KVM: s390: introduce post handlers for STSI

The Store System Information (STSI) instruction currently collects all
information it relays to the caller in the kernel. Some information,
however, is only available in user space. An example of this is the
guest name: The kernel always sets "KVMGuest", but user space knows the
actual guest name.

This patch introduces a new exit, KVM_EXIT_S390_STSI, guarded by a
capability that can be enabled by user space if it wants to be able to
insert such data. User space will be provided with the target buffer
and the requested STSI function code.

Reviewed-by: Eric Farman <farman@linux.vnet.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Ekaterina Tumanova <tumanova@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>

1 files changed, 11 insertions, 0 deletions

diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 0e16f2c9f0de..57445ef88097 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -172,6 +172,7 @@ struct kvm_pit_config {
 #define KVM_EXIT_S390_TSCH        22
 #define KVM_EXIT_EPR              23
 #define KVM_EXIT_SYSTEM_EVENT     24
+#define KVM_EXIT_S390_STSI        25
 
 /* For KVM_EXIT_INTERNAL_ERROR */
 /* Emulate instruction failed. */
@@ -309,6 +310,15 @@ struct kvm_run {
                         __u32 type;
                         __u64 flags;
                 } system_event;
+                /* KVM_EXIT_S390_STSI */
+                struct {
+                        __u64 addr;
+                        __u8 ar;
+                        __u8 reserved;
+                        __u8 fc;
+                        __u8 sel1;
+                        __u16 sel2;
+                } s390_stsi;
                 /* Fix the size of the union. */
                 char padding[256];
         };
@@ -780,6 +790,7 @@ struct kvm_ppc_smmu_info {
 #define KVM_CAP_S390_USER_SIGP 106
 #define KVM_CAP_S390_VECTOR_REGISTERS 107
 #define KVM_CAP_S390_MEM_OP 108
+#define KVM_CAP_S390_USER_STSI 109
 
 #ifdef KVM_CAP_IRQ_ROUTING