> -----Original Message----- > From: Peter Maydell [mailto:peter.maydell@xxxxxxxxxx] > Sent: Friday, July 26, 2013 10:31 AM > To: Yoder Stuart-B08248 > Cc: kvmarm@xxxxxxxxxxxxxxxxxxxxx > Subject: Re: CPU seen by guest in VM > > On 26 July 2013 15:54, Yoder Stuart-B08248 <B08248@xxxxxxxxxxxxx> wrote: > > On the question of what GIC is exposed, wouldn't that be exposed > > in the device tree and be orthogonal to the question of which > > CPU a VM sees? > > > > Even if ARM v8 CPU requires a GICv3, it seems like a bad > > assumption for an OS to just assume a GIC v3 without > > checking what is advertised in the device tree. > > This seems to me to be something of a Linuxism. You can't > assume that every guest OS will take a device tree as > its means of figuring out what it's running on. I think of it less as a Linuxism and more of a question of what 'platform' assumptions an OS makes: -what is the physical address map of a system -how many cpus are there, how are they started -how are non-probe-able devices discovered -are there runtime services in the platform (the kind of things that ePAPR, UEFI, ACPI, etc address) If everything is just hardcoded in the OS it will be difficult for it to run except in a narrow range of systems. But it certainly is the case that not every OS is there yet. However, a fair question related to this is whether we expect to _only_ run operating systems in VMs. Do we need to run boot firmware such as u-boot or UEFI in a VM? Stuart _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/cucslists/listinfo/kvmarm
