Merge remote-tracking branch 'remotes/cohuck/tags/s390x-20200605' into staging

s390x update:
- enhance s390x documentation
- allow ORBs without prefetch specified for vfio-ccw
- various cleanups and enhancements

# gpg: Signature made Fri 05 Jun 2020 16:32:43 BST
# gpg:                using RSA key C3D0D66DC3624FF6A8C018CEDECF6B93C6F02FAF
# gpg:                issuer "cohuck@redhat.com"
# gpg: Good signature from "Cornelia Huck <conny@cornelia-huck.de>" [marginal]
# gpg:                 aka "Cornelia Huck <huckc@linux.vnet.ibm.com>" [full]
# gpg:                 aka "Cornelia Huck <cornelia.huck@de.ibm.com>" [full]
# gpg:                 aka "Cornelia Huck <cohuck@kernel.org>" [marginal]
# gpg:                 aka "Cornelia Huck <cohuck@redhat.com>" [marginal]
# Primary key fingerprint: C3D0 D66D C362 4FF6 A8C0  18CE DECF 6B93 C6F0 2FAF

* remotes/cohuck/tags/s390x-20200605:
  target/s390x: Restrict system-mode declarations
  target/s390x/helper: Clean ifdef'ry
  target/s390x: Only compile decode_basedisp() on system-mode
  MAINTAINERS: add Thomas as additional s390x maintainer
  docs/s390x: document vfio-ccw
  vfio-ccw: allow non-prefetch ORBs
  docs/s390x: document 3270
  docs/s390x: document the virtual css
  s390x: pv: Fix KVM_PV_PREP_RESET command wrapper name
  s390x/kvm: help valgrind in several places

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

12 files changed, 219 insertions, 26 deletions

diff --git a/MAINTAINERS b/MAINTAINERS
index 3e7d9cb..6e7890c 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -85,6 +85,7 @@ Architecture support
 --------------------
 S390 general architecture support
 M: Cornelia Huck <cohuck@redhat.com>
+M: Thomas Huth <thuth@redhat.com>
 S: Supported
 F: default-configs/s390x-softmmu.mak
 F: gdb-xml/s390*.xml
diff --git a/docs/system/s390x/3270.rst b/docs/system/s390x/3270.rst
new file mode 100644
index 0000000..1774cdc
--- /dev/null
+++ b/docs/system/s390x/3270.rst
@@ -0,0 +1,32 @@
+3270 devices
+============
+
+QEMU supports connecting an external 3270 terminal emulator (such as
+``x3270``) to make a single 3270 device available to a guest. Note that this
+supports basic features only.
+
+To provide a 3270 device to a guest, create a ``x-terminal3270`` linked to
+a ``tn3270`` chardev. The guest will see a 3270 channel device. In order
+to actually be able to use it, attach the ``x3270`` emulator to the chardev.
+
+Example configuration
+---------------------
+
+* Add a ``tn3270`` chardev and a ``x-terminal3270`` to the QEMU command line::
+
+    -chardev socket,id=char_0,host=0.0.0.0,port=2300,nowait,server,tn3270
+    -device x-terminal3270,chardev=char_0,devno=fe.0.000a,id=terminal_0
+
+* Start the guest. In the guest, use ``chccwdev -e 0.0.000a`` to enable
+  the device.
+
+* On the host, start the ``x3270`` emulator::
+
+    x3270 <host>:2300
+
+* In the guest, locate the 3270 device node under ``/dev/3270/`` (say,
+  ``tty1``) and start a getty on it::
+
+    systemctl start serial-getty@3270-tty1.service
+
+This should get you an addtional tty for logging into the guest.
diff --git a/docs/system/s390x/css.rst b/docs/system/s390x/css.rst
new file mode 100644
index 0000000..3b40161
--- /dev/null
+++ b/docs/system/s390x/css.rst
@@ -0,0 +1,86 @@
+The virtual channel subsystem
+=============================
+
+QEMU implements a virtual channel subsystem with subchannels, (mostly
+functionless) channel paths, and channel devices (virtio-ccw, 3270, and
+devices passed via vfio-ccw). It supports multiple subchannel sets (MSS) and
+multiple channel subsystems extended (MCSS-E).
+
+All channel devices support the ``devno`` property, which takes a parameter
+in the form ``<cssid>.<ssid>.<device number>``.
+
+The default channel subsystem image id (``<cssid>``) is ``0xfe``. Devices in
+there will show up in channel subsystem image ``0`` to guests that do not
+enable MCSS-E. Note that devices with a different cssid will not be visible
+if the guest OS does not enable MCSS-E (which is true for all supported guest
+operating systems today).
+
+Supported values for the subchannel set id (``<ssid>``) range from ``0-3``.
+Devices with a ssid that is not ``0`` will not be visible if the guest OS
+does not enable MSS (any Linux version that supports virtio also enables MSS).
+Any device may be put into any subchannel set, there is no restriction by
+device type.
+
+The device number can range from ``0-0xffff``.
+
+If the ``devno`` property is not specified for a device, QEMU will choose the
+next free device number in subchannel set 0, skipping to the next subchannel
+set if no more device numbers are free.
+
+QEMU places a device at the first free subchannel in the specified subchannel
+set. If a device is hotunplugged and later replugged, it may appear at a
+different subchannel. (This is similar to how z/VM works.)
+
+
+Examples
+--------
+
+* a virtio-net device, cssid/ssid/devno automatically assigned::
+
+    -device virtio-net-ccw
+
+  In a Linux guest (without default devices and no other devices specified
+  prior to this one), this will show up as ``0.0.0000`` under subchannel
+  ``0.0.0000``.
+
+  The auto-assigned-properties in QEMU (as seen via e.g. ``info qtree``)
+  would be ``dev_id = "fe.0.0000"`` and ``subch_id = "fe.0.0000"``.
+
+* a virtio-rng device in subchannel set ``0``::
+
+    -device virtio-rng-ccw,devno=fe.0.0042
+
+  If added to the same Linux guest as above, it would show up as ``0.0.0042``
+  under subchannel ``0.0.0001``.
+
+  The properties for the device would be ``dev_id = "fe.0.0042"`` and
+  ``subch_id = "fe.0.0001"``.
+
+* a virtio-gpu device in subchannel set ``2``::
+
+    -device virtio-gpu-ccw,devno=fe.2.1111
+
+  If added to the same Linux guest as above, it would show up as ``0.2.1111``
+  under subchannel ``0.2.0000``.
+
+  The properties for the device would be ``dev_id = "fe.2.1111"`` and
+  ``subch_id = "fe.2.0000"``.
+
+* a virtio-mouse device in a non-standard channel subsystem image::
+
+    -device virtio-mouse-ccw,devno=2.0.2222
+
+  This would not show up in a standard Linux guest.
+
+  The properties for the device would be ``dev_id = "2.0.2222"`` and
+  ``subch_id = "2.0.0000"``.
+
+* a virtio-keyboard device in another non-standard channel subsystem image::
+
+    -device virtio-keyboard-ccw,devno=0.0.1234
+
+  This would not show up in a standard Linux guest, either, as ``0`` is not
+  the standard channel subsystem image id.
+
+  The properties for the device would be ``dev_id = "0.0.1234"`` and
+  ``subch_id = "0.0.0000"``.
diff --git a/docs/system/s390x/vfio-ccw.rst b/docs/system/s390x/vfio-ccw.rst
new file mode 100644
index 0000000..8f65442
--- /dev/null
+++ b/docs/system/s390x/vfio-ccw.rst
@@ -0,0 +1,77 @@
+Subchannel passthrough via vfio-ccw
+===================================
+
+vfio-ccw (based upon the mediated vfio device infrastructure) allows to
+make certain I/O subchannels and their devices available to a guest. The
+host will not interact with those subchannels/devices any more.
+
+Note that while vfio-ccw should work with most non-QDIO devices, only ECKD
+DASDs have really been tested.
+
+Example configuration
+---------------------
+
+Step 1: configure the host device
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+As every mdev is identified by a uuid, the first step is to obtain one::
+
+  [root@host ~]# uuidgen
+  7e270a25-e163-4922-af60-757fc8ed48c6
+
+Note: it is recommended to use the ``mdevctl`` tool for actually configuring
+the host device.
+
+To define the same device as configured below to be started
+automatically, use
+
+::
+
+   [root@host ~]# driverctl -b css set-override 0.0.0313 vfio_ccw
+   [root@host ~]# mdevctl define -u 7e270a25-e163-4922-af60-757fc8ed48c6 \
+                  -p 0.0.0313 -t vfio-ccw_io -a
+
+If using ``mdevctl`` is not possible or wanted, follow the manual procedure
+below.
+
+* Locate the subchannel for the device (in this example, ``0.0.2b09``)::
+
+    [root@host ~]# lscss | grep 0.0.2b09 | awk '{print $2}'
+    0.0.0313
+
+* Unbind the subchannel (in this example, ``0.0.0313``) from the standard
+  I/O subchannel driver and bind it to the vfio-ccw driver::
+
+    [root@host ~]# echo 0.0.0313 > /sys/bus/css/devices/0.0.0313/driver/unbind
+    [root@host ~]# echo 0.0.0313 > /sys/bus/css/drivers/vfio_ccw/bind
+
+* Create the mediated device (identified by the uuid)::
+
+    [root@host ~]# echo "7e270a25-e163-4922-af60-757fc8ed48c6" > \
+    /sys/bus/css/devices/0.0.0313/mdev_supported_types/vfio_ccw-io/create
+
+Step 2: configure QEMU
+~~~~~~~~~~~~~~~~~~~~~~
+
+* Reference the created mediated device and (optionally) pick a device id to
+  be presented in the guest (here, ``fe.0.1234``, which will end up visible
+  in the guest as ``0.0.1234``::
+
+    -device vfio-ccw,devno=fe.0.1234,sysfsdev=\
+    /sys/bus/mdev/devices/7e270a25-e163-4922-af60-757fc8ed48c6
+
+* Start the guest. The device (here, ``0.0.1234``) should now be usable::
+
+    [root@guest ~]# lscss -d 0.0.1234
+    Device   Subchan.  DevType CU Type Use  PIM PAM POM  CHPID
+    ----------------------------------------------------------------------
+    0.0.1234 0.0.0007  3390/0e 3990/e9      f0  f0  ff   1a2a3a0a 00000000
+    [root@guest ~]# chccwdev -e 0.0.1234
+    Setting device 0.0.1234 online
+    Done
+    [root@guest ~]# dmesg -t
+    (...)
+    dasd-eckd 0.0.1234: A channel path to the device has become operational
+    dasd-eckd 0.0.1234: New DASD 3390/0E (CU 3990/01) with 10017 cylinders, 15 heads, 224 sectors
+    dasd-eckd 0.0.1234: DASD with 4 KB/block, 7212240 KB total size, 48 KB/track, compatible disk layout
+    dasda:VOL1/  0X2B09: dasda1
diff --git a/docs/system/target-s390x.rst b/docs/system/target-s390x.rst
index 7d76ae9..644e404 100644
--- a/docs/system/target-s390x.rst
+++ b/docs/system/target-s390x.rst
@@ -23,6 +23,9 @@ or vfio-ap is also available.
 
 .. toctree::
    s390x/vfio-ap
+   s390x/css
+   s390x/3270
+   s390x/vfio-ccw
 
 Architectural features
 ======================
diff --git a/hw/s390x/pv.c b/hw/s390x/pv.c
index f11868e..ab3a248 100644
--- a/hw/s390x/pv.c
+++ b/hw/s390x/pv.c
@@ -88,7 +88,7 @@ int s390_pv_unpack(uint64_t addr, uint64_t size, uint64_t tweak)
     return s390_pv_cmd(KVM_PV_UNPACK, &args);
 }
 
-void s390_pv_perf_clear_reset(void)
+void s390_pv_prep_reset(void)
 {
     s390_pv_cmd_exit(KVM_PV_PREP_RESET, NULL);
 }
diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
index 67ae2e0..60b16fe 100644
--- a/hw/s390x/s390-virtio-ccw.c
+++ b/hw/s390x/s390-virtio-ccw.c
@@ -401,7 +401,7 @@ static void s390_pv_prepare_reset(S390CcwMachineState *ms)
         s390_cpu_set_state(S390_CPU_STATE_STOPPED, S390_CPU(cs));
     }
     s390_pv_unshare();
-    s390_pv_perf_clear_reset();
+    s390_pv_prep_reset();
 }
 
 static void s390_machine_reset(MachineState *machine)
diff --git a/hw/vfio/ccw.c b/hw/vfio/ccw.c
index c862494..6340618 100644
--- a/hw/vfio/ccw.c
+++ b/hw/vfio/ccw.c
@@ -74,16 +74,9 @@ static IOInstEnding vfio_ccw_handle_request(SubchDev *sch)
     struct ccw_io_region *region = vcdev->io_region;
     int ret;
 
-    if (!(sch->orb.ctrl0 & ORB_CTRL0_MASK_PFCH)) {
-        if (!(vcdev->force_orb_pfch)) {
-            warn_once_pfch(vcdev, sch, "requires PFCH flag set");
-            sch_gen_unit_exception(sch);
-            css_inject_io_interrupt(sch);
-            return IOINST_CC_EXPECTED;
-        } else {
-            sch->orb.ctrl0 |= ORB_CTRL0_MASK_PFCH;
-            warn_once_pfch(vcdev, sch, "PFCH flag forced");
-        }
+    if (!(sch->orb.ctrl0 & ORB_CTRL0_MASK_PFCH) && vcdev->force_orb_pfch) {
+        sch->orb.ctrl0 |= ORB_CTRL0_MASK_PFCH;
+        warn_once_pfch(vcdev, sch, "PFCH flag forced");
     }
 
     QEMU_BUILD_BUG_ON(sizeof(region->orb_area) != sizeof(ORB));
diff --git a/include/hw/s390x/pv.h b/include/hw/s390x/pv.h
index 522ca6a..aee758b 100644
--- a/include/hw/s390x/pv.h
+++ b/include/hw/s390x/pv.h
@@ -39,7 +39,7 @@ int s390_pv_vm_enable(void);
 void s390_pv_vm_disable(void);
 int s390_pv_set_sec_parms(uint64_t origin, uint64_t length);
 int s390_pv_unpack(uint64_t addr, uint64_t size, uint64_t tweak);
-void s390_pv_perf_clear_reset(void);
+void s390_pv_prep_reset(void);
 int s390_pv_verify(void);
 void s390_pv_unshare(void);
 void s390_pv_inject_reset_error(CPUState *cs);
@@ -49,7 +49,7 @@ static inline int s390_pv_vm_enable(void) { return 0; }
 static inline void s390_pv_vm_disable(void) {}
 static inline int s390_pv_set_sec_parms(uint64_t origin, uint64_t length) { return 0; }
 static inline int s390_pv_unpack(uint64_t addr, uint64_t size, uint64_t tweak) { return 0; }
-static inline void s390_pv_perf_clear_reset(void) {}
+static inline void s390_pv_prep_reset(void) {}
 static inline int s390_pv_verify(void) { return 0; }
 static inline void s390_pv_unshare(void) {}
 static inline void s390_pv_inject_reset_error(CPUState *cs) {};
diff --git a/target/s390x/helper.c b/target/s390x/helper.c
index 09f6040..9257d38 100644
--- a/target/s390x/helper.c
+++ b/target/s390x/helper.c
@@ -42,9 +42,6 @@ void s390x_cpu_timer(void *opaque)
 {
     cpu_inject_cpu_timer((S390CPU *) opaque);
 }
-#endif
-
-#ifndef CONFIG_USER_ONLY
 
 hwaddr s390_cpu_get_phys_page_debug(CPUState *cs, vaddr vaddr)
 {
@@ -98,14 +95,12 @@ void s390_handle_wait(S390CPU *cpu)
     CPUState *cs = CPU(cpu);
 
     if (s390_cpu_halt(cpu) == 0) {
-#ifndef CONFIG_USER_ONLY
         if (is_special_wait_psw(cpu->env.psw.addr)) {
             qemu_system_shutdown_request(SHUTDOWN_CAUSE_GUEST_SHUTDOWN);
         } else {
             cpu->env.crash_reason = S390_CRASH_REASON_DISABLED_WAIT;
             qemu_system_guest_panicked(cpu_get_crash_info(cs));
         }
-#endif
     }
 }
 
diff --git a/target/s390x/internal.h b/target/s390x/internal.h
index 8c95c73..b1e0ebf 100644
--- a/target/s390x/internal.h
+++ b/target/s390x/internal.h
@@ -204,6 +204,8 @@ enum cc_op {
     CC_OP_MAX
 };
 
+#ifndef CONFIG_USER_ONLY
+
 static inline hwaddr decode_basedisp_s(CPUS390XState *env, uint32_t ipb,
                                        uint8_t *ar)
 {
@@ -225,6 +227,8 @@ static inline hwaddr decode_basedisp_s(CPUS390XState *env, uint32_t ipb,
 /* Base/displacement are at the same locations. */
 #define decode_basedisp_rs decode_basedisp_s
 
+#endif /* CONFIG_USER_ONLY */
+
 /* arch_dump.c */
 int s390_cpu_write_elf64_note(WriteCoreDumpFunction f, CPUState *cs,
                               int cpuid, void *opaque);
@@ -232,9 +236,11 @@ int s390_cpu_write_elf64_note(WriteCoreDumpFunction f, CPUState *cs,
 
 /* cc_helper.c */
 const char *cc_name(enum cc_op cc_op);
-void load_psw(CPUS390XState *env, uint64_t mask, uint64_t addr);
 uint32_t calc_cc(CPUS390XState *env, uint32_t cc_op, uint64_t src, uint64_t dst,
                  uint64_t vr);
+#ifndef CONFIG_USER_ONLY
+void load_psw(CPUS390XState *env, uint64_t mask, uint64_t addr);
+#endif /* CONFIG_USER_ONLY */
 
 
 /* cpu.c */
@@ -299,18 +305,18 @@ void s390_cpu_gdb_init(CPUState *cs);
 
 /* helper.c */
 void s390_cpu_dump_state(CPUState *cpu, FILE *f, int flags);
-hwaddr s390_cpu_get_phys_page_debug(CPUState *cpu, vaddr addr);
-hwaddr s390_cpu_get_phys_addr_debug(CPUState *cpu, vaddr addr);
+void do_restart_interrupt(CPUS390XState *env);
+#ifndef CONFIG_USER_ONLY
 uint64_t get_psw_mask(CPUS390XState *env);
 void s390_cpu_recompute_watchpoints(CPUState *cs);
 void s390x_tod_timer(void *opaque);
 void s390x_cpu_timer(void *opaque);
-void do_restart_interrupt(CPUS390XState *env);
 void s390_handle_wait(S390CPU *cpu);
+hwaddr s390_cpu_get_phys_page_debug(CPUState *cpu, vaddr addr);
+hwaddr s390_cpu_get_phys_addr_debug(CPUState *cpu, vaddr addr);
 #define S390_STORE_STATUS_DEF_ADDR offsetof(LowCore, floating_pt_save_area)
 int s390_store_status(S390CPU *cpu, hwaddr addr, bool store_arch);
 int s390_store_adtl_status(S390CPU *cpu, hwaddr addr, hwaddr len);
-#ifndef CONFIG_USER_ONLY
 LowCore *cpu_map_lowcore(CPUS390XState *env);
 void cpu_unmap_lowcore(LowCore *lowcore);
 #endif /* CONFIG_USER_ONLY */
diff --git a/target/s390x/kvm.c b/target/s390x/kvm.c
index 69881a0..f2f75d2 100644
--- a/target/s390x/kvm.c
+++ b/target/s390x/kvm.c
@@ -2165,7 +2165,7 @@ int kvm_arch_msi_data_to_gsi(uint32_t data)
 
 static int query_cpu_subfunc(S390FeatBitmap features)
 {
-    struct kvm_s390_vm_cpu_subfunc prop;
+    struct kvm_s390_vm_cpu_subfunc prop = {};
     struct kvm_device_attr attr = {
         .group = KVM_S390_VM_CPU_MODEL,
         .attr = KVM_S390_VM_CPU_MACHINE_SUBFUNC,
@@ -2292,7 +2292,7 @@ static int kvm_to_feat[][2] = {
 
 static int query_cpu_feat(S390FeatBitmap features)
 {
-    struct kvm_s390_vm_cpu_feat prop;
+    struct kvm_s390_vm_cpu_feat prop = {};
     struct kvm_device_attr attr = {
         .group = KVM_S390_VM_CPU_MODEL,
         .attr = KVM_S390_VM_CPU_MACHINE_FEAT,