Re: [PATCH v3] docs: add PVH specification

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

> >> +`CR0` has the following bits set by Xen:
> >> +
> >> +  * PE (bit 0): protected mode enable.
> >> +  * ET (bit 4): 387 or newer processor.
> >> +  * PG (bit 31): paging enabled.
> > 
> > Also TS (at least that is what the Linux code says:
> > 
> > /* Some of these are setup in 'secondary_startup_64'. The others:       
> > * X86_CR0_TS, X86_CR0_PE, X86_CR0_ET are set by Xen for HVM guests     
> > * (which PVH shared codepaths), while X86_CR0_PG is for PVH. */        
> > 
> > Perhaps it is incorrect?
> 
> I think this comment is outdated/incorrect. This is the CR0 value I see 
> on a FreeBSD PVH start-of-day:
> 
> 0x80000011 (PE, ET and PG bits set)
> 

Reading the code I see

construct_vmcs
	hvm_update_guest_cr(v, 0);
		vmx_update_guest_cr

Then this code:
	1234         if ( !(v->arch.hvm_vcpu.guest_cr[0] & X86_CR0_TS) )                     
	1235         {                                                                       
	1236             if ( v != current )                                                 
	1237                 hw_cr0_mask |= X86_CR0_TS;                                      

	...
	1279         v->arch.hvm_vcpu.hw_cr[0] =                                             
	1280             v->arch.hvm_vcpu.guest_cr[0] | hw_cr0_mask;                         
	1281         __vmwrite(GUEST_CR0, v->arch.hvm_vcpu.hw_cr[0]);                        

Same logic on the AMD side, albeit less complicated.

But this is Monday morning so I must be missing something
as your values don't match with this.