Re: Workings/effectiveness of the xen-acpi-processor driver

[Boris Ostrovsky <boris.ostrovsky@amd.com>]

On 05/02/2012 12:08 PM, Konrad Rzeszutek Wilk wrote:
> diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
> index a8f8844..d816448 100644
> --- a/arch/x86/xen/enlighten.c
> +++ b/arch/x86/xen/enlighten.c
> @@ -811,7 +811,29 @@ static void xen_io_delay(void)
>   #ifdef CONFIG_X86_LOCAL_APIC
>   static u32 xen_apic_read(u32 reg)
>   {
> -	return 0;
> +	struct xen_platform_op op = {
> +		.cmd = XENPF_get_cpuinfo,
> +		.interface_version = XENPF_INTERFACE_VERSION,
> +		.u.pcpu_info.xen_cpuid = 0,


Is this always zero? This will probably solve the current problem but I 
am wondering whether in the future we might hit another bug because this 
routine will return the same APICID for all VCPUs.

-boris


> +	};
> +	int ret = 0;
> +
> +	/* Shouldn't need this as APIC is turned off for PV, and we only
> +	 * get called on the bootup processor. But just in case. */
> +	if (!xen_initial_domain() || smp_processor_id())
> +		return 0;
> +
> +	if (reg == APIC_LVR)
> +		return 0x10;
> +
> +	if (reg != APIC_ID)
> +		return 0;
> +
> +	ret = HYPERVISOR_dom0_op(&op);
> +	if (ret)
> +		return 0;
> +
> +	return op.u.pcpu_info.apic_id;
>   }
>
>   static void xen_apic_write(u32 reg, u32 val)
>