Re: [Xen-devel] [PATCH v2 06/11] ioreq: allow dispatching ioreqs to internal servers

[Paul Durrant <Paul.Durrant@xxxxxxxxxx>]

> -----Original Message-----
> From: Roger Pau Monne <roger.pau@xxxxxxxxxx>
> Sent: 03 September 2019 17:14
> To: xen-devel@xxxxxxxxxxxxxxxxxxxx
> Cc: Roger Pau Monne <roger.pau@xxxxxxxxxx>; Paul Durrant 
> <Paul.Durrant@xxxxxxxxxx>; Jan Beulich
> <jbeulich@xxxxxxxx>; Andrew Cooper <Andrew.Cooper3@xxxxxxxxxx>; Wei Liu 
> <wl@xxxxxxx>
> Subject: [PATCH v2 06/11] ioreq: allow dispatching ioreqs to internal servers
> 
> Internal ioreq servers are always processed first, and ioreqs are
> dispatched by calling the handler function. Note this is already the
> case due to the implementation of FOR_EACH_IOREQ_SERVER.
> 

I'd re-jig this a bit. Something like...

"Internal ioreq servers will be processed first due to the implementation
 of FOR_EACH_IOREQ_SERVER, and ioreqs are dispatched simply by calling
 the handler function."

> Note that hvm_send_ioreq doesn't get passed the ioreq server id, so
> obtain it from the ioreq server data by doing pointer arithmetic.
> 

I think this 2nd paragraph is stale now?

> Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>

Otherwise LGTM, so with those things fixed up...

Reviewed-by: Paul Durrant <paul.durrant@xxxxxxxxxx>

> ---
> Changes since v1:
>  - Avoid having to iterate twice over the list of ioreq servers since
>    now internal servers are always processed first by
>    FOR_EACH_IOREQ_SERVER.
>  - Obtain ioreq server id using pointer arithmetic.
> ---
>  xen/arch/x86/hvm/ioreq.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/xen/arch/x86/hvm/ioreq.c b/xen/arch/x86/hvm/ioreq.c
> index dbc5e6b4c5..8331a89eae 100644
> --- a/xen/arch/x86/hvm/ioreq.c
> +++ b/xen/arch/x86/hvm/ioreq.c
> @@ -1493,9 +1493,18 @@ int hvm_send_ioreq(ioservid_t id, ioreq_t *proto_p, 
> bool buffered)
> 
>      ASSERT(s);
> 
> +    if ( hvm_ioreq_is_internal(id) && buffered )
> +    {
> +        ASSERT_UNREACHABLE();
> +        return X86EMUL_UNHANDLEABLE;
> +    }
> +
>      if ( buffered )
>          return hvm_send_buffered_ioreq(s, proto_p);
> 
> +    if ( hvm_ioreq_is_internal(id) )
> +        return s->handler(curr, proto_p, s->data);
> +
>      if ( unlikely(!vcpu_start_shutdown_deferral(curr)) )
>          return X86EMUL_RETRY;
> 
> --
> 2.22.0

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