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>

1 files changed, 4 insertions, 17 deletions

diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c
index 729573b844e5..93ecafbfb1b6 100644
--- a/drivers/kvm/kvm_main.c
+++ b/drivers/kvm/kvm_main.c
@@ -333,26 +333,13 @@ int __kvm_set_memory_region(struct kvm *kvm,
         if (mem->slot >= kvm->nmemslots)
                 kvm->nmemslots = mem->slot + 1;
 
+        *memslot = new;
+
         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);
-                }
+                unsigned int nr_mmu_pages = kvm_mmu_calculate_mmu_pages(kvm);
+                kvm_mmu_change_mmu_pages(kvm, nr_mmu_pages);
         }
 
-        *memslot = new;
-
         kvm_mmu_slot_remove_write_access(kvm, mem->slot);
         kvm_flush_remote_tlbs(kvm);