[PATCH v7 17/29] KVM: x86: Don't call kvm_mmu_change_mmu_pages() if the count hasn't changed

From: Maciej S. Szmigiero
Date: Mon Dec 06 2021 - 14:56:48 EST


From: "Maciej S. Szmigiero" <maciej.szmigiero@xxxxxxxxxx>

There is no point in calling kvm_mmu_change_mmu_pages() for memslot
operations that don't change the total page count, so do it just for
KVM_MR_CREATE and KVM_MR_DELETE.

Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@xxxxxxxxxx>
Reviewed-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
arch/x86/kvm/x86.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index f25d224d21d9..13048683db60 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -11832,7 +11832,8 @@ void kvm_arch_commit_memory_region(struct kvm *kvm,
const struct kvm_memory_slot *new,
enum kvm_mr_change change)
{
- if (!kvm->arch.n_requested_mmu_pages)
+ if (!kvm->arch.n_requested_mmu_pages &&
+ (change == KVM_MR_CREATE || change == KVM_MR_DELETE))
kvm_mmu_change_mmu_pages(kvm,
kvm_mmu_calculate_default_mmu_pages(kvm));