Re: [PATCH v1 18/19] xen/sysctl: wrap around arch-specific arch_do_sysctl

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Wed, 12 Mar 2025, Penny Zheng wrote:
> Function arch_do_sysctl is to perform arch-specific sysctl op.
> Some functions, like psr_get_info for x86, DTB overlay support for arm,
> are solely available through sysctl op, then they all shall be wrapped
> with CONFIG_SYSCTL
> 
> Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxx>
> Signed-off-by: Sergiy Kibrik <Sergiy_Kibrik@xxxxxxxx>
> Signed-off-by: Penny Zheng <Penny.Zheng@xxxxxxx>
> ---
>  xen/arch/arm/Kconfig           |  2 +-
>  xen/arch/arm/Makefile          |  2 +-
>  xen/arch/arm/sysctl.c          |  2 --
>  xen/arch/riscv/stubs.c         |  2 +-
>  xen/arch/x86/Makefile          |  2 +-
>  xen/arch/x86/include/asm/psr.h |  2 ++
>  xen/arch/x86/psr.c             | 18 ++++++++++++++++++
>  xen/arch/x86/sysctl.c          |  2 --
>  xen/include/xen/hypercall.h    |  8 ++++++++
>  9 files changed, 32 insertions(+), 8 deletions(-)
> 
> diff --git a/xen/arch/arm/Kconfig b/xen/arch/arm/Kconfig
> index a26d3e1182..001e65b336 100644
> --- a/xen/arch/arm/Kconfig
> +++ b/xen/arch/arm/Kconfig
> @@ -140,7 +140,7 @@ config HAS_ITS
>          depends on GICV3 && !NEW_VGIC && !ARM_32
>  
>  config OVERLAY_DTB
> -     bool "DTB overlay support (UNSUPPORTED)" if UNSUPPORTED
> +     bool "DTB overlay support (UNSUPPORTED)" if UNSUPPORTED && SYSCTL
>       help
>         Dynamic addition/removal of Xen device tree nodes using a dtbo.
>  
> diff --git a/xen/arch/arm/Makefile b/xen/arch/arm/Makefile
> index fb0948f067..5819c7e4d3 100644
> --- a/xen/arch/arm/Makefile
> +++ b/xen/arch/arm/Makefile
> @@ -54,7 +54,7 @@ obj-y += smpboot.o
>  obj-$(CONFIG_STATIC_EVTCHN) += static-evtchn.init.o
>  obj-$(CONFIG_STATIC_MEMORY) += static-memory.init.o
>  obj-$(CONFIG_STATIC_SHM) += static-shmem.init.o
> -obj-y += sysctl.o
> +obj-$(CONFIG_SYSCTL) += sysctl.o
>  obj-y += time.o
>  obj-y += traps.o
>  obj-y += vcpreg.o
> diff --git a/xen/arch/arm/sysctl.c b/xen/arch/arm/sysctl.c
> index 2d350b700a..32cab4feff 100644
> --- a/xen/arch/arm/sysctl.c
> +++ b/xen/arch/arm/sysctl.c
> @@ -15,7 +15,6 @@
>  #include <asm/arm64/sve.h>
>  #include <public/sysctl.h>
>  
> -#ifdef CONFIG_SYSCTL

Why remove CONFIG_SYSCTL here?


>  void arch_do_physinfo(struct xen_sysctl_physinfo *pi)
>  {
>      pi->capabilities |= XEN_SYSCTL_PHYSCAP_hvm | XEN_SYSCTL_PHYSCAP_hap;
> @@ -23,7 +22,6 @@ void arch_do_physinfo(struct xen_sysctl_physinfo *pi)
>      pi->arch_capabilities |= MASK_INSR(sve_encode_vl(get_sys_vl_len()),
>                                         XEN_SYSCTL_PHYSCAP_ARM_SVE_MASK);
>  }
> -#endif
>  
>  long arch_do_sysctl(struct xen_sysctl *sysctl,
>                      XEN_GUEST_HANDLE_PARAM(xen_sysctl_t) u_sysctl)
> diff --git a/xen/arch/riscv/stubs.c b/xen/arch/riscv/stubs.c
> index 0321ad57f0..28590efb65 100644
> --- a/xen/arch/riscv/stubs.c
> +++ b/xen/arch/riscv/stubs.c
> @@ -322,13 +322,13 @@ unsigned long raw_copy_from_guest(void *to, const void 
> __user *from,
>  
>  /* sysctl.c */
>  
> +#ifdef CONFIG_SYSCTL
>  long arch_do_sysctl(struct xen_sysctl *sysctl,
>                      XEN_GUEST_HANDLE_PARAM(xen_sysctl_t) u_sysctl)
>  {
>      BUG_ON("unimplemented");
>  }
>  
> -#ifdef CONFIG_SYSCTL
>  void arch_do_physinfo(struct xen_sysctl_physinfo *pi)
>  {
>      BUG_ON("unimplemented");
> diff --git a/xen/arch/x86/Makefile b/xen/arch/x86/Makefile
> index c763f80b0b..1949c4276e 100644
> --- a/xen/arch/x86/Makefile
> +++ b/xen/arch/x86/Makefile
> @@ -79,7 +79,7 @@ ifneq ($(CONFIG_PV_SHIM_EXCLUSIVE),y)
>  obj-y += domctl.o
>  obj-y += platform_hypercall.o
>  obj-$(CONFIG_COMPAT) += x86_64/platform_hypercall.o
> -obj-y += sysctl.o
> +obj-$(CONFIG_SYSCTL) += sysctl.o
>  endif
>  
>  extra-y += asm-macros.i
> diff --git a/xen/arch/x86/include/asm/psr.h b/xen/arch/x86/include/asm/psr.h
> index d21a59d98f..e466da7428 100644
> --- a/xen/arch/x86/include/asm/psr.h
> +++ b/xen/arch/x86/include/asm/psr.h
> @@ -75,8 +75,10 @@ static inline bool psr_cmt_enabled(void)
>  int psr_alloc_rmid(struct domain *d);
>  void psr_free_rmid(struct domain *d);
>  
> +#ifdef CONFIG_SYSCTL
>  int psr_get_info(unsigned int socket, enum psr_type type,
>                   uint32_t data[], unsigned int array_len);
> +#endif
>  int psr_get_val(struct domain *d, unsigned int socket,
>                  uint32_t *val, enum psr_type type);
>  int psr_set_val(struct domain *d, unsigned int socket,
> diff --git a/xen/arch/x86/psr.c b/xen/arch/x86/psr.c
> index 5815a35335..34d5de8d2c 100644
> --- a/xen/arch/x86/psr.c
> +++ b/xen/arch/x86/psr.c
> @@ -133,9 +133,11 @@ static const struct feat_props {
>       */
>      enum psr_type alt_type;
>  
> +#ifdef CONFIG_SYSCTL
>      /* get_feat_info is used to return feature HW info through sysctl. */
>      bool (*get_feat_info)(const struct feat_node *feat,
>                            uint32_t data[], unsigned int array_len);
> +#endif
>  
>      /* write_msr is used to write out feature MSR register. */
>      void (*write_msr)(unsigned int cos, uint32_t val, enum psr_type type);
> @@ -418,6 +420,7 @@ static bool mba_init_feature(const struct cpuid_leaf 
> *regs,
>      return true;
>  }
>  
> +#ifdef CONFIG_SYSCTL
>  static bool cf_check cat_get_feat_info(
>      const struct feat_node *feat, uint32_t data[], unsigned int array_len)
>  {
> @@ -430,6 +433,7 @@ static bool cf_check cat_get_feat_info(
>  
>      return true;
>  }
> +#endif
>  
>  /* L3 CAT props */
>  static void cf_check l3_cat_write_msr(
> @@ -442,11 +446,14 @@ static const struct feat_props l3_cat_props = {
>      .cos_num = 1,
>      .type[0] = PSR_TYPE_L3_CBM,
>      .alt_type = PSR_TYPE_UNKNOWN,
> +#ifdef CONFIG_SYSCTL
>      .get_feat_info = cat_get_feat_info,
> +#endif
>      .write_msr = l3_cat_write_msr,
>      .sanitize = cat_check_cbm,
>  };
>  
> +#ifdef CONFIG_SYSCTL
>  /* L3 CDP props */
>  static bool cf_check l3_cdp_get_feat_info(
>      const struct feat_node *feat, uint32_t data[], uint32_t array_len)
> @@ -458,6 +465,7 @@ static bool cf_check l3_cdp_get_feat_info(
>  
>      return true;
>  }
> +#endif
>  
>  static void cf_check l3_cdp_write_msr(
>      unsigned int cos, uint32_t val, enum psr_type type)
> @@ -473,7 +481,9 @@ static const struct feat_props l3_cdp_props = {
>      .type[0] = PSR_TYPE_L3_DATA,
>      .type[1] = PSR_TYPE_L3_CODE,
>      .alt_type = PSR_TYPE_L3_CBM,
> +#ifdef CONFIG_SYSCTL
>      .get_feat_info = l3_cdp_get_feat_info,
> +#endif
>      .write_msr = l3_cdp_write_msr,
>      .sanitize = cat_check_cbm,
>  };
> @@ -489,11 +499,14 @@ static const struct feat_props l2_cat_props = {
>      .cos_num = 1,
>      .type[0] = PSR_TYPE_L2_CBM,
>      .alt_type = PSR_TYPE_UNKNOWN,
> +#ifdef CONFIG_SYSCTL
>      .get_feat_info = cat_get_feat_info,
> +#endif
>      .write_msr = l2_cat_write_msr,
>      .sanitize = cat_check_cbm,
>  };
>  
> +#ifdef CONFIG_SYSCTL
>  /* MBA props */
>  static bool cf_check mba_get_feat_info(
>      const struct feat_node *feat, uint32_t data[], unsigned int array_len)
> @@ -508,6 +521,7 @@ static bool cf_check mba_get_feat_info(
>  
>      return true;
>  }
> +#endif
>  
>  static void cf_check mba_write_msr(
>      unsigned int cos, uint32_t val, enum psr_type type)
> @@ -545,7 +559,9 @@ static const struct feat_props mba_props = {
>      .cos_num = 1,
>      .type[0] = PSR_TYPE_MBA_THRTL,
>      .alt_type = PSR_TYPE_UNKNOWN,
> +#ifdef CONFIG_SYSCTL
>      .get_feat_info = mba_get_feat_info,
> +#endif
>      .write_msr = mba_write_msr,
>      .sanitize = mba_sanitize_thrtl,
>  };
> @@ -808,6 +824,7 @@ static struct psr_socket_info *get_socket_info(unsigned 
> int socket)
>      return socket_info + socket;
>  }
>  
> +#ifdef CONFIG_SYSCTL
>  int psr_get_info(unsigned int socket, enum psr_type type,
>                   uint32_t data[], unsigned int array_len)
>  {
> @@ -839,6 +856,7 @@ int psr_get_info(unsigned int socket, enum psr_type type,
>  
>      return -EINVAL;
>  }
> +#endif /* CONFIG_SYSCTL */
>  
>  int psr_get_val(struct domain *d, unsigned int socket,
>                  uint32_t *val, enum psr_type type)
> diff --git a/xen/arch/x86/sysctl.c b/xen/arch/x86/sysctl.c
> index d7da476379..1b04947516 100644
> --- a/xen/arch/x86/sysctl.c
> +++ b/xen/arch/x86/sysctl.c
> @@ -91,7 +91,6 @@ static long cf_check smt_up_down_helper(void *data)
>      return ret;
>  }
>  
> -#ifdef CONFIG_SYSCTL

and also here?


>  void arch_do_physinfo(struct xen_sysctl_physinfo *pi)
>  {
>      memcpy(pi->hw_cap, boot_cpu_data.x86_capability,
> @@ -105,7 +104,6 @@ void arch_do_physinfo(struct xen_sysctl_physinfo *pi)
>      if ( IS_ENABLED(CONFIG_SHADOW_PAGING) )
>          pi->capabilities |= XEN_SYSCTL_PHYSCAP_shadow;
>  }
> -#endif
>  
>  long arch_do_sysctl(
>      struct xen_sysctl *sysctl, XEN_GUEST_HANDLE_PARAM(xen_sysctl_t) u_sysctl)
> diff --git a/xen/include/xen/hypercall.h b/xen/include/xen/hypercall.h
> index 15b6be6ec8..d0ea64b332 100644
> --- a/xen/include/xen/hypercall.h
> +++ b/xen/include/xen/hypercall.h
> @@ -29,10 +29,18 @@ arch_do_domctl(
>      struct xen_domctl *domctl, struct domain *d,
>      XEN_GUEST_HANDLE_PARAM(xen_domctl_t) u_domctl);
>  
> +#ifdef CONFIG_SYSCTL
>  extern long
>  arch_do_sysctl(
>      struct xen_sysctl *sysctl,
>      XEN_GUEST_HANDLE_PARAM(xen_sysctl_t) u_sysctl);
> +#else
> +static inline long arch_do_sysctl(struct xen_sysctl *sysctl,
> +                                  XEN_GUEST_HANDLE_PARAM(xen_sysctl_t) 
> u_sysctl)
> +{
> +    return -EOPNOTSUPP;
> +}
> +#endif
>  
>  extern long
>  pci_physdev_op(
> -- 
> 2.34.1
>