[Qemu-devel] [PATCH 06/18] virtio: find version 1.0 virtio capabilities

[Gerd Hoffmann <kraxel@redhat.com>]

virtio 1.0 specifies the location of the various virtio regions
using pci capabilities.  Look them up and store the results.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 src/hw/virtio-pci.c | 55 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/hw/virtio-pci.h |  8 ++++++++
 2 files changed, 63 insertions(+)

diff --git a/src/hw/virtio-pci.c b/src/hw/virtio-pci.c
index ed5bfcb..2abe601 100644
--- a/src/hw/virtio-pci.c
+++ b/src/hw/virtio-pci.c
@@ -88,6 +88,61 @@ fail:
 struct vp_device *vp_init_simple(struct pci_device *pci)
 {
     struct vp_device *vp = malloc_low(sizeof(*vp));
+    u8 cap = pci_find_capability(pci, PCI_CAP_ID_VNDR, 0);
+    struct vp_cap *vp_cap;
+    u32 addr, offset;
+    u8 type;
+
+    memset(vp, 0, sizeof(*vp));
+    while (cap != 0) {
+        type = pci_config_readb(pci->bdf, cap +
+                                offsetof(struct virtio_pci_cap, cfg_type));
+        switch (type) {
+        case VIRTIO_PCI_CAP_COMMON_CFG:
+            vp_cap = &vp->common;
+            break;
+        case VIRTIO_PCI_CAP_NOTIFY_CFG:
+            vp_cap = &vp->notify;
+            break;
+        case VIRTIO_PCI_CAP_ISR_CFG:
+            vp_cap = &vp->isr;
+            break;
+        case VIRTIO_PCI_CAP_DEVICE_CFG:
+            vp_cap = &vp->device;
+            break;
+        default:
+            vp_cap = NULL;
+            break;
+        }
+        if (vp_cap) {
+            vp_cap->cap = cap;
+            vp_cap->bar = pci_config_readb(pci->bdf, cap +
+                                           offsetof(struct virtio_pci_cap, bar));
+            offset = pci_config_readl(pci->bdf, cap +
+                                      offsetof(struct virtio_pci_cap, offset));
+            addr = pci_config_readl(pci->bdf, PCI_BASE_ADDRESS_0 + 4 * vp_cap->bar);
+            if (addr & PCI_BASE_ADDRESS_SPACE_IO) {
+                vp_cap->is_io = 1;
+                addr &= PCI_BASE_ADDRESS_IO_MASK;
+            } else {
+                vp_cap->is_io = 0;
+                addr &= PCI_BASE_ADDRESS_MEM_MASK;
+            }
+            vp_cap->addr = addr + offset;
+            dprintf(3, "pci dev %x:%x virtio cap at 0x%x type %d "
+                    "bar %d at 0x%08x off +0x%04x [%s]\n",
+                    pci_bdf_to_bus(pci->bdf), pci_bdf_to_dev(pci->bdf),
+                    vp_cap->cap, type, vp_cap->bar, addr, offset,
+                    vp_cap->is_io ? "io" : "mmio");
+        }
+
+        cap = pci_find_capability(pci, PCI_CAP_ID_VNDR, cap);
+    }
+
+    if (vp->common.cap && vp->notify.cap && vp->isr.cap && vp->device.cap) {
+        dprintf(1, "pci dev %x:%x supports virtio 1.0\n",
+                pci_bdf_to_bus(pci->bdf), pci_bdf_to_dev(pci->bdf));
+    }
 
     vp->ioaddr = pci_config_readl(pci->bdf, PCI_BASE_ADDRESS_0) &
         PCI_BASE_ADDRESS_IO_MASK;
diff --git a/src/hw/virtio-pci.h b/src/hw/virtio-pci.h
index e6f9c0b..893a7dd 100644
--- a/src/hw/virtio-pci.h
+++ b/src/hw/virtio-pci.h
@@ -99,8 +99,16 @@ typedef struct virtio_pci_isr {
 } virtio_pci_isr;
 
 
+struct vp_cap {
+    u32 addr;
+    u8 cap;
+    u8 bar;
+    u8 is_io;
+};
+
 struct vp_device {
     unsigned int ioaddr;
+    struct vp_cap common, notify, isr, device;
 };
 
 static inline u32 vp_get_features(struct vp_device *vp)
-- 
1.8.3.1