linux-kernel - Re: [PATCH v9 1/6] KVM: arm64: Rename the device variable to s2_force

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Message-ID: <20250704134133.GC1410929@nvidia.com>
Date: Fri, 4 Jul 2025 10:41:33 -0300
From: Jason Gunthorpe <jgg@...dia.com>
To: ankita@...dia.com
Cc: maz@...nel.org, oliver.upton@...ux.dev, joey.gouly@....com,
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Subject: Re: [PATCH v9 1/6] KVM: arm64: Rename the device variable to
 s2_force_noncacheable

On Sat, Jun 21, 2025 at 04:21:06AM +0000, ankita@...dia.com wrote:
> From: Ankit Agrawal <ankita@...dia.com>
> 
> For cache maintenance on a region, ARM KVM relies on that
> region to be mapped to the Kernal virtual address as CMOs
> operate on VA.
> 
> Currently the device variable is effectively trying to setup
> the S2 mapping as non cacheable for memory regions that are
> not mapped in the Kernel VA. This could be either device or
> Normal_NC depending on the VM_ALLOW_ANY_UNCACHED flag in the
> VMA.
> 
> Thus "device" could be better renamed to s2_force_noncacheable
> which implies that it is ensuring that region be mapped as
> non-cacheable.
> 
> CC: Catalin Marinas <catalin.marinas@....com>
> Suggested-by: Jason Gunthorpe <jgg@...dia.com>
> Signed-off-by: Ankit Agrawal <ankita@...dia.com>
> ---
>  arch/arm64/kvm/mmu.c | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)

I think this is much clearer

Reviewed-by: Jason Gunthorpe <jgg@...dia.com>

Jason