MSI support for platform devices.

Signed-off-by: Vikas Gupta <vikas.gu...@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

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