[Qemu-devel] [RFC PATCH 5/8] virtio-pci: address space translation service (ATS) support

[Jason Wang <jasowang@redhat.com>]

This patches enable the Address Translation Service support for virtio
pci devices. This is needed for a guest visible Device IOTLB
implementation and will be used by vhost device IOTLB API.

Cc: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 hw/virtio/virtio-pci.c                    | 14 ++++++++++++--
 hw/virtio/virtio-pci.h                    |  4 ++++
 include/standard-headers/linux/pci_regs.h |  1 +
 3 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
index 5508b1c..0c4212c 100644
--- a/hw/virtio/virtio-pci.c
+++ b/hw/virtio/virtio-pci.c
@@ -1821,8 +1821,10 @@ static void virtio_pci_realize(PCIDevice *pci_dev, Error **errp)
 
     address_space_init(&proxy->modern_as, &proxy->modern_cfg, "virtio-pci-cfg-as");
 
-    if (pci_is_express(pci_dev) && pci_bus_is_express(pci_dev->bus) &&
-        !pci_bus_is_root(pci_dev->bus)) {
+    if (pci_is_express(pci_dev) && pci_bus_is_express(pci_dev->bus)) {
+        /* FIXME:
+         * &&!pci_bus_is_root(pci_dev->bus)) {
+         */
         int pos;
 
         pos = pcie_endpoint_cap_init(pci_dev, 0);
@@ -1836,6 +1838,12 @@ static void virtio_pci_realize(PCIDevice *pci_dev, Error **errp)
          * PCI Power Management Interface Specification.
          */
         pci_set_word(pci_dev->config + pos + PCI_PM_PMC, 0x3);
+
+        if (proxy->flags & VIRTIO_PCI_FLAG_ATS) {
+            pcie_add_capability(pci_dev, PCI_EXT_CAP_ID_ATS, 0x1,
+                                256, PCI_EXT_CAP_ATS_SIZEOF);
+        }
+
     } else {
         /*
          * make future invocations of pci_is_express() return false
@@ -1886,6 +1894,8 @@ static Property virtio_pci_properties[] = {
                     VIRTIO_PCI_FLAG_MODERN_PIO_NOTIFY_BIT, false),
     DEFINE_PROP_BIT("x-disable-pcie", VirtIOPCIProxy, flags,
                     VIRTIO_PCI_FLAG_DISABLE_PCIE_BIT, false),
+    DEFINE_PROP_BIT("ats", VirtIOPCIProxy, flags,
+                    VIRTIO_PCI_FLAG_ATS_BIT, false),
     DEFINE_PROP_END_OF_LIST(),
 };
 
diff --git a/hw/virtio/virtio-pci.h b/hw/virtio/virtio-pci.h
index e4548c2..f3b93a0 100644
--- a/hw/virtio/virtio-pci.h
+++ b/hw/virtio/virtio-pci.h
@@ -66,6 +66,7 @@ enum {
     VIRTIO_PCI_FLAG_MIGRATE_EXTRA_BIT,
     VIRTIO_PCI_FLAG_MODERN_PIO_NOTIFY_BIT,
     VIRTIO_PCI_FLAG_DISABLE_PCIE_BIT,
+    VIRTIO_PCI_FLAG_ATS_BIT,
 };
 
 /* Need to activate work-arounds for buggy guests at vmstate load. */
@@ -88,6 +89,9 @@ enum {
 #define VIRTIO_PCI_FLAG_MODERN_PIO_NOTIFY \
     (1 << VIRTIO_PCI_FLAG_MODERN_PIO_NOTIFY_BIT)
 
+/* address space translation service */
+#define VIRTIO_PCI_FLAG_ATS (1 << VIRTIO_PCI_FLAG_ATS_BIT)
+
 typedef struct {
     MSIMessage msg;
     int virq;
diff --git a/include/standard-headers/linux/pci_regs.h b/include/standard-headers/linux/pci_regs.h
index 1becea8..cfb798a 100644
--- a/include/standard-headers/linux/pci_regs.h
+++ b/include/standard-headers/linux/pci_regs.h
@@ -673,6 +673,7 @@
 #define PCI_EXT_CAP_ID_MAX	PCI_EXT_CAP_ID_PASID
 
 #define PCI_EXT_CAP_DSN_SIZEOF	12
+#define PCI_EXT_CAP_ATS_SIZEOF	8
 #define PCI_EXT_CAP_MCAST_ENDPOINT_SIZEOF 40
 
 /* Advanced Error Reporting */
-- 
2.5.0