RE: [PATCH 1/2] PCI: hv: Reuse existing ITRE allocation in compose_msi_msg()

[Dexuan Cui]

> From: Jeffrey Hugo <quic_jhugo@xxxxxxxxxxx>
> Sent: Monday, May 9, 2022 2:48 PM
> Subject: [PATCH 1/2] PCI: hv: Reuse existing ITRE allocation in

s/ITRE/IRTE. I suppose Wei can help fix this without a v2 :-)

> compose_msi_msg()
> ...
> Currently if compose_msi_msg() is called multiple times, it will free any
> previous ITRE allocation, and generate a new allocation.  While nothing
> prevents this from occurring, it is extranious when Linux could just reuse

s/extranious/extraneous

> the existing allocation and avoid a bunch of overhead.
> 
> However, when future ITRE allocations operate on blocks of MSIs instead of

s/ITRE/IRTE

> a single line, freeing the allocation will impact all of the lines.  This
> could cause an issue where an allocation of N MSIs occurs, then some of
> the lines are retargeted, and finally the allocation is freed/reallocated.
> The freeing of the allocation removes all of the configuration for the
> entire block, which requires all the lines to be retargeted, which might
> not happen since some lines might already be unmasked/active.
> 
> Signed-off-by: Jeffrey Hugo <quic_jhugo@xxxxxxxxxxx>

Reviewed-by: Dexuan Cui <decui@xxxxxxxxxxxxx>
Tested-by: Dexuan Cui <decui@xxxxxxxxxxxxx>