On 18/04/18 11:08, Alastair D'Silva wrote:
From: Alastair D'Silva <alast...@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 <alast...@d-silva.org>

nitpicks below

Acked-by: Andrew Donnellan <andrew.donnel...@au1.ibm.com>

---
  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          | 10 ++++++++
  6 files changed, 113 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;

Declarations at the top

+
+                       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..6c6d4e61888e 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

What's the difference between u16 and __u16...

  };
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..8d2748e69c84 100644
--- a/include/uapi/misc/ocxl.h
+++ b/include/uapi/misc/ocxl.h
@@ -48,6 +48,15 @@ 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 +71,6 @@ 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 */


--
Andrew Donnellan              OzLabs, ADL Canberra
andrew.donnel...@au1.ibm.com  IBM Australia Limited

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