Re: [PATCH v12 13/84] KVM: Annotate that all paths in hva_to_pfn() might sleep

Sean Christopherson [off-list ref] writes:

On Thu, Aug 08, 2024, Alex Bennée wrote:

quoted

Sean Christopherson [off-list ref] writes:

quoted

On Thu, Aug 08, 2024, Alex Bennée wrote:

quoted

Sean Christopherson [off-list ref] writes:

quoted

Now that hva_to_pfn() no longer supports being called in atomic context,
move the might_sleep() annotation from hva_to_pfn_slow() to
hva_to_pfn().

The commentary for hva_to_pfn_fast disagrees.

  /*
   * The fast path to get the writable pfn which will be stored in @pfn,
   * true indicates success, otherwise false is returned.  It's also the
   * only part that runs if we can in atomic context.
   */
  static bool hva_to_pfn_fast(struct kvm_follow_pfn *kfp, kvm_pfn_t *pfn)

At which point did it loose the ability to run in the atomic context? I
couldn't work it out from the commits.

It didn't lose the ability per se (calling hva_to_pfn_fast() in atomic context
would still be functionally ok), rather the previous patch

  KVM: Drop @atomic param from gfn=>pfn and hva=>pfn APIs

removed support for doing so in order to simplify hva_to_pfn() as a whole.

It still sticks out given the only caller no longer enforces this. 

Oh, sorry, I should have been more explicit.  I'll fix the comment, I simply
missed it.

No worries, with the fixed comment:

Reviewed-by: Alex Bennée <redacted>

-- 
Alex Bennée
Virtualisation Tech Lead @ Linaro