KVM: SVM: Account scratch allocations used to decrypt SEV guest memory

Account the temp/scratch allocation used to decrypt unaligned debug
accesses to SEV guest memory, the allocation is very much tied to the
target VM.
Reported-by: Mingwei Zhang <mizhang@google.com>
Signed-off-by: Anish Ghulati <aghulati@google.com>
Link: https://lore.kernel.org/r/20230113220923.2834699-1-aghulati@google.comSigned-off-by: Sean Christopherson <seanjc@google.com>

arch/x86/kvm/svm/sev.c

@@ -813,7 +813,7 @@ static int __sev_dbg_decrypt_user(struct kvm *kvm, unsigned long paddr,
 	if (!IS_ALIGNED(dst_paddr, 16) ||
 	    !IS_ALIGNED(paddr,     16) ||
 	    !IS_ALIGNED(size,      16)) {
-		tpage = (void *)alloc_page(GFP_KERNEL | __GFP_ZERO);
+		tpage = (void *)alloc_page(GFP_KERNEL_ACCOUNT | __GFP_ZERO);
 		if (!tpage)
 			return -ENOMEM;