diff options
| -rw-r--r-- | drivers/gpu/drm/xe/xe_guard.h | 119 | ||||
| -rw-r--r-- | drivers/gpu/drm/xe/xe_pci_sriov.c | 21 | ||||
| -rw-r--r-- | drivers/gpu/drm/xe/xe_sriov_pf.c | 97 | ||||
| -rw-r--r-- | drivers/gpu/drm/xe/xe_sriov_pf.h | 4 | ||||
| -rw-r--r-- | drivers/gpu/drm/xe/xe_sriov_pf_debugfs.c | 30 | ||||
| -rw-r--r-- | drivers/gpu/drm/xe/xe_sriov_pf_helpers.h | 5 | ||||
| -rw-r--r-- | drivers/gpu/drm/xe/xe_sriov_pf_types.h | 4 |
7 files changed, 280 insertions, 0 deletions
diff --git a/drivers/gpu/drm/xe/xe_guard.h b/drivers/gpu/drm/xe/xe_guard.h new file mode 100644 index 000000000000..333f8e13b5a1 --- /dev/null +++ b/drivers/gpu/drm/xe/xe_guard.h @@ -0,0 +1,119 @@ +/* SPDX-License-Identifier: MIT */ +/* + * Copyright © 2025 Intel Corporation + */ + +#ifndef _XE_GUARD_H_ +#define _XE_GUARD_H_ + +#include <linux/spinlock.h> + +/** + * struct xe_guard - Simple logic to protect a feature. + * + * Implements simple semaphore-like logic that can be used to lockdown the + * feature unless it is already in use. Allows enabling of the otherwise + * incompatible features, where we can't follow the strict owner semantics + * required by the &rw_semaphore. + * + * NOTE! It shouldn't be used to protect a data, use &rw_semaphore instead. + */ +struct xe_guard { + /** + * @counter: implements simple exclusive/lockdown logic: + * if == 0 then guard/feature is idle/not in use, + * if < 0 then feature is active and can't be locked-down, + * if > 0 then feature is lockded-down and can't be activated. + */ + int counter; + + /** @name: the name of the guard (useful for debug) */ + const char *name; + + /** @owner: the info about the last owner of the guard (for debug) */ + void *owner; + + /** @lock: protects guard's data */ + spinlock_t lock; +}; + +/** + * xe_guard_init() - Initialize the guard. + * @guard: the &xe_guard to init + * @name: name of the guard + */ +static inline void xe_guard_init(struct xe_guard *guard, const char *name) +{ + spin_lock_init(&guard->lock); + guard->counter = 0; + guard->name = name; +} + +/** + * xe_guard_arm() - Arm the guard for the exclusive/lockdown mode. + * @guard: the &xe_guard to arm + * @lockdown: arm for lockdown(true) or exclusive(false) mode + * @who: optional owner info (for debug only) + * + * Multiple lockdown requests are allowed. + * Only single exclusive access can be granted. + * Will fail if the guard is already in exclusive mode. + * On success, must call the xe_guard_disarm() to release. + * + * Return: 0 on success or a negative error code on failure. + */ +static inline int xe_guard_arm(struct xe_guard *guard, bool lockdown, void *who) +{ + guard(spinlock)(&guard->lock); + + if (lockdown) { + if (guard->counter < 0) + return -EBUSY; + guard->counter++; + } else { + if (guard->counter > 0) + return -EPERM; + if (guard->counter < 0) + return -EUSERS; + guard->counter--; + } + + guard->owner = who; + return 0; +} + +/** + * xe_guard_disarm() - Disarm the guard from exclusive/lockdown mode. + * @guard: the &xe_guard to disarm + * @lockdown: disarm from lockdown(true) or exclusive(false) mode + * + * Return: true if successfully disarmed or false in case of mismatch. + */ +static inline bool xe_guard_disarm(struct xe_guard *guard, bool lockdown) +{ + guard(spinlock)(&guard->lock); + + if (lockdown) { + if (guard->counter <= 0) + return false; + guard->counter--; + } else { + if (guard->counter != -1) + return false; + guard->counter++; + } + return true; +} + +/** + * xe_guard_mode_str() - Convert guard mode into a string. + * @lockdown: flag used to select lockdown or exclusive mode + * + * Return: "lockdown" or "exclusive" string. + */ +static inline const char *xe_guard_mode_str(bool lockdown) +{ + return lockdown ? "lockdown" : "exclusive"; +} + +#endif diff --git a/drivers/gpu/drm/xe/xe_pci_sriov.c b/drivers/gpu/drm/xe/xe_pci_sriov.c index d0fcde66a774..9ff69c4843b0 100644 --- a/drivers/gpu/drm/xe/xe_pci_sriov.c +++ b/drivers/gpu/drm/xe/xe_pci_sriov.c @@ -94,6 +94,20 @@ static int resize_vf_vram_bar(struct xe_device *xe, int num_vfs) return pci_iov_vf_bar_set_size(pdev, VF_LMEM_BAR, __fls(sizes)); } +static int pf_prepare_vfs_enabling(struct xe_device *xe) +{ + xe_assert(xe, IS_SRIOV_PF(xe)); + /* make sure we are not locked-down by other components */ + return xe_sriov_pf_arm_guard(xe, &xe->sriov.pf.guard_vfs_enabling, false, NULL); +} + +static void pf_finish_vfs_enabling(struct xe_device *xe) +{ + xe_assert(xe, IS_SRIOV_PF(xe)); + /* allow other components to lockdown VFs enabling */ + xe_sriov_pf_disarm_guard(xe, &xe->sriov.pf.guard_vfs_enabling, false, NULL); +} + static int pf_enable_vfs(struct xe_device *xe, int num_vfs) { struct pci_dev *pdev = to_pci_dev(xe->drm.dev); @@ -109,6 +123,10 @@ static int pf_enable_vfs(struct xe_device *xe, int num_vfs) if (err) goto out; + err = pf_prepare_vfs_enabling(xe); + if (err) + goto out; + /* * We must hold additional reference to the runtime PM to keep PF in D0 * during VFs lifetime, as our VFs do not implement the PM capability. @@ -148,6 +166,7 @@ static int pf_enable_vfs(struct xe_device *xe, int num_vfs) failed: xe_sriov_pf_unprovision_vfs(xe, num_vfs); xe_pm_runtime_put(xe); + pf_finish_vfs_enabling(xe); out: xe_sriov_notice(xe, "Failed to enable %u VF%s (%pe)\n", num_vfs, str_plural(num_vfs), ERR_PTR(err)); @@ -179,6 +198,8 @@ static int pf_disable_vfs(struct xe_device *xe) /* not needed anymore - see pf_enable_vfs() */ xe_pm_runtime_put(xe); + pf_finish_vfs_enabling(xe); + xe_sriov_info(xe, "Disabled %u VF%s\n", num_vfs, str_plural(num_vfs)); return 0; } diff --git a/drivers/gpu/drm/xe/xe_sriov_pf.c b/drivers/gpu/drm/xe/xe_sriov_pf.c index b8af93eb5b5f..59b32b3c8acc 100644 --- a/drivers/gpu/drm/xe/xe_sriov_pf.c +++ b/drivers/gpu/drm/xe/xe_sriov_pf.c @@ -102,6 +102,8 @@ int xe_sriov_pf_init_early(struct xe_device *xe) if (err) return err; + xe_guard_init(&xe->sriov.pf.guard_vfs_enabling, "vfs_enabling"); + xe_sriov_pf_service_init(xe); return 0; @@ -163,6 +165,101 @@ int xe_sriov_pf_wait_ready(struct xe_device *xe) } /** + * xe_sriov_pf_arm_guard() - Arm the guard for exclusive/lockdown mode. + * @xe: the PF &xe_device + * @guard: the &xe_guard to arm + * @lockdown: arm for lockdown(true) or exclusive(false) mode + * @who: the address of the new owner, or NULL if it's a caller + * + * This function can only be called on PF. + * + * It is a simple wrapper for xe_guard_arm() with additional debug + * messages. + * + * Return: 0 on success or a negative error code on failure. + */ +int xe_sriov_pf_arm_guard(struct xe_device *xe, struct xe_guard *guard, + bool lockdown, void *who) +{ + void *new_owner = who ?: __builtin_return_address(0); + int err; + + err = xe_guard_arm(guard, lockdown, new_owner); + if (err) { + xe_sriov_dbg(xe, "%s/%s mode denied (%pe) last owner %ps\n", + guard->name, xe_guard_mode_str(lockdown), + ERR_PTR(err), guard->owner); + return err; + } + + xe_sriov_dbg_verbose(xe, "%s/%s by %ps\n", + guard->name, xe_guard_mode_str(lockdown), + new_owner); + return 0; +} + +/** + * xe_sriov_pf_disarm_guard() - Disarm the guard. + * @xe: the PF &xe_device + * @guard: the &xe_guard to disarm + * @lockdown: disarm from lockdown(true) or exclusive(false) mode + * @who: the address of the indirect owner, or NULL if it's a caller + * + * This function can only be called on PF. + * + * It is a simple wrapper for xe_guard_disarm() with additional debug + * messages and xe_assert() to easily catch any illegal calls. + */ +void xe_sriov_pf_disarm_guard(struct xe_device *xe, struct xe_guard *guard, + bool lockdown, void *who) +{ + bool disarmed; + + xe_sriov_dbg_verbose(xe, "%s/%s by %ps\n", + guard->name, xe_guard_mode_str(lockdown), + who ?: __builtin_return_address(0)); + + disarmed = xe_guard_disarm(guard, lockdown); + xe_assert_msg(xe, disarmed, "%s/%s not armed? last owner %ps", + guard->name, xe_guard_mode_str(lockdown), guard->owner); +} + +/** + * xe_sriov_pf_lockdown() - Lockdown the PF to prevent VFs enabling. + * @xe: the PF &xe_device + * + * This function can only be called on PF. + * + * Once the PF is locked down, it will not enable VFs. + * If VFs are already enabled, the -EBUSY will be returned. + * To allow the PF enable VFs again call xe_sriov_pf_end_lockdown(). + * + * Return: 0 on success or a negative error code on failure. + */ +int xe_sriov_pf_lockdown(struct xe_device *xe) +{ + xe_assert(xe, IS_SRIOV_PF(xe)); + + return xe_sriov_pf_arm_guard(xe, &xe->sriov.pf.guard_vfs_enabling, true, + __builtin_return_address(0)); +} + +/** + * xe_sriov_pf_end_lockdown() - Allow the PF to enable VFs again. + * @xe: the PF &xe_device + * + * This function can only be called on PF. + * See xe_sriov_pf_lockdown() for details. + */ +void xe_sriov_pf_end_lockdown(struct xe_device *xe) +{ + xe_assert(xe, IS_SRIOV_PF(xe)); + + xe_sriov_pf_disarm_guard(xe, &xe->sriov.pf.guard_vfs_enabling, true, + __builtin_return_address(0)); +} + +/** * xe_sriov_pf_print_vfs_summary - Print SR-IOV PF information. * @xe: the &xe_device to print info from * @p: the &drm_printer diff --git a/drivers/gpu/drm/xe/xe_sriov_pf.h b/drivers/gpu/drm/xe/xe_sriov_pf.h index cba3fde9581f..b4d050ad5b7c 100644 --- a/drivers/gpu/drm/xe/xe_sriov_pf.h +++ b/drivers/gpu/drm/xe/xe_sriov_pf.h @@ -17,11 +17,15 @@ bool xe_sriov_pf_readiness(struct xe_device *xe); int xe_sriov_pf_init_early(struct xe_device *xe); int xe_sriov_pf_init_late(struct xe_device *xe); int xe_sriov_pf_wait_ready(struct xe_device *xe); +int xe_sriov_pf_lockdown(struct xe_device *xe); +void xe_sriov_pf_end_lockdown(struct xe_device *xe); void xe_sriov_pf_print_vfs_summary(struct xe_device *xe, struct drm_printer *p); #else static inline bool xe_sriov_pf_readiness(struct xe_device *xe) { return false; } static inline int xe_sriov_pf_init_early(struct xe_device *xe) { return 0; } static inline int xe_sriov_pf_init_late(struct xe_device *xe) { return 0; } +static inline int xe_sriov_pf_lockdown(struct xe_device *xe) { return 0; } +static inline void xe_sriov_pf_end_lockdown(struct xe_device *xe) { } #endif #endif diff --git a/drivers/gpu/drm/xe/xe_sriov_pf_debugfs.c b/drivers/gpu/drm/xe/xe_sriov_pf_debugfs.c index a81aa05c5532..1c5d19ce7b63 100644 --- a/drivers/gpu/drm/xe/xe_sriov_pf_debugfs.c +++ b/drivers/gpu/drm/xe/xe_sriov_pf_debugfs.c @@ -98,10 +98,40 @@ static inline int xe_sriov_pf_restore_auto_provisioning(struct xe_device *xe) DEFINE_SRIOV_ATTRIBUTE(restore_auto_provisioning); +static int lockdown_vfs_enabling_open(struct inode *inode, struct file *file) +{ + struct dentry *dent = file_dentry(file); + struct xe_device *xe = extract_xe(dent); + ssize_t ret; + + ret = xe_sriov_pf_lockdown(xe); + if (ret < 0) + return ret; + + file->private_data = xe; + return nonseekable_open(inode, file); +} + +static int lockdown_vfs_enabling_release(struct inode *inode, struct file *file) +{ + struct xe_device *xe = file->private_data; + + xe_sriov_pf_end_lockdown(xe); + return 0; +} + +static const struct file_operations lockdown_vfs_enabling_fops = { + .owner = THIS_MODULE, + .open = lockdown_vfs_enabling_open, + .release = lockdown_vfs_enabling_release, +}; + static void pf_populate_root(struct xe_device *xe, struct dentry *dent) { debugfs_create_file("restore_auto_provisioning", 0200, dent, xe, &restore_auto_provisioning_fops); + debugfs_create_file("lockdown_vfs_enabling", 0400, dent, xe, + &lockdown_vfs_enabling_fops); } static int simple_show(struct seq_file *m, void *data) diff --git a/drivers/gpu/drm/xe/xe_sriov_pf_helpers.h b/drivers/gpu/drm/xe/xe_sriov_pf_helpers.h index 3ddeba4451cd..9054fdc34597 100644 --- a/drivers/gpu/drm/xe/xe_sriov_pf_helpers.h +++ b/drivers/gpu/drm/xe/xe_sriov_pf_helpers.h @@ -65,4 +65,9 @@ static inline struct mutex *xe_sriov_pf_master_mutex(struct xe_device *xe) return &xe->sriov.pf.master_lock; } +int xe_sriov_pf_arm_guard(struct xe_device *xe, struct xe_guard *guard, + bool write, void *who); +void xe_sriov_pf_disarm_guard(struct xe_device *xe, struct xe_guard *guard, + bool write, void *who); + #endif diff --git a/drivers/gpu/drm/xe/xe_sriov_pf_types.h b/drivers/gpu/drm/xe/xe_sriov_pf_types.h index b3cd9797194b..2fb5f426d588 100644 --- a/drivers/gpu/drm/xe/xe_sriov_pf_types.h +++ b/drivers/gpu/drm/xe/xe_sriov_pf_types.h @@ -9,6 +9,7 @@ #include <linux/mutex.h> #include <linux/types.h> +#include "xe_guard.h" #include "xe_sriov_pf_provision_types.h" #include "xe_sriov_pf_service_types.h" @@ -38,6 +39,9 @@ struct xe_device_pf { /** @driver_max_vfs: Maximum number of VFs supported by the driver. */ u16 driver_max_vfs; + /** @guard_vfs_enabling: guards VFs enabling */ + struct xe_guard guard_vfs_enabling; + /** @master_lock: protects all VFs configurations across GTs */ struct mutex master_lock; |