Re: [PATCH] xen/acpi: Don't fail if SPCR table is absent

[Stefano Stabellini]

On Wed, 21 Oct 2020, Elliott Mitchell wrote:
> Absence of a SPCR table likely means the console is a framebuffer.  In
> such case acpi_iomem_deny_access() should NOT fail.
> 
> Signed-off-by: Elliott Mitchell <ehem+...@m5p.com>

Reviewed-by: Stefano Stabellini <sstabell...@kernel.org>


> ---
>  xen/arch/arm/acpi/domain_build.c | 19 ++++++++++---------
>  1 file changed, 10 insertions(+), 9 deletions(-)
> 
> diff --git a/xen/arch/arm/acpi/domain_build.c 
> b/xen/arch/arm/acpi/domain_build.c
> index 1b1cfabb00..bbdc90f92c 100644
> --- a/xen/arch/arm/acpi/domain_build.c
> +++ b/xen/arch/arm/acpi/domain_build.c
> @@ -42,17 +42,18 @@ static int __init acpi_iomem_deny_access(struct domain *d)
>      status = acpi_get_table(ACPI_SIG_SPCR, 0,
>                              (struct acpi_table_header **)&spcr);
>  
> -    if ( ACPI_FAILURE(status) )
> +    if ( ACPI_SUCCESS(status) )
>      {
> -        printk("Failed to get SPCR table\n");
> -        return -EINVAL;
> +        mfn = spcr->serial_port.address >> PAGE_SHIFT;
> +        /* Deny MMIO access for UART */
> +        rc = iomem_deny_access(d, mfn, mfn + 1);
> +        if ( rc )
> +            return rc;
> +    }
> +    else
> +    {
> +        printk("Failed to get SPCR table, Xen console may be unavailable\n");
>      }
> -
> -    mfn = spcr->serial_port.address >> PAGE_SHIFT;
> -    /* Deny MMIO access for UART */
> -    rc = iomem_deny_access(d, mfn, mfn + 1);
> -    if ( rc )
> -        return rc;
>  
>      /* Deny MMIO access for GIC regions */
>      return gic_iomem_deny_access(d);