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;