KVM: s390: Pass initialized arg even if unused

This silences smatch warnings reported by kbuild bot:
arch/s390/kvm/gaccess.c:859 guest_range_to_gpas() error: uninitialized symbol 'prot'.
arch/s390/kvm/gaccess.c:1064 access_guest_with_key() error: uninitialized symbol 'prot'.

This is because it cannot tell that the value is not used in this case.
The trans_exc* only examine prot if code is PGM_PROTECTION.
Pass a dummy value for other codes.

Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Link: https://lore.kernel.org/r/20220825192540.1560559-1-scgl@linux.ibm.com
Signed-off-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>

diff --git a/arch/s390/kvm/gaccess.c b/arch/s390/kvm/gaccess.c
index 082ec5f..0243b6e 100644 (file)
--- a/arch/s390/kvm/gaccess.c
+++ b/arch/s390/kvm/gaccess.c
@@ -489,6 +489,8 @@ enum prot_type {
        PROT_TYPE_ALC  = 2,
        PROT_TYPE_DAT  = 3,
        PROT_TYPE_IEP  = 4,
+       /* Dummy value for passing an initialized value when code != PGM_PROTECTION */
+       PROT_NONE,
 };
 
 static int trans_exc_ending(struct kvm_vcpu *vcpu, int code, unsigned long gva, u8 ar,
@@ -504,6 +506,10 @@ static int trans_exc_ending(struct kvm_vcpu *vcpu, int code, unsigned long gva,
        switch (code) {
        case PGM_PROTECTION:
                switch (prot) {
+               case PROT_NONE:
+                       /* We should never get here, acts like termination */
+                       WARN_ON_ONCE(1);
+                       break;
                case PROT_TYPE_IEP:
                        tec->b61 = 1;
                        fallthrough;
@@ -968,8 +974,10 @@ static int guest_range_to_gpas(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar,
                                return rc;
                } else {
                        gpa = kvm_s390_real_to_abs(vcpu, ga);
-                       if (kvm_is_error_gpa(vcpu->kvm, gpa))
+                       if (kvm_is_error_gpa(vcpu->kvm, gpa)) {
                                rc = PGM_ADDRESSING;
+                               prot = PROT_NONE;
+                       }
                }
                if (rc)
                        return trans_exc(vcpu, rc, ga, ar, mode, prot);
@@ -1112,8 +1120,6 @@ int access_guest_with_key(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar,
                if (rc == PGM_PROTECTION && try_storage_prot_override)
                        rc = access_guest_page_with_key(vcpu->kvm, mode, gpas[idx],
                                                        data, fragment_len, PAGE_SPO_ACC);
-               if (rc == PGM_PROTECTION)
-                       prot = PROT_TYPE_KEYC;
                if (rc)
                        break;
                len -= fragment_len;
@@ -1123,6 +1129,10 @@ int access_guest_with_key(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar,
        if (rc > 0) {
                bool terminate = (mode == GACC_STORE) && (idx > 0);
 
+               if (rc == PGM_PROTECTION)
+                       prot = PROT_TYPE_KEYC;
+               else
+                       prot = PROT_NONE;
                rc = trans_exc_ending(vcpu, rc, ga, ar, mode, prot, terminate);
        }
 out_unlock: