KVM: Recalculate mmu pages needed for every memory region change
Instead of incrementally changing the mmu cache size for every memory slot
operation, recalculate it from scratch. This is simpler and safer.
Signed-off-by: Zhang Xiantao <xiantao.zhang@intel.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c
index 729573b..93ecafb 100644
--- a/drivers/kvm/kvm_main.c
+++ b/drivers/kvm/kvm_main.c
@@ -333,26 +333,13 @@
if (mem->slot >= kvm->nmemslots)
kvm->nmemslots = mem->slot + 1;
- if (!kvm->n_requested_mmu_pages) {
- unsigned int n_pages;
-
- if (npages) {
- n_pages = npages * KVM_PERMILLE_MMU_PAGES / 1000;
- kvm_mmu_change_mmu_pages(kvm, kvm->n_alloc_mmu_pages +
- n_pages);
- } else {
- unsigned int nr_mmu_pages;
-
- n_pages = old.npages * KVM_PERMILLE_MMU_PAGES / 1000;
- nr_mmu_pages = kvm->n_alloc_mmu_pages - n_pages;
- nr_mmu_pages = max(nr_mmu_pages,
- (unsigned int) KVM_MIN_ALLOC_MMU_PAGES);
- kvm_mmu_change_mmu_pages(kvm, nr_mmu_pages);
- }
- }
-
*memslot = new;
+ if (!kvm->n_requested_mmu_pages) {
+ unsigned int nr_mmu_pages = kvm_mmu_calculate_mmu_pages(kvm);
+ kvm_mmu_change_mmu_pages(kvm, nr_mmu_pages);
+ }
+
kvm_mmu_slot_remove_write_access(kvm, mem->slot);
kvm_flush_remote_tlbs(kvm);
diff --git a/drivers/kvm/mmu.c b/drivers/kvm/mmu.c
index 4624f37..101cd53 100644
--- a/drivers/kvm/mmu.c
+++ b/drivers/kvm/mmu.c
@@ -1535,6 +1535,25 @@
return -ENOMEM;
}
+/*
+ * Caculate mmu pages needed for kvm.
+ */
+unsigned int kvm_mmu_calculate_mmu_pages(struct kvm *kvm)
+{
+ int i;
+ unsigned int nr_mmu_pages;
+ unsigned int nr_pages = 0;
+
+ for (i = 0; i < kvm->nmemslots; i++)
+ nr_pages += kvm->memslots[i].npages;
+
+ nr_mmu_pages = nr_pages * KVM_PERMILLE_MMU_PAGES / 1000;
+ nr_mmu_pages = max(nr_mmu_pages,
+ (unsigned int) KVM_MIN_ALLOC_MMU_PAGES);
+
+ return nr_mmu_pages;
+}
+
#ifdef AUDIT
static const char *audit_msg;
diff --git a/drivers/kvm/x86.h b/drivers/kvm/x86.h
index 90b791b..71f2477 100644
--- a/drivers/kvm/x86.h
+++ b/drivers/kvm/x86.h
@@ -236,6 +236,7 @@
int kvm_mmu_reset_context(struct kvm_vcpu *vcpu);
void kvm_mmu_slot_remove_write_access(struct kvm *kvm, int slot);
void kvm_mmu_zap_all(struct kvm *kvm);
+unsigned int kvm_mmu_calculate_mmu_pages(struct kvm *kvm);
void kvm_mmu_change_mmu_pages(struct kvm *kvm, unsigned int kvm_nr_mmu_pages);
enum emulation_result {