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RE: [Xen-devel] [PATCH 0/3] Enable Option ROM support in Guest BIOS

Hi, Shan-san

I read option ROM from /sys/devices/pci0000\:00/<BDF>/rom like the below.
1. echo 1 > /sys/devices/pci0000\:00/0000\:00\:01.0/0000\:01\:00.0/rom
2. dd if=/sys/devices/pci0000\:00/0000\:00\:01.0/0000\:01\:00.0/rom of=

The rom didn't have any contents.

Best Regards,

Akio Takebe

>Takebe San,
>For the empty option ROM case, do you mean that you can not see any contents 
>by reading the PCI expansion ROM bar address? Or they are indeed empty?
>I have met a problem when developing the patches; I can not read any contents 
>from expansion ROM bar. I wonder whether they are the same problem.
>Shan Haitao
>-----Original Message-----
>From: Akio Takebe [mailto:takebe_akio@xxxxxxxxxxxxxx] 
>Sent: 2008年11月25日 8:35
>To: Shan, Haitao; 'Keir Fraser'
>Cc: 'xen-devel@xxxxxxxxxxxxxxxxxxx'
>Subject: Re: [Xen-devel] [PATCH 0/3] Enable Option ROM support in Guest BIOS
>Hi, Shan
>>Note: There is no support for booting from SCSI disk now. Since guest BIOS 
>>lacks support for that. Please see the comments below.
>>// BIOS Boot Specification 1.0.1 compatibility
>>// Very basic support for the BIOS Boot Specification, which allows 
>>// ROMs to register themselves as boot devices, instead of just stealing the
>>// INT 19h boot vector.
>>// This is a hack: to do it properly requires a proper PnP BIOS and we 
>>// one; we just lie to the option ROMs to make them behave correctly.
>>// We also don't support letting option ROMs register as bootable disk
>>// drives (BCVs), only as bootable devices (BEVs).
>>// http://www.phoenix.com/en/Customer+Services/White+Papers-Specs/pc+
>We have also worked for enabling option ROM.
>I and Kouya made the patch for supporting BCV. And we could boot HVM 
>guest from SAN storage. (please see my presentation of XenSummit Tokyo)
>I'll check your patch and remake the patch soon.
>BTW, I found some problems, they are:
>- Some device require services that are not supported by ROMBIOS.
>  (I think updating ROMBIOS to the latest bochs is better.)
>- Some devcies have empty option ROM or option ROM for EFI.
>  (e.g. NIC cards)
>Best Regards,
>Akio Takebe

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