Re: [PATCH v3 2/8] KVM: x86/mmu: Factor out allocating memslot rmap

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On 06.05.21 20:42, Ben Gardon wrote:
Small refactor to facilitate allocating rmaps for all memslots at once.

No functional change expected.

Signed-off-by: Ben Gardon <bgardon@xxxxxxxxxx>
---
  arch/x86/kvm/x86.c | 41 ++++++++++++++++++++++++++++++++---------
  1 file changed, 32 insertions(+), 9 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 5bcf07465c47..fc32a7dbe4c4 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -10842,10 +10842,37 @@ void kvm_arch_free_memslot(struct kvm *kvm, struct kvm_memory_slot *slot)
  	kvm_page_track_free_memslot(slot);
  }
+static int alloc_memslot_rmap(struct kvm_memory_slot *slot,
+			      unsigned long npages)

I'd have called the functions memslot_rmap_alloc() and memslot_rmap_free()


+{
+	int i;
+
+	for (i = 0; i < KVM_NR_PAGE_SIZES; ++i) {
+		int lpages;
+		int level = i + 1;
+
+		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;

you can just avoid the goto here and do the free_memslot_rmap() right away.

+	}
+
+	return 0;
+
+out_free:
+	free_memslot_rmap(slot);
+	return -ENOMEM;
+}
+
  static int kvm_alloc_memslot_metadata(struct kvm_memory_slot *slot,
  				      unsigned long npages)
  {
  	int i;
+	int r;
/*
  	 * Clear out the previous array pointers for the KVM_MR_MOVE case.  The
@@ -10854,7 +10881,11 @@ 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 = alloc_memslot_rmap(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;
@@ -10863,14 +10894,6 @@ 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;


apart from that LGTM

--
Thanks,

David / dhildenb




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