[PATCH v3 0/2] accel/tcg: Test unaligned stores to s390x low-address-protected lowcore

[PATCH v3 0/2] accel/tcg: Test unaligned stores to s390x low-address-protected lowcore

[Ilya Leoshkevich]

Hi,

This is a follow-up series for [1].

The fix has been committed.

I asked Christian what might be a good alternative for the
mmio-debug-exit device for testing, and he suggested to look into
shutdown/panic actions.

Patch 1 adds a new panic action.
Patch 2 tests unaligned stores to s390x low-address-protected lowcore;
it performs a shutdown on success and panic on failure.

Best regards,
Ilya

[1] https://lists.gnu.org/archive/html/qemu-devel/2022-07/msg01876.html

v2: https://lists.gnu.org/archive/html/qemu-devel/2022-07/msg04129.html
v2 -> v3: Add @since tag (Eric).
          Fix a small style issue in the test.

Ilya Leoshkevich (2):
  qapi: Add exit-failure PanicAction
  tests/tcg/s390x: Test unaligned accesses to lowcore

 include/sysemu/sysemu.h                 |  2 +-
 qapi/run-state.json                     |  5 ++++-
 qemu-options.hx                         |  2 +-
 softmmu/main.c                          |  6 ++++--
 softmmu/runstate.c                      | 17 +++++++++++++----
 tests/tcg/s390x/Makefile.softmmu-target |  9 +++++++++
 tests/tcg/s390x/unaligned-lowcore.S     | 19 +++++++++++++++++++
 7 files changed, 51 insertions(+), 9 deletions(-)
 create mode 100644 tests/tcg/s390x/Makefile.softmmu-target
 create mode 100644 tests/tcg/s390x/unaligned-lowcore.S

-- 
2.35.3

[PATCH v3 1/2] qapi: Add exit-failure PanicAction

[Ilya Leoshkevich]

Currently QEMU exits with code 0 on both panic an shutdown. For tests
it is useful to return 1 on panic, so that it counts as a test
failure.

Introduce a new exit-failure PanicAction that makes main() return
EXIT_FAILURE. Tests can use -action panic=exit-failure option to
activate this behavior.

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
---
 include/sysemu/sysemu.h |  2 +-
 qapi/run-state.json     |  5 ++++-
 qemu-options.hx         |  2 +-
 softmmu/main.c          |  6 ++++--
 softmmu/runstate.c      | 17 +++++++++++++----
 5 files changed, 23 insertions(+), 9 deletions(-)

diff --git a/include/sysemu/sysemu.h b/include/sysemu/sysemu.h
index 812f66a31a..31aa45160b 100644
--- a/include/sysemu/sysemu.h
+++ b/include/sysemu/sysemu.h
@@ -103,7 +103,7 @@ void qemu_boot_set(const char *boot_order, Error **errp);
 bool defaults_enabled(void);
 
 void qemu_init(int argc, char **argv, char **envp);
-void qemu_main_loop(void);
+int qemu_main_loop(void);
 void qemu_cleanup(void);
 
 extern QemuOptsList qemu_legacy_drive_opts;
diff --git a/qapi/run-state.json b/qapi/run-state.json
index 6e2162d7b3..9273ea6516 100644
--- a/qapi/run-state.json
+++ b/qapi/run-state.json
@@ -364,10 +364,13 @@
 #
 # @shutdown: Shutdown the VM and exit, according to the shutdown action
 #
+# @exit-failure: Shutdown the VM and exit with nonzero status
+#                (since 7.1)
+#
 # Since: 6.0
 ##
 { 'enum': 'PanicAction',
-  'data': [ 'pause', 'shutdown', 'none' ] }
+  'data': [ 'pause', 'shutdown', 'exit-failure', 'none' ] }
 
 ##
 # @watchdog-set-action:
diff --git a/qemu-options.hx b/qemu-options.hx
index 79e00916a1..8e17c5064a 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -4239,7 +4239,7 @@ DEF("action", HAS_ARG, QEMU_OPTION_action,
     "                   action when guest reboots [default=reset]\n"
     "-action shutdown=poweroff|pause\n"
     "                   action when guest shuts down [default=poweroff]\n"
-    "-action panic=pause|shutdown|none\n"
+    "-action panic=pause|shutdown|exit-failure|none\n"
     "                   action when guest panics [default=shutdown]\n"
     "-action watchdog=reset|shutdown|poweroff|inject-nmi|pause|debug|none\n"
     "                   action when watchdog fires [default=reset]\n",
diff --git a/softmmu/main.c b/softmmu/main.c
index c00432ff09..1b675a8c03 100644
--- a/softmmu/main.c
+++ b/softmmu/main.c
@@ -32,11 +32,13 @@
 
 int qemu_main(int argc, char **argv, char **envp)
 {
+    int status;
+
     qemu_init(argc, argv, envp);
-    qemu_main_loop();
+    status = qemu_main_loop();
     qemu_cleanup();
 
-    return 0;
+    return status;
 }
 
 #ifndef CONFIG_COCOA
diff --git a/softmmu/runstate.c b/softmmu/runstate.c
index 168e1b78a0..1e68680b9d 100644
--- a/softmmu/runstate.c
+++ b/softmmu/runstate.c
@@ -482,7 +482,8 @@ void qemu_system_guest_panicked(GuestPanicInformation *info)
         qapi_event_send_guest_panicked(GUEST_PANIC_ACTION_PAUSE,
                                         !!info, info);
         vm_stop(RUN_STATE_GUEST_PANICKED);
-    } else if (panic_action == PANIC_ACTION_SHUTDOWN) {
+    } else if (panic_action == PANIC_ACTION_SHUTDOWN ||
+               panic_action == PANIC_ACTION_EXIT_FAILURE) {
         qapi_event_send_guest_panicked(GUEST_PANIC_ACTION_POWEROFF,
                                        !!info, info);
         vm_stop(RUN_STATE_GUEST_PANICKED);
@@ -662,7 +663,7 @@ void qemu_system_debug_request(void)
     qemu_notify_event();
 }
 
-static bool main_loop_should_exit(void)
+static bool main_loop_should_exit(int *status)
 {
     RunState r;
     ShutdownCause request;
@@ -680,6 +681,10 @@ static bool main_loop_should_exit(void)
         if (shutdown_action == SHUTDOWN_ACTION_PAUSE) {
             vm_stop(RUN_STATE_SHUTDOWN);
         } else {
+            if (request == SHUTDOWN_CAUSE_GUEST_PANIC &&
+                panic_action == PANIC_ACTION_EXIT_FAILURE) {
+                *status = EXIT_FAILURE;
+            }
             return true;
         }
     }
@@ -715,12 +720,14 @@ static bool main_loop_should_exit(void)
     return false;
 }
 
-void qemu_main_loop(void)
+int qemu_main_loop(void)
 {
+    int status = EXIT_SUCCESS;
 #ifdef CONFIG_PROFILER
     int64_t ti;
 #endif
-    while (!main_loop_should_exit()) {
+
+    while (!main_loop_should_exit(&status)) {
 #ifdef CONFIG_PROFILER
         ti = profile_getclock();
 #endif
@@ -729,6 +736,8 @@ void qemu_main_loop(void)
         dev_time += profile_getclock() - ti;
 #endif
     }
+
+    return status;
 }
 
 void qemu_add_exit_notifier(Notifier *notify)
-- 
2.35.3

[PATCH v3 2/2] tests/tcg/s390x: Test unaligned accesses to lowcore

[Ilya Leoshkevich]

Add a small test to avoid regressions.

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Acked-by: Richard Henderson <richard.henderson@linaro.org>
Acked-by: Thomas Huth <thuth@redhat.com>
---
 tests/tcg/s390x/Makefile.softmmu-target |  9 +++++++++
 tests/tcg/s390x/unaligned-lowcore.S     | 19 +++++++++++++++++++
 2 files changed, 28 insertions(+)
 create mode 100644 tests/tcg/s390x/Makefile.softmmu-target
 create mode 100644 tests/tcg/s390x/unaligned-lowcore.S

diff --git a/tests/tcg/s390x/Makefile.softmmu-target b/tests/tcg/s390x/Makefile.softmmu-target
new file mode 100644
index 0000000000..a34fa68473
--- /dev/null
+++ b/tests/tcg/s390x/Makefile.softmmu-target
@@ -0,0 +1,9 @@
+S390X_SRC=$(SRC_PATH)/tests/tcg/s390x
+VPATH+=$(S390X_SRC)
+QEMU_OPTS=-action panic=exit-failure -kernel
+
+%: %.S
+	$(CC) -march=z13 -m64 -nostartfiles -static -Wl,-Ttext=0 \
+		-Wl,--build-id=none $< -o $@
+
+TESTS += unaligned-lowcore
diff --git a/tests/tcg/s390x/unaligned-lowcore.S b/tests/tcg/s390x/unaligned-lowcore.S
new file mode 100644
index 0000000000..f5da2ae64c
--- /dev/null
+++ b/tests/tcg/s390x/unaligned-lowcore.S
@@ -0,0 +1,19 @@
+    .org 0x1D0                         /* program new PSW */
+    .quad 0x2000000000000,0            /* disabled wait */
+    .org 0x200                         /* lowcore padding */
+
+    .globl _start
+_start:
+    lctlg %c0,%c0,_c0
+    vst %v0,_unaligned
+    lpswe quiesce_psw
+
+    .align 8
+quiesce_psw:
+    .quad 0x2000000000000,0xfff        /* see is_special_wait_psw() */
+_c0:
+    .quad 0x10060000                   /* lowcore protection, AFP, VX */
+
+    .byte 0
+_unaligned:
+    .octa 0
-- 
2.35.3

Re: [PATCH v3 1/2] qapi: Add exit-failure PanicAction

[Markus Armbruster]

Ilya Leoshkevich <iii@linux.ibm.com> writes:

> Currently QEMU exits with code 0 on both panic an shutdown. For tests
> it is useful to return 1 on panic, so that it counts as a test
> failure.
>
> Introduce a new exit-failure PanicAction that makes main() return
> EXIT_FAILURE. Tests can use -action panic=exit-failure option to
> activate this behavior.
>
> Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
> Reviewed-by: David Hildenbrand <david@redhat.com>

[...]

> diff --git a/qapi/run-state.json b/qapi/run-state.json
> index 6e2162d7b3..9273ea6516 100644
> --- a/qapi/run-state.json
> +++ b/qapi/run-state.json
> @@ -364,10 +364,13 @@
   ##
   # @PanicAction:

This is the type of set-action argument @panic, which is documented as
"action taken on guest panic."

   #
   # @none: Continue VM execution

I guess this is effectively "do nothing / ignore".

   #
   # @pause: Pause the VM

Clear enough.

>  #
>  # @shutdown: Shutdown the VM and exit, according to the shutdown action

I guess this is the value of set-action argument @shutdown, which is
can be

* @poweroff, documented as "Shutdown the VM and exit"

  Do we exit successfully, i.e. with zero status?

* @pause, documented as "pause the VM"

  PanicAction's documentation claims "shutdown the VM and exit", but we
  don't, we pause instead.  Not this patch's problem.

>  #
> +# @exit-failure: Shutdown the VM and exit with nonzero status

non-zero

> +#                (since 7.1)
> +#
>  # Since: 6.0
>  ##
>  { 'enum': 'PanicAction',
> -  'data': [ 'pause', 'shutdown', 'none' ] }
> +  'data': [ 'pause', 'shutdown', 'exit-failure', 'none' ] }
>  
>  ##
>  # @watchdog-set-action:

Not this patch's problem, but here goes anyway:

   ##
   # @set-action:
   #
   # Set the actions that will be taken by the emulator in response to guest
   # events.
   #
   # @reboot: @RebootAction action taken on guest reboot.
   #
   # @shutdown: @ShutdownAction action taken on guest shutdown.
   #
   # @panic: @PanicAction action taken on guest panic.
   #
   # @watchdog: @WatchdogAction action taken when watchdog timer expires .
   #
   # Returns: Nothing on success.
   #
   # Since: 6.0
   #
   # Example:
   #
   # -> { "execute": "set-action",
   #      "arguments": { "reboot": "shutdown",
   #                     "shutdown" : "pause",
   #                     "panic": "pause",
   #                     "watchdog": "inject-nmi" } }
   # <- { "return": {} }
   ##

The arguments are all optional, but the documentation neglects to spell
out what "absent" means.  I guess it means "no change".

The documentation also neglects to spell out the initial settings,
i.e. behavior when you don't configure an action with set-action.

[...]