On Wed, 21 Jan 2026 17:52:22 +0000
Shameer Kolothum <[email protected]> wrote:

> Accelerated SMMUv3 instances rely on the physical SMMUv3 for nested
> translation (guest Stage-1, host Stage-2). In this mode, the guest Stage-1
> tables are programmed directly into hardware, and QEMU must not attempt to
> walk them for translation, as doing so is not reliably safe. For vfio-pci
> endpoints behind such a vSMMU, the only translation QEMU needs to perform
> is for the MSI doorbell used during KVM MSI setup.
> 
> Implement the callback so that kvm_arch_fixup_msi_route() can retrieve the
> MSI doorbell GPA directly, instead of attempting a software walk of the
> guest translation tables.
> 
> Also introduce an SMMUv3 device property to carry the MSI doorbell GPA.
> This property will be set by the virt machine in a subsequent patch.
> 
> Reviewed-by: Nicolin Chen <[email protected]>
> Reviewed-by: Eric Auger <[email protected]>
> Tested-by: Eric Auger <[email protected]>
> Tested-by: Zhangfei Gao <[email protected]>
> Signed-off-by: Shameer Kolothum <[email protected]>
Reviewed-by: Jonathan Cameron <[email protected]>

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