linux-kernel - Re: [PATCH v6 3/5] kvm: arm64: New memslot flag to indicate cacheable mapping

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Date: Mon, 16 Jun 2025 11:37:52 +0000
From: Ankit Agrawal <ankita@...dia.com>
To: Oliver Upton <oliver.upton@...ux.dev>, Sean Christopherson
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Subject: Re: [PATCH v6 3/5] kvm: arm64: New memslot flag to indicate cacheable
 mapping

> So, in the absence of a complete solution, I guess we can forgo the
> memslot flag. OTOH, the KVM cap is still useful since even now we do the
> wrong thing with cacheable PFNMAP so KVM_SET_USER_MEMORY_REGION
> accepting a VMA doesn't mean much.

Thanks Sean, Jason and Oliver for sharing your thoughts. I'll remove this
flag, and continue to keep the KVM cap in the next version posting.

>> > https://lore.kernel.org/all/aAdKCGCuwlUeUXKY@linux.dev/
>> > Oliver, could you please confirm if you are convinced with not having this
>> > flag? Can we rely on MT_NORMAL in vma mapping to convey this?
>
> Yes, following the VMAs memory attributes is the right thing to do. To
> be clear, this is something I'd really like to have settled for 6.17.

Ack.