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Date: Thu, 5 May 2016 09:54:07 +0000
From: David Laight <David.Laight@...LAB.COM>
To: "'Tian, Kevin'" <kevin.tian@...el.com>,
Yongji Xie <xyjxie@...ux.vnet.ibm.com>,
"kvm@...r.kernel.org" <kvm@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"linux-pci@...r.kernel.org" <linux-pci@...r.kernel.org>,
"linuxppc-dev@...ts.ozlabs.org" <linuxppc-dev@...ts.ozlabs.org>,
"iommu@...ts.linux-foundation.org" <iommu@...ts.linux-foundation.org>
CC: "alex.williamson@...hat.com" <alex.williamson@...hat.com>,
"bhelgaas@...gle.com" <bhelgaas@...gle.com>,
"aik@...abs.ru" <aik@...abs.ru>,
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Subject: RE: [PATCH 5/5] vfio-pci: Allow to mmap MSI-X table if interrupt
remapping is supported
From: Tian, Kevin
> Sent: 05 May 2016 10:37
...
> > Acutually, we are not aimed at accessing MSI-X table from
> > guest. So I think it's safe to passthrough MSI-X table if we
> > can make sure guest kernel would not touch MSI-X table in
> > normal code path such as para-virtualized guest kernel on PPC64.
> >
>
> Then how do you prevent malicious guest kernel accessing it?
Or a malicious guest driver for an ethernet card setting up
the receive buffer ring to contain a single word entry that
contains the address associated with an MSI-X interrupt and
then using a loopback mode to cause a specific packet be
received that writes the required word through that address.
Remember the PCIe cycle for an interrupt is a normal memory write
cycle.
David
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