On Tue, Jan 08, 2013 at 03:04:33PM -0500, Konrad Rzeszutek Wilk wrote: > 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.
And I am looking at the wrong code. The "x86_64_start_kernel" is absolutly fine. It is "x86_64_start_reservations" that is invoked by Xen. I got thrown off by the "copy_bootdata(.." which on v3.7 is in "x86_64_start_reservations". Duh! > > Or am I looking at an old version of these patches. > > > > -hpa > > > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
