Commit 2de36e3f authored by Piotr Piórkowski's avatar Piotr Piórkowski Committed by Michał Winiarski
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drm/xe/pf: Add FLR_PREPARE state to VF control flow 



Our xe-vfio-pci component relies on the confirmation from the PF
that VF FLR processing has finished, but due to the notification
latency on the HW/FW side, PF might be unaware yet of the already
triggered VF FLR.

Update VF state machine with new FLR_PREPARE state that indicate
imminent VF FLR notification and treat that as a begin of the FLR
sequence. Also introduce function that xe-vfio-pci should call to
guarantee correct synchronization.

v2: move PREPARE into WIP, update commit msg (Michal)

Signed-off-by: default avatarPiotr Piórkowski <piotr.piorkowski@intel.com>
Co-developed-by: default avatarMichal Wajdeczko <michal.wajdeczko@intel.com>
Signed-off-by: default avatarMichal Wajdeczko <michal.wajdeczko@intel.com>
Reviewed-by: default avatarMichał Winiarski <michal.winiarski@intel.com>
Link: https://patch.msgid.link/20260309152449.910636-2-piotr.piorkowski@intel.com


Signed-off-by: default avatarMichał Winiarski <michal.winiarski@intel.com>
parent a3156676

drivers/gpu/drm/xe/xe_gt_sriov_pf_control.c

+62 −16
Original line number Diff line number Diff line
@@ -171,6 +171,7 @@ static const char *control_bit_to_string(enum xe_gt_sriov_control_bits bit) 
	case XE_GT_SRIOV_STATE_##_X: return #_X

	CASE2STR(WIP);

	CASE2STR(FLR_WIP);

	CASE2STR(FLR_PREPARE);

	CASE2STR(FLR_SEND_START);

	CASE2STR(FLR_WAIT_GUC);

	CASE2STR(FLR_GUC_DONE);
@@ -1486,11 +1487,15 @@ int xe_gt_sriov_pf_control_stop_vf(struct xe_gt *gt, unsigned int vfid) 
 * The VF FLR state machine looks like::

 *

 *	 (READY,PAUSED,STOPPED)<------------<--------------o

 *	    |                                               \

 *	   flr                                               \

 *	    |                                                 \

 *	....V..........................FLR_WIP...........      \

 *	:    \                                          :       \

 *	    |             |                                 \

 *	   flr           prepare                             \

 *	    |             |                                   \

 *	....V.............V............FLR_WIP...........      \

 *	:   |             |                             :       \

 *	:   |    FLR_PREPARE                            :        |

 *	:   |    /                                      :        |

 *	:   \   flr                                     :        |

 *	:    \ /                                        :        |

 *	:     \   o----<----busy                        :        |

 *	:      \ /            /                         :        |

 *	:       FLR_SEND_START---failed----->-----------o--->(FLR_FAILED)<---o
@@ -1539,20 +1544,28 @@ static void pf_enter_vf_flr_send_start(struct xe_gt *gt, unsigned int vfid) 
	pf_queue_vf(gt, vfid);

}



static void pf_enter_vf_flr_wip(struct xe_gt *gt, unsigned int vfid)

static bool pf_exit_vf_flr_prepare(struct xe_gt *gt, unsigned int vfid)

{

	if (!pf_enter_vf_state(gt, vfid, XE_GT_SRIOV_STATE_FLR_WIP)) {

		xe_gt_sriov_dbg(gt, "VF%u FLR is already in progress\n", vfid);

		return;

	if (!pf_exit_vf_state(gt, vfid, XE_GT_SRIOV_STATE_FLR_PREPARE))

		return false;



	pf_enter_vf_flr_send_start(gt, vfid);

	return true;

}



static bool pf_enter_vf_flr_wip(struct xe_gt *gt, unsigned int vfid)

{

	if (!pf_enter_vf_state(gt, vfid, XE_GT_SRIOV_STATE_FLR_WIP))

		return false;



	pf_enter_vf_wip(gt, vfid);

	pf_enter_vf_flr_send_start(gt, vfid);

	return true;

}



static void pf_exit_vf_flr_wip(struct xe_gt *gt, unsigned int vfid)

{

	if (pf_exit_vf_state(gt, vfid, XE_GT_SRIOV_STATE_FLR_WIP)) {

		pf_escape_vf_state(gt, vfid, XE_GT_SRIOV_STATE_FLR_PREPARE);

		pf_escape_vf_state(gt, vfid, XE_GT_SRIOV_STATE_FLR_SEND_FINISH);

		pf_escape_vf_state(gt, vfid, XE_GT_SRIOV_STATE_FLR_RESET_MMIO);

		pf_escape_vf_state(gt, vfid, XE_GT_SRIOV_STATE_FLR_RESET_DATA);
@@ -1760,21 +1773,54 @@ static void pf_enter_vf_flr_guc_done(struct xe_gt *gt, unsigned int vfid) 
}



/**

 * xe_gt_sriov_pf_control_trigger_flr - Start a VF FLR sequence.

 * xe_gt_sriov_pf_control_prepare_flr() - Notify PF that VF FLR request was issued.

 * @gt: the &xe_gt

 * @vfid: the VF identifier

 *

 * This is an optional early notification path used to mark pending FLR before

 * the GuC notifies the PF with a FLR event.

 *

 * This function is for PF only.

 *

 * Return: 0 on success or a negative error code on failure.

 */

int xe_gt_sriov_pf_control_trigger_flr(struct xe_gt *gt, unsigned int vfid)

int xe_gt_sriov_pf_control_prepare_flr(struct xe_gt *gt, unsigned int vfid)

{

	pf_enter_vf_flr_wip(gt, vfid);

	if (!pf_enter_vf_flr_wip(gt, vfid))

		return -EALREADY;



	pf_enter_vf_state(gt, vfid, XE_GT_SRIOV_STATE_FLR_PREPARE);

	return 0;

}



static int pf_begin_vf_flr(struct xe_gt *gt, unsigned int vfid)

{

	if (pf_enter_vf_flr_wip(gt, vfid)) {

		pf_enter_vf_flr_send_start(gt, vfid);

		return 0;

	}



	if (pf_exit_vf_flr_prepare(gt, vfid))

		return 0;



	xe_gt_sriov_dbg(gt, "VF%u FLR is already in progress\n", vfid);

	return -EALREADY;

}



/**

 * xe_gt_sriov_pf_control_trigger_flr - Start a VF FLR sequence.

 * @gt: the &xe_gt

 * @vfid: the VF identifier

 *

 * This function is for PF only.

 *

 * Return: 0 on success or a negative error code on failure.

 */

int xe_gt_sriov_pf_control_trigger_flr(struct xe_gt *gt, unsigned int vfid)

{

	return pf_begin_vf_flr(gt, vfid);

}



/**

 * xe_gt_sriov_pf_control_sync_flr() - Synchronize on the VF FLR checkpoint.

 * @gt: the &xe_gt
@@ -1879,9 +1925,9 @@ static void pf_handle_vf_flr(struct xe_gt *gt, u32 vfid) 


	if (needs_dispatch_flr(xe)) {

		for_each_gt(gtit, xe, gtid)

			pf_enter_vf_flr_wip(gtit, vfid);

			pf_begin_vf_flr(gtit, vfid);

	} else {

		pf_enter_vf_flr_wip(gt, vfid);

		pf_begin_vf_flr(gt, vfid);

	}

}

drivers/gpu/drm/xe/xe_gt_sriov_pf_control.h

+1 −0
Original line number Diff line number Diff line
@@ -27,6 +27,7 @@ int xe_gt_sriov_pf_control_process_restore_data(struct xe_gt *gt, unsigned int v 
int xe_gt_sriov_pf_control_trigger_restore_vf(struct xe_gt *gt, unsigned int vfid);

int xe_gt_sriov_pf_control_finish_restore_vf(struct xe_gt *gt, unsigned int vfid);

int xe_gt_sriov_pf_control_stop_vf(struct xe_gt *gt, unsigned int vfid);

int xe_gt_sriov_pf_control_prepare_flr(struct xe_gt *gt, unsigned int vfid);

int xe_gt_sriov_pf_control_trigger_flr(struct xe_gt *gt, unsigned int vfid);

int xe_gt_sriov_pf_control_sync_flr(struct xe_gt *gt, unsigned int vfid, bool sync);

int xe_gt_sriov_pf_control_wait_flr(struct xe_gt *gt, unsigned int vfid);

drivers/gpu/drm/xe/xe_gt_sriov_pf_control_types.h

+2 −0
Original line number Diff line number Diff line
@@ -15,6 +15,7 @@ 
 *

 * @XE_GT_SRIOV_STATE_WIP: indicates that some operations are in progress.

 * @XE_GT_SRIOV_STATE_FLR_WIP: indicates that a VF FLR is in progress.

 * @XE_GT_SRIOV_STATE_FLR_PREPARE: indicates that the PF received early VF FLR prepare notification.

 * @XE_GT_SRIOV_STATE_FLR_SEND_START: indicates that the PF wants to send a FLR START command.

 * @XE_GT_SRIOV_STATE_FLR_WAIT_GUC: indicates that the PF awaits for a response from the GuC.

 * @XE_GT_SRIOV_STATE_FLR_GUC_DONE: indicates that the PF has received a response from the GuC.
@@ -56,6 +57,7 @@ enum xe_gt_sriov_control_bits { 
	XE_GT_SRIOV_STATE_WIP = 1,



	XE_GT_SRIOV_STATE_FLR_WIP,

	XE_GT_SRIOV_STATE_FLR_PREPARE,

	XE_GT_SRIOV_STATE_FLR_SEND_START,

	XE_GT_SRIOV_STATE_FLR_WAIT_GUC,

	XE_GT_SRIOV_STATE_FLR_GUC_DONE,

drivers/gpu/drm/xe/xe_sriov_pf_control.c

+24 −0
Original line number Diff line number Diff line
@@ -123,6 +123,30 @@ int xe_sriov_pf_control_reset_vf(struct xe_device *xe, unsigned int vfid) 
	return result;

}



/**

 * xe_sriov_pf_control_prepare_flr() - Notify PF that VF FLR prepare has started.

 * @xe: the &xe_device

 * @vfid: the VF identifier

 *

 * This function is for PF only.

 *

 * Return: 0 on success or a negative error code on failure.

 */

int xe_sriov_pf_control_prepare_flr(struct xe_device *xe, unsigned int vfid)

{

	struct xe_gt *gt;

	unsigned int id;

	int result = 0;

	int err;



	for_each_gt(gt, xe, id) {

		err = xe_gt_sriov_pf_control_prepare_flr(gt, vfid);

		result = result ? -EUCLEAN : err;

	}



	return result;

}



/**

 * xe_sriov_pf_control_wait_flr() - Wait for a VF reset (FLR) to complete.

 * @xe: the &xe_device

drivers/gpu/drm/xe/xe_sriov_pf_control.h

+1 −0
Original line number Diff line number Diff line
@@ -12,6 +12,7 @@ int xe_sriov_pf_control_pause_vf(struct xe_device *xe, unsigned int vfid); 
int xe_sriov_pf_control_resume_vf(struct xe_device *xe, unsigned int vfid);

int xe_sriov_pf_control_stop_vf(struct xe_device *xe, unsigned int vfid);

int xe_sriov_pf_control_reset_vf(struct xe_device *xe, unsigned int vfid);

int xe_sriov_pf_control_prepare_flr(struct xe_device *xe, unsigned int vfid);

int xe_sriov_pf_control_wait_flr(struct xe_device *xe, unsigned int vfid);

int xe_sriov_pf_control_sync_flr(struct xe_device *xe, unsigned int vfid);

int xe_sriov_pf_control_trigger_save_vf(struct xe_device *xe, unsigned int vfid);