Re: [Xen-devel] Fatal crash on xen4.2 HVM + qemu-xen dm + NFS

[Alex Bligh <alex@xxxxxxxxxxx>]

Ian,

--On 22 January 2013 10:05:16 +0000 Ian Campbell <Ian.Campbell@xxxxxxxxxx> 
wrote:
> I've never looked inside xen_qdisk so I can't really advise, but that
> sound broadly correct, except you'd want to use gnttab_copy not mmap
> +memcpy. e.g. (totally making up the API because I'm too lazy to go
> look):
>         buffer = malloc(SIZE)
>         if (writing)
>                 gnttab_copy_from(buffer, gntref, size)
>
>         io->buffer = buffer
>         submit(io)
> ... wait for completion:
>         if (reading)
>                 gnttab_copy_to(...)
>         free(io->buffer)
>
> Hopefully you get the idea ;-) Sounds like before the ... goes in
> ioreq_map and after the ... goes in ioreq_unmap.
Thanks. If the O_DIRECT thing doesn't fix it, I'll take a look again.
My initial analysis was that a copy interface wasn't available through
xc_ type functions.

--
Alex Bligh

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