Re: [PATCH v9 11/25] iommu/arm-smmu-v3-kvm: Add the kernel driver

[Nicolin Chen <nicolinc@nvidia.com>]

On Thu, Nov 12, 2026 at 01:32:36PM +0000, Mostafa Saleh wrote:
> On Tue, Nov 10, 2026 at 10:24:58AM -0800, Nicolin Chen wrote:
> > On Tue, Nov 10, 2026 at 10:41:27AM +0000, Mostafa Saleh wrote:
> > > In Android, in that case, pKVM clears the FW (called pvmfw) that loads
> > > the protected VM and authenticate it so any protected VM knows the
> > > system is not trusted. This part is not upstream yet. [1]
> > 
> > You might want to double check a dual-SMMU case, where one gets
> > accepted by pkvm driver and the other fails and so bound to the
> > main driver.
> > 
> > It seems the pkvm driver would still pkvm_iommu_register_driver
> > and carry on with an untrusted SMMU. Would it also clear the FW
> > and mark the system as not trusted?
> > 
> 
> That shouldn't be possible, if one SMMU fail the whole thing will
> and the driver should clean up after as the probe is done through:
> 	ret = platform_driver_probe(&smmuv3_nesting_driver, smmuv3_nesting_probe);

Hmm, if I read __platform_driver_probe correctly:
 * __driver_attach() doesn't propagate ret from driver_probe_device()
   via bus_for_each_dev to the caller
 * bus_for_each_dev(..., is_bound_to_driver) at the end also returns
   true, as one SMMU is bound to the driver while the other failed
?

Nicolin