[edk2-devel] VirtIO Sound Driver (GSoC 2021)

[Michael Brown]

On 16/04/2021 01:59, Ethin Probst wrote:
> Also, I'm a bit confused. I've looked at several VirtIO devices now
> and have seen things like this:
> #define VIRTIO_PCI_DEVICE_SIGNATURE   SIGNATURE_32 ('V', 'P', 'C', 'I')
> // ...
>    UINT32                 Signature;
> I'm quite confused because I can't seem to find this anywhere in the
> VirtIO specification. The spec says nothing about signature values
> anywhere, just the magic value of 0x74726976. So where does this come
> from?

 From a quick look at the code, it seems to be a private signature value 
applied to a software-only data structure used by the UEFI driver, and 
is used solely for sanity checking that a pointer is pointing to the 
right kind of object.

Michael


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