linux-kernel - [PATCH 2/2] KVM: use __vcalloc for very large allocations

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Date: Fri, 26 Jan 2024 12:40:23 +0300
From: oficerovas@...linux.org
To: oficerovas@...linux.org,
	linux-kernel@...r.kernel.org,
	kvm@...r.kernel.org
Cc: kovalev@...linux.org
Subject: [PATCH 2/2] KVM: use __vcalloc for very large allocations

From: Alexander Ofitserov <oficerovas@...linux.org>

From: Paolo Bonzini <pbonzini@...hat.com>

commit 37b2a6510a48 ("KVM: use __vcalloc for very large allocations")

Allocations whose size is related to the memslot size can be arbitrarily
large.  Do not use kvzalloc/kvcalloc, as those are limited to "not crazy"
sizes that fit in 32 bits.

URL: https://lore.kernel.org/lkml/20220711090606.962822924@linuxfoundation.org/
Reviewed-by: David Hildenbrand <david@...hat.com>
Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
Signed-off-by: Alexander Ofitserov <oficerovas@...linux.org>
---
 arch/powerpc/kvm/book3s_hv_uvmem.c | 2 +-
 arch/x86/kvm/mmu/page_track.c      | 2 +-
 arch/x86/kvm/x86.c                 | 4 ++--
 virt/kvm/kvm_main.c                | 4 ++--
 4 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/arch/powerpc/kvm/book3s_hv_uvmem.c b/arch/powerpc/kvm/book3s_hv_uvmem.c
index 3dd58b4ee33e5..5f6b3f80023de 100644
--- a/arch/powerpc/kvm/book3s_hv_uvmem.c
+++ b/arch/powerpc/kvm/book3s_hv_uvmem.c
@@ -250,7 +250,7 @@ int kvmppc_uvmem_slot_init(struct kvm *kvm, const struct kvm_memory_slot *slot)
 	p = kzalloc(sizeof(*p), GFP_KERNEL);
 	if (!p)
 		return -ENOMEM;
-	p->pfns = vzalloc(array_size(slot->npages, sizeof(*p->pfns)));
+	p->pfns = vcalloc(slot->npages, sizeof(*p->pfns));
 	if (!p->pfns) {
 		kfree(p);
 		return -ENOMEM;
diff --git a/arch/x86/kvm/mmu/page_track.c b/arch/x86/kvm/mmu/page_track.c
index 81cf4babbd0b4..3c379335ea477 100644
--- a/arch/x86/kvm/mmu/page_track.c
+++ b/arch/x86/kvm/mmu/page_track.c
@@ -35,7 +35,7 @@ int kvm_page_track_create_memslot(struct kvm_memory_slot *slot,
 
 	for (i = 0; i < KVM_PAGE_TRACK_MAX; i++) {
 		slot->arch.gfn_track[i] =
-			kvcalloc(npages, sizeof(*slot->arch.gfn_track[i]),
+			__vcalloc(npages, sizeof(*slot->arch.gfn_track[i]),
 				 GFP_KERNEL_ACCOUNT);
 		if (!slot->arch.gfn_track[i])
 			goto track_free;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 13e4699a0744f..6c2bf7cd7aec6 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -10826,14 +10826,14 @@ static int kvm_alloc_memslot_metadata(struct kvm_memory_slot *slot,
 				      slot->base_gfn, level) + 1;
 
 		slot->arch.rmap[i] =
-			kvcalloc(lpages, sizeof(*slot->arch.rmap[i]),
+			__vcalloc(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);
+		linfo = __vcalloc(lpages, sizeof(*linfo), GFP_KERNEL_ACCOUNT);
 		if (!linfo)
 			goto out_free;
 
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 356fd5d1a4285..b7638c3c9eb7d 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1008,9 +1008,9 @@ static int kvm_vm_release(struct inode *inode, struct file *filp)
  */
 static int kvm_alloc_dirty_bitmap(struct kvm_memory_slot *memslot)
 {
-	unsigned long dirty_bytes = 2 * kvm_dirty_bitmap_bytes(memslot);
+	unsigned long dirty_bytes = kvm_dirty_bitmap_bytes(memslot);
 
-	memslot->dirty_bitmap = kvzalloc(dirty_bytes, GFP_KERNEL_ACCOUNT);
+	memslot->dirty_bitmap = __vcalloc(2, dirty_bytes, GFP_KERNEL_ACCOUNT);
 	if (!memslot->dirty_bitmap)
 		return -ENOMEM;
 
-- 
2.42.1