Re: [PATCH v4 1/8] media: virtio: Add protocol

[Bryan O'Donoghue]

On 22/06/2026 21:43, Brian Daniels wrote:
> +	u32 __reserved;

Knowing ~ nothing about virtio with ~ no experience of it I'll offer up 
a question/statement anyway.

Aren't your reservations here a bit conservative ? Would you not be well 
advised to reserve a bit more space per other virtio protocols ?

➜   grep reserved ./include/uapi/linux/*.h | grep virtio
./include/uapi/linux/virtio_balloon.h: *         __u8 reserved[6];
./include/uapi/linux/virtio_balloon.h: * In other words, add explicit 
reserved fields to align field and
./include/uapi/linux/virtio_blk.h:      __u8 reserved[38];
./include/uapi/linux/virtio_blk.h:      __u8 reserved[56];
./include/uapi/linux/virtio_config.h: * VIRTIO_TRANSPORT_F_END are 
reserved for the transport
./include/uapi/linux/virtio_crypto.h:   __le32 reserved;
./include/uapi/linux/virtio_i2c.h: * Copyright (c) 2021 Intel 
Corporation. All rights reserved.
./include/uapi/linux/virtio_input.h:    __u8    reserved[5];
./include/uapi/linux/virtio_iommu.h:    __u8 
       reserved[3];
./include/uapi/linux/virtio_iommu.h:    __u8 
       reserved[3];
./include/uapi/linux/virtio_iommu.h:    __u8 
       reserved[3];
./include/uapi/linux/virtio_iommu.h:    __u8 
       reserved[4];
./include/uapi/linux/virtio_iommu.h:    __u8 
       reserved[8];
./include/uapi/linux/virtio_iommu.h:    __u8 
       reserved[4];
./include/uapi/linux/virtio_iommu.h:    __u8 
       reserved[3];
./include/uapi/linux/virtio_iommu.h:    __u8 
       reserved[64];
./include/uapi/linux/virtio_iommu.h:    __u8 
       reserved[3];
./include/uapi/linux/virtio_iommu.h:    __u8 
       reserved2[4];
./include/uapi/linux/virtio_net.h:      __le16 reserved[4];
./include/uapi/linux/virtio_net.h:      __le16 reserved;
./include/uapi/linux/virtio_net.h:              __le16 reserved[3];
./include/uapi/linux/virtio_net.h:      __u8 reserved;
./include/uapi/linux/virtio_net.h:      __le16 reserved1;
./include/uapi/linux/virtio_pcidev.h: * @VIRTIO_PCIDEV_OP_RESERVED: 
reserved to catch errors
./include/uapi/linux/virtio_pcidev.h: * @reserved: reserved
./include/uapi/linux/virtio_pcidev.h:   __u16 reserved;
./include/uapi/linux/virtio_pci.h:      * 2-65535 - reserved
./include/uapi/linux/virtio_pci.h:      /* Unused, reserved for future 
extensions. */
./include/uapi/linux/virtio_pci.h:      __u8 reserved1[12];
./include/uapi/linux/virtio_pci.h:      /* Unused, reserved for future 
extensions. */
./include/uapi/linux/virtio_pci.h:      __u8 reserved2[4];
./include/uapi/linux/virtio_pci.h:      __u8 reserved[7];
./include/uapi/linux/virtio_pci.h:      __u8 reserved[6];
./include/uapi/linux/virtio_pci.h:      __u8 reserved[6];
./include/uapi/linux/virtio_pci.h:      __u8 reserved[2];
./include/uapi/linux/virtio_pci.h:      __u8 reserved[7];
./include/uapi/linux/virtio_pci.h:      __u8 reserved[7];
./include/uapi/linux/virtio_pci.h:      __u8 reserved;
./include/uapi/linux/virtio_pci.h:                      __le32 reserved;
./include/uapi/linux/virtio_pci.h:                      __u8 reserved[6];
./include/uapi/linux/virtio_pci.h:                      __le32 reserved;
./include/uapi/linux/virtio_pci.h:                      __le32 reserved;
./include/uapi/linux/virtio_pci.h:                      __le32 reserved;
./include/uapi/linux/virtio_pci.h:      __u8 reserved[7];
./include/uapi/linux/virtio_rtc.h: * Copyright (c) 2024 Qualcomm 
Innovation Center, Inc. All rights reserved.
./include/uapi/linux/virtio_rtc.h:      __u8 reserved[6];
./include/uapi/linux/virtio_rtc.h:      __u8 reserved[7];
./include/uapi/linux/virtio_rtc.h:      __u8 reserved[6];
./include/uapi/linux/virtio_rtc.h:      __u8 reserved[6];
./include/uapi/linux/virtio_rtc.h:      __u8 reserved[5];
./include/uapi/linux/virtio_rtc.h:      __u8 reserved[6];
./include/uapi/linux/virtio_rtc.h:      __u8 reserved[6];
./include/uapi/linux/virtio_rtc.h:      __u8 reserved[5];
./include/uapi/linux/virtio_rtc.h:      __u8 reserved[5];
./include/uapi/linux/virtio_rtc.h:      __u8 reserved[7];
./include/uapi/linux/virtio_rtc.h:      __u8 reserved[6];
./include/uapi/linux/virtio_rtc.h:      __u8 reserved[7];
./include/uapi/linux/virtio_rtc.h:      __u8 reserved[5];
./include/uapi/linux/virtio_rtc.h:      __u8 reserved[5];
./include/uapi/linux/virtio_rtc.h:      __u8 reserved[6];
./include/uapi/linux/virtio_spi.h: * Copyright (C) 2025 Qualcomm 
Innovation Center, Inc. All rights reserved.
./include/uapi/linux/virtio_spi.h: *   other bits are reserved as 0, 
1-bit transfer is always supported.
./include/uapi/linux/virtio_spi.h: *   other bits are reserved as 0, 
1-bit transfer is always supported.
./include/uapi/linux/virtio_spi.h: * @reserved: for future use.
./include/uapi/linux/virtio_spi.h:      __u8 reserved[3];+      u32 
__reserved;

---
bod