Re: [PATCH v3 2/8] KVM: Integrate gfn_to_memslot_approx() into search_memslots()

From: Maciej S. Szmigiero
Date: Fri May 21 2021 - 03:07:23 EST

On 19.05.2021 23:24, Sean Christopherson wrote:
On Sun, May 16, 2021, Maciej S. Szmigiero wrote:
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 8895b95b6a22..3c40c7d32f7e 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -1091,10 +1091,14 @@ bool kvm_arch_irqfd_allowed(struct kvm *kvm, struct kvm_irqfd *args);
* gfn_to_memslot() itself isn't here as an inline because that would
* bloat other code too much.
+ * With "approx" set returns the memslot also when the address falls
+ * in a hole. In that case one of the memslots bordering the hole is
+ * returned.
+ *
* IMPORTANT: Slots are sorted from highest GFN to lowest GFN!
static inline struct kvm_memory_slot *
-search_memslots(struct kvm_memslots *slots, gfn_t gfn)
+search_memslots(struct kvm_memslots *slots, gfn_t gfn, bool approx)

An alternative to modifying the PPC code would be to make the existing
search_memslots() a wrapper to __search_memslots(), with the latter taking

I guess you mean that if search_memslots() only does an exact search
(like the current code does) its 3 callers won't have to be modified.
Will do it then.

We might also want to make this __always_inline to improve the likelihood of the
compiler optimizing away @approx. I doubt it matters in practice...

Sounds like a good idea, will do.