STRUCT VIRTIO_PCM_MSG(9)

💖 struct virtio_pcm_msg(9) 💖

okay so bestie, welcome to the Kernel API Manual — today's main character is struct virtio_pcm_msg, and no cap, it's literally the little envelope that carries your audio data around in VirtIO land. 🎀

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✨ NAME ✨

struct virtio_pcm_msg — a VirtIO I/O message. that's it, that's the vibe. one struct, one job, and it does it flawlessly. 💅

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🌸 SYNOPSIS 🌸

okay here's the whole thing laid out, look at her:

struct virtio_pcm_msg {
    struct virtio_pcm_substream *substream;
    struct virtio_snd_pcm_xfer xfer;
    struct virtio_snd_pcm_status status;
    size_t length;
    struct scatterlist sgs[];
};

ngl, that trailing sgs[] is giving flexible array member energy and we stan. 🦋

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🧚 MEMBERS 🧚

time for the member-by-member vibe check, bestie — every single one, no skipping:

• substream — the VirtIO PCM substream. like, which stream is this message even for? this one. she's the reference back home. 🏠
• xfer — the request header payload. this is what you're asking the other side to do. the ask, the slay. ✨
• status — the response header payload. the clapback. the receipts. the "did it work tho" energy. 💀
• length — data length in bytes. a size_t, because we're not monsters. 🔥
• sgs — payload scatter-gather table. iconic, scattered, gathered, exactly as intended. 🌈

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👑 SEE ALSO 👑

the whole friend group, fr fr — Kernel file ./sound/virtio/virtio_pcm_msg.c plus:

• enum pcm_msg_sg_index(9)
• virtsnd_pcm_sg_num(9)
• virtsnd_pcm_sg_from(9)
• virtsnd_pcm_msg_alloc(9)
• virtsnd_pcm_msg_free(9)
• virtsnd_pcm_msg_send(9)
• virtsnd_pcm_msg_pending_num(9)
• virtsnd_pcm_msg_complete(9)
• virtsnd_pcm_notify_cb(9)
• virtsnd_pcm_tx_notify_cb(9)
• virtsnd_pcm_rx_notify_cb(9)
• virtsnd_pcm_ctl_msg_alloc(9)

like, go read them, they're all part of the same squad. 🫶

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bestie reminder: this is the whole page, so if you were hoping for more lore, the lore is the struct. go read the SEE ALSOs, iykyk. 💜

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and that's a wrap, periodt! 🎀 this absolute banger of a page lives in ./sound/virtio (that's the source/version, mwah 💋) and it's dated October 2026, so she's fresh. bye bestie, go make some audio messages! 🦋⭐

struct virtio_pcm_msg(9) 💅