On Tue, Jan 08, 2013 at 11:47:39AM -0800, H. Peter Anvin wrote:
> On 01/08/2013 11:46 AM, Konrad Rzeszutek Wilk wrote:
> >
> > OK. I am trying to figure out whether this usage of native_* for the
> > MSRs was done on purpose - and it sounds like the answer is no. If so -
> > can it be done using the normal 'safe_rdmsr' and 'wrmsr'?
> >
> > That would allow at least in the case of Xen, to omit a whole bunch
> > of MSR writes/reads during the boot that are not neccessary as we would
> > not trap in the hypervisor - but could use the pvops version of
> > read/write MSR calls to just do a nop.
> >
>
> Why is this code invoked on Xen at all? That seems crazy.
[PATCH v4 09/11] x86/head64.c: Early update ucode in 64-bit
has this in x86_64_start_kernel:
..
load_idt((const struct desc_ptr *)&idt_descr);
+ /*
+ * Load microcode early on BSP.
+ */
+ load_ucode_bsp(__va(real_mode_data));
+
copy_bootdata(__va(real_mode_data));
Which gets called after xen_start_kernel has setup pagetables,
bootparams, etc ready for the generic code to be invoked.
Or am I looking at an old version of these patches.
>
> -hpa
>
>
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