Re: [PATCH v3 2/3] x86/boot: Clear XD_DISABLE from the early boot path

[Andrew Cooper]

On 29/06/2023 1:17 pm, Alejandro Vallejo wrote:
> diff --git a/xen/arch/x86/cpu/intel.c b/xen/arch/x86/cpu/intel.c
> index 168cd58f36..b2443b6831 100644
> --- a/xen/arch/x86/cpu/intel.c
> +++ b/xen/arch/x86/cpu/intel.c
> @@ -304,24 +304,20 @@ static void cf_check early_init_intel(struct 
> cpuinfo_x86 *c)
>       if (c->x86 == 15 && c->x86_cache_alignment == 64)
>               c->x86_cache_alignment = 128;
>  
> +     if (bootsym(trampoline_misc_enable_off) &
> +         MSR_IA32_MISC_ENABLE_XD_DISABLE)
> +             printk(KERN_INFO
> +                    "re-enabled NX (Execute Disable) protection\n");

One other thing, which I'll also fix on commit.

This now prints per CPU on any system where we had to set XD_DISABLE. 
It want's a c == &boot_cpu_data to limit it to once-only.

~Andrew