On Mon, May 05, 2025 at 02:08:07PM -0300, Jason Gunthorpe wrote:
On Wed, Apr 30, 2025 at 12:58:47AM -0700, Nicolin Chen wrote:
... and I just hit a problem with it - this is basically guest BDFn and it works as long as I'm hotplugging the TEE-IO VF into an SNP VM but does not when I pass through via the QEMU cmdline - bus numbers are not assigned yet. So I have to postpone the vdevice allocation till run time, did I miss something here? Thanks,
I have a similar case with QEMU ARM64's VM: so vDEVICE on ARM is allocated at runtime as well because the BDF number isn't ready at the boot time.
Oh that's ugly then.. So you'll need to add some kind of 'modify sid/bdf' operation I think.
But the initial vDEVICE would be still unusable. Its BDF number is literally 0 in my case. It can't be used for SID-based invalidation nor the reverse vSID lookup for fault injection..
The bus numbers can be reassigned at any time on the fly by the guest by reprogramming the PCI hierarchy.
Yes. If we take some aggressive use case into account, where its BDF number could change multiple times, I think it's natural for VMM to simply destroy the previous vDEVICE and allocate a new one with a new BDF number, right?
Thanks Nicolin