checking
> availability of IRQ remapping is enough to decide whether mmap
> MSI-X table is safe. x86 with VT-d can be configured to a mode
> requiring host control of both MSI-X entry and IRQ remapping hardware
> (without source id check). In such case it's insufficient to make
> decision simply based on IRQ remapping availability. We need a way
> to query from IRQ remapping module whether it's actually safe to
> mmap MSI-X.
> 

Or another way is to have VFIO explicitly request intel-iommu to
enforce sid check when IRQ remapping is enabled...

Thanks
Kevin

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RE: [PATCH 5/5] vfio-pci: Allow to mmap MSI-X table if interrupt  remapping is supported "Tian, Kevin" <kevin.tian@intel.com> - 2016-05-03 07:40 +0200
  Re: [PATCH 5/5] vfio-pci: Allow to mmap MSI-X table if interrupt  remapping is supported Yongji Xie <xyjxie@linux.vnet.ibm.com> - 2016-05-03 08:10 +0200
    RE: [PATCH 5/5] vfio-pci: Allow to mmap MSI-X table if interrupt  remapping is supported "Tian, Kevin" <kevin.tian@intel.com> - 2016-05-03 08:30 +0200
      Re: [PATCH 5/5] vfio-pci: Allow to mmap MSI-X table if interrupt  remapping is supported Yongji Xie <xyjxie@linux.vnet.ibm.com> - 2016-05-03 09:40 +0200
        RE: [PATCH 5/5] vfio-pci: Allow to mmap MSI-X table if interrupt  remapping is supported "Tian, Kevin" <kevin.tian@intel.com> - 2016-05-05 11:40 +0200
          RE: [PATCH 5/5] vfio-pci: Allow to mmap MSI-X table if interrupt  remapping is supported David Laight <David.Laight@ACULAB.COM> - 2016-05-05 12:00 +0200
            Re: [PATCH 5/5] vfio-pci: Allow to mmap MSI-X table if interrupt  remapping is supported Yongji Xie <xyjxie@linux.vnet.ibm.com> - 2016-05-05 13:50 +0200
              RE: [PATCH 5/5] vfio-pci: Allow to mmap MSI-X table if interrupt  remapping is supported "Tian, Kevin" <kevin.tian@intel.com> - 2016-05-05 14:20 +0200
                Re: [PATCH 5/5] vfio-pci: Allow to mmap MSI-X table if interrupt  remapping is supported Yongji Xie <xyjxie@linux.vnet.ibm.com> - 2016-05-05 15:30 +0200
                Re: [PATCH 5/5] vfio-pci: Allow to mmap MSI-X table if interrupt  remapping is supported Alex Williamson <alex.williamson@redhat.com> - 2016-05-05 17:10 +0200
                Re: [PATCH 5/5] vfio-pci: Allow to mmap MSI-X table if interrupt  remapping is supported Alexey Kardashevskiy <aik@ozlabs.ru> - 2016-05-06 08:40 +0200
                Re: [PATCH 5/5] vfio-pci: Allow to mmap MSI-X table if interrupt  remapping is supported Alex Williamson <alex.williamson@redhat.com> - 2016-05-06 19:00 +0200
                RE: [PATCH 5/5] vfio-pci: Allow to mmap MSI-X table if interrupt  remapping is supported "Tian, Kevin" <kevin.tian@intel.com> - 2016-05-11 08:30 +0200
                Re: [PATCH 5/5] vfio-pci: Allow to mmap MSI-X table if interrupt  remapping is supported Alex Williamson <alex.williamson@redhat.com> - 2016-05-11 18:00 +0200
                RE: [PATCH 5/5] vfio-pci: Allow to mmap MSI-X table if interrupt  remapping is supported "Tian, Kevin" <kevin.tian@intel.com> - 2016-05-12 03:30 +0200
                Re: [PATCH 5/5] vfio-pci: Allow to mmap MSI-X table if interrupt  remapping is supported Alex Williamson <alex.williamson@redhat.com> - 2016-05-12 04:30 +0200
                RE: [PATCH 5/5] vfio-pci: Allow to mmap MSI-X table if interrupt  remapping is supported "Tian, Kevin" <kevin.tian@intel.com> - 2016-05-12 07:00 +0200
                Re: [PATCH 5/5] vfio-pci: Allow to mmap MSI-X table if interrupt  remapping is supported Alex Williamson <alex.williamson@redhat.com> - 2016-05-12 19:50 +0200
                RE: [PATCH 5/5] vfio-pci: Allow to mmap MSI-X table if interrupt  remapping is supported "Tian, Kevin" <kevin.tian@intel.com> - 2016-05-13 04:40 +0200
                RE: [PATCH 5/5] vfio-pci: Allow to mmap MSI-X table if interrupt  remapping is supported "Tian, Kevin" <kevin.tian@intel.com> - 2016-05-13 04:40 +0200
                Re: [PATCH 5/5] vfio-pci: Allow to mmap MSI-X table if interrupt  remapping is supported Alex Williamson <alex.williamson@redhat.com> - 2016-05-13 07:40 +0200
                RE: [PATCH 5/5] vfio-pci: Allow to mmap MSI-X table if interrupt  remapping is supported "Tian, Kevin" <kevin.tian@intel.com> - 2016-05-13 09:00 +0200
                Re: [PATCH 5/5] vfio-pci: Allow to mmap MSI-X table if interrupt  remapping is supported Alex Williamson <alex.williamson@redhat.com> - 2016-05-13 18:50 +0200
                RE: [PATCH 5/5] vfio-pci: Allow to mmap MSI-X table if interrupt  remapping is supported David Laight <David.Laight@ACULAB.COM> - 2016-05-13 11:20 +0200
          Re: [PATCH 5/5] vfio-pci: Allow to mmap MSI-X table if interrupt  remapping is supported Yongji Xie <xyjxie@linux.vnet.ibm.com> - 2016-05-05 13:50 +0200

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