[xen staging] xen/arm: acpi: Allow Xen to boot with ACPI 5.1

[patchbot@xxxxxxx]

commit 0ff2c7e5b4ff9b3066d6cbba9adf95b948b418c9
Author:     Julien Grall <julien.grall@xxxxxxx>
AuthorDate: Thu Nov 19 17:08:29 2020 +0000
Commit:     Stefano Stabellini <sstabellini@xxxxxxxxxx>
CommitDate: Thu Nov 19 16:25:28 2020 -0800

    xen/arm: acpi: Allow Xen to boot with ACPI 5.1
    
    At the moment Xen requires the FADT ACPI table to be at least version
    6.0, apparently because of some reliance on other ACPI v6.0 features.
    
    But actually this is overzealous, and Xen works now fine with ACPI v5.1.
    
    Let's relax the version check for the FADT table to allow QEMU to
    run the hypervisor with ACPI.
    
    Signed-off-by: Julien Grall <julien.grall@xxxxxxx>
    Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx>
    Signed-off-by: Julien Grall <jgrall@xxxxxxxxxx>
    Acked-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
    Reviewed-by: Bertrand Marquis <bertrand.marquis@xxxxxxx>
---
 xen/arch/arm/acpi/boot.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/xen/arch/arm/acpi/boot.c b/xen/arch/arm/acpi/boot.c
index 55c3e5cbc8..7ea2990cb8 100644
--- a/xen/arch/arm/acpi/boot.c
+++ b/xen/arch/arm/acpi/boot.c
@@ -181,8 +181,8 @@ static int __init acpi_parse_fadt(struct acpi_table_header 
*table)
      * we only deal with ACPI 6.0 or newer revision to get GIC and SMP
      * boot protocol configuration data, or we will disable ACPI.
      */
-    if ( table->revision > 6
-         || (table->revision == 6 && fadt->minor_revision >= 0) )
+    if ( table->revision > 5
+         || (table->revision == 5 && fadt->minor_revision >= 1) )
         return 0;
 
     printk("Unsupported FADT revision %d.%d, should be 6.0+, will disable 
ACPI\n",
--
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