KVM: s390: randomize sca address (f6c137ff) · Commits · 戴 / test

We allocate a page for the 2k sca, so lets use the space to improve hit rate of some internal cpu caches. No need to change the freeing of the page, as this will shift away the page offset bits anyway. Signed-off-by:

Christian Borntraeger <borntraeger@de.ibm.com> Reviewed-by:

David Hildenbrand <dahi@linux.vnet.ibm.com>

arch/s390/kvm/kvm-s390.c

+5 −0

Original line number	Diff line number	Diff line
		@@ -215,6 +215,7 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
		{
		int rc;
		char debug_name[16];
		static unsigned long sca_offset;

		rc = -EINVAL;
		#ifdef CONFIG_KVM_S390_UCONTROL
		@@ -236,6 +237,10 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
		kvm->arch.sca = (struct sca_block *) get_zeroed_page(GFP_KERNEL);
		if (!kvm->arch.sca)
		goto out_err;
		spin_lock(&kvm_lock);
		sca_offset = (sca_offset + 16) & 0x7f0;
		kvm->arch.sca = (struct sca_block ) ((char ) kvm->arch.sca + sca_offset);
		spin_unlock(&kvm_lock);

		sprintf(debug_name, "kvm-%u", current->pid);

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