Re: [Qemu-devel] [PATCH] block: vpc support for ~2 TB disks

[Paolo Bonzini]

Il 15/11/2012 17:46, Charles Arnold ha scritto:
>>> We don't use qemu's VHD driver in XenServer. Instead, we use blktap2
>>> >> to create a block device in dom0 serving the VHD file in question,
>>> >> and have qemu open that block device instead of the VHD file itself.
>> > 
>> > Yes, the question is how you handle disks bigger than 127GB, so that
>> > QEMU can do the same.
>> > 
> In analyzing a 160 GB VHD fixed disk image created on Windows 2008 R2, it 
> appears that
> MS is also ignoring the CHS values in the footer geometry field in whatever
> driver they use for accessing the image.  The CHS values are set at 
> 65535,16,255
> which obviously doesn't represent an image size of 160 GB.

Thanks, this would have been useful in the commit message.

The patch looks good,

Reviewed-by: Paolo Bonzini <address@hidden>

Paolo

> This patch only extends the existing qemu driver to allow a larger image by 
> allowing
> more heads.  On real hardware, only 4 bits would be allowed for heads but we 
> don't
> have that restriction in qemu.