[xen master] x86/ACPI: Ignore entries with invalid APIC IDs when parsing MADT

[patchbot@xxxxxxx]

commit 47342d8f490c3e9f0db76d2423c83543a07b0427
Author:     Simon Gaiser <simon@xxxxxxxxxxxxxxxxxxxxxx>
AuthorDate: Mon Aug 7 11:38:25 2023 +0200
Commit:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CommitDate: Tue Aug 29 15:54:45 2023 +0100

    x86/ACPI: Ignore entries with invalid APIC IDs when parsing MADT
    
    It seems some firmwares put dummy entries in the ACPI MADT table for non
    existing processors. On my NUC11TNHi5 those have the invalid APIC ID
    0xff. Linux already has code to handle those cases both in
    acpi_parse_lapic [1] as well as in acpi_parse_x2apic [2]. So add the
    same check to Xen.
    
    Link: 
https://git.kernel.org/torvalds/c/f3bf1dbe64b62a2058dd1944c00990df203e8e7a # [1]
    Link: 
https://git.kernel.org/torvalds/c/10daf10ab154e31237a8c07242be3063fb6a9bf4 # [2]
    Signed-off-by: Simon Gaiser <simon@xxxxxxxxxxxxxxxxxxxxxx>
    Acked-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
    Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
 xen/arch/x86/acpi/boot.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/xen/arch/x86/acpi/boot.c b/xen/arch/x86/acpi/boot.c
index 54b72d716b..ead41bd535 100644
--- a/xen/arch/x86/acpi/boot.c
+++ b/xen/arch/x86/acpi/boot.c
@@ -87,14 +87,17 @@ acpi_parse_x2apic(struct acpi_subtable_header *header, 
const unsigned long end)
        if (BAD_MADT_ENTRY(processor, end))
                return -EINVAL;
 
+       /* Ignore entries with invalid x2APIC ID */
+       if (processor->local_apic_id == 0xffffffff)
+               return 0;
+
        /* Don't register processors that cannot be onlined. */
        if (madt_revision >= 5 &&
            !(processor->lapic_flags & ACPI_MADT_ENABLED) &&
            !(processor->lapic_flags & ACPI_MADT_ONLINE_CAPABLE))
                return 0;
 
-       if ((processor->lapic_flags & ACPI_MADT_ENABLED) ||
-           processor->local_apic_id != 0xffffffff || opt_cpu_info) {
+       if ((processor->lapic_flags & ACPI_MADT_ENABLED) || opt_cpu_info) {
                acpi_table_print_madt_entry(header);
                log = true;
        }
@@ -143,14 +146,17 @@ acpi_parse_lapic(struct acpi_subtable_header * header, 
const unsigned long end)
        if (BAD_MADT_ENTRY(processor, end))
                return -EINVAL;
 
+       /* Ignore entries with invalid APIC ID */
+       if (processor->id == 0xff)
+               return 0;
+
        /* Don't register processors that cannot be onlined. */
        if (madt_revision >= 5 &&
            !(processor->lapic_flags & ACPI_MADT_ENABLED) &&
            !(processor->lapic_flags & ACPI_MADT_ONLINE_CAPABLE))
                return 0;
 
-       if ((processor->lapic_flags & ACPI_MADT_ENABLED) ||
-           processor->id != 0xff || opt_cpu_info)
+       if ((processor->lapic_flags & ACPI_MADT_ENABLED) || opt_cpu_info)
                acpi_table_print_madt_entry(header);
 
        /* Record local apic id only when enabled */
--
generated by git-patchbot for /home/xen/git/xen.git#master