On Mon, Feb 17, 2025 at 05:40:10PM +0100, Albert Esteve wrote:
> Add a shmem BAR block in the vhost-user-device,
> which files can be directly mapped into.
>
> The number, shmid, and size of the VIRTIO Shared
> Memory subregions is retrieved through a
> get_shmem_config message sent by the
> vhost-user-base module on the realize step,
> after virtio_init().
>
> By default, if VHOST_USER_PROTOCOL_F_SHMEM
> feature is not supported by the backend,
> there is no cache.
>
> Signed-off-by: Albert Esteve <aest...@redhat.com>
> ---
> hw/virtio/vhost-user-base.c | 47 +++++++++++++++++++++++++++++--
> hw/virtio/vhost-user-device-pci.c | 36 +++++++++++++++++++++--
> 2 files changed, 78 insertions(+), 5 deletions(-)
>
> diff --git a/hw/virtio/vhost-user-base.c b/hw/virtio/vhost-user-base.c
> index 2bc3423326..8d4bca98a8 100644
> --- a/hw/virtio/vhost-user-base.c
> +++ b/hw/virtio/vhost-user-base.c
> @@ -16,6 +16,7 @@
> #include "hw/virtio/virtio-bus.h"
> #include "hw/virtio/vhost-user-base.h"
> #include "qemu/error-report.h"
> +#include "migration/blocker.h"
>
> static void vub_start(VirtIODevice *vdev)
> {
> @@ -271,7 +272,8 @@ static void vub_device_realize(DeviceState *dev, Error
> **errp)
> {
> VirtIODevice *vdev = VIRTIO_DEVICE(dev);
> VHostUserBase *vub = VHOST_USER_BASE(dev);
> - int ret;
> + uint64_t memory_sizes[VIRTIO_MAX_SHMEM_REGIONS];
> + int i, ret, nregions;
>
> if (!vub->chardev.chr) {
> error_setg(errp, "vhost-user-base: missing chardev");
> @@ -314,7 +316,7 @@ static void vub_device_realize(DeviceState *dev, Error
> **errp)
>
> /* Allocate queues */
> vub->vqs = g_ptr_array_sized_new(vub->num_vqs);
> - for (int i = 0; i < vub->num_vqs; i++) {
> + for (i = 0; i < vub->num_vqs; i++) {
> g_ptr_array_add(vub->vqs,
> virtio_add_queue(vdev, vub->vq_size,
> vub_handle_output));
> @@ -328,11 +330,50 @@ static void vub_device_realize(DeviceState *dev, Error
> **errp)
> VHOST_BACKEND_TYPE_USER, 0, errp);
>
> if (ret < 0) {
> - do_vhost_user_cleanup(vdev, vub);
> + goto err;
> + }
> +
> + ret = vub->vhost_dev.vhost_ops->vhost_get_shmem_config(&vub->vhost_dev,
> + &nregions,
> + memory_sizes,
> + errp);
> +
> + if (ret < 0) {
> + goto err;
> + }
> +
> + for (i = 0; i < nregions; i++) {
> + if (memory_sizes[i]) {
> + if (vub->vhost_dev.migration_blocker == NULL) {
> + error_setg(&vub->vhost_dev.migration_blocker,
> + "Migration disabled: devices with VIRTIO Shared
> Memory "
> + "Regions do not support migration yet.");
> + ret = migrate_add_blocker_normal(
> + &vub->vhost_dev.migration_blocker,
> + errp);
> +
> + if (ret < 0) {
> + goto err;
> + }
> + }
> +
> + if (memory_sizes[i] % qemu_real_host_page_size() != 0) {
> + error_setg(errp, "Shared memory %d size must be a power of 2
> "
> + "no smaller than the page size", i);
> + goto err;
> + }
> +
> + memory_region_init(virtio_new_shmem_region(vdev)->mr,
Does this code support non-contiguous shmids? For example, if a device
has two Shared Memory Regions defined in its spec but the first one is
optional, then the device might have memory_sizes[0] == 0 and
memory_sizes[1] > 0. In that case the Shared Memory Region must have
shmid 1 and not shmid 0.
> + OBJECT(vdev), "vub-shm-" + i,
> + memory_sizes[i]);
> + }
> }
>
> qemu_chr_fe_set_handlers(&vub->chardev, NULL, NULL, vub_event, NULL,
> dev, NULL, true);
> + return;
> +err:
> + do_vhost_user_cleanup(vdev, vub);
> }
>
> static void vub_device_unrealize(DeviceState *dev)
> diff --git a/hw/virtio/vhost-user-device-pci.c
> b/hw/virtio/vhost-user-device-pci.c
> index efaf55d3dd..f215cae925 100644
> --- a/hw/virtio/vhost-user-device-pci.c
> +++ b/hw/virtio/vhost-user-device-pci.c
> @@ -8,14 +8,18 @@
> */
>
> #include "qemu/osdep.h"
> +#include "qapi/error.h"
> #include "hw/qdev-properties.h"
> #include "hw/virtio/vhost-user-base.h"
> #include "hw/virtio/virtio-pci.h"
>
> +#define VIRTIO_DEVICE_PCI_SHMEM_BAR 2
> +
> struct VHostUserDevicePCI {
> VirtIOPCIProxy parent_obj;
>
> VHostUserBase vub;
> + MemoryRegion shmembar;
> };
>
> #define TYPE_VHOST_USER_DEVICE_PCI "vhost-user-device-pci-base"
> @@ -25,10 +29,38 @@ OBJECT_DECLARE_SIMPLE_TYPE(VHostUserDevicePCI,
> VHOST_USER_DEVICE_PCI)
> static void vhost_user_device_pci_realize(VirtIOPCIProxy *vpci_dev, Error
> **errp)
> {
> VHostUserDevicePCI *dev = VHOST_USER_DEVICE_PCI(vpci_dev);
> - DeviceState *vdev = DEVICE(&dev->vub);
> + DeviceState *dev_state = DEVICE(&dev->vub);
> + VirtIODevice *vdev = VIRTIO_DEVICE(dev_state);
> + MemoryRegion *mr;
> + uint64_t offset = 0, shmem_size = 0;
> + int i;
>
> vpci_dev->nvectors = 1;
> - qdev_realize(vdev, BUS(&vpci_dev->bus), errp);
> + qdev_realize(dev_state, BUS(&vpci_dev->bus), errp);
> +
> + for (i = 0; i < vdev->n_shmem_regions; i++) {
> + mr = vdev->shmem_list[i].mr;
> + if (mr->size > UINT64_MAX - shmem_size) {
> + error_setg(errp, "Total shared memory required overflow");
> + return;
> + }
> + shmem_size = shmem_size + mr->size;
> + }
> + if (shmem_size) {
> + memory_region_init(&dev->shmembar, OBJECT(vpci_dev),
> + "vhost-device-pci-shmembar", shmem_size);
> + for (i = 0; i < vdev->n_shmem_regions; i++) {
> + memory_region_add_subregion(&dev->shmembar, offset, mr);
> + virtio_pci_add_shm_cap(vpci_dev, VIRTIO_DEVICE_PCI_SHMEM_BAR,
> + offset, mr->size, i);
> + offset = offset + mr->size;
> + }
> + pci_register_bar(&vpci_dev->pci_dev, VIRTIO_DEVICE_PCI_SHMEM_BAR,
> + PCI_BASE_ADDRESS_SPACE_MEMORY |
> + PCI_BASE_ADDRESS_MEM_PREFETCH |
> + PCI_BASE_ADDRESS_MEM_TYPE_64,
> + &dev->shmembar);
> + }
> }
>
> static void vhost_user_device_pci_class_init(ObjectClass *klass, void *data)
> --
> 2.48.1
>
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