AMD/IOMMU: without XT, x2APIC needs to be forced into physical mode

An earlier change with the same title (commit 1ba66a870eba) altered only
the path where x2apic_phys was already set to false (perhaps from the
command line). The same of course needs applying when the variable
wasn't modified yet from its initial value.

Reported-by: Elliott Mitchell <ehem+xen@m5p.com>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
master commit: 0d2686f6b66b4b1b3c72c3525083b0ce02830054
master date: 2023-03-21 09:23:25 +0100

diff --git a/xen/arch/x86/genapic/x2apic.c b/xen/arch/x86/genapic/x2apic.c
index 7dfc793514b22ed45e6100109242581a23ac78b7..d512c50fc5adf3ae79dd33811e5c785f1f8f2012 100644 (file)
--- a/xen/arch/x86/genapic/x2apic.c
+++ b/xen/arch/x86/genapic/x2apic.c
@@ -236,11 +236,11 @@ const struct genapic *__init apic_x2apic_probe(void)
     if ( x2apic_phys < 0 )
     {
         /*
-         * Force physical mode if there's no interrupt remapping support: The
-         * ID in clustered mode requires a 32 bit destination field due to
+         * Force physical mode if there's no (full) interrupt remapping support:
+         * The ID in clustered mode requires a 32 bit destination field due to
          * the usage of the high 16 bits to hold the cluster ID.
          */
-        x2apic_phys = !iommu_intremap ||
+        x2apic_phys = iommu_intremap != iommu_intremap_full ||
                       (acpi_gbl_FADT.flags & ACPI_FADT_APIC_PHYSICAL) ||
                       (IS_ENABLED(CONFIG_X2APIC_PHYSICAL) &&
                        !(acpi_gbl_FADT.flags & ACPI_FADT_APIC_CLUSTER));