[PATCH v2 07/13] ocxl: Add AFU interrupt support
From: Frederic Barrat
Date: Tue Jan 23 2018 - 06:33:11 EST
Add user APIs through ioctl to allocate, free, and be notified of an
AFU interrupt.
For opencapi, an AFU can trigger an interrupt on the host by sending a
specific command targeting a 64-bit object handle. On POWER9, this is
implemented by mapping a special page in the address space of a
process and a write to that page will trigger an interrupt.
Signed-off-by: Frederic Barrat <fbarrat@xxxxxxxxxxxxxxxxxx>
---
arch/powerpc/include/asm/pnv-ocxl.h | 3 +
arch/powerpc/platforms/powernv/ocxl.c | 30 ++++++
drivers/misc/ocxl/afu_irq.c | 197 ++++++++++++++++++++++++++++++++++
drivers/misc/ocxl/context.c | 51 ++++++++-
drivers/misc/ocxl/file.c | 34 ++++++
drivers/misc/ocxl/link.c | 28 +++++
drivers/misc/ocxl/ocxl_internal.h | 7 ++
include/uapi/misc/ocxl.h | 9 ++
8 files changed, 357 insertions(+), 2 deletions(-)
create mode 100644 drivers/misc/ocxl/afu_irq.c
diff --git a/arch/powerpc/include/asm/pnv-ocxl.h b/arch/powerpc/include/asm/pnv-ocxl.h
index 398d05b30600..f6945d3bc971 100644
--- a/arch/powerpc/include/asm/pnv-ocxl.h
+++ b/arch/powerpc/include/asm/pnv-ocxl.h
@@ -30,4 +30,7 @@ extern int pnv_ocxl_spa_setup(struct pci_dev *dev, void *spa_mem, int PE_mask,
extern void pnv_ocxl_spa_release(void *platform_data);
extern int pnv_ocxl_spa_remove_pe(void *platform_data, int pe_handle);
+extern int pnv_ocxl_alloc_xive_irq(u32 *irq, u64 *trigger_addr);
+extern void pnv_ocxl_free_xive_irq(u32 irq);
+
#endif /* _ASM_PNV_OCXL_H */
diff --git a/arch/powerpc/platforms/powernv/ocxl.c b/arch/powerpc/platforms/powernv/ocxl.c
index 1faaa4ef6903..fa9b53af3c7b 100644
--- a/arch/powerpc/platforms/powernv/ocxl.c
+++ b/arch/powerpc/platforms/powernv/ocxl.c
@@ -2,6 +2,7 @@
// Copyright 2017 IBM Corp.
#include <asm/pnv-ocxl.h>
#include <asm/opal.h>
+#include <asm/xive.h>
#include <misc/ocxl-config.h>
#include "pci.h"
@@ -483,3 +484,32 @@ int pnv_ocxl_spa_remove_pe(void *platform_data, int pe_handle)
return rc;
}
EXPORT_SYMBOL_GPL(pnv_ocxl_spa_remove_pe);
+
+int pnv_ocxl_alloc_xive_irq(u32 *irq, u64 *trigger_addr)
+{
+ __be64 flags, trigger_page;
+ s64 rc;
+ u32 hwirq;
+
+ hwirq = xive_native_alloc_irq();
+ if (!hwirq)
+ return -ENOENT;
+
+ rc = opal_xive_get_irq_info(hwirq, &flags, NULL, &trigger_page, NULL,
+ NULL);
+ if (rc || !trigger_page) {
+ xive_native_free_irq(hwirq);
+ return -ENOENT;
+ }
+ *irq = hwirq;
+ *trigger_addr = be64_to_cpu(trigger_page);
+ return 0;
+
+}
+EXPORT_SYMBOL_GPL(pnv_ocxl_alloc_xive_irq);
+
+void pnv_ocxl_free_xive_irq(u32 irq)
+{
+ xive_native_free_irq(irq);
+}
+EXPORT_SYMBOL_GPL(pnv_ocxl_free_xive_irq);
diff --git a/drivers/misc/ocxl/afu_irq.c b/drivers/misc/ocxl/afu_irq.c
new file mode 100644
index 000000000000..f40d853de401
--- /dev/null
+++ b/drivers/misc/ocxl/afu_irq.c
@@ -0,0 +1,197 @@
+// SPDX-License-Identifier: GPL-2.0+
+// Copyright 2017 IBM Corp.
+#include <linux/interrupt.h>
+#include <linux/eventfd.h>
+#include <asm/pnv-ocxl.h>
+#include "ocxl_internal.h"
+
+struct afu_irq {
+ int id;
+ int hw_irq;
+ unsigned int virq;
+ char *name;
+ u64 trigger_page;
+ struct eventfd_ctx *ev_ctx;
+};
+
+static int irq_offset_to_id(struct ocxl_context *ctx, u64 offset)
+{
+ return (offset - ctx->afu->irq_base_offset) >> PAGE_SHIFT;
+}
+
+static u64 irq_id_to_offset(struct ocxl_context *ctx, int id)
+{
+ return ctx->afu->irq_base_offset + (id << PAGE_SHIFT);
+}
+
+static irqreturn_t afu_irq_handler(int virq, void *data)
+{
+ struct afu_irq *irq = (struct afu_irq *) data;
+
+ if (irq->ev_ctx)
+ eventfd_signal(irq->ev_ctx, 1);
+ return IRQ_HANDLED;
+}
+
+static int setup_afu_irq(struct ocxl_context *ctx, struct afu_irq *irq)
+{
+ int rc;
+
+ irq->virq = irq_create_mapping(NULL, irq->hw_irq);
+ if (!irq->virq) {
+ pr_err("irq_create_mapping failed\n");
+ return -ENOMEM;
+ }
+ pr_debug("hw_irq %d mapped to virq %u\n", irq->hw_irq, irq->virq);
+
+ irq->name = kasprintf(GFP_KERNEL, "ocxl-afu-%u", irq->virq);
+ if (!irq->name) {
+ irq_dispose_mapping(irq->virq);
+ return -ENOMEM;
+ }
+
+ rc = request_irq(irq->virq, afu_irq_handler, 0, irq->name, irq);
+ if (rc) {
+ kfree(irq->name);
+ irq->name = NULL;
+ irq_dispose_mapping(irq->virq);
+ pr_err("request_irq failed: %d\n", rc);
+ return rc;
+ }
+ return 0;
+}
+
+static void release_afu_irq(struct afu_irq *irq)
+{
+ free_irq(irq->virq, irq);
+ irq_dispose_mapping(irq->virq);
+ kfree(irq->name);
+}
+
+int ocxl_afu_irq_alloc(struct ocxl_context *ctx, u64 *irq_offset)
+{
+ struct afu_irq *irq;
+ int rc;
+
+ irq = kzalloc(sizeof(struct afu_irq), GFP_KERNEL);
+ if (!irq)
+ return -ENOMEM;
+
+ /*
+ * We limit the number of afu irqs per context and per link to
+ * avoid a single process or user depleting the pool of IPIs
+ */
+
+ mutex_lock(&ctx->irq_lock);
+
+ irq->id = idr_alloc(&ctx->irq_idr, irq, 0, MAX_IRQ_PER_CONTEXT,
+ GFP_KERNEL);
+ if (irq->id < 0) {
+ rc = -ENOSPC;
+ goto err_unlock;
+ }
+
+ rc = ocxl_link_irq_alloc(ctx->afu->fn->link, &irq->hw_irq,
+ &irq->trigger_page);
+ if (rc)
+ goto err_idr;
+
+ rc = setup_afu_irq(ctx, irq);
+ if (rc)
+ goto err_alloc;
+
+ *irq_offset = irq_id_to_offset(ctx, irq->id);
+
+ mutex_unlock(&ctx->irq_lock);
+ return 0;
+
+err_alloc:
+ ocxl_link_free_irq(ctx->afu->fn->link, irq->hw_irq);
+err_idr:
+ idr_remove(&ctx->irq_idr, irq->id);
+err_unlock:
+ mutex_unlock(&ctx->irq_lock);
+ kfree(irq);
+ return rc;
+}
+
+static void afu_irq_free(struct afu_irq *irq, struct ocxl_context *ctx)
+{
+ if (ctx->mapping)
+ unmap_mapping_range(ctx->mapping,
+ irq_id_to_offset(ctx, irq->id),
+ 1 << PAGE_SHIFT, 1);
+ release_afu_irq(irq);
+ if (irq->ev_ctx)
+ eventfd_ctx_put(irq->ev_ctx);
+ ocxl_link_free_irq(ctx->afu->fn->link, irq->hw_irq);
+ kfree(irq);
+}
+
+int ocxl_afu_irq_free(struct ocxl_context *ctx, u64 irq_offset)
+{
+ struct afu_irq *irq;
+ int id = irq_offset_to_id(ctx, irq_offset);
+
+ mutex_lock(&ctx->irq_lock);
+
+ irq = idr_find(&ctx->irq_idr, id);
+ if (!irq) {
+ mutex_unlock(&ctx->irq_lock);
+ return -EINVAL;
+ }
+ idr_remove(&ctx->irq_idr, irq->id);
+ afu_irq_free(irq, ctx);
+ mutex_unlock(&ctx->irq_lock);
+ return 0;
+}
+
+void ocxl_afu_irq_free_all(struct ocxl_context *ctx)
+{
+ struct afu_irq *irq;
+ int id;
+
+ mutex_lock(&ctx->irq_lock);
+ idr_for_each_entry(&ctx->irq_idr, irq, id)
+ afu_irq_free(irq, ctx);
+ mutex_unlock(&ctx->irq_lock);
+}
+
+int ocxl_afu_irq_set_fd(struct ocxl_context *ctx, u64 irq_offset, int eventfd)
+{
+ struct afu_irq *irq;
+ struct eventfd_ctx *ev_ctx;
+ int rc = 0, id = irq_offset_to_id(ctx, irq_offset);
+
+ mutex_lock(&ctx->irq_lock);
+ irq = idr_find(&ctx->irq_idr, id);
+ if (!irq) {
+ rc = -EINVAL;
+ goto unlock;
+ }
+
+ ev_ctx = eventfd_ctx_fdget(eventfd);
+ if (IS_ERR(ev_ctx)) {
+ rc = -EINVAL;
+ goto unlock;
+ }
+
+ irq->ev_ctx = ev_ctx;
+unlock:
+ mutex_unlock(&ctx->irq_lock);
+ return rc;
+}
+
+u64 ocxl_afu_irq_get_addr(struct ocxl_context *ctx, u64 irq_offset)
+{
+ struct afu_irq *irq;
+ int id = irq_offset_to_id(ctx, irq_offset);
+ u64 addr = 0;
+
+ mutex_lock(&ctx->irq_lock);
+ irq = idr_find(&ctx->irq_idr, id);
+ if (irq)
+ addr = irq->trigger_page;
+ mutex_unlock(&ctx->irq_lock);
+ return addr;
+}
diff --git a/drivers/misc/ocxl/context.c b/drivers/misc/ocxl/context.c
index b34b836f924c..269149490063 100644
--- a/drivers/misc/ocxl/context.c
+++ b/drivers/misc/ocxl/context.c
@@ -31,6 +31,8 @@ int ocxl_context_init(struct ocxl_context *ctx, struct ocxl_afu *afu,
mutex_init(&ctx->mapping_lock);
init_waitqueue_head(&ctx->events_wq);
mutex_init(&ctx->xsl_error_lock);
+ mutex_init(&ctx->irq_lock);
+ idr_init(&ctx->irq_idr);
/*
* Keep a reference on the AFU to make sure it's valid for the
* duration of the life of the context
@@ -80,6 +82,19 @@ int ocxl_context_attach(struct ocxl_context *ctx, u64 amr)
return rc;
}
+static int map_afu_irq(struct vm_area_struct *vma, unsigned long address,
+ u64 offset, struct ocxl_context *ctx)
+{
+ u64 trigger_addr;
+
+ trigger_addr = ocxl_afu_irq_get_addr(ctx, offset);
+ if (!trigger_addr)
+ return VM_FAULT_SIGBUS;
+
+ vm_insert_pfn(vma, address, trigger_addr >> PAGE_SHIFT);
+ return VM_FAULT_NOPAGE;
+}
+
static int map_pp_mmio(struct vm_area_struct *vma, unsigned long address,
u64 offset, struct ocxl_context *ctx)
{
@@ -118,7 +133,10 @@ static int ocxl_mmap_fault(struct vm_fault *vmf)
pr_debug("%s: pasid %d address 0x%lx offset 0x%llx\n", __func__,
ctx->pasid, vmf->address, offset);
- rc = map_pp_mmio(vma, vmf->address, offset, ctx);
+ if (offset < ctx->afu->irq_base_offset)
+ rc = map_pp_mmio(vma, vmf->address, offset, ctx);
+ else
+ rc = map_afu_irq(vma, vmf->address, offset, ctx);
return rc;
}
@@ -126,6 +144,30 @@ static const struct vm_operations_struct ocxl_vmops = {
.fault = ocxl_mmap_fault,
};
+static int check_mmap_afu_irq(struct ocxl_context *ctx,
+ struct vm_area_struct *vma)
+{
+ /* only one page */
+ if (vma_pages(vma) != 1)
+ return -EINVAL;
+
+ /* check offset validty */
+ if (!ocxl_afu_irq_get_addr(ctx, vma->vm_pgoff << PAGE_SHIFT))
+ return -EINVAL;
+
+ /*
+ * trigger page should only be accessible in write mode.
+ *
+ * It's a bit theoretical, as a page mmaped with only
+ * PROT_WRITE is currently readable, but it doesn't hurt.
+ */
+ if ((vma->vm_flags & VM_READ) || (vma->vm_flags & VM_EXEC) ||
+ !(vma->vm_flags & VM_WRITE))
+ return -EINVAL;
+ vma->vm_flags &= ~(VM_MAYREAD | VM_MAYEXEC);
+ return 0;
+}
+
static int check_mmap_mmio(struct ocxl_context *ctx,
struct vm_area_struct *vma)
{
@@ -139,7 +181,10 @@ int ocxl_context_mmap(struct ocxl_context *ctx, struct vm_area_struct *vma)
{
int rc;
- rc = check_mmap_mmio(ctx, vma);
+ if ((vma->vm_pgoff << PAGE_SHIFT) < ctx->afu->irq_base_offset)
+ rc = check_mmap_mmio(ctx, vma);
+ else
+ rc = check_mmap_afu_irq(ctx, vma);
if (rc)
return rc;
@@ -224,6 +269,8 @@ void ocxl_context_free(struct ocxl_context *ctx)
idr_remove(&ctx->afu->contexts_idr, ctx->pasid);
mutex_unlock(&ctx->afu->contexts_lock);
+ ocxl_afu_irq_free_all(ctx);
+ idr_destroy(&ctx->irq_idr);
/* reference to the AFU taken in ocxl_context_init */
ocxl_afu_put(ctx->afu);
kfree(ctx);
diff --git a/drivers/misc/ocxl/file.c b/drivers/misc/ocxl/file.c
index 6f0befda6a8a..c90c1a578d2f 100644
--- a/drivers/misc/ocxl/file.c
+++ b/drivers/misc/ocxl/file.c
@@ -103,12 +103,17 @@ static long afu_ioctl_attach(struct ocxl_context *ctx,
}
#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" : \
"UNKNOWN")
static long afu_ioctl(struct file *file, unsigned int cmd,
unsigned long args)
{
struct ocxl_context *ctx = file->private_data;
+ struct ocxl_ioctl_irq_fd irq_fd;
+ u64 irq_offset;
long rc;
pr_debug("%s for context %d, command %s\n", __func__, ctx->pasid,
@@ -123,6 +128,35 @@ static long afu_ioctl(struct file *file, unsigned int cmd,
(struct ocxl_ioctl_attach __user *) args);
break;
+ case OCXL_IOCTL_IRQ_ALLOC:
+ rc = ocxl_afu_irq_alloc(ctx, &irq_offset);
+ if (!rc) {
+ rc = copy_to_user((u64 __user *) args, &irq_offset,
+ sizeof(irq_offset));
+ if (rc)
+ ocxl_afu_irq_free(ctx, irq_offset);
+ }
+ break;
+
+ case OCXL_IOCTL_IRQ_FREE:
+ rc = copy_from_user(&irq_offset, (u64 __user *) args,
+ sizeof(irq_offset));
+ if (rc)
+ return -EFAULT;
+ rc = ocxl_afu_irq_free(ctx, irq_offset);
+ break;
+
+ case OCXL_IOCTL_IRQ_SET_FD:
+ rc = copy_from_user(&irq_fd, (u64 __user *) args,
+ sizeof(irq_fd));
+ if (rc)
+ return -EFAULT;
+ if (irq_fd.reserved)
+ return -EINVAL;
+ rc = ocxl_afu_irq_set_fd(ctx, irq_fd.irq_offset,
+ irq_fd.eventfd);
+ break;
+
default:
rc = -EINVAL;
}
diff --git a/drivers/misc/ocxl/link.c b/drivers/misc/ocxl/link.c
index 64d7a98c904a..8bdcef9c3cba 100644
--- a/drivers/misc/ocxl/link.c
+++ b/drivers/misc/ocxl/link.c
@@ -601,3 +601,31 @@ int ocxl_link_remove_pe(void *link_handle, int pasid)
mutex_unlock(&spa->spa_lock);
return rc;
}
+
+int ocxl_link_irq_alloc(void *link_handle, int *hw_irq, u64 *trigger_addr)
+{
+ struct link *link = (struct link *) link_handle;
+ int rc, irq;
+ u64 addr;
+
+ if (atomic_dec_if_positive(&link->irq_available) < 0)
+ return -ENOSPC;
+
+ rc = pnv_ocxl_alloc_xive_irq(&irq, &addr);
+ if (rc) {
+ atomic_inc(&link->irq_available);
+ return rc;
+ }
+
+ *hw_irq = irq;
+ *trigger_addr = addr;
+ return 0;
+}
+
+void ocxl_link_free_irq(void *link_handle, int hw_irq)
+{
+ struct link *link = (struct link *) link_handle;
+
+ pnv_ocxl_free_xive_irq(hw_irq);
+ atomic_inc(&link->irq_available);
+}
diff --git a/drivers/misc/ocxl/ocxl_internal.h b/drivers/misc/ocxl/ocxl_internal.h
index 04fc160c7bd5..a89b88ac67eb 100644
--- a/drivers/misc/ocxl/ocxl_internal.h
+++ b/drivers/misc/ocxl/ocxl_internal.h
@@ -190,4 +190,11 @@ extern void ocxl_context_free(struct ocxl_context *ctx);
extern int ocxl_sysfs_add_afu(struct ocxl_afu *afu);
extern void ocxl_sysfs_remove_afu(struct ocxl_afu *afu);
+extern int ocxl_afu_irq_alloc(struct ocxl_context *ctx, u64 *irq_offset);
+extern int ocxl_afu_irq_free(struct ocxl_context *ctx, u64 irq_offset);
+extern void ocxl_afu_irq_free_all(struct ocxl_context *ctx);
+extern int ocxl_afu_irq_set_fd(struct ocxl_context *ctx, u64 irq_offset,
+ int eventfd);
+extern u64 ocxl_afu_irq_get_addr(struct ocxl_context *ctx, u64 irq_offset);
+
#endif /* _OCXL_INTERNAL_H_ */
diff --git a/include/uapi/misc/ocxl.h b/include/uapi/misc/ocxl.h
index a37e34edf52f..4b0b0b756f3e 100644
--- a/include/uapi/misc/ocxl.h
+++ b/include/uapi/misc/ocxl.h
@@ -32,9 +32,18 @@ struct ocxl_ioctl_attach {
__u64 reserved3;
};
+struct ocxl_ioctl_irq_fd {
+ __u64 irq_offset;
+ __s32 eventfd;
+ __u32 reserved;
+};
+
/* ioctl numbers */
#define OCXL_MAGIC 0xCA
/* AFU devices */
#define OCXL_IOCTL_ATTACH _IOW(OCXL_MAGIC, 0x10, struct ocxl_ioctl_attach)
+#define OCXL_IOCTL_IRQ_ALLOC _IOR(OCXL_MAGIC, 0x11, __u64)
+#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)
#endif /* _UAPI_MISC_OCXL_H */
--
2.14.1