Re: [Xen-devel] [PATCH] x86: Move microcode loading earlier

[Julien Grall <julien.grall@xxxxxxx>]

Hi Andrew,

On 19/04/17 12:12, Andrew Cooper wrote:
> On 18/04/17 16:47, Ross Lagerwall wrote:
> > Move microcode loading earlier for the boot CPU and secondary CPUs so
> > that it takes place before identify_cpu() is called for each CPU.
> > Without this, the detected features may be wrong if the new microcode
> > loading adjusts the feature bits. That could mean that some fixes (e.g.
> > d6e9f8d4f35d ("x86/vmx: fix vmentry failure with TSX bits in LBR"))
> > don't work as expected.
> >
> > Previously during boot, the microcode loader was invoked for each
> > secondary CPU started and then again for each CPU as part of an
> > initcall. Simplify the code so that it is invoked exactly once for each
> > CPU during boot.
> >
> > Signed-off-by: Ross Lagerwall <ross.lagerwall@xxxxxxxxxx>
> CC'ing Julien.  This should be taken in 4.9
>
> This also resolves my LBR XTF test, so
>
> Tested-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
>
> Also, Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>, with 3
> corrections (which I can fix on commit)
Release-acked-by: Julien Grall <julien.grall@xxxxxxx>

Cheers,

> > @@ -409,50 +381,55 @@ static struct notifier_block microcode_percpu_nfb = {
> >      .notifier_call = microcode_percpu_callback,
> >  };
> >
> > -static int __init microcode_presmp_init(void)
> > +int __init early_microcode_update_cpu(bool_t start_update)
> s/bool_t/bool/ throughout.
>
> > diff --git a/xen/arch/x86/smpboot.c b/xen/arch/x86/smpboot.c
> > index 82559ed..4e01c7b 100644
> > --- a/xen/arch/x86/smpboot.c
> > +++ b/xen/arch/x86/smpboot.c
> > @@ -83,22 +83,22 @@ static enum cpu_state {
> >
> >  void *stack_base[NR_CPUS];
> >
> > +void initialize_cpu_data(unsigned int cpu)
> > +{
> > +    *(cpu_data + cpu) = boot_cpu_data;
> cpu_data[cpu] = boot_cpu_data;
>
> > +}
> > +
> >  static void smp_store_cpu_info(int id)
> >  {
> > -    struct cpuinfo_x86 *c = cpu_data + id;
> >      unsigned int socket;
> >
> > -    *c = boot_cpu_data;
> > -    if ( id != 0 )
> > -    {
> > -        identify_cpu(c);
> > +    identify_cpu(cpu_data + id);
> &cpu_data[id]
>
> ~Andrew
--
Julien Grall

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