[PATCH 2/2] target/s390x: kvm: Honor storage keys during emulation

[Janis Schoetterl-Glausch]

Storage key controlled protection is currently not honored when
emulating instructions.
If available, enable key protection for the MEM_OP ioctl, thereby
enabling it for the s390_cpu_virt_mem_* functions, when using kvm.
As a result, the emulation of the following instructions honors storage
keys:

* CLP
        The Synch I/O CLP command would need special handling in order
        to support storage keys, but is currently not supported.
* CHSC
        Performing commands asynchronously would require special
        handling, but commands are currently always synchronous.
* STSI
* TSCH
        Must (and does) not change channel if terminated due to
        protection.
* MSCH
        Suppressed on protection, works because fetching instruction.
* SSCH
        Suppressed on protection, works because fetching instruction.
* STSCH
* STCRW
        Suppressed on protection, this works because no partial store is
        possible, because the operand cannot span multiple pages.
* PCISTB
* MPCIFC
* STPCIFC

Signed-off-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com>
---
 target/s390x/kvm/kvm.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/target/s390x/kvm/kvm.c b/target/s390x/kvm/kvm.c
index 53098bf541..7bd8db0e7b 100644
--- a/target/s390x/kvm/kvm.c
+++ b/target/s390x/kvm/kvm.c
@@ -151,12 +151,15 @@ const KVMCapabilityInfo kvm_arch_required_capabilities[] 
= {
 static int cap_sync_regs;
 static int cap_async_pf;
 static int cap_mem_op;
+static int cap_mem_op_extension;
 static int cap_s390_irq;
 static int cap_ri;
 static int cap_hpage_1m;
 static int cap_vcpu_resets;
 static int cap_protected;
 
+static bool mem_op_storage_key_support;
+
 static int active_cmma;
 
 static int kvm_s390_query_mem_limit(uint64_t *memory_limit)
@@ -354,6 +357,8 @@ int kvm_arch_init(MachineState *ms, KVMState *s)
     cap_sync_regs = kvm_check_extension(s, KVM_CAP_SYNC_REGS);
     cap_async_pf = kvm_check_extension(s, KVM_CAP_ASYNC_PF);
     cap_mem_op = kvm_check_extension(s, KVM_CAP_S390_MEM_OP);
+    cap_mem_op_extension = kvm_check_extension(s, 
KVM_CAP_S390_MEM_OP_EXTENSION);
+    mem_op_storage_key_support = cap_mem_op_extension > 0;
     cap_s390_irq = kvm_check_extension(s, KVM_CAP_S390_INJECT_IRQ);
     cap_vcpu_resets = kvm_check_extension(s, KVM_CAP_S390_VCPU_RESETS);
     cap_protected = kvm_check_extension(s, KVM_CAP_S390_PROTECTED);
@@ -842,6 +847,7 @@ int kvm_s390_mem_op(S390CPU *cpu, vaddr addr, uint8_t ar, 
void *hostbuf,
                        : KVM_S390_MEMOP_LOGICAL_READ,
         .buf = (uint64_t)hostbuf,
         .ar = ar,
+        .key = (cpu->env.psw.mask & PSW_MASK_KEY) >> PSW_SHIFT_KEY,
     };
     int ret;
 
@@ -851,6 +857,9 @@ int kvm_s390_mem_op(S390CPU *cpu, vaddr addr, uint8_t ar, 
void *hostbuf,
     if (!hostbuf) {
         mem_op.flags |= KVM_S390_MEMOP_F_CHECK_ONLY;
     }
+    if (mem_op_storage_key_support) {
+        mem_op.flags |= KVM_S390_MEMOP_F_SKEY_PROTECTION;
+    }
 
     ret = kvm_vcpu_ioctl(CPU(cpu), KVM_S390_MEM_OP, &mem_op);
     if (ret < 0) {
-- 
2.32.0