KVM: MMU: drop zeroing on mmu_memory_cache_alloc

KVM: MMU: drop zeroing on mmu_memory_cache_alloc

[Marcelo Tosatti]

Zeroing on mmu_memory_cache_alloc is unnecessary since:

- Smaller areas are pre-allocated with kmem_cache_zalloc.
- Page pointed by ->spt is overwritten with prefetch_page 
  and entries in page pointed by ->gfns are initialized 
  before reading.

[avi: zeroing pages is unnecessary]

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 10bdb2a..823d0cd 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -352,7 +352,6 @@ static void *mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc,
 
 	BUG_ON(!mc->nobjs);
 	p = mc->objects[--mc->nobjs];
-	memset(p, 0, size);
 	return p;
 }
 

Re: KVM: MMU: drop zeroing on mmu_memory_cache_alloc

[Avi Kivity]

Marcelo Tosatti wrote:
> Zeroing on mmu_memory_cache_alloc is unnecessary since:
>
> - Smaller areas are pre-allocated with kmem_cache_zalloc.
> - Page pointed by ->spt is overwritten with prefetch_page 
>   and entries in page pointed by ->gfns are initialized 
>   before reading.
>
> [avi: zeroing pages is unnecessary]
>
>   

Applied, thanks.

-- 
error compiling committee.c: too many arguments to function