[PATCH v6 16/17] RFC: kvm: pass kvm argument to follow_pfn callsites

Paolo Bonzini pbonzini at redhat.com
Fri Nov 20 10:33:44 EST 2020


On 19/11/20 15:41, Daniel Vetter wrote:
> Both Christoph Hellwig and Jason Gunthorpe suggested that usage of
> follow_pfn by modules should be locked down more. To do so callers
> need to be able to pass the mmu_notifier subscription corresponding
> to the mm_struct to follow_pfn().
> 
> This patch does the rote work of doing that in the kvm subsystem. In
> most places this is solved by passing struct kvm * down the call
> stacks as an additional parameter, since that contains the
> mmu_notifier.
> 
> Compile tested on all affected arch.

It's a bit of a pity, it's making an API more complex (the point of 
gfn_to_pfn_memslot vs gfn_to_pfn is exactly that you don't need a 
"struct kvm*" and it's clear that you've already done the lookup into 
that struct kvm.

But it's not a big deal, and the rationale at least makes sense.  So,

Acked-by: Paolo Bonzini <pbonzini at redhat.com>

Paolo



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