Re: [PATCH 3/3] KVM: Explicitly disallow activatating a gfn_to_pfn_cache with INVALID_GPA

From: David Woodhouse
Date: Wed Mar 20 2024 - 04:21:34 EST


On Tue, 2024-03-19 at 17:15 -0700, Sean Christopherson wrote:
> Explicit disallow activating a gfn_to_pfn_cache with an error gpa, i.e.
> INVALID_GPA, to ensure that KVM doesn't mistake a GPA-based cache for an
> HVA-based cache (KVM uses INVALID_GPA as a magic value to differentiate
> between GPA-based and HVA-based caches).
>
> WARN if KVM attempts to activate a cache with INVALID_GPA, purely so that
> new caches need to at least consider what to do with a "bad" GPA, as all
> existing usage of kvm_gpc_activate() guarantees gpa != INVALID_GPA.  I.e.
> removing the WARN in the future is completely reasonable if doing so would
> yield cleaner/better code overall.
>
> Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>


Reviewed-by: David Woodhouse <dwmw@xxxxxxxxxxxx>

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