[RFC, v0 1/3] vfio/platform: add support for msi

[Vikas Gupta <vikas.gupta@broadcom.com>]

[-- Attachment #1: Type: text/plain, Size: 15647 bytes --]

MSI support for platform devices.

Signed-off-by: Vikas Gupta <vikas.gupta@broadcom.com>
---
 drivers/vfio/platform/vfio_platform_common.c  |  84 ++++++-
 drivers/vfio/platform/vfio_platform_irq.c     | 235 +++++++++++++++++-
 drivers/vfio/platform/vfio_platform_private.h |  23 ++
 include/uapi/linux/vfio.h                     |   1 +
 4 files changed, 329 insertions(+), 14 deletions(-)

diff --git a/drivers/vfio/platform/vfio_platform_common.c b/drivers/vfio/platform/vfio_platform_common.c
index c0771a9567fb..c713f4e4c552 100644
--- a/drivers/vfio/platform/vfio_platform_common.c
+++ b/drivers/vfio/platform/vfio_platform_common.c
@@ -26,6 +26,10 @@
 #define VFIO_PLATFORM_IS_ACPI(vdev) ((vdev)->acpihid != NULL)
 
 static LIST_HEAD(reset_list);
+
+/* devices having MSI support */
+static LIST_HEAD(msi_list);
+
 static DEFINE_MUTEX(driver_lock);
 
 static vfio_platform_reset_fn_t vfio_platform_lookup_reset(const char *compat,
@@ -47,6 +51,26 @@ static vfio_platform_reset_fn_t vfio_platform_lookup_reset(const char *compat,
 	return reset_fn;
 }
 
+static bool vfio_platform_lookup_msi(struct vfio_platform_device *vdev)
+{
+	bool has_msi = false;
+	struct vfio_platform_msi_node *iter;
+
+	mutex_lock(&driver_lock);
+	list_for_each_entry(iter, &msi_list, link) {
+		if (!strcmp(iter->compat, vdev->compat) &&
+		    try_module_get(iter->owner)) {
+			vdev->msi_module = iter->owner;
+			vdev->of_get_msi = iter->of_get_msi;
+			vdev->of_msi_write = iter->of_msi_write;
+			has_msi = true;
+			break;
+		}
+	}
+	mutex_unlock(&driver_lock);
+	return has_msi;
+}
+
 static int vfio_platform_acpi_probe(struct vfio_platform_device *vdev,
 				    struct device *dev)
 {
@@ -110,6 +134,11 @@ static bool vfio_platform_has_reset(struct vfio_platform_device *vdev)
 	return vdev->of_reset ? true : false;
 }
 
+static bool vfio_platform_has_msi(struct vfio_platform_device *vdev)
+{
+	return vdev->of_get_msi ? true : false;
+}
+
 static int vfio_platform_get_reset(struct vfio_platform_device *vdev)
 {
 	if (VFIO_PLATFORM_IS_ACPI(vdev))
@@ -126,6 +155,19 @@ static int vfio_platform_get_reset(struct vfio_platform_device *vdev)
 	return vdev->of_reset ? 0 : -ENOENT;
 }
 
+static int vfio_platform_get_msi(struct vfio_platform_device *vdev)
+{
+	bool has_msi;
+
+	has_msi = vfio_platform_lookup_msi(vdev);
+	if (!has_msi) {
+		request_module("vfio-msi:%s", vdev->compat);
+		has_msi = vfio_platform_lookup_msi(vdev);
+	}
+
+	return has_msi ? 0 : -ENOENT;
+}
+
 static void vfio_platform_put_reset(struct vfio_platform_device *vdev)
 {
 	if (VFIO_PLATFORM_IS_ACPI(vdev))
@@ -135,6 +177,12 @@ static void vfio_platform_put_reset(struct vfio_platform_device *vdev)
 		module_put(vdev->reset_module);
 }
 
+static void vfio_platform_put_msi(struct vfio_platform_device *vdev)
+{
+	if (vdev->of_get_msi)
+		module_put(vdev->msi_module);
+}
+
 static int vfio_platform_regions_init(struct vfio_platform_device *vdev)
 {
 	int cnt = 0, i;
@@ -313,6 +361,10 @@ static long vfio_platform_ioctl(void *device_data,
 
 		if (vfio_platform_has_reset(vdev))
 			vdev->flags |= VFIO_DEVICE_FLAGS_RESET;
+
+		if (vfio_platform_has_msi(vdev))
+			vdev->flags |= VFIO_DEVICE_FLAGS_MSI;
+
 		info.flags = vdev->flags;
 		info.num_regions = vdev->num_regions;
 		info.num_irqs = vdev->num_irqs;
@@ -679,11 +731,15 @@ int vfio_platform_probe_common(struct vfio_platform_device *vdev,
 		return ret;
 	}
 
+	ret = vfio_platform_get_msi(vdev);
+	if (ret)
+		dev_info(vdev->device, "msi not supported\n");
+
 	group = vfio_iommu_group_get(dev);
 	if (!group) {
 		dev_err(dev, "No IOMMU group for device %s\n", vdev->name);
 		ret = -EINVAL;
-		goto put_reset;
+		goto put_msi;
 	}
 
 	ret = vfio_add_group_dev(dev, &vfio_platform_ops, vdev);
@@ -697,6 +753,8 @@ int vfio_platform_probe_common(struct vfio_platform_device *vdev,
 
 put_iommu:
 	vfio_iommu_group_put(group, dev);
+put_msi:
+	vfio_platform_put_msi(vdev);
 put_reset:
 	vfio_platform_put_reset(vdev);
 	return ret;
@@ -745,6 +803,30 @@ void vfio_platform_unregister_reset(const char *compat,
 }
 EXPORT_SYMBOL_GPL(vfio_platform_unregister_reset);
 
+void __vfio_platform_register_msi(struct vfio_platform_msi_node *node)
+{
+	mutex_lock(&driver_lock);
+	list_add(&node->link, &msi_list);
+	mutex_unlock(&driver_lock);
+}
+EXPORT_SYMBOL_GPL(__vfio_platform_register_msi);
+
+void vfio_platform_unregister_msi(const char *compat)
+{
+	struct vfio_platform_msi_node *iter, *temp;
+
+	mutex_lock(&driver_lock);
+	list_for_each_entry_safe(iter, temp, &msi_list, link) {
+		if (!strcmp(iter->compat, compat)) {
+			list_del(&iter->link);
+			break;
+		}
+	}
+
+	mutex_unlock(&driver_lock);
+}
+EXPORT_SYMBOL_GPL(vfio_platform_unregister_msi);
+
 MODULE_VERSION(DRIVER_VERSION);
 MODULE_LICENSE("GPL v2");
 MODULE_AUTHOR(DRIVER_AUTHOR);
diff --git a/drivers/vfio/platform/vfio_platform_irq.c b/drivers/vfio/platform/vfio_platform_irq.c
index c5b09ec0a3c9..14b544c3aa42 100644
--- a/drivers/vfio/platform/vfio_platform_irq.c
+++ b/drivers/vfio/platform/vfio_platform_irq.c
@@ -8,10 +8,12 @@
 
 #include <linux/eventfd.h>
 #include <linux/interrupt.h>
+#include <linux/eventfd.h>
 #include <linux/slab.h>
 #include <linux/types.h>
 #include <linux/vfio.h>
 #include <linux/irq.h>
+#include <linux/msi.h>
 
 #include "vfio_platform_private.h"
 
@@ -253,6 +255,176 @@ static int vfio_platform_set_irq_trigger(struct vfio_platform_device *vdev,
 	return 0;
 }
 
+/* MSI/MSIX */
+static irqreturn_t vfio_msihandler(int irq, void *arg)
+{
+	struct eventfd_ctx *trigger = arg;
+
+	eventfd_signal(trigger, 1);
+	return IRQ_HANDLED;
+}
+
+static void msi_write(struct msi_desc *desc, struct msi_msg *msg)
+{
+	struct device *dev = msi_desc_to_dev(desc);
+	struct vfio_device *device = dev_get_drvdata(dev);
+	struct vfio_platform_device *vdev = (struct vfio_platform_device *)
+						vfio_device_data(device);
+
+	vdev->of_msi_write(vdev, desc, msg);
+}
+
+static int vfio_msi_enable(struct vfio_platform_device *vdev, int nvec)
+{
+	int ret;
+	int msi_idx = 0;
+	struct msi_desc *desc;
+	struct device *dev = vdev->device;
+	u32 msi_off = vdev->num_irqs - vdev->num_msis;
+
+	/* Allocate platform MSIs */
+	ret = platform_msi_domain_alloc_irqs(dev, nvec, msi_write);
+	if (ret < 0)
+		return ret;
+
+	for_each_msi_entry(desc, dev) {
+		vdev->irqs[msi_off + msi_idx].hwirq = desc->irq;
+		msi_idx++;
+	}
+
+	vdev->num_msis = nvec;
+	vdev->config_msi = 1;
+
+	return 0;
+}
+
+static int vfio_msi_set_vector_signal(struct vfio_platform_device *vdev,
+				      int vector, int fd)
+{
+	struct eventfd_ctx *trigger;
+	int irq, ret;
+	u32 msi_off = vdev->num_irqs - vdev->num_msis;
+
+	if (vector < 0 || vector >= vdev->num_msis)
+		return -EINVAL;
+
+	irq = vdev->irqs[msi_off + vector].hwirq;
+
+	if (vdev->irqs[vector].trigger) {
+		free_irq(irq, vdev->irqs[vector].trigger);
+		kfree(vdev->irqs[vector].name);
+		eventfd_ctx_put(vdev->irqs[vector].trigger);
+		vdev->irqs[vector].trigger = NULL;
+	}
+
+	if (fd < 0)
+		return 0;
+
+	vdev->irqs[vector].name = kasprintf(GFP_KERNEL,
+					    "vfio-msi[%d]", vector);
+	if (!vdev->irqs[vector].name)
+		return -ENOMEM;
+
+	trigger = eventfd_ctx_fdget(fd);
+	if (IS_ERR(trigger)) {
+		kfree(vdev->irqs[vector].name);
+		return PTR_ERR(trigger);
+	}
+
+	ret = request_irq(irq, vfio_msihandler, 0,
+			  vdev->irqs[vector].name, trigger);
+	if (ret) {
+		kfree(vdev->irqs[vector].name);
+		eventfd_ctx_put(trigger);
+		return ret;
+	}
+
+	vdev->irqs[vector].trigger = trigger;
+
+	return 0;
+}
+
+static int vfio_msi_set_block(struct vfio_platform_device *vdev, unsigned int start,
+			      unsigned int count, int32_t *fds)
+{
+	int i, j, ret = 0;
+
+	if (start >= vdev->num_msis || start + count > vdev->num_msis)
+		return -EINVAL;
+
+	for (i = 0, j = start; i < count && !ret; i++, j++) {
+		int fd = fds ? fds[i] : -1;
+
+		ret = vfio_msi_set_vector_signal(vdev, j, fd);
+	}
+
+	if (ret) {
+		for (--j; j >= (int)start; j--)
+			vfio_msi_set_vector_signal(vdev, j, -1);
+	}
+
+	return ret;
+}
+
+static void vfio_msi_disable(struct vfio_platform_device *vdev)
+{
+	struct device *dev = vdev->device;
+
+	vfio_msi_set_block(vdev, 0, vdev->num_msis, NULL);
+	platform_msi_domain_free_irqs(dev);
+
+	vdev->config_msi = 0;
+	vdev->num_msis = 0;
+}
+
+static int vfio_set_msi_trigger(struct vfio_platform_device *vdev,
+				unsigned int index, unsigned int start,
+				unsigned int count, uint32_t flags, void *data)
+{
+	int i;
+
+	if (start + count > vdev->num_msis)
+		return -EINVAL;
+
+	if (!count && (flags & VFIO_IRQ_SET_DATA_NONE)) {
+		vfio_msi_disable(vdev);
+		return 0;
+	}
+
+	if (flags & VFIO_IRQ_SET_DATA_EVENTFD) {
+		s32 *fds = data;
+		int ret;
+
+		if (vdev->config_msi)
+			return vfio_msi_set_block(vdev, start, count,
+						  fds);
+		ret = vfio_msi_enable(vdev, start + count);
+		if (ret)
+			return ret;
+
+		ret = vfio_msi_set_block(vdev, start, count, fds);
+		if (ret)
+			vfio_msi_disable(vdev);
+
+		return ret;
+	}
+
+	for (i = start; i < start + count; i++) {
+		if (!vdev->irqs[i].trigger)
+			continue;
+		if (flags & VFIO_IRQ_SET_DATA_NONE) {
+			eventfd_signal(vdev->irqs[i].trigger, 1);
+		} else if (flags & VFIO_IRQ_SET_DATA_BOOL) {
+			u8 *bools = data;
+
+			if (bools[i - start])
+				eventfd_signal(vdev->irqs[i].trigger, 1);
+		}
+	}
+
+	return 0;
+}
+
 int vfio_platform_set_irqs_ioctl(struct vfio_platform_device *vdev,
 				 uint32_t flags, unsigned index, unsigned start,
 				 unsigned count, void *data)
@@ -261,16 +433,29 @@ int vfio_platform_set_irqs_ioctl(struct vfio_platform_device *vdev,
 		    unsigned start, unsigned count, uint32_t flags,
 		    void *data) = NULL;
 
-	switch (flags & VFIO_IRQ_SET_ACTION_TYPE_MASK) {
-	case VFIO_IRQ_SET_ACTION_MASK:
-		func = vfio_platform_set_irq_mask;
-		break;
-	case VFIO_IRQ_SET_ACTION_UNMASK:
-		func = vfio_platform_set_irq_unmask;
-		break;
-	case VFIO_IRQ_SET_ACTION_TRIGGER:
-		func = vfio_platform_set_irq_trigger;
-		break;
+	struct vfio_platform_irq *irq = &vdev->irqs[index];
+
+	if (!irq->is_msi) {
+		switch (flags & VFIO_IRQ_SET_ACTION_TYPE_MASK) {
+		case VFIO_IRQ_SET_ACTION_MASK:
+			func = vfio_platform_set_irq_mask;
+			break;
+		case VFIO_IRQ_SET_ACTION_UNMASK:
+			func = vfio_platform_set_irq_unmask;
+			break;
+		case VFIO_IRQ_SET_ACTION_TRIGGER:
+			func = vfio_platform_set_irq_trigger;
+			break;
+		}
+	} else {
+		switch (flags & VFIO_IRQ_SET_ACTION_TYPE_MASK) {
+		case VFIO_IRQ_SET_ACTION_MASK:
+		case VFIO_IRQ_SET_ACTION_UNMASK:
+			break;
+		case VFIO_IRQ_SET_ACTION_TRIGGER:
+			func = vfio_set_msi_trigger;
+			break;
+		}
 	}
 
 	if (!func)
@@ -282,11 +467,17 @@ int vfio_platform_set_irqs_ioctl(struct vfio_platform_device *vdev,
 int vfio_platform_irq_init(struct vfio_platform_device *vdev)
 {
 	int cnt = 0, i;
+	int msi_cnt = 0;
 
 	while (vdev->get_irq(vdev, cnt) >= 0)
 		cnt++;
 
-	vdev->irqs = kcalloc(cnt, sizeof(struct vfio_platform_irq), GFP_KERNEL);
+	if (vdev->of_get_msi)
+		msi_cnt = vdev->of_get_msi(vdev);
+	vdev->num_msis = msi_cnt;
+
+	vdev->irqs = kcalloc(cnt + msi_cnt, sizeof(struct vfio_platform_irq),
+			     GFP_KERNEL);
 	if (!vdev->irqs)
 		return -ENOMEM;
 
@@ -309,7 +500,18 @@ int vfio_platform_irq_init(struct vfio_platform_device *vdev)
 		vdev->irqs[i].masked = false;
 	}
 
-	vdev->num_irqs = cnt;
+	for (i = cnt; i < msi_cnt + cnt; i++) {
+		spin_lock_init(&vdev->irqs[i].lock);
+
+		vdev->irqs[i].flags = VFIO_IRQ_INFO_EVENTFD;
+
+		vdev->irqs[i].count = 1;
+		vdev->irqs[i].hwirq = 0;
+		vdev->irqs[i].masked = false;
+		vdev->irqs[i].is_msi = true;
+	}
+
+	vdev->num_irqs = cnt + msi_cnt;
 
 	return 0;
 err:
@@ -320,10 +522,17 @@ int vfio_platform_irq_init(struct vfio_platform_device *vdev)
 void vfio_platform_irq_cleanup(struct vfio_platform_device *vdev)
 {
 	int i;
+	int non_msi_cnt = vdev->num_irqs - vdev->num_msis;
 
-	for (i = 0; i < vdev->num_irqs; i++)
+	for (i = 0; i < non_msi_cnt; i++)
 		vfio_set_trigger(vdev, i, -1, NULL);
 
+	if (vdev->num_msis) {
+		vfio_set_msi_trigger(vdev, 0, 0, 0,
+				     VFIO_IRQ_SET_DATA_NONE, NULL);
+		vdev->num_msis = 0;
+	}
+
 	vdev->num_irqs = 0;
 	kfree(vdev->irqs);
 }
diff --git a/drivers/vfio/platform/vfio_platform_private.h b/drivers/vfio/platform/vfio_platform_private.h
index 289089910643..2aea445e1071 100644
--- a/drivers/vfio/platform/vfio_platform_private.h
+++ b/drivers/vfio/platform/vfio_platform_private.h
@@ -9,6 +9,7 @@
 
 #include <linux/types.h>
 #include <linux/interrupt.h>
+#include <linux/msi.h>
 
 #define VFIO_PLATFORM_OFFSET_SHIFT   40
 #define VFIO_PLATFORM_OFFSET_MASK (((u64)(1) << VFIO_PLATFORM_OFFSET_SHIFT) - 1)
@@ -26,6 +27,7 @@ struct vfio_platform_irq {
 	char			*name;
 	struct eventfd_ctx	*trigger;
 	bool			masked;
+	bool			is_msi;
 	spinlock_t		lock;
 	struct virqfd		*unmask;
 	struct virqfd		*mask;
@@ -46,13 +48,16 @@ struct vfio_platform_device {
 	u32				num_regions;
 	struct vfio_platform_irq	*irqs;
 	u32				num_irqs;
+	u32				num_msis;
 	int				refcnt;
 	struct mutex			igate;
 	struct module			*parent_module;
 	const char			*compat;
 	const char			*acpihid;
 	struct module			*reset_module;
+	struct module			*msi_module;
 	struct device			*device;
+	int				config_msi;
 
 	/*
 	 * These fields should be filled by the bus specific binder
@@ -65,11 +70,19 @@ struct vfio_platform_device {
 		(*get_resource)(struct vfio_platform_device *vdev, int i);
 	int	(*get_irq)(struct vfio_platform_device *vdev, int i);
 	int	(*of_reset)(struct vfio_platform_device *vdev);
+	u32	(*of_get_msi)(struct vfio_platform_device *vdev);
+	int	(*of_msi_write)(struct vfio_platform_device *vdev,
+				struct msi_desc *desc,
+				struct msi_msg *msg);
 
 	bool				reset_required;
 };
 
 typedef int (*vfio_platform_reset_fn_t)(struct vfio_platform_device *vdev);
+typedef u32 (*vfio_platform_get_msi_fn_t)(struct vfio_platform_device *vdev);
+typedef int (*vfio_platform_msi_write_fn_t)(struct vfio_platform_device *vdev,
+					    struct msi_desc *desc,
+					    struct msi_msg *msg);
 
 struct vfio_platform_reset_node {
 	struct list_head link;
@@ -78,6 +91,14 @@ struct vfio_platform_reset_node {
 	vfio_platform_reset_fn_t of_reset;
 };
 
+struct vfio_platform_msi_node {
+	struct list_head link;
+	char *compat;
+	struct module *owner;
+	vfio_platform_get_msi_fn_t of_get_msi;
+	vfio_platform_msi_write_fn_t of_msi_write;
+};
+
 extern int vfio_platform_probe_common(struct vfio_platform_device *vdev,
 				      struct device *dev);
 extern struct vfio_platform_device *vfio_platform_remove_common
@@ -94,6 +115,8 @@ extern int vfio_platform_set_irqs_ioctl(struct vfio_platform_device *vdev,
 extern void __vfio_platform_register_reset(struct vfio_platform_reset_node *n);
 extern void vfio_platform_unregister_reset(const char *compat,
 					   vfio_platform_reset_fn_t fn);
+void __vfio_platform_register_msi(struct vfio_platform_msi_node *n);
+void vfio_platform_unregister_msi(const char *compat);
 #define vfio_platform_register_reset(__compat, __reset)		\
 static struct vfio_platform_reset_node __reset ## _node = {	\
 	.owner = THIS_MODULE,					\
diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
index 2f313a238a8f..aab051e8338d 100644
--- a/include/uapi/linux/vfio.h
+++ b/include/uapi/linux/vfio.h
@@ -203,6 +203,7 @@ struct vfio_device_info {
 #define VFIO_DEVICE_FLAGS_AP	(1 << 5)	/* vfio-ap device */
 #define VFIO_DEVICE_FLAGS_FSL_MC (1 << 6)	/* vfio-fsl-mc device */
 #define VFIO_DEVICE_FLAGS_CAPS	(1 << 7)	/* Info supports caps */
+#define VFIO_DEVICE_FLAGS_MSI	(1 << 8)	/* Device supports msi */
 	__u32	num_regions;	/* Max region index + 1 */
 	__u32	num_irqs;	/* Max IRQ index + 1 */
 	__u32   cap_offset;	/* Offset within info struct of first cap */
-- 
2.17.1


[-- Attachment #2: S/MIME Cryptographic Signature --]
[-- Type: application/pkcs7-signature, Size: 4163 bytes --]