RE: [PATCH v8 1/2] xen+tools: Report Interrupt Controller Virtualization capabilities on x86

["Tian, Kevin" <kevin.tian@xxxxxxxxx>]

> From: Jane Malalane
> Sent: Wednesday, March 16, 2022 5:13 PM
> 
> Add XEN_SYSCTL_PHYSCAP_X86_ASSISTED_XAPIC and
> XEN_SYSCTL_PHYSCAP_X86_ASSISTED_X2APIC to report accelerated xAPIC
> and
> x2APIC, on x86 hardware. This is so that xAPIC and x2APIC virtualization
> can subsequently be enabled on a per-domain basis.
> No such features are currently implemented on AMD hardware.
> 
> HW assisted xAPIC virtualization will be reported if HW, at the
> minimum, supports virtualize_apic_accesses as this feature alone means
> that an access to the APIC page will cause an APIC-access VM exit. An
> APIC-access VM exit provides a VMM with information about the access
> causing the VM exit, unlike a regular EPT fault, thus simplifying some
> internal handling.
> 
> HW assisted x2APIC virtualization will be reported if HW supports
> virtualize_x2apic_mode and, at least, either apic_reg_virt or
> virtual_intr_delivery. This also means that
> sysctl follows the conditionals in vmx_vlapic_msr_changed().
> 
> For that purpose, also add an arch-specific "capabilities" parameter
> to struct xen_sysctl_physinfo.
> 
> Note that this interface is intended to be compatible with AMD so that
> AVIC support can be introduced in a future patch. Unlike Intel that
> has multiple controls for APIC Virtualization, AMD has one global
> 'AVIC Enable' control bit, so fine-graining of APIC virtualization
> control cannot be done on a common interface.
> 
> Suggested-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
> Signed-off-by: Jane Malalane <jane.malalane@xxxxxxxxxx>

Reviewed-by: Kevin Tian <kevin.tian@xxxxxxxxx>

btw the r-b from Roger is lost...

> ---
> CC: Wei Liu <wl@xxxxxxx>
> CC: Anthony PERARD <anthony.perard@xxxxxxxxxx>
> CC: Juergen Gross <jgross@xxxxxxxx>
> CC: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
> CC: George Dunlap <george.dunlap@xxxxxxxxxx>
> CC: Jan Beulich <jbeulich@xxxxxxxx>
> CC: Julien Grall <julien@xxxxxxx>
> CC: Stefano Stabellini <sstabellini@xxxxxxxxxx>
> CC: Volodymyr Babchuk <Volodymyr_Babchuk@xxxxxxxx>
> CC: Bertrand Marquis <bertrand.marquis@xxxxxxx>
> CC: Jun Nakajima <jun.nakajima@xxxxxxxxx>
> CC: Kevin Tian <kevin.tian@xxxxxxxxx>
> CC: "Roger Pau Monné" <roger.pau@xxxxxxxxxx>
> 
> v8:
>  * Improve commit message
> 
> v7:
>  * Make sure assisted_x{2}apic_available evaluates to false, to ensure
>    Xen builds, when !CONFIG_HVM
>  * Fix coding style issues
> 
> v6:
>  * Limit abi check to x86
>  * Fix coding style issue
> 
> v5:
>  * Have assisted_xapic_available solely depend on
>    cpu_has_vmx_virtualize_apic_accesses and assisted_x2apic_available
>    depend on cpu_has_vmx_virtualize_x2apic_mode and
>    cpu_has_vmx_apic_reg_virt OR cpu_has_vmx_virtual_intr_delivery
> 
> v4:
>  * Fallback to the original v2/v1 conditions for setting
>    assisted_xapic_available and assisted_x2apic_available so that in
>    the future APIC virtualization can be exposed on AMD hardware
>    since fine-graining of "AVIC" is not supported, i.e., AMD solely
>    uses "AVIC Enable". This also means that sysctl mimics what's
>    exposed in CPUID
> 
> v3:
>  * Define XEN_SYSCTL_PHYSCAP_ARCH_MAX for ABI checking and actually
>    set "arch_capbilities", via a call to c_bitmap_to_ocaml_list()
>  * Have assisted_x2apic_available only depend on
>    cpu_has_vmx_virtualize_x2apic_mode
> 
> v2:
>  * Use one macro LIBXL_HAVE_PHYSINFO_ASSISTED_APIC instead of two
>  * Pass xcpyshinfo as a pointer in libxl__arch_get_physinfo
>  * Set assisted_x{2}apic_available to be conditional upon "bsp" and
>    annotate it with __ro_after_init
>  * Change XEN_SYSCTL_PHYSCAP_ARCH_ASSISTED_X{2}APIC to
>    _X86_ASSISTED_X{2}APIC
>  * Keep XEN_SYSCTL_PHYSCAP_X86_ASSISTED_X{2}APIC contained within
>    sysctl.h
>  * Fix padding introduced in struct xen_sysctl_physinfo and bump
>    XEN_SYSCTL_INTERFACE_VERSION
> ---
>  tools/golang/xenlight/helpers.gen.go |  4 ++++
>  tools/golang/xenlight/types.gen.go   |  2 ++
>  tools/include/libxl.h                |  7 +++++++
>  tools/libs/light/libxl.c             |  3 +++
>  tools/libs/light/libxl_arch.h        |  4 ++++
>  tools/libs/light/libxl_arm.c         |  5 +++++
>  tools/libs/light/libxl_types.idl     |  2 ++
>  tools/libs/light/libxl_x86.c         | 11 +++++++++++
>  tools/ocaml/libs/xc/xenctrl.ml       |  5 +++++
>  tools/ocaml/libs/xc/xenctrl.mli      |  5 +++++
>  tools/ocaml/libs/xc/xenctrl_stubs.c  | 15 +++++++++++++--
>  tools/xl/xl_info.c                   |  6 ++++--
>  xen/arch/x86/hvm/hvm.c               |  3 +++
>  xen/arch/x86/hvm/vmx/vmcs.c          |  9 +++++++++
>  xen/arch/x86/include/asm/hvm/hvm.h   |  5 +++++
>  xen/arch/x86/sysctl.c                |  4 ++++
>  xen/include/public/sysctl.h          | 11 ++++++++++-
>  17 files changed, 96 insertions(+), 5 deletions(-)
> 
> diff --git a/tools/golang/xenlight/helpers.gen.go
> b/tools/golang/xenlight/helpers.gen.go
> index b746ff1081..dd4e6c9f14 100644
> --- a/tools/golang/xenlight/helpers.gen.go
> +++ b/tools/golang/xenlight/helpers.gen.go
> @@ -3373,6 +3373,8 @@ x.CapVmtrace = bool(xc.cap_vmtrace)
>  x.CapVpmu = bool(xc.cap_vpmu)
>  x.CapGnttabV1 = bool(xc.cap_gnttab_v1)
>  x.CapGnttabV2 = bool(xc.cap_gnttab_v2)
> +x.CapAssistedXapic = bool(xc.cap_assisted_xapic)
> +x.CapAssistedX2Apic = bool(xc.cap_assisted_x2apic)
> 
>   return nil}
> 
> @@ -3407,6 +3409,8 @@ xc.cap_vmtrace = C.bool(x.CapVmtrace)
>  xc.cap_vpmu = C.bool(x.CapVpmu)
>  xc.cap_gnttab_v1 = C.bool(x.CapGnttabV1)
>  xc.cap_gnttab_v2 = C.bool(x.CapGnttabV2)
> +xc.cap_assisted_xapic = C.bool(x.CapAssistedXapic)
> +xc.cap_assisted_x2apic = C.bool(x.CapAssistedX2Apic)
> 
>   return nil
>   }
> diff --git a/tools/golang/xenlight/types.gen.go
> b/tools/golang/xenlight/types.gen.go
> index b1e84d5258..87be46c745 100644
> --- a/tools/golang/xenlight/types.gen.go
> +++ b/tools/golang/xenlight/types.gen.go
> @@ -1014,6 +1014,8 @@ CapVmtrace bool
>  CapVpmu bool
>  CapGnttabV1 bool
>  CapGnttabV2 bool
> +CapAssistedXapic bool
> +CapAssistedX2Apic bool
>  }
> 
>  type Connectorinfo struct {
> diff --git a/tools/include/libxl.h b/tools/include/libxl.h
> index 51a9b6cfac..94e6355822 100644
> --- a/tools/include/libxl.h
> +++ b/tools/include/libxl.h
> @@ -528,6 +528,13 @@
>  #define LIBXL_HAVE_MAX_GRANT_VERSION 1
> 
>  /*
> + * LIBXL_HAVE_PHYSINFO_ASSISTED_APIC indicates that libxl_physinfo has
> + * cap_assisted_xapic and cap_assisted_x2apic fields, which indicates
> + * the availability of x{2}APIC hardware assisted virtualization.
> + */
> +#define LIBXL_HAVE_PHYSINFO_ASSISTED_APIC 1
> +
> +/*
>   * libxl ABI compatibility
>   *
>   * The only guarantee which libxl makes regarding ABI compatibility
> diff --git a/tools/libs/light/libxl.c b/tools/libs/light/libxl.c
> index a0bf7d186f..6d699951e2 100644
> --- a/tools/libs/light/libxl.c
> +++ b/tools/libs/light/libxl.c
> @@ -15,6 +15,7 @@
>  #include "libxl_osdeps.h"
> 
>  #include "libxl_internal.h"
> +#include "libxl_arch.h"
> 
>  int libxl_ctx_alloc(libxl_ctx **pctx, int version,
>                      unsigned flags, xentoollog_logger * lg)
> @@ -410,6 +411,8 @@ int libxl_get_physinfo(libxl_ctx *ctx, libxl_physinfo
> *physinfo)
>      physinfo->cap_gnttab_v2 =
>          !!(xcphysinfo.capabilities & XEN_SYSCTL_PHYSCAP_gnttab_v2);
> 
> +    libxl__arch_get_physinfo(physinfo, &xcphysinfo);
> +
>      GC_FREE;
>      return 0;
>  }
> diff --git a/tools/libs/light/libxl_arch.h b/tools/libs/light/libxl_arch.h
> index 1522ecb97f..207ceac6a1 100644
> --- a/tools/libs/light/libxl_arch.h
> +++ b/tools/libs/light/libxl_arch.h
> @@ -86,6 +86,10 @@ int libxl__arch_extra_memory(libxl__gc *gc,
>                               uint64_t *out);
> 
>  _hidden
> +void libxl__arch_get_physinfo(libxl_physinfo *physinfo,
> +                              const xc_physinfo_t *xcphysinfo);
> +
> +_hidden
>  void libxl__arch_update_domain_config(libxl__gc *gc,
>                                        libxl_domain_config *dst,
>                                        const libxl_domain_config *src);
> diff --git a/tools/libs/light/libxl_arm.c b/tools/libs/light/libxl_arm.c
> index eef1de0939..39fdca1b49 100644
> --- a/tools/libs/light/libxl_arm.c
> +++ b/tools/libs/light/libxl_arm.c
> @@ -1431,6 +1431,11 @@ int
> libxl__arch_passthrough_mode_setdefault(libxl__gc *gc,
>      return rc;
>  }
> 
> +void libxl__arch_get_physinfo(libxl_physinfo *physinfo,
> +                              const xc_physinfo_t *xcphysinfo)
> +{
> +}
> +
>  void libxl__arch_update_domain_config(libxl__gc *gc,
>                                        libxl_domain_config *dst,
>                                        const libxl_domain_config *src)
> diff --git a/tools/libs/light/libxl_types.idl 
> b/tools/libs/light/libxl_types.idl
> index 2a42da2f7d..42ac6c357b 100644
> --- a/tools/libs/light/libxl_types.idl
> +++ b/tools/libs/light/libxl_types.idl
> @@ -1068,6 +1068,8 @@ libxl_physinfo = Struct("physinfo", [
>      ("cap_vpmu", bool),
>      ("cap_gnttab_v1", bool),
>      ("cap_gnttab_v2", bool),
> +    ("cap_assisted_xapic", bool),
> +    ("cap_assisted_x2apic", bool),
>      ], dir=DIR_OUT)
> 
>  libxl_connectorinfo = Struct("connectorinfo", [
> diff --git a/tools/libs/light/libxl_x86.c b/tools/libs/light/libxl_x86.c
> index 1feadebb18..e0a06ecfe3 100644
> --- a/tools/libs/light/libxl_x86.c
> +++ b/tools/libs/light/libxl_x86.c
> @@ -866,6 +866,17 @@ int
> libxl__arch_passthrough_mode_setdefault(libxl__gc *gc,
>      return rc;
>  }
> 
> +void libxl__arch_get_physinfo(libxl_physinfo *physinfo,
> +                              const xc_physinfo_t *xcphysinfo)
> +{
> +    physinfo->cap_assisted_xapic =
> +        !!(xcphysinfo->arch_capabilities &
> +           XEN_SYSCTL_PHYSCAP_X86_ASSISTED_XAPIC);
> +    physinfo->cap_assisted_x2apic =
> +        !!(xcphysinfo->arch_capabilities &
> +           XEN_SYSCTL_PHYSCAP_X86_ASSISTED_X2APIC);
> +}
> +
>  void libxl__arch_update_domain_config(libxl__gc *gc,
>                                        libxl_domain_config *dst,
>                                        const libxl_domain_config *src)
> diff --git a/tools/ocaml/libs/xc/xenctrl.ml b/tools/ocaml/libs/xc/xenctrl.ml
> index 7503031d8f..712456e098 100644
> --- a/tools/ocaml/libs/xc/xenctrl.ml
> +++ b/tools/ocaml/libs/xc/xenctrl.ml
> @@ -127,6 +127,10 @@ type physinfo_cap_flag =
>       | CAP_Gnttab_v1
>       | CAP_Gnttab_v2
> 
> +type physinfo_arch_cap_flag =
> +     | CAP_X86_ASSISTED_XAPIC
> +     | CAP_X86_ASSISTED_X2APIC
> +
>  type physinfo =
>  {
>       threads_per_core : int;
> @@ -140,6 +144,7 @@ type physinfo =
>       (* XXX hw_cap *)
>       capabilities     : physinfo_cap_flag list;
>       max_nr_cpus      : int;
> +     arch_capabilities : physinfo_arch_cap_flag list;
>  }
> 
>  type version =
> diff --git a/tools/ocaml/libs/xc/xenctrl.mli b/tools/ocaml/libs/xc/xenctrl.mli
> index d1d9c9247a..b034434f68 100644
> --- a/tools/ocaml/libs/xc/xenctrl.mli
> +++ b/tools/ocaml/libs/xc/xenctrl.mli
> @@ -112,6 +112,10 @@ type physinfo_cap_flag =
>    | CAP_Gnttab_v1
>    | CAP_Gnttab_v2
> 
> +type physinfo_arch_cap_flag =
> +  | CAP_X86_ASSISTED_XAPIC
> +  | CAP_X86_ASSISTED_X2APIC
> +
>  type physinfo = {
>    threads_per_core : int;
>    cores_per_socket : int;
> @@ -123,6 +127,7 @@ type physinfo = {
>    scrub_pages      : nativeint;
>    capabilities     : physinfo_cap_flag list;
>    max_nr_cpus      : int; (** compile-time max possible number of nr_cpus *)
> +  arch_capabilities : physinfo_arch_cap_flag list;
>  }
>  type version = { major : int; minor : int; extra : string; }
>  type compile_info = {
> diff --git a/tools/ocaml/libs/xc/xenctrl_stubs.c
> b/tools/ocaml/libs/xc/xenctrl_stubs.c
> index 5b4fe72c8d..7e9c32ad1b 100644
> --- a/tools/ocaml/libs/xc/xenctrl_stubs.c
> +++ b/tools/ocaml/libs/xc/xenctrl_stubs.c
> @@ -712,7 +712,7 @@ CAMLprim value stub_xc_send_debug_keys(value
> xch, value keys)
>  CAMLprim value stub_xc_physinfo(value xch)
>  {
>       CAMLparam1(xch);
> -     CAMLlocal2(physinfo, cap_list);
> +     CAMLlocal3(physinfo, cap_list, arch_cap_list);
>       xc_physinfo_t c_physinfo;
>       int r;
> 
> @@ -731,7 +731,7 @@ CAMLprim value stub_xc_physinfo(value xch)
>               /* ! XEN_SYSCTL_PHYSCAP_ XEN_SYSCTL_PHYSCAP_MAX max
> */
>               (c_physinfo.capabilities);
> 
> -     physinfo = caml_alloc_tuple(10);
> +     physinfo = caml_alloc_tuple(11);
>       Store_field(physinfo, 0, Val_int(c_physinfo.threads_per_core));
>       Store_field(physinfo, 1, Val_int(c_physinfo.cores_per_socket));
>       Store_field(physinfo, 2, Val_int(c_physinfo.nr_cpus));
> @@ -743,6 +743,17 @@ CAMLprim value stub_xc_physinfo(value xch)
>       Store_field(physinfo, 8, cap_list);
>       Store_field(physinfo, 9, Val_int(c_physinfo.max_cpu_id + 1));
> 
> +#if defined(__i386__) || defined(__x86_64__)
> +     /*
> +      * arch_capabilities: physinfo_arch_cap_flag list;
> +      */
> +     arch_cap_list = c_bitmap_to_ocaml_list
> +             /* ! physinfo_arch_cap_flag CAP_ none */
> +             /* ! XEN_SYSCTL_PHYSCAP_ XEN_SYSCTL_PHYSCAP_X86_MAX
> max */
> +             (c_physinfo.arch_capabilities);
> +     Store_field(physinfo, 10, arch_cap_list);
> +#endif
> +
>       CAMLreturn(physinfo);
>  }
> 
> diff --git a/tools/xl/xl_info.c b/tools/xl/xl_info.c
> index 712b7638b0..3205270754 100644
> --- a/tools/xl/xl_info.c
> +++ b/tools/xl/xl_info.c
> @@ -210,7 +210,7 @@ static void output_physinfo(void)
>           info.hw_cap[4], info.hw_cap[5], info.hw_cap[6], info.hw_cap[7]
>          );
> 
> -    maybe_printf("virt_caps              :%s%s%s%s%s%s%s%s%s%s%s\n",
> +    maybe_printf("virt_caps              :%s%s%s%s%s%s%s%s%s%s%s%s%s\n",
>           info.cap_pv ? " pv" : "",
>           info.cap_hvm ? " hvm" : "",
>           info.cap_hvm && info.cap_hvm_directio ? " hvm_directio" : "",
> @@ -221,7 +221,9 @@ static void output_physinfo(void)
>           info.cap_vmtrace ? " vmtrace" : "",
>           info.cap_vpmu ? " vpmu" : "",
>           info.cap_gnttab_v1 ? " gnttab-v1" : "",
> -         info.cap_gnttab_v2 ? " gnttab-v2" : ""
> +         info.cap_gnttab_v2 ? " gnttab-v2" : "",
> +         info.cap_assisted_xapic ? " assisted_xapic" : "",
> +         info.cap_assisted_x2apic ? " assisted_x2apic" : ""
>          );
> 
>      vinfo = libxl_get_version_info(ctx);
> diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
> index 709a4191ef..e5dde9f8ce 100644
> --- a/xen/arch/x86/hvm/hvm.c
> +++ b/xen/arch/x86/hvm/hvm.c
> @@ -117,6 +117,9 @@ static const char __initconst warning_hvm_fep[] =
>  static bool_t __initdata opt_altp2m_enabled = 0;
>  boolean_param("altp2m", opt_altp2m_enabled);
> 
> +bool __ro_after_init assisted_xapic_available;
> +bool __ro_after_init assisted_x2apic_available;
> +
>  static int cf_check cpu_callback(
>      struct notifier_block *nfb, unsigned long action, void *hcpu)
>  {
> diff --git a/xen/arch/x86/hvm/vmx/vmcs.c b/xen/arch/x86/hvm/vmx/vmcs.c
> index e1e1fa14e6..77ce0b2121 100644
> --- a/xen/arch/x86/hvm/vmx/vmcs.c
> +++ b/xen/arch/x86/hvm/vmx/vmcs.c
> @@ -343,6 +343,15 @@ static int vmx_init_vmcs_config(bool bsp)
>              MSR_IA32_VMX_PROCBASED_CTLS2, &mismatch);
>      }
> 
> +    /* Check whether hardware supports accelerated xapic and x2apic. */
> +    if ( bsp )
> +    {
> +        assisted_xapic_available = cpu_has_vmx_virtualize_apic_accesses;
> +        assisted_x2apic_available = cpu_has_vmx_virtualize_x2apic_mode &&
> +                                    (cpu_has_vmx_apic_reg_virt ||
> +                                     cpu_has_vmx_virtual_intr_delivery);
> +    }
> +
>      /* The IA32_VMX_EPT_VPID_CAP MSR exists only when EPT or VPID
> available */
>      if ( _vmx_secondary_exec_control & (SECONDARY_EXEC_ENABLE_EPT |
>                                          SECONDARY_EXEC_ENABLE_VPID) )
> diff --git a/xen/arch/x86/include/asm/hvm/hvm.h
> b/xen/arch/x86/include/asm/hvm/hvm.h
> index 5b7ec0cf69..e0d9348878 100644
> --- a/xen/arch/x86/include/asm/hvm/hvm.h
> +++ b/xen/arch/x86/include/asm/hvm/hvm.h
> @@ -373,6 +373,9 @@ int hvm_get_param(struct domain *d, uint32_t index,
> uint64_t *value);
>  #define hvm_tsc_scaling_ratio(d) \
>      ((d)->arch.hvm.tsc_scaling_ratio)
> 
> +extern bool assisted_xapic_available;
> +extern bool assisted_x2apic_available;
> +
>  #define hvm_get_guest_time(v) hvm_get_guest_time_fixed(v, 0)
> 
>  #define hvm_paging_enabled(v) \
> @@ -872,6 +875,8 @@ static inline void hvm_set_reg(struct vcpu *v,
> unsigned int reg, uint64_t val)
>  #define hvm_tsc_scaling_supported false
>  #define hap_has_1gb false
>  #define hap_has_2mb false
> +#define assisted_xapic_available false
> +#define assisted_x2apic_available false
> 
>  #define hvm_paging_enabled(v) ((void)(v), false)
>  #define hvm_wp_enabled(v) ((void)(v), false)
> diff --git a/xen/arch/x86/sysctl.c b/xen/arch/x86/sysctl.c
> index f82abc2488..716525f72f 100644
> --- a/xen/arch/x86/sysctl.c
> +++ b/xen/arch/x86/sysctl.c
> @@ -135,6 +135,10 @@ void arch_do_physinfo(struct xen_sysctl_physinfo
> *pi)
>          pi->capabilities |= XEN_SYSCTL_PHYSCAP_hap;
>      if ( IS_ENABLED(CONFIG_SHADOW_PAGING) )
>          pi->capabilities |= XEN_SYSCTL_PHYSCAP_shadow;
> +    if ( assisted_xapic_available )
> +        pi->arch_capabilities |= XEN_SYSCTL_PHYSCAP_X86_ASSISTED_XAPIC;
> +    if ( assisted_x2apic_available )
> +        pi->arch_capabilities |= XEN_SYSCTL_PHYSCAP_X86_ASSISTED_X2APIC;
>  }
> 
>  long arch_do_sysctl(
> diff --git a/xen/include/public/sysctl.h b/xen/include/public/sysctl.h
> index 55252e97f2..fbb9912067 100644
> --- a/xen/include/public/sysctl.h
> +++ b/xen/include/public/sysctl.h
> @@ -35,7 +35,7 @@
>  #include "domctl.h"
>  #include "physdev.h"
> 
> -#define XEN_SYSCTL_INTERFACE_VERSION 0x00000014
> +#define XEN_SYSCTL_INTERFACE_VERSION 0x00000015
> 
>  /*
>   * Read console content from Xen buffer ring.
> @@ -111,6 +111,13 @@ struct xen_sysctl_tbuf_op {
>  /* Max XEN_SYSCTL_PHYSCAP_* constant.  Used for ABI checking. */
>  #define XEN_SYSCTL_PHYSCAP_MAX XEN_SYSCTL_PHYSCAP_gnttab_v2
> 
> +/* The platform supports x{2}apic hardware assisted emulation. */
> +#define XEN_SYSCTL_PHYSCAP_X86_ASSISTED_XAPIC  (1u << 0)
> +#define XEN_SYSCTL_PHYSCAP_X86_ASSISTED_X2APIC (1u << 1)
> +
> +/* Max XEN_SYSCTL_PHYSCAP_X86__* constant. Used for ABI checking. */
> +#define XEN_SYSCTL_PHYSCAP_X86_MAX
> XEN_SYSCTL_PHYSCAP_X86_ASSISTED_X2APIC
> +
>  struct xen_sysctl_physinfo {
>      uint32_t threads_per_core;
>      uint32_t cores_per_socket;
> @@ -120,6 +127,8 @@ struct xen_sysctl_physinfo {
>      uint32_t max_node_id; /* Largest possible node ID on this host */
>      uint32_t cpu_khz;
>      uint32_t capabilities;/* XEN_SYSCTL_PHYSCAP_??? */
> +    uint32_t arch_capabilities;/* XEN_SYSCTL_PHYSCAP_{X86,ARM,...}_??? */
> +    uint32_t pad;
>      uint64_aligned_t total_pages;
>      uint64_aligned_t free_pages;
>      uint64_aligned_t scrub_pages;
> --
> 2.11.0
>