jailhouse: Provide detection for non-x86 systems

Implement jailhouse_paravirt() via device tree probing on architectures
!= x86. Will be used by the PCI core.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Juergen Gross <jgross@suse.com>
Cc: jailhouse-dev@googlegroups.com
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: linux-pci@vger.kernel.org
Cc: virtualization@lists.linux-foundation.org
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Link: https://lkml.kernel.org/r/dae9fe0c6e63141c28ca90492fa5712b4c33ffb5.1520408357.git.jan.kiszka@siemens.com

3 files changed, 24 insertions, 3 deletions

diff --git a/Documentation/devicetree/bindings/jailhouse.txt b/Documentation/devicetree/bindings/jailhouse.txt
new file mode 100644
index 000000000000..2901c25ff340
--- /dev/null
+++ b/Documentation/devicetree/bindings/jailhouse.txt
@@ -0,0 +1,8 @@
+Jailhouse non-root cell device tree bindings
+--------------------------------------------
+
+When running in a non-root Jailhouse cell (partition), the device tree of this
+platform shall have a top-level "hypervisor" node with the following
+properties:
+
+- compatible = "jailhouse,cell"
diff --git a/arch/x86/include/asm/jailhouse_para.h b/arch/x86/include/asm/jailhouse_para.h
index 875b54376689..b885a961a150 100644
--- a/arch/x86/include/asm/jailhouse_para.h
+++ b/arch/x86/include/asm/jailhouse_para.h
@@ -1,7 +1,7 @@
 /* SPDX-License-Identifier: GPL2.0 */
 
 /*
- * Jailhouse paravirt_ops implementation
+ * Jailhouse paravirt detection
  *
  * Copyright (c) Siemens AG, 2015-2017
  *
diff --git a/include/linux/hypervisor.h b/include/linux/hypervisor.h
index b19563f9a8eb..fc08b433c856 100644
--- a/include/linux/hypervisor.h
+++ b/include/linux/hypervisor.h
@@ -8,15 +8,28 @@
  */
 
 #ifdef CONFIG_X86
+
+#include <asm/jailhouse_para.h>
 #include <asm/x86_init.h>
+
 static inline void hypervisor_pin_vcpu(int cpu)
 {
         x86_platform.hyper.pin_vcpu(cpu);
 }
-#else
+
+#else /* !CONFIG_X86 */
+
+#include <linux/of.h>
+
 static inline void hypervisor_pin_vcpu(int cpu)
 {
 }
-#endif
+
+static inline bool jailhouse_paravirt(void)
+{
+        return of_find_compatible_node(NULL, NULL, "jailhouse,cell");
+}
+
+#endif /* !CONFIG_X86 */
 
 #endif /* __LINUX_HYPEVISOR_H */