[RFC PATCH 27/31] 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. Signed-off-by: Alex Bennée <alex.bennee(a)linaro.org&gt; Reviewed-by: Philippe Mathieu-Daudé <philmd(a)linaro.org&gt; Message-Id: <20230519170454.2353945-5-alex.bennee(a)linaro.org&gt; --- v2 - more kerneldoc annotations --- include/sysemu/accel-ops.h | 18 ++++++++++++- include/sysemu/cpu-timers.h | 27 ++++++++++++++++++- softmmu/cpus.c | 11 ++++++++ ...t-virtual-clock.c => cpus-virtual-clock.c} | 5 ++++ stubs/meson.build | 2 +- 5 files changed, 60 insertions(+), 3 deletions(-) rename stubs/{cpus-get-virtual-clock.c => cpus-virtual-clock.c} (68%) diff --git a/include/sysemu/accel-ops.h b/include/sysemu/accel-ops.h index 3c1fab4b1e..224e85a649 100644 --- 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; @@ -43,7 +48,18 @@ 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 2e786fe7fb..31ab2bbd4e 100644 --- a/include/sysemu/cpu-timers.h +++ b/include/sysemu/cpu-timers.h @@ -84,8 +84,33 @@ 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 */ +/** + * cpus_get_virtual_clock() - return current virtual clock. + * + * This is a wrapper around accelerator specific get_virtual_clock() + * + * Returns: ns of virtual time + */ int64_t cpus_get_virtual_clock(void); + +/** + * cpus_set_virtual_clock() - set the virtual clock + * @new_time: new value in ns + * + * This is a wrapper around accelerator specific set_virtual_clock() + */ +void cpus_set_virtual_clock(int64_t new_time); + +/** + * cpus_get_elapsed_ticks() - get elapsed host time + * + * This is usually the current value of the host tick counter (i.e. + * not taking into account guest pauses). However some accelerators + * which want to keep elapsed time in sync with virtual time will + * return the virtual clock. + * + * Returns: ticks of elapsed host time (usually ns) + */ int64_t cpus_get_elapsed_ticks(void); #endif /* SYSEMU_CPU_TIMERS_H */ diff --git a/softmmu/cpus.c b/softmmu/cpus.c index 0848e0dbdb..b645c462e1 100644 --- a/softmmu/cpus.c +++ b/softmmu/cpus.c @@ -221,6 +221,17 @@ 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 diff --git a/stubs/cpus-get-virtual-clock.c b/stubs/cpus-virtual-clock.c similarity index 68% rename from stubs/cpus-get-virtual-clock.c rename to stubs/cpus-virtual-clock.c index fd447d53f3..af7c1a1d40 100644 --- a/stubs/cpus-get-virtual-clock.c +++ b/stubs/cpus-virtual-clock.c @@ -6,3 +6,8 @@ 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 ef6e39a64d..2ea43ee076 100644 --- a/stubs/meson.build +++ b/stubs/meson.build @@ -5,7 +5,7 @@ stub_ss.add(files('blockdev-close-all-bdrv-states.c')) stub_ss.add(files('change-state-handler.c')) stub_ss.add(files('cmos.c')) stub_ss.add(files('cpu-get-clock.c')) -stub_ss.add(files('cpus-get-virtual-clock.c')) +stub_ss.add(files('cpus-virtual-clock.c')) stub_ss.add(files('qemu-timer-notify-cb.c')) stub_ss.add(files('icount.c')) stub_ss.add(files('dump.c')) -- 2.39.2