Re: New CPUID/MSR driver; virtualization hooks

["H. Peter Anvin" <hpa@zytor.com>]

Zachary Amsden wrote:
 > H. Peter Anvin wrote:
 >> http://www.kernel.org/pub/linux/kernel/people/hpa/new-cpuid-msr.patch
 >
 > The requested URL /pub/linux/kernel/people/hpa/new-cpuid-msr.patch 
was > not found on this server.

Fixed.

>> It's not *quite* that easy.  The assembly code around this is pretty 
>> extensive, because it has to stand on its head in order to present the 
>> proper register image.
> 
> Having just stood on my head for 55 breaths, might I suggest we 
> implement a binary equivalent CPUID paravirt-ops wrapper; then the 
> assembly code can just call CPUID and we can redefine it to call to a 
> stub, which makes the pv-ops CPUID call, the puts the outputs back in 
> the proper registers.
> 
> The VMI ROM CPUID is binary identical in register format with the native 
> instruction, so it need not do a headstand.  For the others,
> 
[snip]

This code is almost entirely identical to the setgpr_wrapper in the 
patch (except for the fact that setgpr_wrapper sets and captures *ALL* 
the GPRs), and it seems rather pointless to use another wrapper.  It 
takes a pointer to an entrypoint (default to "cpuid; ret" in the CPUID 
case), so it should do what you need.

	-hpa