KVM: s390: prepare to read random guest instructions

We will have to read instructions not residing at the current PSW
address.

Reviewed-by: Eric Farman <farman@linux.vnet.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Cc: David Hildenbrand <david@redhat.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>

arch/s390/kvm/gaccess.h

@@ -247,21 +247,22 @@ int read_guest(struct kvm_vcpu *vcpu, unsigned long ga, u8 ar, void *data,
 /**
  * read_guest_instr - copy instruction data from guest space to kernel space
  * @vcpu: virtual cpu
+ * @ga: guest address
  * @data: destination address in kernel space
  * @len: number of bytes to copy
  *
- * Copy @len bytes from the current psw address (guest space) to @data (kernel
+ * Copy @len bytes from the given address (guest space) to @data (kernel
  * space).
  *
  * The behaviour of read_guest_instr is identical to read_guest, except that
  * instruction data will be read from primary space when in home-space or
  * address-space mode.
  */
 static inline __must_check
-int read_guest_instr(struct kvm_vcpu *vcpu, void *data, unsigned long len)
+int read_guest_instr(struct kvm_vcpu *vcpu, unsigned long ga, void *data,
+		     unsigned long len)
 {
-	return access_guest(vcpu, vcpu->arch.sie_block->gpsw.addr, 0, data, len,
-			    GACC_IFETCH);
+	return access_guest(vcpu, ga, 0, data, len, GACC_IFETCH);
 }
 
 /**

arch/s390/kvm/kvm-s390.c

@@ -2588,7 +2588,7 @@ static int vcpu_post_run_fault_in_sie(struct kvm_vcpu *vcpu)
 	 * to look up the current opcode to get the length of the instruction
 	 * to be able to forward the PSW.
 	 */
-	rc = read_guest_instr(vcpu, &opcode, 1);
+	rc = read_guest_instr(vcpu, vcpu->arch.sie_block->gpsw.addr, &opcode, 1);
 	ilen = insn_length(opcode);
 	if (rc < 0) {
 		return rc;