[PATCH v2 04/12] powerpc/pseries/svm: Add a powerpc version of prot_guest_has()

[Tom Lendacky <thomas.lendacky@amd.com>]

Introduce a powerpc version of the prot_guest_has() function. This will
be used to replace the powerpc mem_encrypt_active() implementation, so
the implementation will initially only support the PATTR_MEM_ENCRYPT
attribute.

Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
---
 arch/powerpc/include/asm/protected_guest.h | 30 ++++++++++++++++++++++
 arch/powerpc/platforms/pseries/Kconfig     |  1 +
 2 files changed, 31 insertions(+)
 create mode 100644 arch/powerpc/include/asm/protected_guest.h

diff --git a/arch/powerpc/include/asm/protected_guest.h b/arch/powerpc/include/asm/protected_guest.h
new file mode 100644
index 000000000000..ce55c2c7e534
--- /dev/null
+++ b/arch/powerpc/include/asm/protected_guest.h
@@ -0,0 +1,30 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Protected Guest (and Host) Capability checks
+ *
+ * Copyright (C) 2021 Advanced Micro Devices, Inc.
+ *
+ * Author: Tom Lendacky <thomas.lendacky@amd.com>
+ */
+
+#ifndef _POWERPC_PROTECTED_GUEST_H
+#define _POWERPC_PROTECTED_GUEST_H
+
+#include <asm/svm.h>
+
+#ifndef __ASSEMBLY__
+
+static inline bool prot_guest_has(unsigned int attr)
+{
+	switch (attr) {
+	case PATTR_MEM_ENCRYPT:
+		return is_secure_guest();
+
+	default:
+		return false;
+	}
+}
+
+#endif	/* __ASSEMBLY__ */
+
+#endif	/* _POWERPC_PROTECTED_GUEST_H */
diff --git a/arch/powerpc/platforms/pseries/Kconfig b/arch/powerpc/platforms/pseries/Kconfig
index 5e037df2a3a1..8ce5417d6feb 100644
--- a/arch/powerpc/platforms/pseries/Kconfig
+++ b/arch/powerpc/platforms/pseries/Kconfig
@@ -159,6 +159,7 @@ config PPC_SVM
 	select SWIOTLB
 	select ARCH_HAS_MEM_ENCRYPT
 	select ARCH_HAS_FORCE_DMA_UNENCRYPTED
+	select ARCH_HAS_PROTECTED_GUEST
 	help
 	 There are certain POWER platforms which support secure guests using
 	 the Protected Execution Facility, with the help of an Ultravisor
-- 
2.32.0