This patch changes virtio_pci to use a shared memory area for virtio config
info instead of using the PCI configuration space. This is closer semantically
to what the virtio API exposes and is it a lot easier to implement on both
ends.
Signed-off-by: Anthony Liguori <aliguori@xxxxxxxxxx>
diff --git a/drivers/virtio/virtio_pci.c b/drivers/virtio/virtio_pci.c
index eb9a8e0..7e6e453 100644
--- a/drivers/virtio/virtio_pci.c
+++ b/drivers/virtio/virtio_pci.c
@@ -39,6 +39,12 @@ struct virtio_pci_device
/* the IO mapping for the PCI config space */
void *ioaddr;
+ /* the shared device configuration */
+ void *config;
+
+ /* the size of the shared device configuration */
+ u32 config_len;
+
/* a list of queues so we can dispatch IRQs */
spinlock_t lock;
struct list_head virtqueues;
@@ -111,47 +117,12 @@ static void vp_get(struct virtio_device *vdev, unsigned offset,
void *buf, unsigned len)
{
struct virtio_pci_device *vp_dev = to_vp_device(vdev);
- void *ioaddr = vp_dev->ioaddr + VIRTIO_PCI_CONFIG + offset;
-
- /* We translate appropriately sized get requests into more natural
- * IO operations. These functions also take care of endianness
- * conversion. */
- switch (len) {
- case 1: {
- u8 val;
- val = ioread8(ioaddr);
- memcpy(buf, &val, sizeof(val));
- break;
- }
- case 2: {
- u16 val;
- val = ioread16(ioaddr);
- memcpy(buf, &val, sizeof(val));
- break;
- }
- case 4: {
- u32 val;
- val = ioread32(ioaddr);
- memcpy(buf, &val, sizeof(val));
- break;
- }
- case 8: {
- u64 val;
- val = (u64)ioread32(ioaddr) << 32;
- val |= ioread32(ioaddr + 4);
- memcpy(buf, &val, sizeof(val));
- break;
- }
- default: {
- uint8_t *ptr = buf;
- int i;
+ BUG_ON(vp_dev->config == NULL);
- for (i = 0; i < len; i++)
- ptr[i] = ioread8(ioaddr + i);
- break;
- }
- }
+ BUG_ON(vp_dev->config_len < (offset + len));
+
+ memcpy(buf, vp_dev->config + offset, len);
}
/* the config->set() implementation. it's symmetric to the config->get()
@@ -160,43 +131,10 @@ static void vp_set(struct virtio_device *vdev, unsigned offset,
const void *buf, unsigned len)
{
struct virtio_pci_device *vp_dev = to_vp_device(vdev);
- void *ioaddr = vp_dev->ioaddr + VIRTIO_PCI_CONFIG + offset;
-
- switch (len) {
- case 1: {
- u8 val;
- memcpy(&val, buf, sizeof(val));
- iowrite8(val, ioaddr);
- break;
- }
- case 2: {
- u16 val;
- memcpy(&val, buf, sizeof(val));
- iowrite16(val, ioaddr);
- break;
- }
- case 4: {
- u32 val;
- memcpy(&val, buf, sizeof(val));
- iowrite32(val, ioaddr);
- break;
- }
- case 8: {
- u64 val;
- memcpy(&val, buf, sizeof(val));
- iowrite32(val >> 32, ioaddr);
- iowrite32(val, ioaddr + 4);
- break;
- }
- default: {
- const uint8_t *ptr = buf;
- int i;
- for (i = 0; i < len; i++)
- iowrite8(ptr[i], ioaddr + i);
- break;
- }
- }
+ BUG_ON(vp_dev->config_len < (offset + len));
+
+ memcpy(vp_dev->config + offset, buf, len);
}
/* config->{get,set}_status() implementations */
@@ -281,7 +219,7 @@ static struct virtqueue *vp_find_vq(struct virtio_device *vdev, unsigned index,
info->queue_index = index;
info->num = num;
- info->queue = kmalloc(vring_size(num), GFP_KERNEL | __GFP_ZERO);
+ info->queue = kzalloc(PAGE_ALIGN(vring_size(num)), GFP_KERNEL);
if (info->queue == NULL) {
err = -ENOMEM;
goto out_info;
@@ -390,11 +328,25 @@ static int __devinit virtio_pci_probe(struct pci_dev *pci_dev,
vp_dev->vdev.id.vendor = pci_dev->subsystem_vendor;
vp_dev->vdev.id.device = pci_dev->subsystem_device;
+ vp_dev->config_len = ioread32(vp_dev->ioaddr + VIRTIO_PCI_CONFIG_LEN);
+ if (vp_dev->config_len) {
+ /* round up to nearest page size to ensure proper alignment */
+ vp_dev->config = kzalloc(PAGE_ALIGN(vp_dev->config_len),
+ GFP_KERNEL);
+ if (vp_dev->config == NULL)
+ goto out_set_drvdata;
+
+ /* tell the host about our config space */
+ iowrite32(virt_to_phys(vp_dev->config) >> PAGE_SHIFT,
+ vp_dev->ioaddr + VIRTIO_PCI_CONFIG_PFN);
+ } else
+ vp_dev->config = NULL;
+
/* register a handler for the queue with the PCI device's interrupt */
err = request_irq(vp_dev->pci_dev->irq, vp_interrupt, IRQF_SHARED,
vp_dev->vdev.dev.bus_id, vp_dev);
if (err)
- goto out_set_drvdata;
+ goto out_alloc_config;
/* finally register the virtio device */
err = register_virtio_device(&vp_dev->vdev);
@@ -405,6 +357,8 @@ static int __devinit virtio_pci_probe(struct pci_dev *pci_dev,
out_req_irq:
free_irq(pci_dev->irq, vp_dev);
+out_alloc_config:
+ kfree(vp_dev->config);
out_set_drvdata:
pci_set_drvdata(pci_dev, NULL);
pci_iounmap(pci_dev, vp_dev->ioaddr);
@@ -422,6 +376,7 @@ static void __devexit virtio_pci_remove(struct pci_dev *pci_dev)
struct virtio_pci_device *vp_dev = pci_get_drvdata(pci_dev);
free_irq(pci_dev->irq, vp_dev);
+ kfree(vp_dev->config);
pci_set_drvdata(pci_dev, NULL);
pci_iounmap(pci_dev, vp_dev->ioaddr);
pci_release_regions(pci_dev);
diff --git a/include/linux/virtio_pci.h b/include/linux/virtio_pci.h
index 4b28409..79e6641 100644
--- a/include/linux/virtio_pci.h
+++ b/include/linux/virtio_pci.h
@@ -45,8 +45,12 @@
* a read-and-acknowledge. */
#define VIRTIO_PCI_ISR 19
-/* The remaining space is defined by each driver as the per-driver
- * configuration space */
-#define VIRTIO_PCI_CONFIG 20
+/* A 32-bit r/o configuration size. This is the amount of memory required
+ * to be allocated for VIRTIO_PCI_CONFIG_PFN. */
+#define VIRTIO_PCI_CONFIG_LEN 20
+
+/* A 32-bit r/w PFN for the shared configuration information. The PA written
+ * by the host must point to at least VIRTIO_PCI_CONFIG_LEN bytes */
+#define VIRTIO_PCI_CONFIG_PFN 24
#endif
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