KVM: s390/CPACF: Choose crypto control block format

We need to specify a different format for the crypto control block
depending on whether the APXA facility is installed or not. Let's
test for it by executing the PQAP(QCI) function and use either a
format-1 or a format-2 crypto control block accordingly. This is a
host only change for z13 and does not affect the guest view.

Signed-off-by: Tony Krowiak <akrowiak@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>

1 files changed, 47 insertions, 2 deletions

diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 3acf08ba88e4..deac47378f77 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -654,6 +654,52 @@ long kvm_arch_vm_ioctl(struct file *filp,
 	return r;
 }
 
+static int kvm_s390_query_ap_config(u8 *config)
+{
+	u32 fcn_code = 0x04000000UL;
+	u32 cc;
+
+	asm volatile(
+		"lgr 0,%1\n"
+		"lgr 2,%2\n"
+		".long 0xb2af0000\n"		/* PQAP(QCI) */
+		"ipm %0\n"
+		"srl %0,28\n"
+		: "=r" (cc)
+		: "r" (fcn_code), "r" (config)
+		: "cc", "0", "2", "memory"
+	);
+
+	return cc;
+}
+
+static int kvm_s390_apxa_installed(void)
+{
+	u8 config[128];
+	int cc;
+
+	if (test_facility(2) && test_facility(12)) {
+		cc = kvm_s390_query_ap_config(config);
+
+		if (cc)
+			pr_err("PQAP(QCI) failed with cc=%d", cc);
+		else
+			return config[0] & 0x40;
+	}
+
+	return 0;
+}
+
+static void kvm_s390_set_crycb_format(struct kvm *kvm)
+{
+	kvm->arch.crypto.crycbd = (__u32)(unsigned long) kvm->arch.crypto.crycb;
+
+	if (kvm_s390_apxa_installed())
+		kvm->arch.crypto.crycbd |= CRYCB_FORMAT2;
+	else
+		kvm->arch.crypto.crycbd |= CRYCB_FORMAT1;
+}
+
 static int kvm_s390_crypto_init(struct kvm *kvm)
 {
 	if (!test_vfacility(76))
@@ -664,8 +710,7 @@ static int kvm_s390_crypto_init(struct kvm *kvm)
 	if (!kvm->arch.crypto.crycb)
 		return -ENOMEM;
 
-	kvm->arch.crypto.crycbd = (__u32) (unsigned long) kvm->arch.crypto.crycb |
-				  CRYCB_FORMAT1;
+	kvm_s390_set_crycb_format(kvm);
 
 	/* Disable AES/DEA protected key functions by default */
 	kvm->arch.crypto.aes_kw = 0;