[PATCH 6/6] vdpa: vp_vdpa: report doorbell location

[Jason Wang]

This patch adds support for reporting doorbell location in vp_vdpa
driver. The doorbell mapping could be then enabled by e.g launching
qemu's virtio-net-pci device with page-per-vq enabled.

Signed-off-by: Jason Wang <jasow...@redhat.com>
---
 drivers/vdpa/vp_vdpa/vp_vdpa.c | 29 +++++++++++++++++++++++++----
 1 file changed, 25 insertions(+), 4 deletions(-)

diff --git a/drivers/vdpa/vp_vdpa/vp_vdpa.c b/drivers/vdpa/vp_vdpa/vp_vdpa.c
index e59c310e2156..a5ca49533138 100644
--- a/drivers/vdpa/vp_vdpa/vp_vdpa.c
+++ b/drivers/vdpa/vp_vdpa/vp_vdpa.c
@@ -30,6 +30,7 @@
 struct vp_vring {
        void __iomem *notify;
        char msix_name[256];
+       resource_size_t notify_pa;
        struct vdpa_callback cb;
        int irq;
 };
@@ -136,7 +137,8 @@ static int find_capability(struct pci_dev *dev, u8 cfg_type,
        return 0;
 }
 
-static void __iomem *map_capability(struct vp_vdpa *vp_vdpa, int off)
+static void __iomem *map_capability(struct vp_vdpa *vp_vdpa, int off,
+                                   resource_size_t *pa)
 {
        struct pci_dev *pdev = vp_vdpa->pdev;
        u32 offset;
@@ -149,6 +151,9 @@ static void __iomem *map_capability(struct vp_vdpa 
*vp_vdpa, int off)
                              off + offsetof(struct virtio_pci_cap, offset),
                              &offset);
 
+       if (pa)
+               *pa = pci_resource_start(pdev, bar) + offset;
+
        return vp_vdpa->base[bar] + offset;
 }
 
@@ -283,6 +288,18 @@ static u64 vp_vdpa_get_vq_state(struct vdpa_device *vdpa, 
u16 qid)
        return 0;
 }
 
+static struct vdpa_notification_area
+vp_vdpa_get_vq_notification(struct vdpa_device *vdpa, u16 qid)
+{
+       struct vp_vdpa *vp_vdpa = vdpa_to_vp(vdpa);
+       struct vdpa_notification_area notify;
+
+       notify.addr = vp_vdpa->vring[qid].notify_pa;
+       notify.size = vp_vdpa->notify_off_multiplier;
+
+       return notify;
+}
+
 static int vp_vdpa_set_vq_state(struct vdpa_device *vdpa, u16 qid,
                                u64 num)
 {
@@ -423,6 +440,7 @@ static const struct vdpa_config_ops vp_vdpa_ops = {
        .set_status     = vp_vdpa_set_status,
        .get_vq_num_max = vp_vdpa_get_vq_num_max,
        .get_vq_state   = vp_vdpa_get_vq_state,
+       .get_vq_notification = vp_vdpa_get_vq_notification,
        .set_vq_state   = vp_vdpa_set_vq_state,
        .set_vq_cb      = vp_vdpa_set_vq_cb,
        .set_vq_ready   = vp_vdpa_set_vq_ready,
@@ -445,6 +463,7 @@ static int vp_vdpa_probe(struct pci_dev *pdev, const struct 
pci_device_id *id)
        struct vp_vdpa *vp_vdpa;
        int common, notify, device, ret, i;
        struct virtio_device_id virtio_id;
+       resource_size_t notify_pa;
        u16 notify_off;
 
        /* We only own devices >= 0x1000 and <= 0x107f: leave the rest. */
@@ -525,9 +544,9 @@ static int vp_vdpa_probe(struct pci_dev *pdev, const struct 
pci_device_id *id)
        if (ret)
                dev_warn(&pdev->dev, "Failed to enable 64-bit or 32-bit DMA.  
Trying to continue, but this might not work.\n");
 
-       vp_vdpa->device = map_capability(vp_vdpa, device);
-       vp_vdpa->notify = map_capability(vp_vdpa, notify);
-       vp_vdpa->common = map_capability(vp_vdpa, common);
+       vp_vdpa->device = map_capability(vp_vdpa, device, NULL);
+       vp_vdpa->notify = map_capability(vp_vdpa, notify, &notify_pa);
+       vp_vdpa->common = map_capability(vp_vdpa, common, NULL);
        vp_vdpa->id = virtio_id;
 
        ret = vdpa_register_device(&vp_vdpa->vdpa);
@@ -545,6 +564,8 @@ static int vp_vdpa_probe(struct pci_dev *pdev, const struct 
pci_device_id *id)
                vp_vdpa->vring[i].irq = -1;
                vp_vdpa->vring[i].notify = vp_vdpa->notify +
                        notify_off * vp_vdpa->notify_off_multiplier;
+               vp_vdpa->vring[i].notify_pa = notify_pa +
+                       notify_off * vp_vdpa->notify_off_multiplier;
        }
 
        return 0;
-- 
2.20.1