[PATCH v3 10/17] s390x: Add SIDA memory ops

[Janosch Frank <frankja@linux.ibm.com>]

Protected guests save the instruction control blocks in the SIDA
instead of QEMU/KVM directly accessing the guest's memory.

Let's introduce new functions to access the SIDA.

Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
---
 linux-headers/linux/kvm.h |  6 +++++-
 target/s390x/cpu.h        |  7 ++++++-
 target/s390x/kvm.c        | 23 +++++++++++++++++++++++
 target/s390x/kvm_s390x.h  |  2 ++
 target/s390x/mmu_helper.c |  9 +++++++++
 5 files changed, 45 insertions(+), 2 deletions(-)

diff --git a/linux-headers/linux/kvm.h b/linux-headers/linux/kvm.h
index e5ad5f9c4d..c6f0d04115 100644
--- a/linux-headers/linux/kvm.h
+++ b/linux-headers/linux/kvm.h
@@ -475,11 +475,15 @@ struct kvm_s390_mem_op {
 	__u32 op;		/* type of operation */
 	__u64 buf;		/* buffer in userspace */
 	__u8 ar;		/* the access register number */
-	__u8 reserved[31];	/* should be set to 0 */
+	__u8 reserved21[3];     /* should be set to 0 */
+	__u32 offset;           /* offset into the sida */
+	__u8 reserved28[24];	/* should be set to 0 */
 };
 /* types for kvm_s390_mem_op->op */
 #define KVM_S390_MEMOP_LOGICAL_READ	0
 #define KVM_S390_MEMOP_LOGICAL_WRITE	1
+#define KVM_S390_MEMOP_SIDA_READ	2
+#define KVM_S390_MEMOP_SIDA_WRITE	3
 /* flags for kvm_s390_mem_op->flags */
 #define KVM_S390_MEMOP_F_CHECK_ONLY		(1ULL << 0)
 #define KVM_S390_MEMOP_F_INJECT_EXCEPTION	(1ULL << 1)
diff --git a/target/s390x/cpu.h b/target/s390x/cpu.h
index cbc53c99cf..491d6860a8 100644
--- a/target/s390x/cpu.h
+++ b/target/s390x/cpu.h
@@ -823,7 +823,12 @@ int s390_cpu_virt_mem_rw(S390CPU *cpu, vaddr laddr, uint8_t ar, void *hostbuf,
 #define s390_cpu_virt_mem_check_write(cpu, laddr, ar, len)   \
         s390_cpu_virt_mem_rw(cpu, laddr, ar, NULL, len, true)
 void s390_cpu_virt_mem_handle_exc(S390CPU *cpu, uintptr_t ra);
-
+int s390_cpu_pv_mem_rw(S390CPU *cpu, unsigned int offset,  void *hostbuf,
+                       int len, bool is_write);
+#define s390_cpu_pv_mem_read(cpu, offset, dest, len)    \
+        s390_cpu_pv_mem_rw(cpu, offset, dest, len, false)
+#define s390_cpu_pv_mem_write(cpu, offset, dest, len)       \
+        s390_cpu_pv_mem_rw(cpu, offset, dest, len, true)
 
 /* sigp.c */
 int s390_cpu_restart(S390CPU *cpu);
diff --git a/target/s390x/kvm.c b/target/s390x/kvm.c
index fe669ed24c..e4f8242be7 100644
--- a/target/s390x/kvm.c
+++ b/target/s390x/kvm.c
@@ -846,6 +846,29 @@ int kvm_s390_mem_op(S390CPU *cpu, vaddr addr, uint8_t ar, void *hostbuf,
     return ret;
 }
 
+int kvm_s390_mem_op_pv(S390CPU *cpu, uint64_t offset, void *hostbuf,
+                       int len, bool is_write)
+{
+    int ret = 0;
+    struct kvm_s390_mem_op mem_op = {
+        .offset = offset,
+        .size = len,
+        .op = is_write ? KVM_S390_MEMOP_SIDA_WRITE
+                       : KVM_S390_MEMOP_SIDA_READ,
+        .buf = (uint64_t)hostbuf,
+    };
+
+    if (!cap_mem_op) {
+        return -ENOSYS;
+    }
+
+    ret = kvm_vcpu_ioctl(CPU(cpu), KVM_S390_MEM_OP, &mem_op);
+    if (ret < 0) {
+        warn_report("KVM_S390_MEM_OP failed: %s", strerror(-ret));
+    }
+    return ret;
+}
+
 /*
  * Legacy layout for s390:
  * Older S390 KVM requires the topmost vma of the RAM to be
diff --git a/target/s390x/kvm_s390x.h b/target/s390x/kvm_s390x.h
index 0b21789796..9c38f6ccce 100644
--- a/target/s390x/kvm_s390x.h
+++ b/target/s390x/kvm_s390x.h
@@ -19,6 +19,8 @@ void kvm_s390_vcpu_interrupt(S390CPU *cpu, struct kvm_s390_irq *irq);
 void kvm_s390_access_exception(S390CPU *cpu, uint16_t code, uint64_t te_code);
 int kvm_s390_mem_op(S390CPU *cpu, vaddr addr, uint8_t ar, void *hostbuf,
                     int len, bool is_write);
+int kvm_s390_mem_op_pv(S390CPU *cpu, vaddr addr, void *hostbuf, int len,
+                       bool is_write);
 void kvm_s390_program_interrupt(S390CPU *cpu, uint16_t code);
 int kvm_s390_set_cpu_state(S390CPU *cpu, uint8_t cpu_state);
 void kvm_s390_vcpu_interrupt_pre_save(S390CPU *cpu);
diff --git a/target/s390x/mmu_helper.c b/target/s390x/mmu_helper.c
index c9f3f34750..ad485399db 100644
--- a/target/s390x/mmu_helper.c
+++ b/target/s390x/mmu_helper.c
@@ -474,6 +474,15 @@ static int translate_pages(S390CPU *cpu, vaddr addr, int nr_pages,
     return 0;
 }
 
+int s390_cpu_pv_mem_rw(S390CPU *cpu, unsigned int offset, void *hostbuf,
+                       int len, bool is_write)
+{
+    int ret;
+
+    ret = kvm_s390_mem_op_pv(cpu, offset, hostbuf, len, is_write);
+    return ret;
+}
+
 /**
  * s390_cpu_virt_mem_rw:
  * @laddr:     the logical start address
-- 
2.20.1