No reason to make callers take mmu_lock since we do not need to protect
kvm_mmu_change_mmu_pages() and kvm_mmu_slot_remove_write_access()
together by mmu_lock in kvm_arch_commit_memory_region(): the former
calls kvm_mmu_commit_zap_page() and flushes TLBs by itself.
Note: we do not need to protect kvm->arch.n_requested_mmu_pages by
mmu_lock as can be seen from the fact that it is read locklessly.
Signed-off-by: Takuya Yoshikawa <yoshikawa_takuya_b1@xxxxxxxxxxxxx>
---
arch/x86/kvm/mmu.c | 4 ++++
arch/x86/kvm/x86.c | 9 ++++-----
2 files changed, 8 insertions(+), 5 deletions(-)
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index bb964b3..fc7d84a 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2143,6 +2143,8 @@ void kvm_mmu_change_mmu_pages(struct kvm *kvm, unsigned int goal_nr_mmu_pages)
* change the value
*/
+ spin_lock(&kvm->mmu_lock);
+
if (kvm->arch.n_used_mmu_pages > goal_nr_mmu_pages) {
while (kvm->arch.n_used_mmu_pages > goal_nr_mmu_pages &&
!list_empty(&kvm->arch.active_mmu_pages)) {
@@ -2157,6 +2159,8 @@ void kvm_mmu_change_mmu_pages(struct kvm *kvm, unsigned int goal_nr_mmu_pages)
}
kvm->arch.n_max_mmu_pages = goal_nr_mmu_pages;
+
+ spin_unlock(&kvm->mmu_lock);
}
int kvm_mmu_unprotect_page(struct kvm *kvm, gfn_t gfn)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index add5e48..080bbdc 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3270,12 +3270,10 @@ static int kvm_vm_ioctl_set_nr_mmu_pages(struct kvm *kvm,
return -EINVAL;
mutex_lock(&kvm->slots_lock);
- spin_lock(&kvm->mmu_lock);
kvm_mmu_change_mmu_pages(kvm, kvm_nr_mmu_pages);
kvm->arch.n_requested_mmu_pages = kvm_nr_mmu_pages;
- spin_unlock(&kvm->mmu_lock);
mutex_unlock(&kvm->slots_lock);
return 0;
}
@@ -6894,7 +6892,6 @@ void kvm_arch_commit_memory_region(struct kvm *kvm,
if (!kvm->arch.n_requested_mmu_pages)
nr_mmu_pages = kvm_mmu_calculate_mmu_pages(kvm);
- spin_lock(&kvm->mmu_lock);
if (nr_mmu_pages)
kvm_mmu_change_mmu_pages(kvm, nr_mmu_pages);
/*
@@ -6902,9 +6899,11 @@ void kvm_arch_commit_memory_region(struct kvm *kvm,
* Existing largepage mappings are destroyed here and new ones will
* not be created until the end of the logging.
*/
- if (npages && (mem->flags & KVM_MEM_LOG_DIRTY_PAGES))
+ if (npages && (mem->flags & KVM_MEM_LOG_DIRTY_PAGES)) {
+ spin_lock(&kvm->mmu_lock);
kvm_mmu_slot_remove_write_access(kvm, mem->slot);
- spin_unlock(&kvm->mmu_lock);
+ spin_unlock(&kvm->mmu_lock);
+ }
/*
* If memory slot is created, or moved, we need to clear all
* mmio sptes.
--
1.7.5.4
--
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