> From: Jeffrey Hugo <quic_jhugo@xxxxxxxxxxx>
> Sent: Monday, May 9, 2022 2:48 PM
> ...
> According to Dexuan, the hypervisor folks beleive that multi-msi
> allocations are not correct. compose_msi_msg() will allocate multi-msi
> one by one. However, multi-msi is a block of related MSIs, with alignment
> requirements. In order for the hypervisor to allocate properly aligned
> and consecutive entries in the IOMMU Interrupt Remapping Table, there
> should be a single mapping request that requests all of the multi-msi
> vectors in one shot.
>
> Dexuan suggests detecting the multi-msi case and composing a single
> request related to the first MSI. Then for the other MSIs in the same
> block, use the cached information. This appears to be viable, so do it.
>
> Suggested-by: Dexuan Cui <decui@xxxxxxxxxxxxx>
> Signed-off-by: Jeffrey Hugo <quic_jhugo@xxxxxxxxxxx>
Reviewed-by: Dexuan Cui <decui@xxxxxxxxxxxxx>
> + if (!msi_desc->pci.msi_attrib.is_msix && msi_desc->nvec_used > 1) {
> + /*
> + * if this is not the first MSI of Multi MSI, we already have
s/if/If
