KVM: x86/mmu: Factor out allocating memslot rmap

Small refactor to facilitate allocating rmaps for all memslots at once.

No functional change expected.

Signed-off-by: Ben Gardon <bgardon@google.com>
Message-Id: <20210518173414.450044-3-bgardon@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index eaa01e6..5f66a59 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -10941,10 +10941,31 @@ void kvm_arch_free_memslot(struct kvm *kvm, struct kvm_memory_slot *slot)
        kvm_page_track_free_memslot(slot);
 }
 
+static int memslot_rmap_alloc(struct kvm_memory_slot *slot,
+                             unsigned long npages)
+{
+       const int sz = sizeof(*slot->arch.rmap[0]);
+       int i;
+
+       for (i = 0; i < KVM_NR_PAGE_SIZES; ++i) {
+               int level = i + 1;
+               int lpages = gfn_to_index(slot->base_gfn + npages - 1,
+                                         slot->base_gfn, level) + 1;
+
+               slot->arch.rmap[i] = kvcalloc(lpages, sz, GFP_KERNEL_ACCOUNT);
+               if (!slot->arch.rmap[i]) {
+                       memslot_rmap_free(slot);
+                       return -ENOMEM;
+               }
+       }
+
+       return 0;
+}
+
 static int kvm_alloc_memslot_metadata(struct kvm_memory_slot *slot,
                                      unsigned long npages)
 {
-       int i;
+       int i, r;
 
        /*
         * Clear out the previous array pointers for the KVM_MR_MOVE case.  The
@@ -10953,7 +10974,11 @@ static int kvm_alloc_memslot_metadata(struct kvm_memory_slot *slot,
         */
        memset(&slot->arch, 0, sizeof(slot->arch));
 
-       for (i = 0; i < KVM_NR_PAGE_SIZES; ++i) {
+       r = memslot_rmap_alloc(slot, npages);
+       if (r)
+               return r;
+
+       for (i = 1; i < KVM_NR_PAGE_SIZES; ++i) {
                struct kvm_lpage_info *linfo;
                unsigned long ugfn;
                int lpages;
@@ -10962,14 +10987,6 @@ static int kvm_alloc_memslot_metadata(struct kvm_memory_slot *slot,
                lpages = gfn_to_index(slot->base_gfn + npages - 1,
                                      slot->base_gfn, level) + 1;
 
-               slot->arch.rmap[i] =
-                       kvcalloc(lpages, sizeof(*slot->arch.rmap[i]),
-                                GFP_KERNEL_ACCOUNT);
-               if (!slot->arch.rmap[i])
-                       goto out_free;
-               if (i == 0)
-                       continue;
-
                linfo = kvcalloc(lpages, sizeof(*linfo), GFP_KERNEL_ACCOUNT);
                if (!linfo)
                        goto out_free;