sysemu: add set_virtual_time to accel ops

We are about to remove direct calls to individual accelerators for
this information and will need a central point for plugins to hook
into time changes.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20240530220610.1245424-2-pierrick.bouvier@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20240620152220.2192768-5-alex.bennee@linaro.org>

diff --git a/include/sysemu/accel-ops.h b/include/sysemu/accel-ops.h
index ef91fc28bbdfa3dab181e11c5a4dc42fce1bad92..a0886722305f660620dd933f3d86ea0d4482e519 100644 (file)
--- a/include/sysemu/accel-ops.h
+++ b/include/sysemu/accel-ops.h
@@ -20,7 +20,12 @@
 typedef struct AccelOpsClass AccelOpsClass;
 DECLARE_CLASS_CHECKERS(AccelOpsClass, ACCEL_OPS, TYPE_ACCEL_OPS)
 
-/* cpus.c operations interface */
+/**
+ * struct AccelOpsClass - accelerator interfaces
+ *
+ * This structure is used to abstract accelerator differences from the
+ * core CPU code. Not all have to be implemented.
+ */
 struct AccelOpsClass {
     /*< private >*/
     ObjectClass parent_class;
@@ -44,7 +49,18 @@ struct AccelOpsClass {
 
     void (*handle_interrupt)(CPUState *cpu, int mask);
 
+    /**
+     * @get_virtual_clock: fetch virtual clock
+     * @set_virtual_clock: set virtual clock
+     *
+     * These allow the timer subsystem to defer to the accelerator to
+     * fetch time. The set function is needed if the accelerator wants
+     * to track the changes to time as the timer is warped through
+     * various timer events.
+     */
     int64_t (*get_virtual_clock)(void);
+    void (*set_virtual_clock)(int64_t time);
+
     int64_t (*get_elapsed_ticks)(void);
 
     /* gdbstub hooks */

diff --git a/include/sysemu/cpu-timers.h b/include/sysemu/cpu-timers.h
index d86738a378dbe9db6b8a78493f6d1fb255471e51..7bfa960fbd690bd5809be08635870a9e7cd63ec7 100644 (file)
--- a/include/sysemu/cpu-timers.h
+++ b/include/sysemu/cpu-timers.h
@@ -96,8 +96,9 @@ int64_t cpu_get_clock(void);
 
 void qemu_timer_notify_cb(void *opaque, QEMUClockType type);
 
-/* get the VIRTUAL clock and VM elapsed ticks via the cpus accel interface */
+/* get/set VIRTUAL clock and VM elapsed ticks via the cpus accel interface */
 int64_t cpus_get_virtual_clock(void);
+void cpus_set_virtual_clock(int64_t new_time);
 int64_t cpus_get_elapsed_ticks(void);
 
 #endif /* SYSEMU_CPU_TIMERS_H */

diff --git a/stubs/cpus-get-virtual-clock.c b/stubs/cpus-get-virtual-clock.c
deleted file mode 100644 (file)
index fd447d5..0000000
--- a/stubs/cpus-get-virtual-clock.c
+++ /dev/null
@@ -1,8 +0,0 @@
-#include "qemu/osdep.h"
-#include "sysemu/cpu-timers.h"
-#include "qemu/main-loop.h"
-
-int64_t cpus_get_virtual_clock(void)
-{
-    return cpu_get_clock();
-}

diff --git a/stubs/cpus-virtual-clock.c b/stubs/cpus-virtual-clock.c
new file mode 100644 (file)
index 0000000..af7c1a1
--- /dev/null
+++ b/stubs/cpus-virtual-clock.c
@@ -0,0 +1,13 @@
+#include "qemu/osdep.h"
+#include "sysemu/cpu-timers.h"
+#include "qemu/main-loop.h"
+
+int64_t cpus_get_virtual_clock(void)
+{
+    return cpu_get_clock();
+}
+
+void cpus_set_virtual_clock(int64_t new_time)
+{
+    /* do nothing */
+}

diff --git a/stubs/meson.build b/stubs/meson.build
index f15b48d01f08b7f0ecdec68fa5ce1056bcb643cd..772a3e817df2c87c1b0e1b134afebd2fa876d387 100644 (file)
--- a/stubs/meson.build
+++ b/stubs/meson.build
@@ -29,7 +29,7 @@ endif
 if have_block or have_ga
   stub_ss.add(files('replay-tools.c'))
   # stubs for hooks in util/main-loop.c, util/async.c etc.
-  stub_ss.add(files('cpus-get-virtual-clock.c'))
+  stub_ss.add(files('cpus-virtual-clock.c'))
   stub_ss.add(files('icount.c'))
   stub_ss.add(files('graph-lock.c'))
   if linux_io_uring.found()

diff --git a/system/cpus.c b/system/cpus.c
index f8fa78f33d4b21e1d5ae28f3db913c7e37763166..d3640c95030eaf4f2ecd51d3179d8cbeb8d620c1 100644 (file)
--- a/system/cpus.c
+++ b/system/cpus.c
@@ -229,6 +229,17 @@ int64_t cpus_get_virtual_clock(void)
     return cpu_get_clock();
 }
 
+/*
+ * Signal the new virtual time to the accelerator. This is only needed
+ * by accelerators that need to track the changes as we warp time.
+ */
+void cpus_set_virtual_clock(int64_t new_time)
+{
+    if (cpus_accel && cpus_accel->set_virtual_clock) {
+        cpus_accel->set_virtual_clock(new_time);
+    }
+}
+
 /*
  * return the time elapsed in VM between vm_start and vm_stop.  Unless
  * icount is active, cpus_get_elapsed_ticks() uses units of the host CPU cycle