From 5688fed649f15a232e75148afb0a28864046f44c Mon Sep 17 00:00:00 2001
From: Anthony Yznaga <anthony.yznaga@oracle.com>
Date: Tue, 2 Jun 2020 13:07:28 -0700
Subject: [PATCH] KVM: x86: remove unnecessary rmap walk of read-only memslots
There's no write access to remove. An existing memslot cannot be updated
to set or clear KVM_MEM_READONLY, and any mappings established in a newly
created or moved read-only memslot will already be read-only.
Signed-off-by: Anthony Yznaga <anthony.yznaga@oracle.com>
Message-Id: <1591128450-11977-2-git-send-email-anthony.yznaga@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
arch/x86/kvm/x86.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 9e41b51353401..e11e0494f833a 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -10142,11 +10142,9 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm,
static void kvm_mmu_slot_apply_flags(struct kvm *kvm,
struct kvm_memory_slot *new)
{
- /* Still write protect RO slot */
- if (new->flags & KVM_MEM_READONLY) {
- kvm_mmu_slot_remove_write_access(kvm, new, PG_LEVEL_4K);
+ /* Nothing to do for RO slots */
+ if (new->flags & KVM_MEM_READONLY)
return;
- }
/*
* Call kvm_x86_ops dirty logging hooks when they are valid.
--
2.30.2