Re: [PATCH v4 3/5] dma: swiotlb: Centralize memory-encryption pool sizing

[sashiko-bot@kernel.org]

> Memory-encrypted guests use shared or unencrypted memory for DMA and may
> route all DMA through SWIOTLB. The default pool can therefore be too
> small for I/O-intensive workloads.
> 
> Move the existing x86 guest-sizing policy into the SWIOTLB core. For
> SWIOTLB_POOL_CC_GUEST, size the pool to 6% of guest memory, clamped
> between the normal default and 1 GiB. Preserve an explicit swiotlb=
> size.
> 
> Provide swiotlb_adjusted_size() so early users, including the x86 crash
> kernel reservation, can account for the prospective guest pool size
> before SWIOTLB initialization. Use the same area-aware alignment for
> both the prospective and allocated sizes.
> 
> Host memory encryption still selects a normal-sized shared pool and
> does not use the guest-sizing policy.
> 
> A restricted DMA pool already provides shared bounce buffers for its
> devices. Record its presence during reserved-memory initialization and
> do not select the confidential-guest default-pool policy solely because
> guest memory encryption is active.
> 
> Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@kernel.org>

Sashiko has reviewed this patch and found no issues. It looks great!

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Sashiko AI review · https://sashiko.dev/#/patchset/20260914070135.313337-1-aneesh.kumar@kernel.org?part=3