[PATCH v2 0/2] virtio-gpu: Shared memory capability

[PATCH v2 0/2] virtio-gpu: Shared memory capability

[Antonio Caggiano]

I guess RFC has been waiting long enough [0].

v2: Squash patch #3 into patch #2, and formatting fixes to patch #1.

[0] https://www.mail-archive.com/qemu-devel@nongnu.org/msg840405.html

Dr. David Alan Gilbert (1):
  virtio: Add shared memory capability

Gerd Hoffmann (1):
  virtio-gpu: hostmem

 hw/display/virtio-gpu-pci.c    | 15 +++++++++++++++
 hw/display/virtio-gpu.c        |  1 +
 hw/display/virtio-vga.c        | 33 ++++++++++++++++++++++++---------
 hw/virtio/virtio-pci.c         | 18 ++++++++++++++++++
 include/hw/virtio/virtio-gpu.h |  5 +++++
 include/hw/virtio/virtio-pci.h |  4 ++++
 6 files changed, 67 insertions(+), 9 deletions(-)

-- 
2.34.1

[PATCH v2 1/2] virtio-gpu: hostmem

[Antonio Caggiano]

From: Gerd Hoffmann <kraxel@redhat.com>

Use VIRTIO_GPU_SHM_ID_HOST_VISIBLE as id for virtio-gpu.

v2: Formatting fixes

Signed-off-by: Antonio Caggiano <antonio.caggiano@collabora.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
---
 hw/display/virtio-gpu-pci.c    | 15 +++++++++++++++
 hw/display/virtio-gpu.c        |  1 +
 hw/display/virtio-vga.c        | 33 ++++++++++++++++++++++++---------
 include/hw/virtio/virtio-gpu.h |  5 +++++
 4 files changed, 45 insertions(+), 9 deletions(-)

diff --git a/hw/display/virtio-gpu-pci.c b/hw/display/virtio-gpu-pci.c
index 93f214ff58..2cbbacd7fe 100644
--- a/hw/display/virtio-gpu-pci.c
+++ b/hw/display/virtio-gpu-pci.c
@@ -33,6 +33,21 @@ static void virtio_gpu_pci_base_realize(VirtIOPCIProxy *vpci_dev, Error **errp)
     DeviceState *vdev = DEVICE(g);
     int i;
 
+    if (virtio_gpu_hostmem_enabled(g->conf)) {
+        vpci_dev->msix_bar_idx = 1;
+        vpci_dev->modern_mem_bar_idx = 2;
+        memory_region_init(&g->hostmem, OBJECT(g), "virtio-gpu-hostmem",
+                           g->conf.hostmem);
+        pci_register_bar(&vpci_dev->pci_dev, 4,
+                         PCI_BASE_ADDRESS_SPACE_MEMORY |
+                         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,
+                               VIRTIO_GPU_SHM_ID_HOST_VISIBLE);
+    }
+
+    qdev_set_parent_bus(vdev, BUS(&vpci_dev->bus), errp);
     virtio_pci_force_virtio_1(vpci_dev);
     if (!qdev_realize(vdev, BUS(&vpci_dev->bus), errp)) {
         return;
diff --git a/hw/display/virtio-gpu.c b/hw/display/virtio-gpu.c
index 20cc703dcc..506b3b8eef 100644
--- a/hw/display/virtio-gpu.c
+++ b/hw/display/virtio-gpu.c
@@ -1424,6 +1424,7 @@ static Property virtio_gpu_properties[] = {
                      256 * MiB),
     DEFINE_PROP_BIT("blob", VirtIOGPU, parent_obj.conf.flags,
                     VIRTIO_GPU_FLAG_BLOB_ENABLED, false),
+    DEFINE_PROP_SIZE("hostmem", VirtIOGPU, parent_obj.conf.hostmem, 0),
     DEFINE_PROP_END_OF_LIST(),
 };
 
diff --git a/hw/display/virtio-vga.c b/hw/display/virtio-vga.c
index 4dcb34c4a7..aa8d1ab993 100644
--- a/hw/display/virtio-vga.c
+++ b/hw/display/virtio-vga.c
@@ -115,17 +115,32 @@ static void virtio_vga_base_realize(VirtIOPCIProxy *vpci_dev, Error **errp)
     pci_register_bar(&vpci_dev->pci_dev, 0,
                      PCI_BASE_ADDRESS_MEM_PREFETCH, &vga->vram);
 
-    /*
-     * Configure virtio bar and regions
-     *
-     * We use bar #2 for the mmio regions, to be compatible with stdvga.
-     * virtio regions are moved to the end of bar #2, to make room for
-     * the stdvga mmio registers at the start of bar #2.
-     */
-    vpci_dev->modern_mem_bar_idx = 2;
-    vpci_dev->msix_bar_idx = 4;
     vpci_dev->modern_io_bar_idx = 5;
 
+    if (!virtio_gpu_hostmem_enabled(g->conf)) {
+        /*
+         * Configure virtio bar and regions
+         *
+         * We use bar #2 for the mmio regions, to be compatible with stdvga.
+         * virtio regions are moved to the end of bar #2, to make room for
+         * the stdvga mmio registers at the start of bar #2.
+         */
+        vpci_dev->modern_mem_bar_idx = 2;
+        vpci_dev->msix_bar_idx = 4;
+    } else {
+        vpci_dev->msix_bar_idx = 1;
+        vpci_dev->modern_mem_bar_idx = 2;
+        memory_region_init(&g->hostmem, OBJECT(g), "virtio-gpu-hostmem",
+                           g->conf.hostmem);
+        pci_register_bar(&vpci_dev->pci_dev, 4,
+                         PCI_BASE_ADDRESS_SPACE_MEMORY |
+                         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,
+                               VIRTIO_GPU_SHM_ID_HOST_VISIBLE);
+    }
+
     if (!(vpci_dev->flags & VIRTIO_PCI_FLAG_PAGE_PER_VQ)) {
         /*
          * with page-per-vq=off there is no padding space we can use
diff --git a/include/hw/virtio/virtio-gpu.h b/include/hw/virtio/virtio-gpu.h
index 2e28507efe..eafce75b04 100644
--- a/include/hw/virtio/virtio-gpu.h
+++ b/include/hw/virtio/virtio-gpu.h
@@ -102,12 +102,15 @@ enum virtio_gpu_base_conf_flags {
     (_cfg.flags & (1 << VIRTIO_GPU_FLAG_DMABUF_ENABLED))
 #define virtio_gpu_blob_enabled(_cfg) \
     (_cfg.flags & (1 << VIRTIO_GPU_FLAG_BLOB_ENABLED))
+#define virtio_gpu_hostmem_enabled(_cfg) \
+    (_cfg.hostmem > 0)
 
 struct virtio_gpu_base_conf {
     uint32_t max_outputs;
     uint32_t flags;
     uint32_t xres;
     uint32_t yres;
+    uint64_t hostmem;
 };
 
 struct virtio_gpu_ctrl_command {
@@ -131,6 +134,8 @@ struct VirtIOGPUBase {
     int renderer_blocked;
     int enable;
 
+    MemoryRegion hostmem;
+
     struct virtio_gpu_scanout scanout[VIRTIO_GPU_MAX_SCANOUTS];
 
     int enabled_output_bitmask;
-- 
2.34.1

[PATCH v2 2/2] virtio: Add shared memory capability

[Antonio Caggiano]

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

Define a new capability type 'VIRTIO_PCI_CAP_SHARED_MEMORY_CFG'
and the data structure 'virtio_pci_shm_cap' to go with it.
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'.

v2: Remove virtio_pci_shm_cap as virtio_pci_cap64 is used instead.
v3: No need for mask32 as cpu_to_le32 truncates the value.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Antonio Caggiano <antonio.caggiano@collabora.com>
---
 hw/virtio/virtio-pci.c         | 18 ++++++++++++++++++
 include/hw/virtio/virtio-pci.h |  4 ++++
 2 files changed, 22 insertions(+)

diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
index 45327f0b31..50bd230122 100644
--- a/hw/virtio/virtio-pci.c
+++ b/hw/virtio/virtio-pci.c
@@ -1164,6 +1164,24 @@ 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,
+    };
+
+    cap.cap.bar = bar;
+    cap.cap.length = cpu_to_le32(length);
+    cap.length_hi = cpu_to_le32(length >> 32);
+    cap.cap.offset = cpu_to_le32(offset);
+    cap.offset_hi = cpu_to_le32(offset >> 32);
+    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/include/hw/virtio/virtio-pci.h b/include/hw/virtio/virtio-pci.h
index 2446dcd9ae..5e5c4a4c6d 100644
--- a/include/hw/virtio/virtio-pci.h
+++ b/include/hw/virtio/virtio-pci.h
@@ -252,4 +252,8 @@ void virtio_pci_types_register(const VirtioPCIDeviceTypeInfo *t);
  */
 unsigned virtio_pci_optimal_num_queues(unsigned fixed_queues);
 
+int virtio_pci_add_shm_cap(VirtIOPCIProxy *proxy,
+                           uint8_t bar, uint64_t offset, uint64_t length,
+                           uint8_t id);
+
 #endif
-- 
2.34.1

Re: [PATCH v2 2/2] virtio: Add shared memory capability

[Michael S. Tsirkin]

On Wed, Aug 03, 2022 at 05:21:35PM +0200, Antonio Caggiano wrote:
> From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
> 
> Define a new capability type 'VIRTIO_PCI_CAP_SHARED_MEMORY_CFG'
> and the data structure 'virtio_pci_shm_cap' to go with it.
> 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'.
> 
> v2: Remove virtio_pci_shm_cap as virtio_pci_cap64 is used instead.
> v3: No need for mask32 as cpu_to_le32 truncates the value.
> 
> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
> Signed-off-by: Antonio Caggiano <antonio.caggiano@collabora.com>


looks like the patches are in the reverse order, 1/2 won't
build without 2/2
> ---
>  hw/virtio/virtio-pci.c         | 18 ++++++++++++++++++
>  include/hw/virtio/virtio-pci.h |  4 ++++
>  2 files changed, 22 insertions(+)
> 
> diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
> index 45327f0b31..50bd230122 100644
> --- a/hw/virtio/virtio-pci.c
> +++ b/hw/virtio/virtio-pci.c
> @@ -1164,6 +1164,24 @@ 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,
> +    };
> +
> +    cap.cap.bar = bar;
> +    cap.cap.length = cpu_to_le32(length);
> +    cap.length_hi = cpu_to_le32(length >> 32);
> +    cap.cap.offset = cpu_to_le32(offset);
> +    cap.offset_hi = cpu_to_le32(offset >> 32);
> +    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/include/hw/virtio/virtio-pci.h b/include/hw/virtio/virtio-pci.h
> index 2446dcd9ae..5e5c4a4c6d 100644
> --- a/include/hw/virtio/virtio-pci.h
> +++ b/include/hw/virtio/virtio-pci.h
> @@ -252,4 +252,8 @@ void virtio_pci_types_register(const VirtioPCIDeviceTypeInfo *t);
>   */
>  unsigned virtio_pci_optimal_num_queues(unsigned fixed_queues);
>  
> +int virtio_pci_add_shm_cap(VirtIOPCIProxy *proxy,
> +                           uint8_t bar, uint64_t offset, uint64_t length,
> +                           uint8_t id);
> +
>  #endif
> -- 
> 2.34.1