Messages in this thread | | | Subject | Re: [PATCH v5 5/7] ocxl: Expose the thread_id needed for wait on POWER9 | From | Frederic Barrat <> | Date | Fri, 11 May 2018 13:03:41 +0200 |
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Le 11/05/2018 à 12:06, Alastair D'Silva a écrit : > >> -----Original Message----- >> From: Frederic Barrat <fbarrat@linux.ibm.com> >> Sent: Friday, 11 May 2018 7:25 PM >> To: Alastair D'Silva <alastair@au1.ibm.com>; linuxppc-dev@lists.ozlabs.org >> Cc: linux-kernel@vger.kernel.org; linux-doc@vger.kernel.org; >> mikey@neuling.org; vaibhav@linux.vnet.ibm.com; >> aneesh.kumar@linux.vnet.ibm.com; malat@debian.org; >> felix@linux.vnet.ibm.com; pombredanne@nexb.com; >> sukadev@linux.vnet.ibm.com; npiggin@gmail.com; >> gregkh@linuxfoundation.org; arnd@arndb.de; >> andrew.donnellan@au1.ibm.com; fbarrat@linux.vnet.ibm.com; >> corbet@lwn.net; Alastair D'Silva <alastair@d-silva.org> >> Subject: Re: [PATCH v5 5/7] ocxl: Expose the thread_id needed for wait on >> POWER9 >> >> >> >> Le 11/05/2018 à 08:13, Alastair D'Silva a écrit : >>> From: Alastair D'Silva <alastair@d-silva.org> >>> >>> In order to successfully issue as_notify, an AFU needs to know the TID >>> to notify, which in turn means that this information should be >>> available in userspace so it can be communicated to the AFU. >>> >>> Signed-off-by: Alastair D'Silva <alastair@d-silva.org> >>> --- >> >> Ok, so we keep the limitation of having only one thread per context able to >> call 'wait', even though we don't have to worry about depleting the pool of >> TIDs any more. I think that's acceptable, though we don't really have a reason >> to justify it any more. Any reason you want to keep it that way? >> > > No strong reason, just trying to minimise the amount of changes. We can always expand the scope later, if we have a use-case for it.
ok. Agreed, it's not worth holding up this series, we can send a follow up patch.
Fred
>> Fred >> >> >>> drivers/misc/ocxl/context.c | 5 ++- >>> drivers/misc/ocxl/file.c | 53 +++++++++++++++++++++++++++++++ >>> drivers/misc/ocxl/link.c | 36 +++++++++++++++++++++ >>> drivers/misc/ocxl/ocxl_internal.h | 1 + >>> include/misc/ocxl.h | 9 ++++++ >>> include/uapi/misc/ocxl.h | 8 +++++ >>> 6 files changed, 111 insertions(+), 1 deletion(-) >>> >>> diff --git a/drivers/misc/ocxl/context.c b/drivers/misc/ocxl/context.c >>> index 909e8807824a..95f74623113e 100644 >>> --- a/drivers/misc/ocxl/context.c >>> +++ b/drivers/misc/ocxl/context.c >>> @@ -34,6 +34,8 @@ int ocxl_context_init(struct ocxl_context *ctx, struct >> ocxl_afu *afu, >>> mutex_init(&ctx->xsl_error_lock); >>> mutex_init(&ctx->irq_lock); >>> idr_init(&ctx->irq_idr); >>> + ctx->tidr = 0; >>> + >>> /* >>> * Keep a reference on the AFU to make sure it's valid for the >>> * duration of the life of the context @@ -65,6 +67,7 @@ int >>> ocxl_context_attach(struct ocxl_context *ctx, u64 amr) >>> { >>> int rc; >>> >>> + // Locks both status & tidr >>> mutex_lock(&ctx->status_mutex); >>> if (ctx->status != OPENED) { >>> rc = -EIO; >>> @@ -72,7 +75,7 @@ int ocxl_context_attach(struct ocxl_context *ctx, u64 >> amr) >>> } >>> >>> rc = ocxl_link_add_pe(ctx->afu->fn->link, ctx->pasid, >>> - current->mm->context.id, 0, amr, current->mm, >>> + current->mm->context.id, ctx->tidr, amr, current- >>> mm, >>> xsl_fault_error, ctx); >>> if (rc) >>> goto out; >>> diff --git a/drivers/misc/ocxl/file.c b/drivers/misc/ocxl/file.c index >>> 038509e5d031..eb409a469f21 100644 >>> --- a/drivers/misc/ocxl/file.c >>> +++ b/drivers/misc/ocxl/file.c >>> @@ -5,6 +5,8 @@ >>> #include <linux/sched/signal.h> >>> #include <linux/uaccess.h> >>> #include <uapi/misc/ocxl.h> >>> +#include <asm/reg.h> >>> +#include <asm/switch_to.h> >>> #include "ocxl_internal.h" >>> >>> >>> @@ -123,11 +125,55 @@ static long afu_ioctl_get_metadata(struct >> ocxl_context *ctx, >>> return 0; >>> } >>> >>> +#ifdef CONFIG_PPC64 >>> +static long afu_ioctl_enable_p9_wait(struct ocxl_context *ctx, >>> + struct ocxl_ioctl_p9_wait __user *uarg) { >>> + struct ocxl_ioctl_p9_wait arg; >>> + >>> + memset(&arg, 0, sizeof(arg)); >>> + >>> + if (cpu_has_feature(CPU_FTR_P9_TIDR)) { >>> + enum ocxl_context_status status; >>> + >>> + // Locks both status & tidr >>> + mutex_lock(&ctx->status_mutex); >>> + if (!ctx->tidr) { >>> + if (set_thread_tidr(current)) >>> + return -ENOENT; >>> + >>> + ctx->tidr = current->thread.tidr; >>> + } >>> + >>> + status = ctx->status; >>> + mutex_unlock(&ctx->status_mutex); >>> + >>> + if (status == ATTACHED) { >>> + int rc; >>> + struct link *link = ctx->afu->fn->link; >>> + >>> + rc = ocxl_link_update_pe(link, ctx->pasid, ctx->tidr); >>> + if (rc) >>> + return rc; >>> + } >>> + >>> + arg.thread_id = ctx->tidr; >>> + } else >>> + return -ENOENT; >>> + >>> + if (copy_to_user(uarg, &arg, sizeof(arg))) >>> + return -EFAULT; >>> + >>> + return 0; >>> +} >>> +#endif >>> + >>> #define CMD_STR(x) (x == OCXL_IOCTL_ATTACH ? "ATTACH" : >> \ >>> x == OCXL_IOCTL_IRQ_ALLOC ? "IRQ_ALLOC" : \ >>> x == OCXL_IOCTL_IRQ_FREE ? "IRQ_FREE" : >> \ >>> x == OCXL_IOCTL_IRQ_SET_FD ? "IRQ_SET_FD" : >> \ >>> x == OCXL_IOCTL_GET_METADATA ? >> "GET_METADATA" : \ >>> + x == OCXL_IOCTL_ENABLE_P9_WAIT ? >> "ENABLE_P9_WAIT" : \ >>> "UNKNOWN") >>> >>> static long afu_ioctl(struct file *file, unsigned int cmd, @@ -186,6 >>> +232,13 @@ static long afu_ioctl(struct file *file, unsigned int cmd, >>> (struct ocxl_ioctl_metadata __user *) args); >>> break; >>> >>> +#ifdef CONFIG_PPC64 >>> + case OCXL_IOCTL_ENABLE_P9_WAIT: >>> + rc = afu_ioctl_enable_p9_wait(ctx, >>> + (struct ocxl_ioctl_p9_wait __user *) args); >>> + break; >>> +#endif >>> + >>> default: >>> rc = -EINVAL; >>> } >>> diff --git a/drivers/misc/ocxl/link.c b/drivers/misc/ocxl/link.c index >>> 656e8610eec2..88876ae8f330 100644 >>> --- a/drivers/misc/ocxl/link.c >>> +++ b/drivers/misc/ocxl/link.c >>> @@ -544,6 +544,42 @@ int ocxl_link_add_pe(void *link_handle, int pasid, >> u32 pidr, u32 tidr, >>> } >>> EXPORT_SYMBOL_GPL(ocxl_link_add_pe); >>> >>> +int ocxl_link_update_pe(void *link_handle, int pasid, __u16 tid) { >>> + struct link *link = (struct link *) link_handle; >>> + struct spa *spa = link->spa; >>> + struct ocxl_process_element *pe; >>> + int pe_handle, rc; >>> + >>> + if (pasid > SPA_PASID_MAX) >>> + return -EINVAL; >>> + >>> + pe_handle = pasid & SPA_PE_MASK; >>> + pe = spa->spa_mem + pe_handle; >>> + >>> + mutex_lock(&spa->spa_lock); >>> + >>> + pe->tid = tid; >>> + >>> + /* >>> + * The barrier makes sure the PE is updated >>> + * before we clear the NPU context cache below, so that the >>> + * old PE cannot be reloaded erroneously. >>> + */ >>> + mb(); >>> + >>> + /* >>> + * hook to platform code >>> + * On powerpc, the entry needs to be cleared from the context >>> + * cache of the NPU. >>> + */ >>> + rc = pnv_ocxl_spa_remove_pe_from_cache(link->platform_data, >> pe_handle); >>> + WARN_ON(rc); >>> + >>> + mutex_unlock(&spa->spa_lock); >>> + return rc; >>> +} >>> + >>> int ocxl_link_remove_pe(void *link_handle, int pasid) >>> { >>> struct link *link = (struct link *) link_handle; diff --git >>> a/drivers/misc/ocxl/ocxl_internal.h >>> b/drivers/misc/ocxl/ocxl_internal.h >>> index 5d421824afd9..a32f2151029f 100644 >>> --- a/drivers/misc/ocxl/ocxl_internal.h >>> +++ b/drivers/misc/ocxl/ocxl_internal.h >>> @@ -77,6 +77,7 @@ struct ocxl_context { >>> struct ocxl_xsl_error xsl_error; >>> struct mutex irq_lock; >>> struct idr irq_idr; >>> + u16 tidr; // Thread ID used for P9 wait implementation >>> }; >>> >>> struct ocxl_process_element { >>> diff --git a/include/misc/ocxl.h b/include/misc/ocxl.h index >>> 51ccf76db293..9ff6ddc28e22 100644 >>> --- a/include/misc/ocxl.h >>> +++ b/include/misc/ocxl.h >>> @@ -188,6 +188,15 @@ extern int ocxl_link_add_pe(void *link_handle, int >> pasid, u32 pidr, u32 tidr, >>> void (*xsl_err_cb)(void *data, u64 addr, u64 dsisr), >>> void *xsl_err_data); >>> >>> +/** >>> + * Update values within a Process Element >>> + * >>> + * link_handle: the link handle associated with the process element >>> + * pasid: the PASID for the AFU context >>> + * tid: the new thread id for the process element */ extern int >>> +ocxl_link_update_pe(void *link_handle, int pasid, __u16 tid); >>> + >>> /* >>> * Remove a Process Element from the Shared Process Area for a link >>> */ >>> diff --git a/include/uapi/misc/ocxl.h b/include/uapi/misc/ocxl.h index >>> 0af83d80fb3e..561e6f0dfcb7 100644 >>> --- a/include/uapi/misc/ocxl.h >>> +++ b/include/uapi/misc/ocxl.h >>> @@ -48,6 +48,13 @@ struct ocxl_ioctl_metadata { >>> __u64 reserved[13]; // Total of 16*u64 >>> }; >>> >>> +struct ocxl_ioctl_p9_wait { >>> + __u16 thread_id; // The thread ID required to wake this thread >>> + __u16 reserved1; >>> + __u32 reserved2; >>> + __u64 reserved3[3]; >>> +}; >>> + >>> struct ocxl_ioctl_irq_fd { >>> __u64 irq_offset; >>> __s32 eventfd; >>> @@ -62,5 +69,6 @@ struct ocxl_ioctl_irq_fd { >>> #define OCXL_IOCTL_IRQ_FREE _IOW(OCXL_MAGIC, 0x12, __u64) >>> #define OCXL_IOCTL_IRQ_SET_FD _IOW(OCXL_MAGIC, 0x13, struct >> ocxl_ioctl_irq_fd) >>> #define OCXL_IOCTL_GET_METADATA _IOR(OCXL_MAGIC, 0x14, struct >>> ocxl_ioctl_metadata) >>> +#define OCXL_IOCTL_ENABLE_P9_WAIT _IOR(OCXL_MAGIC, 0x15, >> struct ocxl_ioctl_p9_wait) >>> >>> #endif /* _UAPI_MISC_OCXL_H */ >>> >> >> >> --- >> This email has been checked for viruses by AVG. >> http://www.avg.com > >
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