Re: [PATCH 2/4] xen: Drop CONFIG_XEN_PVHVM

[Stefano Stabellini <sstabellini@kernel.org>]

On Wed, 5 Aug 2026, Juergen Gross wrote:
> On x86 CONFIG_XEN_PVHVM is now a synonym of CONFIG_XEN.
> 
> In Xen specific x86 code it can be just dropped, in non-Xen specific
> x86 code it can be replaced with CONFIG_XEN.
> 
> In architecture independent code it is used only where CONFIG_XEN is
> defined, so it can be replaced with CONFIG_X86 there.
> 
> Signed-off-by: Juergen Gross <jgross@suse.com>

While I think there is value in compiling a tiny PV-only kernel (in
fact I even have a real-world use case for it) the code addition is
minimal and also considering your reply to Andrew:

Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>


> ---
>  arch/x86/include/asm/idtentry.h   |  2 +-
>  arch/x86/kernel/cpu/hypervisor.c  |  2 +-
>  arch/x86/xen/Kconfig              | 10 +++-------
>  arch/x86/xen/Makefile             |  9 ++++-----
>  arch/x86/xen/time.c               |  2 --
>  arch/x86/xen/xen-ops.h            |  4 ----
>  drivers/xen/Kconfig               |  2 +-
>  drivers/xen/events/events_base.c  |  7 -------
>  drivers/xen/xenbus/xenbus_probe.c |  2 +-
>  include/xen/platform_pci.h        |  6 +++---
>  10 files changed, 14 insertions(+), 32 deletions(-)
> 
> diff --git a/arch/x86/include/asm/idtentry.h b/arch/x86/include/asm/idtentry.h
> index 20f548702404..f400cfac69a6 100644
> --- a/arch/x86/include/asm/idtentry.h
> +++ b/arch/x86/include/asm/idtentry.h
> @@ -745,7 +745,7 @@ DECLARE_IDTENTRY_SYSVEC(HYPERV_STIMER0_VECTOR,		sysvec_hyperv_stimer0);
>  DECLARE_IDTENTRY_SYSVEC(HYPERVISOR_CALLBACK_VECTOR,	sysvec_acrn_hv_callback);
>  #endif
>  
> -#ifdef CONFIG_XEN_PVHVM
> +#ifdef CONFIG_XEN
>  DECLARE_IDTENTRY_SYSVEC(HYPERVISOR_CALLBACK_VECTOR,	sysvec_xen_hvm_callback);
>  #endif
>  
> diff --git a/arch/x86/kernel/cpu/hypervisor.c b/arch/x86/kernel/cpu/hypervisor.c
> index f3e9219845e8..73428afca796 100644
> --- a/arch/x86/kernel/cpu/hypervisor.c
> +++ b/arch/x86/kernel/cpu/hypervisor.c
> @@ -31,7 +31,7 @@ static const __initconst struct hypervisor_x86 * const hypervisors[] =
>  #ifdef CONFIG_XEN_PV
>  	&x86_hyper_xen_pv,
>  #endif
> -#ifdef CONFIG_XEN_PVHVM
> +#ifdef CONFIG_XEN
>  	&x86_hyper_xen_hvm,
>  #endif
>  	&x86_hyper_vmware,
> diff --git a/arch/x86/xen/Kconfig b/arch/x86/xen/Kconfig
> index bb420a4cb75f..9e5bb51eecf4 100644
> --- a/arch/x86/xen/Kconfig
> +++ b/arch/x86/xen/Kconfig
> @@ -50,24 +50,20 @@ config XEN_PV_DOM0
>  	def_bool y
>  	depends on XEN_PV && XEN_DOM0
>  
> -config XEN_PVHVM
> -	def_bool y
> -	depends on XEN
> -
>  config XEN_PVHVM_SMP
>  	def_bool y
> -	depends on XEN_PVHVM && SMP
> +	depends on XEN && SMP
>  
>  config XEN_PVHVM_GUEST
>  	bool "Xen PVHVM guest support"
>  	default y
> -	depends on XEN_PVHVM && PCI
> +	depends on XEN && PCI
>  	help
>  	  Support running as a Xen PVHVM guest.
>  
>  config XEN_PVH
>  	bool "Xen PVH guest support"
> -	depends on XEN && XEN_PVHVM && ACPI
> +	depends on XEN && ACPI
>  	select PVH
>  	help
>  	  Support for running as a Xen PVH guest.
> diff --git a/arch/x86/xen/Makefile b/arch/x86/xen/Makefile
> index 717264ae269b..32d651aa9bc2 100644
> --- a/arch/x86/xen/Makefile
> +++ b/arch/x86/xen/Makefile
> @@ -16,11 +16,10 @@ obj-y				+= mmu.o
>  obj-y				+= time.o
>  obj-y				+= grant-table.o
>  obj-y				+= suspend.o
> -
> -obj-$(CONFIG_XEN_PVHVM)		+= enlighten_hvm.o
> -obj-$(CONFIG_XEN_PVHVM)		+= mmu_hvm.o
> -obj-$(CONFIG_XEN_PVHVM)		+= suspend_hvm.o
> -obj-$(CONFIG_XEN_PVHVM)		+= platform-pci-unplug.o
> +obj-y				+= enlighten_hvm.o
> +obj-y				+= mmu_hvm.o
> +obj-y				+= suspend_hvm.o
> +obj-y				+= platform-pci-unplug.o
>  
>  obj-$(CONFIG_XEN_PV)		+= setup.o
>  obj-$(CONFIG_XEN_PV)		+= apic.o
> diff --git a/arch/x86/xen/time.c b/arch/x86/xen/time.c
> index d62c14334b35..5c7822254a01 100644
> --- a/arch/x86/xen/time.c
> +++ b/arch/x86/xen/time.c
> @@ -586,7 +586,6 @@ void __init xen_init_time_ops(void)
>  		x86_platform.set_wallclock = xen_set_wallclock;
>  }
>  
> -#ifdef CONFIG_XEN_PVHVM
>  static void xen_hvm_setup_cpu_clockevents(void)
>  {
>  	int cpu = smp_processor_id();
> @@ -643,7 +642,6 @@ void __init xen_hvm_init_time_ops(void)
>  
>  	hvm_time_initialized = true;
>  }
> -#endif
>  
>  /* Kernel parameter to specify Xen timer slop */
>  static int __init parse_xen_timer_slop(char *ptr)
> diff --git a/arch/x86/xen/xen-ops.h b/arch/x86/xen/xen-ops.h
> index dc265bdda24d..47eebbb3684a 100644
> --- a/arch/x86/xen/xen-ops.h
> +++ b/arch/x86/xen/xen-ops.h
> @@ -236,11 +236,7 @@ void xen_pin_vcpu(int cpu);
>  
>  void xen_emergency_restart(void);
>  
> -#ifdef CONFIG_XEN_PVHVM
>  void xen_hvm_post_suspend(int suspend_cancelled);
> -#else
> -static inline void xen_hvm_post_suspend(int suspend_cancelled) {}
> -#endif
>  
>  /*
>   * The maximum amount of extra memory compared to the base size.  The
> diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig
> index f9a35ed266ec..cfb517cd77dc 100644
> --- a/drivers/xen/Kconfig
> +++ b/drivers/xen/Kconfig
> @@ -311,7 +311,7 @@ config XEN_EFI
>  
>  config XEN_AUTO_XLATE
>  	def_bool y
> -	depends on ARM || ARM64 || XEN_PVHVM
> +	depends on ARM || ARM64 || X86
>  	help
>  	  Support for auto-translated physmap guests.
>  
> diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c
> index 6ea945508a89..fd16d652c81f 100644
> --- a/drivers/xen/events/events_base.c
> +++ b/drivers/xen/events/events_base.c
> @@ -2180,7 +2180,6 @@ static struct irq_chip xen_percpu_chip __read_mostly = {
>  };
>  
>  #ifdef CONFIG_X86
> -#ifdef CONFIG_XEN_PVHVM
>  /* Vector callbacks are better than PCI interrupts to receive event
>   * channel notifications because we can receive vector callbacks on any
>   * vcpu and we don't need PCI support or APIC interactions. */
> @@ -2242,12 +2241,6 @@ static __init void xen_alloc_callback_vector(void)
>  	pr_info("Xen HVM callback vector for event delivery is enabled\n");
>  	sysvec_install(HYPERVISOR_CALLBACK_VECTOR, sysvec_xen_hvm_callback);
>  }
> -#else
> -void xen_setup_callback_vector(void) {}
> -static inline void xen_init_setup_upcall_vector(void) {}
> -int xen_set_upcall_vector(unsigned int cpu) {}
> -static inline void xen_alloc_callback_vector(void) {}
> -#endif /* CONFIG_XEN_PVHVM */
>  #endif /* CONFIG_X86 */
>  
>  bool xen_fifo_events = true;
> diff --git a/drivers/xen/xenbus/xenbus_probe.c b/drivers/xen/xenbus/xenbus_probe.c
> index fafb2b84fa5c..082b8c1fee8e 100644
> --- a/drivers/xen/xenbus/xenbus_probe.c
> +++ b/drivers/xen/xenbus/xenbus_probe.c
> @@ -831,7 +831,7 @@ static void xenbus_probe(void)
>   */
>  static bool xs_hvm_defer_init_for_callback(void)
>  {
> -#ifdef CONFIG_XEN_PVHVM
> +#ifdef CONFIG_X86
>  	return xen_store_domain_type == XS_HVM &&
>  		!xen_have_vector_callback;
>  #else
> diff --git a/include/xen/platform_pci.h b/include/xen/platform_pci.h
> index e51e7cb71a85..267040c1f504 100644
> --- a/include/xen/platform_pci.h
> +++ b/include/xen/platform_pci.h
> @@ -30,7 +30,7 @@
>  static inline int xen_must_unplug_nics(void) {
>  #if (defined(CONFIG_XEN_NETDEV_FRONTEND) || \
>  		defined(CONFIG_XEN_NETDEV_FRONTEND_MODULE)) && \
> -		defined(CONFIG_XEN_PVHVM)
> +		defined(CONFIG_X86)
>          return 1;
>  #else
>          return 0;
> @@ -40,14 +40,14 @@ static inline int xen_must_unplug_nics(void) {
>  static inline int xen_must_unplug_disks(void) {
>  #if (defined(CONFIG_XEN_BLKDEV_FRONTEND) || \
>  		defined(CONFIG_XEN_BLKDEV_FRONTEND_MODULE)) && \
> -		defined(CONFIG_XEN_PVHVM)
> +		defined(CONFIG_X86)
>          return 1;
>  #else
>          return 0;
>  #endif
>  }
>  
> -#if defined(CONFIG_XEN_PVHVM)
> +#if defined(CONFIG_X86)
>  extern bool xen_has_pv_devices(void);
>  extern bool xen_has_pv_disk_devices(void);
>  extern bool xen_has_pv_nic_devices(void);
> -- 
> 2.55.0
>