From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43)
	id 1KNUNv-00076j-O4
	for qemu-devel@nongnu.org; Mon, 28 Jul 2008 11:11:39 -0400
Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43)
	id 1KNUNu-00075W-0O
	for qemu-devel@nongnu.org; Mon, 28 Jul 2008 11:11:39 -0400
Received: from [199.232.76.173] (port=47153 helo=monty-python.gnu.org)
	by lists.gnu.org with esmtp (Exim 4.43) id 1KNUNt-00075L-Rq
	for qemu-devel@nongnu.org; Mon, 28 Jul 2008 11:11:37 -0400
Received: from mx1.redhat.com ([66.187.233.31]:38777)
	by monty-python.gnu.org with esmtp (Exim 4.60)
	(envelope-from <clalance@redhat.com>) id 1KNUNs-0003cr-W6
	for qemu-devel@nongnu.org; Mon, 28 Jul 2008 11:11:37 -0400
Message-ID: <488DE142.1060100@redhat.com>
Date: Mon, 28 Jul 2008 17:09:54 +0200
From: Chris Lalancette <clalance@redhat.com>
MIME-Version: 1.0
References: <488DC8B2.1070009@redhat.com> <20080728141515.GJ3196@minantech.com>
	<488DD98D.5010907@codemonkey.ws> <488DDA93.4070702@redhat.com>
	<488DDF8B.8020103@codemonkey.ws>
In-Reply-To: <488DDF8B.8020103@codemonkey.ws>
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit
Subject: [Qemu-devel] Re: [PATCH 0/3]: Add UUID command-line option
Reply-To: qemu-devel@nongnu.org
List-Id: qemu-devel.nongnu.org
List-Unsubscribe: <http://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.gnu.org/pipermail/qemu-devel>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <http://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: Anthony Liguori <anthony@codemonkey.ws>
Cc: Gleb Natapov <gleb@qumranet.com>, qemu-devel@nongnu.org

Anthony Liguori wrote:
>> Hm, but that's basically what this does, in combination with the Bochs BIOS.
>> Once the Bochs BIOS reaches the rombios32 code, it makes the calls into the
>> device model VMware backdoor to get the UUID.  Assuming this all succeeds, the
>> Bochs BIOS then plumbs it into the SMBIOS tables.
>>   
> 
> Are there patches for the Bochs BIOS to do this?  Why wouldn't it just 
> use CMOS to get at the UUID?

Yeah, there's a uuid_probe() function that's already been merged into the Bochs
BIOS, and subsequently to most of the downstream projects (including KVM).

void uuid_probe(void)
{
#ifdef BX_QEMU
    uint32_t eax, ebx, ecx, edx;

    // check if backdoor port exists
    asm volatile ("outl %%eax, %%dx"
        : "=a" (eax), "=b" (ebx), "=c" (ecx), "=d" (edx)
        : "a" (0x564d5868), "c" (0xa), "d" (0x5658));
    if (ebx == 0x564d5868) {
        uint32_t *uuid_ptr = (uint32_t *)bios_uuid;
        // get uuid
        asm volatile ("outl %%eax, %%dx"
            : "=a" (eax), "=b" (ebx), "=c" (ecx), "=d" (edx)
            : "a" (0x564d5868), "c" (0x13), "d" (0x5658));
        uuid_ptr[0] = eax;
        uuid_ptr[1] = ebx;
        uuid_ptr[2] = ecx;
        uuid_ptr[3] = edx;
    } else
#endif
    {
        // UUID not set
        memset(bios_uuid, 0, 16);
    }
}

Later on in the rombios32 code the bios_uuid[] is used to build up the SMBIOS
tables.

Chris Lalancette