Re: [Xen-devel] [Patch v6 07/11] IOMMU: propagate IOMMU Device-TLB flush error up to IOMMU suspending (top level ones)

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 31.05.16 at 15:57, <quan.xu@xxxxxxxxx> wrote:
>  static int device_power_down(void)
>  {
> -    console_suspend();
> +    if ( console_suspend() )
> +        return SAVED_NONE;
>  
> -    time_suspend();
> +    if ( time_suspend() )
> +        return SAVED_CONSOLE;
>  
> -    i8259A_suspend();
> +    if ( i8259A_suspend() )
> +        return SAVED_TIME;
>  
> +    /* ioapic_suspend cannot fail */
>      ioapic_suspend();
>  
> -    iommu_suspend();
> +    if ( iommu_suspend() )
> +        return SAVED_IOAPIC;
>  
> -    lapic_suspend();
> +    if ( lapic_suspend() )
> +        return SAVED_IOMMU;
>  
> -    return 0;
> +    return SAVED_NONE;

SAVED_ALL

> @@ -169,6 +203,10 @@ static int enter_state(u32 state)
>      {
>          printk(XENLOG_ERR "Some devices failed to power down.");
>          system_state = SYS_STATE_resume;
> +
> +        if ( error > 0 )
> +            device_power_up(error);

if ( error != SAVED_NONE )

(Or really you could just call this without any if().)

> @@ -2389,16 +2393,25 @@ static int intel_iommu_group_id(u16 seg, u8 bus, u8 
> devfn)
>  }
>  
>  static u32 iommu_state[MAX_IOMMUS][MAX_IOMMU_REGS];
> -static void vtd_suspend(void)
> +
> +static int __must_check vtd_suspend(void)
>  {
>      struct acpi_drhd_unit *drhd;
>      struct iommu *iommu;
>      u32    i;
> +    int rc = 0;

Pointless initializer.

>      if ( !iommu_enabled )
> -        return;
> +        return 0;
>  
> -    iommu_flush_all();
> +    rc = iommu_flush_all();
> +    if ( unlikely(rc) )
> +    {
> +        printk(XENLOG_WARNING VTDPREFIX
> +               " suspend: IOMMU flush all failed: %d\n", rc);
> +
> +        return rc;
> +    }
>  
>      for_each_drhd_unit ( drhd )
>      {
> @@ -2427,6 +2440,8 @@ static void vtd_suspend(void)
>          if ( !iommu_intremap && iommu_qinval )
>              disable_qinval(iommu);
>      }
> +
> +    return rc;
>  }

Perhaps better "return 0" to make obvious that no error path comes
here.

Jan


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