[AMD Official Use Only - General]
> -----Original Message-----
> From: Kuehling, Felix <Felix.Kuehling@xxxxxxx>
> Sent: Monday, March 20, 2023 8:31 PM
> To: Kim, Jonathan <Jonathan.Kim@xxxxxxx>; amd-
> gfx@xxxxxxxxxxxxxxxxxxxxx; dri-devel@xxxxxxxxxxxxxxxxxxxxx
> Subject: Re: [PATCH 19/32] drm/amdkfd: add runtime enable operation
>
>
> On 2023-01-25 14:53, Jonathan Kim wrote:
> > The debugger can attach to a process prior to HSA enablement (i.e.
> > inferior is spawned by the debugger and attached to immediately before
> > target process has been enabled for HSA dispatches) or it
> > can attach to a running target that is already HSA enabled. Either
> > way, the debugger needs to know the enablement status to know when
> > it can inspect queues.
> >
> > For the scenario where the debugger spawns the target process,
> > it will have to wait for ROCr's runtime enable request from the target.
> > The runtime enable request will be able to see that its process has been
> > debug attached. ROCr raises an EC_PROCESS_RUNTIME signal to the
> > debugger then blocks the target process while waiting the debugger's
> > response. Once the debugger has received the runtime signal, it will
> > unblock the target process.
> >
> > For the scenario where the debugger attaches to a running target
> > process, ROCr will set the target process' runtime status as enabled so
> > that on an attach request, the debugger will be able to see this
> > status and will continue with debug enablement as normal.
> >
> > A secondary requirement is to conditionally enable the trap tempories
> only
> > if the user requests it (env var HSA_ENABLE_DEBUG=1) or if the debugger
> > attaches with HSA runtime enabled. This is because setting up the trap
> > temporaries incurs a performance overhead that is unacceptable for
> > microbench performance in normal mode for certain customers.
> >
> > In the scenario where the debugger spawns the target process, when ROCr
> > detects that the debugger has attached during the runtime enable
> > request, it will enable the trap temporaries before it blocks the target
> > process while waiting for the debugger to respond.
> >
> > In the scenario where the debugger attaches to a running target process,
> > it will enable to trap temporaries itself.
> >
> > Finally, there is an additional restriction that is required to be
> > enforced with runtime enable and HW debug mode setting. The debugger
> must
> > first ensure that HW debug mode has been enabled before permitting HW
> debug
> > mode operations.
> >
> > With single process debug devices, allowing the debugger to set debug
> > HW modes prior to trap activation means that debug HW mode setting can
> > occur before the KFD has reserved the debug VMID (0xf) from the hardware
> > scheduler's VMID allocation resource pool. This can result in the
> > hardware scheduler assigning VMID 0xf to a non-debugged process and
> > having that process inherit debug HW mode settings intended for the
> > debugged target process instead, which is both incorrect and potentially
> > fatal for normal mode operation.
> >
> > With multi process debug devices, allowing the debugger to set debug
> > HW modes prior to trap activation means that non-debugged processes
> > migrating to a new VMID could inherit unintended debug settings.
> >
> > All debug operations that touch HW settings must require trap activation
> > where trap activation is triggered by both debug attach and runtime
> > enablement (target has KFD opened and is ready to dispatch work).
> >
> > v2: fix up hierarchy of semantics in description.
> >
> > Signed-off-by: Jonathan Kim <jonathan.kim@xxxxxxx>
> > ---
> > drivers/gpu/drm/amd/amdkfd/kfd_chardev.c | 150
> ++++++++++++++++++++++-
> > drivers/gpu/drm/amd/amdkfd/kfd_debug.c | 6 +-
> > drivers/gpu/drm/amd/amdkfd/kfd_debug.h | 4 +
> > drivers/gpu/drm/amd/amdkfd/kfd_priv.h | 1 +
> > 4 files changed, 157 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
> b/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
> > index 09fe8576dc8c..46f9d453dc5e 100644
> > --- a/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
> > +++ b/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
> > @@ -2654,11 +2654,147 @@ static int kfd_ioctl_criu(struct file *filep,
> struct kfd_process *p, void *data)
> > return ret;
> > }
> >
> > -static int kfd_ioctl_runtime_enable(struct file *filep, struct kfd_process *p,
> void *data)
> > +static int runtime_enable(struct kfd_process *p, uint64_t r_debug,
> > + bool enable_ttmp_setup)
> > {
> > + int i = 0, ret = 0;
> > +
> > + if (p->is_runtime_retry)
> > + goto retry;
> > +
> > + if (p->runtime_info.runtime_state !=
> DEBUG_RUNTIME_STATE_DISABLED)
> > + return -EBUSY;
> > +
> > + for (i = 0; i < p->n_pdds; i++) {
> > + struct kfd_process_device *pdd = p->pdds[i];
> > +
> > + if (pdd->qpd.queue_count)
> > + return -EEXIST;
> > + }
> > +
> > + p->runtime_info.runtime_state =
> DEBUG_RUNTIME_STATE_ENABLED;
> > + p->runtime_info.r_debug = r_debug;
> > + p->runtime_info.ttmp_setup = enable_ttmp_setup;
> > +
> > + if (p->runtime_info.ttmp_setup) {
> > + for (i = 0; i < p->n_pdds; i++) {
> > + struct kfd_process_device *pdd = p->pdds[i];
> > +
> > + if (!kfd_dbg_is_rlc_restore_supported(pdd->dev)) {
> > + amdgpu_gfx_off_ctrl(pdd->dev->adev, false);
> > + pdd->dev->kfd2kgd->enable_debug_trap(
> > + pdd->dev->adev,
> > + true,
> > + pdd->dev-
> >vm_info.last_vmid_kfd);
> > + }
> > +
> > + if (kfd_dbg_is_per_vmid_supported(pdd->dev)) {
>
> Should this be else-if? It seems weird that enable_debug_trap could be
> called twice in a row. If RLC restore is only applicable on
> single-process debug devices, then maybe put the per-VMID case first.
>
>
> > + pdd->spi_dbg_override = pdd->dev->kfd2kgd-
> >enable_debug_trap(
> > + pdd->dev->adev,
> > + false,
> > + pdd->dev-
> >vm_info.last_vmid_kfd);
> > +
> > + if (!pdd->dev-
> >shared_resources.enable_mes)
> > + debug_refresh_runlist(pdd->dev-
> >dqm);
> > + else
> > + kfd_dbg_set_mes_debug_mode(pdd);
>
> Do we really need to update the runlist here? When the runtime gets
> enabled, there are no queues yet for the process. So there should be no
> change to the runlist until the process creates its first queue.
Acked. Yeah this seems unnecessary and can be dropped.
>
>
> > + }
> > + }
> > + }
> > +
> > +retry:
> > + if (p->debug_trap_enabled) {
> > + if (!p->is_runtime_retry) {
> > + kfd_dbg_trap_activate(p);
> > +
> kfd_dbg_ev_raise(KFD_EC_MASK(EC_PROCESS_RUNTIME),
> > + p, NULL, 0, false, NULL, 0);
> > + }
> > +
> > + mutex_unlock(&p->mutex);
> > + ret = down_interruptible(&p->runtime_enable_sema);
> > + mutex_lock(&p->mutex);
> > +
> > + p->is_runtime_retry = !!ret;
> > + }
> > +
> > + return ret;
> > +}
> > +
> > +static int runtime_disable(struct kfd_process *p)
> > +{
> > + int i = 0, ret;
> > + bool was_enabled = p->runtime_info.runtime_state ==
> DEBUG_RUNTIME_STATE_ENABLED;
> > +
> > + p->runtime_info.runtime_state =
> DEBUG_RUNTIME_STATE_DISABLED;
> > + p->runtime_info.r_debug = 0;
> > +
> > + if (p->debug_trap_enabled) {
> > + if (was_enabled)
> > + kfd_dbg_trap_deactivate(p, false, 0);
>
> Does this call kfd_dbg_trap_deactivate multiple times on retry? Is that
> a problem?
I don't think dbg_trap_deactivate gets called again on retry. Prior to the deactivate call, the per-process runtime state gets saved as DEBUG_RUNTIME_STATE_DISABLED and early returns on a down_interruptible error. If the caller retries on the error, this means was_enabled is false so we never deactivate again.
Thanks,
Jon
>
> Regards,
> Felix
>
>
> > +
> > + if (!p->is_runtime_retry)
> > +
> kfd_dbg_ev_raise(KFD_EC_MASK(EC_PROCESS_RUNTIME),
> > + p, NULL, 0, false, NULL, 0);
> > +
> > + mutex_unlock(&p->mutex);
> > + ret = down_interruptible(&p->runtime_enable_sema);
> > + mutex_lock(&p->mutex);
> > +
> > + p->is_runtime_retry = !!ret;
> > + if (ret)
> > + return ret;
> > + }
> > +
> > + if (was_enabled && p->runtime_info.ttmp_setup) {
> > + for (i = 0; i < p->n_pdds; i++) {
> > + struct kfd_process_device *pdd = p->pdds[i];
> > +
> > + if (!kfd_dbg_is_rlc_restore_supported(pdd->dev))
> > + amdgpu_gfx_off_ctrl(pdd->dev->adev, true);
> > + }
> > + }
> > +
> > + p->runtime_info.ttmp_setup = false;
> > +
> > + /* disable DISPATCH_PTR save */
> > + for (i = 0; i < p->n_pdds; i++) {
> > + struct kfd_process_device *pdd = p->pdds[i];
> > +
> > + if (kfd_dbg_is_per_vmid_supported(pdd->dev)) {
> > + pdd->spi_dbg_override =
> > + pdd->dev->kfd2kgd-
> >disable_debug_trap(
> > + pdd->dev->adev,
> > + false,
> > + pdd->dev->vm_info.last_vmid_kfd);
> > +
> > + if (!pdd->dev->shared_resources.enable_mes)
> > + debug_refresh_runlist(pdd->dev->dqm);
> > + else
> > + kfd_dbg_set_mes_debug_mode(pdd);
> > + }
> > + }
> > +
> > return 0;
> > }
> >
> > +static int kfd_ioctl_runtime_enable(struct file *filep, struct kfd_process
> *p, void *data)
> > +{
> > + struct kfd_ioctl_runtime_enable_args *args = data;
> > + int r;
> > +
> > + mutex_lock(&p->mutex);
> > +
> > + if (args->mode_mask &
> KFD_RUNTIME_ENABLE_MODE_ENABLE_MASK)
> > + r = runtime_enable(p, args->r_debug,
> > + !!(args->mode_mask &
> KFD_RUNTIME_ENABLE_MODE_TTMP_SAVE_MASK));
> > + else
> > + r = runtime_disable(p);
> > +
> > + mutex_unlock(&p->mutex);
> > +
> > + return r;
> > +}
> > +
> > static int kfd_ioctl_set_debug_trap(struct file *filep, struct kfd_process
> *p, void *data)
> > {
> > struct kfd_ioctl_dbg_trap_args *args = data;
> > @@ -2720,6 +2856,18 @@ static int kfd_ioctl_set_debug_trap(struct file
> *filep, struct kfd_process *p, v
> > goto unlock_out;
> > }
> >
> > + if (target->runtime_info.runtime_state !=
> DEBUG_RUNTIME_STATE_ENABLED &&
> > + (args->op ==
> KFD_IOC_DBG_TRAP_SET_WAVE_LAUNCH_OVERRIDE ||
> > + args->op ==
> KFD_IOC_DBG_TRAP_SET_WAVE_LAUNCH_MODE ||
> > + args->op == KFD_IOC_DBG_TRAP_SUSPEND_QUEUES
> ||
> > + args->op == KFD_IOC_DBG_TRAP_RESUME_QUEUES
> ||
> > + args->op ==
> KFD_IOC_DBG_TRAP_SET_NODE_ADDRESS_WATCH ||
> > + args->op ==
> KFD_IOC_DBG_TRAP_CLEAR_NODE_ADDRESS_WATCH ||
> > + args->op == KFD_IOC_DBG_TRAP_SET_FLAGS)) {
> > + r = -EPERM;
> > + goto unlock_out;
> > + }
> > +
> > switch (args->op) {
> > case KFD_IOC_DBG_TRAP_ENABLE:
> > if (target != p)
> > diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_debug.c
> b/drivers/gpu/drm/amd/amdkfd/kfd_debug.c
> > index 4174b479ea6f..47f8425a0db3 100644
> > --- a/drivers/gpu/drm/amd/amdkfd/kfd_debug.c
> > +++ b/drivers/gpu/drm/amd/amdkfd/kfd_debug.c
> > @@ -220,7 +220,7 @@ static int kfd_dbg_set_workaround(struct
> kfd_process *target, bool enable)
> > return r;
> > }
> >
> > -static int kfd_dbg_set_mes_debug_mode(struct kfd_process_device *pdd)
> > +int kfd_dbg_set_mes_debug_mode(struct kfd_process_device *pdd)
> > {
> > uint32_t spi_dbg_cntl = pdd->spi_dbg_override | pdd-
> >spi_dbg_launch_mode;
> > uint32_t flags = pdd->process->dbg_flags;
> > @@ -240,7 +240,7 @@ static int kfd_dbg_set_mes_debug_mode(struct
> kfd_process_device *pdd)
> > * to unwind
> > * else: ignored
> > */
> > -static void kfd_dbg_trap_deactivate(struct kfd_process *target, bool
> unwind, int unwind_count)
> > +void kfd_dbg_trap_deactivate(struct kfd_process *target, bool unwind,
> int unwind_count)
> > {
> > int i, count = 0;
> >
> > @@ -311,7 +311,7 @@ int kfd_dbg_trap_disable(struct kfd_process
> *target)
> > return 0;
> > }
> >
> > -static int kfd_dbg_trap_activate(struct kfd_process *target)
> > +int kfd_dbg_trap_activate(struct kfd_process *target)
> > {
> > int i, r = 0, unwind_count = 0;
> >
> > diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_debug.h
> b/drivers/gpu/drm/amd/amdkfd/kfd_debug.h
> > index fefb9dc5cf69..22707f7a2368 100644
> > --- a/drivers/gpu/drm/amd/amdkfd/kfd_debug.h
> > +++ b/drivers/gpu/drm/amd/amdkfd/kfd_debug.h
> > @@ -28,6 +28,8 @@
> > void kgd_gfx_v9_set_wave_launch_stall(struct amdgpu_device *adev,
> > uint32_t vmid,
> > bool stall);
> > +void kfd_dbg_trap_deactivate(struct kfd_process *target, bool unwind,
> int unwind_count);
> > +int kfd_dbg_trap_activate(struct kfd_process *target);
> > bool kfd_dbg_ev_raise(uint64_t event_mask,
> > struct kfd_process *process, struct kfd_dev *dev,
> > unsigned int source_id, bool use_worker,
> > @@ -80,4 +82,6 @@ static inline bool kfd_dbg_has_gws_support(struct
> kfd_dev *dev)
> > /* Assume debugging and cooperative launch supported otherwise.
> */
> > return true;
> > }
> > +
> > +int kfd_dbg_set_mes_debug_mode(struct kfd_process_device *pdd);
> > #endif
> > diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
> b/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
> > index 4cb433a21e3d..63c59ad2a4ca 100644
> > --- a/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
> > +++ b/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
> > @@ -946,6 +946,7 @@ struct kfd_process {
> >
> > /* Tracks runtime enable status */
> > struct semaphore runtime_enable_sema;
> > + bool is_runtime_retry;
> > struct kfd_runtime_info runtime_info;
> >
> > };
