diff mbox series

[3/3] KVM: use vcalloc/__vcalloc for very large allocations

Message ID 20220308105918.615575-4-pbonzini@redhat.com (mailing list archive)
State New
Headers show
Series mm: vmalloc: introduce array allocation functions | expand

Commit Message

Paolo Bonzini March 8, 2022, 10:59 a.m. UTC 
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.  Now that it is available, they can use either
vcalloc or __vcalloc, the latter if accounting is required.

Cc: stable@vger.kernel.org
Cc: kvm@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 arch/powerpc/kvm/book3s_hv_uvmem.c | 2 +-
 arch/x86/kvm/mmu/page_track.c      | 7 ++++---
 arch/x86/kvm/x86.c                 | 4 ++--
 virt/kvm/kvm_main.c                | 4 ++--
 4 files changed, 9 insertions(+), 8 deletions(-)

Comments

David Hildenbrand March 8, 2022, 2:25 p.m. UTC | #1 
On 08.03.22 11:59, Paolo Bonzini wrote:
> 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.  Now that it is available, they can use either
> vcalloc or __vcalloc, the latter if accounting is required.
> 
> Cc: stable@vger.kernel.org
> Cc: kvm@vger.kernel.org
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Fixes: 7661809d493b ("mm: don't allow oversized kvmalloc() calls")

?

Reviewed-by: David Hildenbrand <david@redhat.com>
Andrew Morton March 10, 2022, 4:18 a.m. UTC | #2 
On Tue,  8 Mar 2022 05:59:18 -0500 Paolo Bonzini <pbonzini@redhat.com> wrote:

> 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.  Now that it is available, they can use either
> vcalloc or __vcalloc, the latter if accounting is required.
> 
> Cc: stable@vger.kernel.org

Please fully describe the end user visible runtime effects when
proposing a -stable backport.  And when not proposing a -stable
backport, come to that...
diff mbox series

Patch

diff --git a/arch/powerpc/kvm/book3s_hv_uvmem.c b/arch/powerpc/kvm/book3s_hv_uvmem.c
index e414ca44839f..be441403925b 100644
--- a/arch/powerpc/kvm/book3s_hv_uvmem.c
+++ b/arch/powerpc/kvm/book3s_hv_uvmem.c
@@ -251,7 +251,7 @@  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 68eb1fb548b6..2e09d1b6249f 100644
--- a/arch/x86/kvm/mmu/page_track.c
+++ b/arch/x86/kvm/mmu/page_track.c
@@ -47,8 +47,8 @@  int kvm_page_track_create_memslot(struct kvm *kvm,
 			continue;
 
 		slot->arch.gfn_track[i] =
-			kvcalloc(npages, sizeof(*slot->arch.gfn_track[i]),
-				 GFP_KERNEL_ACCOUNT);
+			__vcalloc(npages, sizeof(*slot->arch.gfn_track[i]),
+				  GFP_KERNEL_ACCOUNT);
 		if (!slot->arch.gfn_track[i])
 			goto track_free;
 	}
@@ -75,7 +75,8 @@  int kvm_page_track_write_tracking_alloc(struct kvm_memory_slot *slot)
 	if (slot->arch.gfn_track[KVM_PAGE_TRACK_WRITE])
 		return 0;
 
-	gfn_track = kvcalloc(slot->npages, sizeof(*gfn_track), GFP_KERNEL_ACCOUNT);
+	gfn_track = __vcalloc(slot->npages, sizeof(*gfn_track),
+			      GFP_KERNEL_ACCOUNT);
 	if (gfn_track == NULL)
 		return -ENOMEM;
 
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index f79bf4552082..4fa4d8269e5b 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -11838,7 +11838,7 @@  int memslot_rmap_alloc(struct kvm_memory_slot *slot, unsigned long npages)
 		if (slot->arch.rmap[i])
 			continue;
 
-		slot->arch.rmap[i] = kvcalloc(lpages, sz, GFP_KERNEL_ACCOUNT);
+		slot->arch.rmap[i] = __vcalloc(lpages, sz, GFP_KERNEL_ACCOUNT);
 		if (!slot->arch.rmap[i]) {
 			memslot_rmap_free(slot);
 			return -ENOMEM;
@@ -11875,7 +11875,7 @@  static int kvm_alloc_memslot_metadata(struct kvm *kvm,
 
 		lpages = __kvm_mmu_slot_lpages(slot, npages, level);
 
-		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 c941b97fa133..a5726099df67 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1274,9 +1274,9 @@  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;