Re: [Xen-devel] [PATCH] XENPF_set_processor_pminfo XEN_PM_CX overflows states array

["Zhang, Yang Z" <yang.z.zhang@xxxxxxxxx>]

Sorry, can you give more descriptions about this issue? I doesn't see any 
problem.

best regards
yang


> -----Original Message-----
> From: xen-devel-bounces@xxxxxxxxxxxxx
> [mailto:xen-devel-bounces@xxxxxxxxxxxxx] On Behalf Of eric
> Sent: Wednesday, March 07, 2012 10:07 PM
> To: xen-devel@xxxxxxxxxxxxx
> Cc: julian.pidancet@xxxxxxxxxxxxx
> Subject: [Xen-devel] [PATCH] XENPF_set_processor_pminfo XEN_PM_CX
> overflows states array
> 
> Calling XENPF_set_processor_pminfo with XEN_PM_CX could cause states array
> in "struct acpi_processor_power" to exceed its limit.
> 
> The array used to be reset (by function cpuidle_init_cpu()) for each 
> hypercall.
> The patch puts it back that way and adds an assertion to make it clear in 
> case that
> happens again.
> 
> Signed-off-by: Eric Chanudet <eric.chanudet@xxxxxxxxxxxxx>
> 
> diff --git a/xen/arch/x86/acpi/cpu_idle.c b/xen/arch/x86/acpi/cpu_idle.c
> --- a/xen/arch/x86/acpi/cpu_idle.c
> +++ b/xen/arch/x86/acpi/cpu_idle.c
> @@ -622,19 +622,19 @@ static int cpuidle_init_cpu(int cpu)
> 
>          for ( i = 0; i < ACPI_PROCESSOR_MAX_POWER; i++ )
>              acpi_power->states[i].idx = i;
> -
> -        acpi_power->states[ACPI_STATE_C1].type = ACPI_STATE_C1;
> -        acpi_power->states[ACPI_STATE_C1].entry_method =
> ACPI_CSTATE_EM_HALT;
> -
> -        acpi_power->states[ACPI_STATE_C0].valid = 1;
> -        acpi_power->states[ACPI_STATE_C1].valid = 1;
> -
> -        acpi_power->count = 2;
> -        acpi_power->safe_state = &acpi_power->states[ACPI_STATE_C1];
> -        acpi_power->cpu = cpu;
>          processor_powers[cpu] = acpi_power;
>      }
> 
> +    acpi_power->states[ACPI_STATE_C1].type = ACPI_STATE_C1;
> +    acpi_power->states[ACPI_STATE_C1].entry_method =
> + ACPI_CSTATE_EM_HALT;
> +
> +    acpi_power->states[ACPI_STATE_C0].valid = 1;
> +    acpi_power->states[ACPI_STATE_C1].valid = 1;
> +
> +    acpi_power->count = 2;
> +    acpi_power->safe_state = &acpi_power->states[ACPI_STATE_C1];
> +    acpi_power->cpu = cpu;
> +
>      if ( cpu == 0 )
>      {
>          if ( boot_cpu_has(X86_FEATURE_NONSTOP_TSC) ) @@ -870,11
> +870,10 @@ static void set_cx(
> 
>      if ( xen_cx->type == ACPI_STATE_C1 )
>          cx = &acpi_power->states[1];
> -    else
> -        cx = &acpi_power->states[acpi_power->count];
> -
> -    if ( !cx->valid )
> -        acpi_power->count++;
> +    else {
> +        ASSERT(acpi_power->count < ACPI_PROCESSOR_MAX_POWER);
> +        cx = &acpi_power->states[acpi_power->count++];
> +    }
> 
>      cx->valid    = 1;
>      cx->type     = xen_cx->type;
> 
> --
> Eric Chanudet
> 
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