Another HPA suggestion: that the device be allowed to offer duplicate
capabilities, particularly so it can offer a mem and an I/O bar and let
the guest decide (Linux guest probably doesn't care?).
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Signed-off-by: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
---
drivers/virtio/virtio_pci_legacy.c | 3 ++-
include/linux/virtio_pci.h | 20 ++++++++++++++++----
2 files changed, 18 insertions(+), 5 deletions(-)
diff --git a/drivers/virtio/virtio_pci_legacy.c b/drivers/virtio/virtio_pci_legacy.c
index 501fa79..c7aadcb 100644
--- a/drivers/virtio/virtio_pci_legacy.c
+++ b/drivers/virtio/virtio_pci_legacy.c
@@ -728,7 +728,8 @@ static int virtio_pci_probe(struct pci_dev *pci_dev,
}
/* We leave modern virtio-pci for the modern driver. */
- cap = virtio_pci_find_capability(pci_dev, VIRTIO_PCI_CAP_COMMON_CFG);
+ cap = virtio_pci_find_capability(pci_dev, VIRTIO_PCI_CAP_COMMON_CFG,
+ IORESOURCE_IO|IORESOURCE_MEM);
if (cap) {
if (force_nonlegacy)
dev_info(&pci_dev->dev,
diff --git a/include/linux/virtio_pci.h b/include/linux/virtio_pci.h
index 2714160..6d2816b 100644
--- a/include/linux/virtio_pci.h
+++ b/include/linux/virtio_pci.h
@@ -4,18 +4,30 @@
#define VIRTIO_PCI_NO_LEGACY
#include <uapi/linux/virtio_pci.h>
-/* Returns offset of the capability, or 0. */
-static inline int virtio_pci_find_capability(struct pci_dev *dev, u8 cfg_type)
+/**
+ * virtio_pci_find_capability - walk capabilities to find device info.
+ * @dev: the pci device
+ * @cfg_type: the VIRTIO_PCI_CAP_* value we seek
+ * @ioresource_types: IORESOURCE_MEM and/or IORESOURCE_IO.
+ *
+ * Returns offset of the capability, or 0.
+ */
+static inline int virtio_pci_find_capability(struct pci_dev *dev, u8 cfg_type,
+ u32 ioresource_types)
{
int pos;
for (pos = pci_find_capability(dev, PCI_CAP_ID_VNDR);
pos > 0;
pos = pci_find_next_capability(dev, pos, PCI_CAP_ID_VNDR)) {
- u8 type;
+ u8 type, bar;
pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,
cfg_type), &type);
- if (type == cfg_type)
+ if (type != cfg_type)
+ continue;
+ pci_read_config_byte(dev, pos + offsetof(struct virtio_pci_cap,
+ bar), &bar);
+ if (pci_resource_flags(dev, bar) & ioresource_types)
return pos;
}
return 0;
--
1.7.10.4
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