Re: [Qemu-devel] [RFC 0/6] vSMMU initialization

[Varun Sethi]

Hi Will,

> -----Original Message-----
> From: Will Deacon [mailto:address@hidden
> Sent: Tuesday, July 14, 2015 4:34 PM
> To: Sethi Varun-B16395
> Cc: Baptiste Reynal; address@hidden;
> address@hidden; address@hidden
> Subject: Re: [RFC 0/6] vSMMU initialization
> 
> On Tue, Jul 14, 2015 at 03:21:03AM +0100, Varun Sethi wrote:
> > Hi Will,
> 
> Hi Varun,
> 
> > > On Fri, Jun 12, 2015 at 03:20:04PM +0100, Baptiste Reynal wrote:
> > > > The ARM SMMU has support for 2-stages address translations,
> > > > allowing a virtual address to be translated at two levels:
> > > > - Stage 1 translates a virtual address (VA) into an intermediate
> > > > physical address (IPA)
> > > > - Stage 2 translates an IPA into a physical address (PA)
> > > >
> > > > Will Deacon introduced a virtual SMMU interface for KVM, which
> > > > gives a virtual machine the possibility to use an IOMMU with native
> drivers.
> > > > While the VM will program the first stage of translation (stage
> > > > 1), the interface will program the second (stage 2) on the physical
> SMMU.
> > >
> > > Please note that I have no plans to merge the kernel-side of this at
> > > the moment. It was merely an exploratory tool to see what a non-PV
> > > vSMMU implementation might look like and certainly not intended to
> > > be used in anger.
> > How do you see the context fault reporting work for the PV interface?
> 
> We could have an interrupt, for the PV IOMMU and have the hypervisor
> inject that, no?
> 
Can you please elaborate on the PV IOMMU interface. I want to understand how 
context fault information would be communicated to the guest.

-Varun