Introduce the CPUID flag to be used in order to signal the support for using an extended destination ID in IO-APIC RTEs and MSI address fields. Such format expands the maximum target APIC ID from 255 to 32768 without requiring the usage of interrupt remapping.
The design document describing the feature can be found at: http://david.woodhou.se/15-bit-msi.pdf Signed-off-by: Roger Pau Monné <roger....@citrix.com> --- Changes since v1: - New in this version. --- xen/include/public/arch-x86/cpuid.h | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/xen/include/public/arch-x86/cpuid.h b/xen/include/public/arch-x86/cpuid.h index ce46305bee..49bcc93b6b 100644 --- a/xen/include/public/arch-x86/cpuid.h +++ b/xen/include/public/arch-x86/cpuid.h @@ -102,6 +102,12 @@ #define XEN_HVM_CPUID_IOMMU_MAPPINGS (1u << 2) #define XEN_HVM_CPUID_VCPU_ID_PRESENT (1u << 3) /* vcpu id is present in EBX */ #define XEN_HVM_CPUID_DOMID_PRESENT (1u << 4) /* domid is present in ECX */ +/* + * Bits 55:49 from the IO-APIC RTE and bits 11:5 from the MSI address can be + * used to store high bits for the Destination ID. This expands the Destination + * ID field from 8 to 15 bits, allowing to target APIC IDs up 32768. + */ +#define XEN_HVM_CPUID_EXT_DEST_ID (1u << 5) /* * Leaf 6 (0x40000x05) -- 2.34.1
