From mboxrd@z Thu Jan  1 00:00:00 1970
From: David Vrabel <david.vrabel@citrix.com>
Subject: Re: [PATCH 1/3] xen-sndfront: add sound frontend driver
Date: Mon, 19 Jan 2015 10:55:39 +0000
Message-ID: <54BCE2AB.9000605@citrix.com>
References: <1421655574-10038-1-git-send-email-oleksandr.dmytryshyn@globallogic.com>
	<1421655574-10038-2-git-send-email-oleksandr.dmytryshyn@globallogic.com>
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To: Oleksandr Dmytryshyn <oleksandr.dmytryshyn@globallogic.com>, xen-devel@lists.xen.org
Cc: Takashi Iwai <tiwai@suse.de>, Iurii Konovalenko <iurii.konovalenko@globallogic.com>, Jaroslav Kysela <perex@perex.cz>
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On 19/01/15 08:19, Oleksandr Dmytryshyn wrote:
> +
> +struct sndif_request_open {
> +	unsigned int dev_num;
> +	unsigned int card_num;
> +	unsigned int dev_type;
> +	unsigned int _pad1;
> +	uint64_t     id;           /* private guest value, echoed in resp  */
> +	unsigned int _pad2;
> +	unsigned int _pad3;
> +} __attribute__((__packed__));

Using types like unsigned int will break 32-bit guests talking to 64-bit
backends.

Always use fixed width types, naturally align them and use explicit
padding.  The packed attribute will be unnecessary.

David