[RFC v2 2/3] cxl: Mark context requiring global TLBIs

[Frederic Barrat]

The PSL needs to see all TLBIs pertinent to the memory contexts used
on the cxl adapter. For the hash memory model, it was done by making
all TLBIs global as soon as the cxl driver is in use. For radix, we
need something similar, but we can refine and only convert to global
the invalidations for contexts actually used by the device.

So mark the contexts being attached to the cxl adapter as requiring
global TLBIs.

Signed-off-by: Frederic Barrat <fbarrat at linux.vnet.ibm.com>
---
 drivers/misc/cxl/api.c  | 12 ++++++++++--
 drivers/misc/cxl/file.c | 12 ++++++++++--
 2 files changed, 20 insertions(+), 4 deletions(-)

diff --git a/drivers/misc/cxl/api.c b/drivers/misc/cxl/api.c
index 1a138c83f877..2cebe214195e 100644
--- a/drivers/misc/cxl/api.c
+++ b/drivers/misc/cxl/api.c
@@ -332,8 +332,17 @@ int cxl_start_context(struct cxl_context *ctx, u64 wed,
 		cxl_context_mm_count_get(ctx);
 
 		/* decrement the use count */
-		if (ctx->mm)
+		if (ctx->mm) {
 			mmput(ctx->mm);
+#ifdef CONFIG_PPC_BOOK3S_64
+			mm_context_set_global_tlbi(&ctx->mm->context);
+			/*
+			 * Barrier guarantees that the device will
+			 * receive all TLBIs from that point on
+			 */
+			smp_wmb();
+#endif
+		}
 	}
 
 	cxl_ctx_get();
@@ -347,7 +356,6 @@ int cxl_start_context(struct cxl_context *ctx, u64 wed,
 			cxl_context_mm_count_put(ctx);
 		goto out;
 	}
-
 	ctx->status = STARTED;
 out:
 	mutex_unlock(&ctx->status_mutex);
diff --git a/drivers/misc/cxl/file.c b/drivers/misc/cxl/file.c
index 0761271d68c5..3ba6a60e0a6d 100644
--- a/drivers/misc/cxl/file.c
+++ b/drivers/misc/cxl/file.c
@@ -222,8 +222,17 @@ static long afu_ioctl_start_work(struct cxl_context *ctx,
 	cxl_context_mm_count_get(ctx);
 
 	/* decrement the use count */
-	if (ctx->mm)
+	if (ctx->mm) {
 		mmput(ctx->mm);
+#ifdef CONFIG_PPC_BOOK3S_64
+		mm_context_set_global_tlbi(&ctx->mm->context);
+		/*
+		 * Barrier guarantees that the device will receive all
+		 * TLBIs from that point on
+		 */
+		smp_wmb();
+#endif
+	}
 
 	trace_cxl_attach(ctx, work.work_element_descriptor, work.num_interrupts, amr);
 
@@ -236,7 +245,6 @@ static long afu_ioctl_start_work(struct cxl_context *ctx,
 		cxl_context_mm_count_put(ctx);
 		goto out;
 	}
-
 	ctx->status = STARTED;
 	rc = 0;
 out:
-- 
2.11.0