[PATCH v4 2/7] KVM: x86/mmu: Factor out allocating memslot rmap

From: Ben Gardon <bgardon@google.com>
To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc: Paolo Bonzini <pbonzini@redhat.com>, Peter Xu <peterx@redhat.com>,
	Sean Christopherson <seanjc@google.com>,
	Peter Shier <pshier@google.com>,
	Yulei Zhang <yulei.kernel@gmail.com>,
	Wanpeng Li <kernellwp@gmail.com>,
	Xiao Guangrong <xiaoguangrong.eric@gmail.com>,
	Kai Huang <kai.huang@intel.com>,
	Keqian Zhu <zhukeqian1@huawei.com>,
	David Hildenbrand <david@redhat.com>,
	Ben Gardon <bgardon@google.com>
Subject: [PATCH v4 2/7] KVM: x86/mmu: Factor out allocating memslot rmap
Date: Tue, 11 May 2021 10:16:05 -0700	[thread overview]
Message-ID: <20210511171610.170160-3-bgardon@google.com> (raw)
In-Reply-To: <20210511171610.170160-1-bgardon@google.com>

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

No functional change expected.

Signed-off-by: Ben Gardon <bgardon@google.com>
---
 arch/x86/kvm/x86.c | 39 ++++++++++++++++++++++++++++++---------
 1 file changed, 30 insertions(+), 9 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 1e1f4f31e586..cc0440b5b35d 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -10911,10 +10911,35 @@ 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)
+{
+	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]) {
+			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 r;
 
 	/*
 	 * Clear out the previous array pointers for the KVM_MR_MOVE case.  The
@@ -10923,7 +10948,11 @@ 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;
@@ -10932,14 +10961,6 @@ 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;
-- 
2.31.1.607.g51e8a6a459-goog

