xen/x86: allow PVH Dom0 without XEN_PV=y

Decouple XEN_DOM0 from XEN_PV, converting some existing uses of XEN_DOM0
to a new XEN_PV_DOM0. (I'm not convinced all are really / should really
be PV-specific, but for starters I've tried to be conservative.)

For PVH Dom0 the hypervisor populates MADT with only x2APIC entries, so
without x2APIC support enabled in the kernel things aren't going to work
very well. (As opposed, DomU-s would only ever see LAPIC entries in MADT
as of now.) Note that this then requires PVH Dom0 to be 64-bit, as
X86_X2APIC depends on X86_64.

In the course of this xen_running_on_version_or_later() needs to be
available more broadly. Move it from a PV-specific to a generic file,
considering that what it does isn't really PV-specific at all anyway.

Note that xen/interface/version.h cannot be included on its own; in
enlighten.c, which uses SCHEDOP_* anyway, include xen/interface/sched.h
first to resolve the apparently sole missing type (xen_ulong_t).

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Juergen Gross <jgross@suse.com>

Link: https://lore.kernel.org/r/983bb72f-53df-b6af-14bd-5e088bd06a08@suse.com
Signed-off-by: Juergen Gross <jgross@suse.com>

5 files changed, 31 insertions, 25 deletions

diff --git a/arch/x86/xen/Kconfig b/arch/x86/xen/Kconfig
index afc1da68b06d..6bcd3d8ca6ac 100644
--- a/arch/x86/xen/Kconfig
+++ b/arch/x86/xen/Kconfig
@@ -43,13 +43,9 @@ config XEN_PV_SMP
 	def_bool y
 	depends on XEN_PV && SMP
 
-config XEN_DOM0
-	bool "Xen PV Dom0 support"
-	default y
-	depends on XEN_PV && PCI_XEN && SWIOTLB_XEN
-	depends on X86_IO_APIC && ACPI && PCI
-	help
-	  Support running as a Xen PV Dom0 guest.
+config XEN_PV_DOM0
+	def_bool y
+	depends on XEN_PV && XEN_DOM0
 
 config XEN_PVHVM
 	def_bool y
@@ -86,3 +82,12 @@ config XEN_PVH
 	def_bool n
 	help
 	  Support for running as a Xen PVH guest.
+
+config XEN_DOM0
+	bool "Xen Dom0 support"
+	default XEN_PV
+	depends on (XEN_PV && SWIOTLB_XEN) || (XEN_PVH && X86_64)
+	depends on X86_IO_APIC && ACPI && PCI
+	select X86_X2APIC if XEN_PVH && X86_64
+	help
+	  Support running as a Xen Dom0 guest.
diff --git a/arch/x86/xen/Makefile b/arch/x86/xen/Makefile
index 40b5779fce21..4953260e281c 100644
--- a/arch/x86/xen/Makefile
+++ b/arch/x86/xen/Makefile
@@ -45,7 +45,7 @@ obj-$(CONFIG_PARAVIRT_SPINLOCKS)+= spinlock.o
 
 obj-$(CONFIG_XEN_DEBUG_FS)	+= debugfs.o
 
-obj-$(CONFIG_XEN_DOM0)		+= vga.o
+obj-$(CONFIG_XEN_PV_DOM0)	+= vga.o
 
 obj-$(CONFIG_SWIOTLB_XEN)	+= pci-swiotlb-xen.o
 
diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index f252faf5028f..501466038075 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -10,6 +10,8 @@
 
 #include <xen/xen.h>
 #include <xen/features.h>
+#include <xen/interface/sched.h>
+#include <xen/interface/version.h>
 #include <xen/page.h>
 
 #include <asm/xen/hypercall.h>
@@ -257,6 +259,21 @@ int xen_vcpu_setup(int cpu)
 	return ((per_cpu(xen_vcpu, cpu) == NULL) ? -ENODEV : 0);
 }
 
+/* Check if running on Xen version (major, minor) or later */
+bool xen_running_on_version_or_later(unsigned int major, unsigned int minor)
+{
+	unsigned int version;
+
+	if (!xen_domain())
+		return false;
+
+	version = HYPERVISOR_xen_version(XENVER_version, NULL);
+	if ((((version >> 16) == major) && ((version & 0xffff) >= minor)) ||
+		((version >> 16) > major))
+		return true;
+	return false;
+}
+
 void xen_reboot(int reason)
 {
 	struct sched_shutdown r = { .reason = reason };
diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
index 6e0d0754f94f..e46953249e39 100644
--- a/arch/x86/xen/enlighten_pv.c
+++ b/arch/x86/xen/enlighten_pv.c
@@ -142,22 +142,6 @@ static void __init xen_pv_guest_late_init(void)
 #endif
 }
 
-/* Check if running on Xen version (major, minor) or later */
-bool
-xen_running_on_version_or_later(unsigned int major, unsigned int minor)
-{
-	unsigned int version;
-
-	if (!xen_domain())
-		return false;
-
-	version = HYPERVISOR_xen_version(XENVER_version, NULL);
-	if ((((version >> 16) == major) && ((version & 0xffff) >= minor)) ||
-		((version >> 16) > major))
-		return true;
-	return false;
-}
-
 static __read_mostly unsigned int cpuid_leaf5_ecx_val;
 static __read_mostly unsigned int cpuid_leaf5_edx_val;
 
diff --git a/arch/x86/xen/xen-ops.h b/arch/x86/xen/xen-ops.h
index 8d7ec49a35fb..6d9b2b3e0c1c 100644
--- a/arch/x86/xen/xen-ops.h
+++ b/arch/x86/xen/xen-ops.h
@@ -109,7 +109,7 @@ static inline void xen_uninit_lock_cpu(int cpu)
 
 struct dom0_vga_console_info;
 
-#ifdef CONFIG_XEN_DOM0
+#ifdef CONFIG_XEN_PV_DOM0
 void __init xen_init_vga(const struct dom0_vga_console_info *, size_t size);
 #else
 static inline void __init xen_init_vga(const struct dom0_vga_console_info *info,