[PATCH 3/7] virtio: Add shared memory capability

[Antonio Caggiano <antonio.caggiano@collabora.com>]

From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>

Define a new capability type 'VIRTIO_PCI_CAP_SHARED_MEMORY_CFG'.
They allow defining shared memory regions with sizes and offsets
of 2^32 and more.
Multiple instances of the capability are allowed and distinguished
by a device-specific 'id'.
Use VIRTIO_GPU_SHM_ID_HOST_VISIBLE as id for virtio-gpu.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Antonio Caggiano <antonio.caggiano@collabora.com>
(cherry picked from commit a5d628a3a3c5e60b98b15ffff197c36a77056115)
---
 hw/display/virtio-gpu-pci.c |  2 +-
 hw/display/virtio-vga.c     |  2 +-
 hw/virtio/virtio-pci.c      | 19 +++++++++++++++++++
 hw/virtio/virtio-pci.h      |  5 +++++
 4 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/hw/display/virtio-gpu-pci.c b/hw/display/virtio-gpu-pci.c
index 9808663d05..a79bd751b2 100644
--- a/hw/display/virtio-gpu-pci.c
+++ b/hw/display/virtio-gpu-pci.c
@@ -43,7 +43,7 @@ static void virtio_gpu_pci_base_realize(VirtIOPCIProxy *vpci_dev, Error **errp)
                          PCI_BASE_ADDRESS_MEM_PREFETCH |
                          PCI_BASE_ADDRESS_MEM_TYPE_64,
                          &g->hostmem);
-        virtio_pci_add_shm_cap(vpci_dev, 4, 0, g->conf.hostmem, 0);
+        virtio_pci_add_shm_cap(vpci_dev, 4, 0, g->conf.hostmem, VIRTIO_GPU_SHM_ID_HOST_VISIBLE);
     }
 
     qdev_set_parent_bus(vdev, BUS(&vpci_dev->bus), errp);
diff --git a/hw/display/virtio-vga.c b/hw/display/virtio-vga.c
index 61993dd3f2..ca841a0799 100644
--- a/hw/display/virtio-vga.c
+++ b/hw/display/virtio-vga.c
@@ -147,7 +147,7 @@ static void virtio_vga_base_realize(VirtIOPCIProxy *vpci_dev, Error **errp)
                          PCI_BASE_ADDRESS_MEM_PREFETCH |
                          PCI_BASE_ADDRESS_MEM_TYPE_64,
                          &g->hostmem);
-        virtio_pci_add_shm_cap(vpci_dev, 4, 0, g->conf.hostmem, 0);
+        virtio_pci_add_shm_cap(vpci_dev, 4, 0, g->conf.hostmem, VIRTIO_GPU_SHM_ID_HOST_VISIBLE);
     }
 
     if (!(vpci_dev->flags & VIRTIO_PCI_FLAG_PAGE_PER_VQ)) {
diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
index 433060ac02..37a50b4658 100644
--- a/hw/virtio/virtio-pci.c
+++ b/hw/virtio/virtio-pci.c
@@ -1149,6 +1149,25 @@ static int virtio_pci_add_mem_cap(VirtIOPCIProxy *proxy,
     return offset;
 }
 
+int virtio_pci_add_shm_cap(VirtIOPCIProxy *proxy,
+                           uint8_t bar, uint64_t offset, uint64_t length,
+                           uint8_t id)
+{
+    struct virtio_pci_cap64 cap = {
+        .cap.cap_len = sizeof cap,
+        .cap.cfg_type = VIRTIO_PCI_CAP_SHARED_MEMORY_CFG,
+    };
+    uint32_t mask32 = ~0;
+
+    cap.cap.bar = bar;
+    cap.cap.length = cpu_to_le32(length & mask32);
+    cap.length_hi = cpu_to_le32((length >> 32) & mask32);
+    cap.cap.offset = cpu_to_le32(offset & mask32);
+    cap.offset_hi = cpu_to_le32((offset >> 32) & mask32);
+    cap.cap.id = id;
+    return virtio_pci_add_mem_cap(proxy, &cap.cap);
+}
+
 static uint64_t virtio_pci_common_read(void *opaque, hwaddr addr,
                                        unsigned size)
 {
diff --git a/hw/virtio/virtio-pci.h b/hw/virtio/virtio-pci.h
index 2446dcd9ae..25c4b7a32d 100644
--- a/hw/virtio/virtio-pci.h
+++ b/hw/virtio/virtio-pci.h
@@ -252,4 +252,9 @@ void virtio_pci_types_register(const VirtioPCIDeviceTypeInfo *t);
  */
 unsigned virtio_pci_optimal_num_queues(unsigned fixed_queues);
 
+/* Add shared memory capability */
+int virtio_pci_add_shm_cap(VirtIOPCIProxy *proxy,
+                           uint8_t bar, uint64_t offset, uint64_t length,
+                           uint8_t id);
+
 #endif
-- 
2.30.2