Re: [PATCH v2] virtio: Implement Virtio Backend for SD/MMC in QEMU

["Michael S. Tsirkin" <mst@redhat.com>]

On Tue, Jul 02, 2024 at 06:58:42PM +0000, Mikhail Krasheninnikov wrote:
> From: Mi <krashmisha@gmail.com>
> 
> Add a Virtio backend for SD/MMC devices. Confirmed interoperability with
> Linux.

Interesting.  With which Linux driver?

> Signed-off-by: Mikhail Krasheninnikov <krashmisha@gmail.com>
> CC: Matwey Kornilov <matwey.kornilov@gmail.com>
> CC: qemu-block@nongnu.org
> CC: Michael S. Tsirkin <mst@redhat.com>
> CC: Kevin Wolf <kwolf@redhat.com>
> CC: Stefan Hajnoczi <stefanha@redhat.com>
> ---
> 
> After a feedback, moved virtio.c from virtio core directory to hw/block.
> >From what I see from the examples of virtio drivers, other files should
> be where they are now. Correct me if I'm wrong.
> 
>  hw/block/Kconfig                            |   5 +
>  hw/block/meson.build                        |   1 +
>  hw/block/virtio-mmc.c                       | 165 ++++++++++++++++++++
>  hw/virtio/meson.build                       |   1 +
>  hw/virtio/virtio-mmc-pci.c                  |  85 ++++++++++
>  hw/virtio/virtio.c                          |   3 +-
>  include/hw/virtio/virtio-mmc.h              |  20 +++
>  include/standard-headers/linux/virtio_ids.h |   1 +
>  8 files changed, 280 insertions(+), 1 deletion(-)
>  create mode 100644 hw/block/virtio-mmc.c
>  create mode 100644 hw/virtio/virtio-mmc-pci.c
>  create mode 100644 include/hw/virtio/virtio-mmc.h
> 
> diff --git a/hw/block/Kconfig b/hw/block/Kconfig
> index 9e8f28f982..a3059261fa 100644
> --- a/hw/block/Kconfig
> +++ b/hw/block/Kconfig
> @@ -44,3 +44,8 @@ config VHOST_USER_BLK
>  
>  config SWIM
>      bool
> +
> +config VIRTIO_MMC
> +    bool
> +    default y
> +    depends on VIRTIO
> diff --git a/hw/block/meson.build b/hw/block/meson.build
> index 8aa4dc3893..4fa6e90b5f 100644
> --- a/hw/block/meson.build
> +++ b/hw/block/meson.build
> @@ -19,5 +19,6 @@ system_ss.add(when: 'CONFIG_TC58128', if_true: files('tc58128.c'))
>  
>  specific_ss.add(when: 'CONFIG_VIRTIO_BLK', if_true: files('virtio-blk.c', 'virtio-blk-common.c'))
>  specific_ss.add(when: 'CONFIG_VHOST_USER_BLK', if_true: files('vhost-user-blk.c', 'virtio-blk-common.c'))
> +specific_ss.add(when: 'CONFIG_VIRTIO_MMC', if_true: files('virtio-mmc.c'))
>  
>  subdir('dataplane')
> diff --git a/hw/block/virtio-mmc.c b/hw/block/virtio-mmc.c
> new file mode 100644
> index 0000000000..50bd7113c5
> --- /dev/null
> +++ b/hw/block/virtio-mmc.c
> @@ -0,0 +1,165 @@
> +#include "qemu/osdep.h"
> +#include "qapi/error.h"
> +
> +#include "hw/virtio/virtio.h"
> +#include "hw/virtio/virtio-mmc.h"
> +#include "qemu/typedefs.h"
> +#include "sysemu/blockdev.h"
> +
> +typedef struct mmc_req {
> +    uint32_t opcode;
> +    uint32_t arg;
> +} mmc_req;
> +
> +typedef struct virtio_mmc_req {
> +    uint8_t flags;
> +
> +#define VIRTIO_MMC_REQUEST_DATA BIT(1)
> +#define VIRTIO_MMC_REQUEST_WRITE BIT(2)
> +#define VIRTIO_MMC_REQUEST_STOP BIT(3)
> +#define VIRTIO_MMC_REQUEST_SBC BIT(4)
> +
> +    mmc_req request;
> +
> +    uint8_t buf[4096];
> +    size_t buf_len;
> +
> +    mmc_req stop_req;
> +    mmc_req sbc_req;
> +} virtio_mmc_req;
> +
> +typedef struct virtio_mmc_resp {
> +    uint32_t response[4];
> +    int resp_len;
> +    uint8_t buf[4096];
> +} virtio_mmc_resp;
> +


At least some of this looks like something that should come
from Linux uapi headers.


> +static void send_command(SDBus *sdbus, mmc_req *mmc_request, uint8_t *response,
> +                         virtio_mmc_resp *virtio_resp)
> +{
> +    SDRequest sdreq;
> +    sdreq.cmd = (uint8_t)mmc_request->opcode;
> +    sdreq.arg = mmc_request->arg;
> +    int resp_len = sdbus_do_command(sdbus, &sdreq, response);
> +    virtio_resp->resp_len = resp_len;
> +
> +    for (int i = 0; i < resp_len / sizeof(uint32_t); i++) {
> +        virtio_resp->response[i] = ldl_be_p(&virtio_resp->response[i]);
> +    }
> +}
> +
> +static void send_command_without_response(SDBus *sdbus, mmc_req *mmc_request)
> +{
> +    SDRequest sdreq;
> +    sdreq.cmd = (uint8_t)mmc_request->opcode;
> +    sdreq.arg = mmc_request->arg;
> +    uint8_t response[4];
> +    sdbus_do_command(sdbus, &sdreq, response);
> +}
> +
> +static void handle_mmc_request(VirtIODevice *vdev, virtio_mmc_req *virtio_req,
> +                               virtio_mmc_resp *virtio_resp)
> +{
> +    VirtIOMMC *vmmc = VIRTIO_MMC(vdev);
> +    SDBus *sdbus = &vmmc->sdbus;
> +
> +    if (virtio_req->flags & VIRTIO_MMC_REQUEST_SBC) {
> +        send_command_without_response(sdbus, &virtio_req->sbc_req);
> +    }
> +
> +    send_command(sdbus, &virtio_req->request,
> +    (uint8_t *)virtio_resp->response, virtio_resp);
> +
> +    if (virtio_req->flags & VIRTIO_MMC_REQUEST_DATA) {
> +        if (virtio_req->flags & VIRTIO_MMC_REQUEST_WRITE) {
> +            sdbus_write_data(sdbus, virtio_req->buf, virtio_req->buf_len);
> +        } else {
> +            sdbus_read_data(sdbus, virtio_resp->buf, virtio_req->buf_len);
> +        }
> +    }
> +
> +    if (virtio_req->flags & VIRTIO_MMC_REQUEST_STOP) {
> +        send_command_without_response(sdbus, &virtio_req->stop_req);
> +    }
> +}
> +
> +static void handle_request(VirtIODevice *vdev, VirtQueue *vq)
> +{
> +    VirtQueueElement *elem;
> +    virtio_mmc_req virtio_req;
> +    virtio_mmc_resp virtio_resp;
> +
> +    elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
> +
> +    iov_to_buf(elem->out_sg, elem->out_num, 0,
> +    &virtio_req, sizeof(virtio_mmc_req));
> +
> +    handle_mmc_request(vdev, &virtio_req, &virtio_resp);
> +
> +    iov_from_buf(elem->in_sg, elem->in_num, 0,
> +    &virtio_resp, sizeof(virtio_mmc_resp));
> +
> +    virtqueue_push(vq, elem, 1);
> +
> +    virtio_notify(vdev, vq);
> +}
> +
> +static void virtio_mmc_realize(DeviceState *dev, Error **errp)
> +{
> +    VirtIODevice *vdev = VIRTIO_DEVICE(dev);
> +    VirtIOMMC *vmmc = VIRTIO_MMC(dev);
> +
> +    virtio_init(vdev, VIRTIO_ID_MMC, 0);
> +
> +    vmmc->vq = virtio_add_queue(vdev, 1, handle_request);
> +
> +    BlockBackend *blk = vmmc->blk;
> +    if (!blk) {
> +        error_setg(errp, "Block backend not found");
> +        return;
> +    }
> +
> +    qbus_init(&vmmc->sdbus, sizeof(vmmc->sdbus), TYPE_SD_BUS, dev, "sd-bus");
> +    DeviceState *card = qdev_new(TYPE_SD_CARD);
> +    qdev_prop_set_drive_err(card, "drive", blk, &error_fatal);
> +    qdev_realize_and_unref(card,
> +    qdev_get_child_bus(dev, "sd-bus"), &error_fatal);
> +}
> +
> +static void virtio_mmc_unrealize(DeviceState *dev)
> +{
> +    VirtIODevice *vdev = VIRTIO_DEVICE(dev);
> +    virtio_cleanup(vdev);
> +}
> +
> +static uint64_t virtio_mmc_get_features(VirtIODevice *vdev,
> +                                        uint64_t features, Error **errp)
> +{
> +    return features;
> +}
> +
> +static void virtio_mmc_class_init(ObjectClass *klass, void *data)
> +{
> +    DeviceClass *dc = DEVICE_CLASS(klass);
> +    VirtioDeviceClass *k = VIRTIO_DEVICE_CLASS(klass);
> +
> +    set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
> +
> +    k->realize = virtio_mmc_realize;
> +    k->unrealize = virtio_mmc_unrealize;
> +    k->get_features = virtio_mmc_get_features;
> +}
> +
> +static const TypeInfo virtio_mmc_info = {
> +    .name = TYPE_VIRTIO_MMC,
> +    .parent = TYPE_VIRTIO_DEVICE,
> +    .instance_size = sizeof(VirtIOMMC),
> +    .class_init = virtio_mmc_class_init,
> +};
> +
> +static void virtio_register_types(void)
> +{
> +    type_register_static(&virtio_mmc_info);
> +}
> +
> +type_init(virtio_register_types)
> diff --git a/hw/virtio/meson.build b/hw/virtio/meson.build
> index 47baf00366..ef05d0d80d 100644
> --- a/hw/virtio/meson.build
> +++ b/hw/virtio/meson.build
> @@ -68,6 +68,7 @@ virtio_pci_ss.add(when: 'CONFIG_VIRTIO_IOMMU', if_true: files('virtio-iommu-pci.
>  virtio_pci_ss.add(when: 'CONFIG_VIRTIO_MEM', if_true: files('virtio-mem-pci.c'))
>  virtio_pci_ss.add(when: 'CONFIG_VHOST_VDPA_DEV', if_true: files('vdpa-dev-pci.c'))
>  virtio_pci_ss.add(when: 'CONFIG_VIRTIO_MD', if_true: files('virtio-md-pci.c'))
> +virtio_pci_ss.add(when: 'CONFIG_VIRTIO_MMC', if_true: files('virtio-mmc-pci.c'))
>  
>  specific_virtio_ss.add_all(when: 'CONFIG_VIRTIO_PCI', if_true: virtio_pci_ss)
>  
> diff --git a/hw/virtio/virtio-mmc-pci.c b/hw/virtio/virtio-mmc-pci.c
> new file mode 100644
> index 0000000000..f0ed17d03b
> --- /dev/null
> +++ b/hw/virtio/virtio-mmc-pci.c
> @@ -0,0 +1,85 @@
> +#include "qemu/osdep.h"
> +
> +#include "hw/virtio/virtio-pci.h"
> +#include "hw/virtio/virtio-mmc.h"
> +#include "hw/qdev-properties-system.h"
> +#include "qemu/typedefs.h"
> +#include "qapi/error.h"
> +#include "sysemu/block-backend-global-state.h"
> +
> +typedef struct VirtIOMMCPCI VirtIOMMCPCI;
> +
> +/*
> + * virtio-mmc-pci: This extends VirtioPCIProxy.
> + */
> +#define TYPE_VIRTIO_MMC_PCI "virtio-mmc-pci-base"
> +DECLARE_INSTANCE_CHECKER(VirtIOMMCPCI, VIRTIO_MMC_PCI,
> +                         TYPE_VIRTIO_MMC_PCI)
> +
> +struct VirtIOMMCPCI {
> +    VirtIOPCIProxy parent_obj;
> +    VirtIOMMC vdev;
> +    BlockBackend *blk;
> +};
> +
> +static void virtio_mmc_pci_realize(VirtIOPCIProxy *vpci_dev, Error **errp)
> +{
> +    VirtIOMMCPCI *vmmc = VIRTIO_MMC_PCI(vpci_dev);
> +    DeviceState *dev = DEVICE(&vmmc->vdev);
> +
> +    if (!vmmc->blk) {
> +        error_setg(errp, "Drive property not set");
> +        return;
> +    }
> +    VirtIOMMC *vmmc_dev = &vmmc->vdev;
> +    vmmc_dev->blk = vmmc->blk;
> +    blk_detach_dev(vmmc->blk, DEVICE(vpci_dev));
> +
> +    qdev_set_parent_bus(dev, BUS(&vpci_dev->bus), errp);
> +
> +    virtio_pci_force_virtio_1(vpci_dev);
> +    object_property_set_bool(OBJECT(dev), "realized", true, errp);
> +}
> +
> +static Property virtio_mmc_properties[] = {
> +    DEFINE_PROP_DRIVE("drive", VirtIOMMCPCI, blk),
> +    DEFINE_PROP_END_OF_LIST(),
> +};
> +
> +static void virtio_mmc_pci_class_init(ObjectClass *oc, void *data)
> +{
> +    DeviceClass *dc = DEVICE_CLASS(oc);
> +    VirtioPCIClass *virtio_pci_class = VIRTIO_PCI_CLASS(oc);
> +    PCIDeviceClass *pci_device_class = PCI_DEVICE_CLASS(oc);
> +
> +    device_class_set_props(dc, virtio_mmc_properties);
> +    set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
> +
> +    virtio_pci_class->realize = virtio_mmc_pci_realize;
> +
> +    pci_device_class->revision = VIRTIO_PCI_ABI_VERSION;
> +    pci_device_class->class_id = PCI_CLASS_MEMORY_FLASH;
> +}
> +
> +static void virtio_mmc_pci_instance_init(Object *obj)
> +{
> +    VirtIOMMCPCI *dev = VIRTIO_MMC_PCI(obj);
> +
> +    virtio_instance_init_common(obj, &dev->vdev, sizeof(dev->vdev),
> +                                TYPE_VIRTIO_MMC);
> +}
> +
> +static const VirtioPCIDeviceTypeInfo virtio_mmc_pci_info = {
> +    .base_name     = TYPE_VIRTIO_MMC_PCI,
> +    .generic_name  = "virtio-mmc-pci",
> +    .instance_size = sizeof(VirtIOMMCPCI),
> +    .class_init    = virtio_mmc_pci_class_init,
> +    .instance_init = virtio_mmc_pci_instance_init,
> +};
> +
> +static void virtio_mmc_pci_register(void)
> +{
> +    virtio_pci_types_register(&virtio_mmc_pci_info);
> +}
> +
> +type_init(virtio_mmc_pci_register)
> diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
> index 7549094154..35f00f06aa 100644
> --- a/hw/virtio/virtio.c
> +++ b/hw/virtio/virtio.c
> @@ -193,7 +193,8 @@ const char *virtio_device_names[] = {
>      [VIRTIO_ID_PARAM_SERV] = "virtio-param-serv",
>      [VIRTIO_ID_AUDIO_POLICY] = "virtio-audio-pol",
>      [VIRTIO_ID_BT] = "virtio-bluetooth",
> -    [VIRTIO_ID_GPIO] = "virtio-gpio"
> +    [VIRTIO_ID_GPIO] = "virtio-gpio",
> +    [VIRTIO_ID_MMC] = "virtio-mmc",
>  };
>  
>  static const char *virtio_id_to_name(uint16_t device_id)
> diff --git a/include/hw/virtio/virtio-mmc.h b/include/hw/virtio/virtio-mmc.h
> new file mode 100644
> index 0000000000..a68f45d7cb
> --- /dev/null
> +++ b/include/hw/virtio/virtio-mmc.h
> @@ -0,0 +1,20 @@
> +#pragma once
> +

don't do this. nest headers sesibly.


> +#include "hw/virtio/virtio.h"
> +#include "hw/sd/sd.h"
> +#include "qemu/typedefs.h"
> +
> +#define VIRTIO_ID_MMC 42

Why duplicate this?


> +
> +#define TYPE_VIRTIO_MMC "virtio-mmc-device"
> +#define VIRTIO_MMC(obj) \
> +    OBJECT_CHECK(VirtIOMMC, (obj), TYPE_VIRTIO_MMC)
> +#define VIRTIO_MMC_GET_PARENT_CLASS(obj) \
> +    OBJECT_GET_PARENT_CLASS(VIRTIO_MMC(obj), TYPE_VIRTIO_MMC)
> +
> +typedef struct VirtIOMMC {
> +    VirtIODevice parent_obj;
> +    VirtQueue *vq;
> +    SDBus sdbus;
> +    BlockBackend *blk;
> +} VirtIOMMC;
> diff --git a/include/standard-headers/linux/virtio_ids.h b/include/standard-headers/linux/virtio_ids.h
> index 7aa2eb7662..0c67fbf709 100644
> --- a/include/standard-headers/linux/virtio_ids.h
> +++ b/include/standard-headers/linux/virtio_ids.h
> @@ -68,6 +68,7 @@
>  #define VIRTIO_ID_AUDIO_POLICY		39 /* virtio audio policy */
>  #define VIRTIO_ID_BT			40 /* virtio bluetooth */
>  #define VIRTIO_ID_GPIO			41 /* virtio gpio */
> +#define VIRTIO_ID_MMC			42 /* virtio mmc */
>  


These headers should come from Linux.
You need to upstream the driver in parallel with this work.



>  /*
>   * Virtio Transitional IDs
> -- 
> 2.34.1