Xen allows the usage of some previously reserved bits in the IO-APIC RTE and the MSI address fields in order to store high bits for the target APIC ID. Such feature is already implemented by QEMU/KVM and HyperV, so in order to enable it just add the handler that checks for it's presence.
Signed-off-by: Roger Pau Monné <[email protected]> --- Must not be applied until the public headers are changed in Xen. --- Cc: Boris Ostrovsky <[email protected]> Cc: Juergen Gross <[email protected]> Cc: Stefano Stabellini <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Dave Hansen <[email protected]> Cc: [email protected] Cc: "H. Peter Anvin" <[email protected]> Cc: [email protected] --- arch/x86/include/asm/xen/cpuid.h | 7 +++++++ arch/x86/xen/enlighten_hvm.c | 6 ++++++ 2 files changed, 13 insertions(+) diff --git a/arch/x86/include/asm/xen/cpuid.h b/arch/x86/include/asm/xen/cpuid.h index a9630104f1c4..78e667a31d6c 100644 --- a/arch/x86/include/asm/xen/cpuid.h +++ b/arch/x86/include/asm/xen/cpuid.h @@ -100,6 +100,13 @@ /* Memory mapped from other domains has valid IOMMU entries */ #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) diff --git a/arch/x86/xen/enlighten_hvm.c b/arch/x86/xen/enlighten_hvm.c index ab8171cbee23..0c5b0ee3a02a 100644 --- a/arch/x86/xen/enlighten_hvm.c +++ b/arch/x86/xen/enlighten_hvm.c @@ -254,6 +254,11 @@ bool __init xen_hvm_need_lapic(void) return true; } +static bool __init msi_ext_dest_id(void) +{ + return cpuid_eax(xen_cpuid_base() + 4) & XEN_HVM_CPUID_EXT_DEST_ID; +} + static __init void xen_hvm_guest_late_init(void) { #ifdef CONFIG_XEN_PVH @@ -316,6 +321,7 @@ struct hypervisor_x86 x86_hyper_xen_hvm __initdata = { .init.x2apic_available = xen_x2apic_para_available, .init.init_mem_mapping = xen_hvm_init_mem_mapping, .init.guest_late_init = xen_hvm_guest_late_init, + .init.msi_ext_dest_id = msi_ext_dest_id, .runtime.pin_vcpu = xen_pin_vcpu, .ignore_nopv = true, }; -- 2.34.1
