[RFC Part1 PATCH 05/13] X86/sev-es: move few helper functions in common file

[Brijesh Singh]

The sev_es_terminate() and sev_es_{wr,rd}_ghcb_msr() helper functions
in a common file so that it can be used by both the SEV-ES and SEV-SNP.

Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Joerg Roedel <jroedel@xxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Tony Luck <tony.luck@xxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxx>
Cc: "Peter Zijlstra (Intel)" <peterz@xxxxxxxxxxxxx>
Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Cc: Tom Lendacky <thomas.lendacky@xxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Sean Christopherson <seanjc@xxxxxxxxxx>
Cc: x86@xxxxxxxxxx
Cc: kvm@xxxxxxxxxxxxxxx
Signed-off-by: Brijesh Singh <brijesh.singh@xxxxxxx>
---
 arch/x86/boot/compressed/sev-common.c | 32 +++++++++++++++++++++++++++
 arch/x86/boot/compressed/sev-es.c     | 22 ++----------------
 arch/x86/kernel/sev-common-shared.c   | 31 ++++++++++++++++++++++++++
 arch/x86/kernel/sev-es-shared.c       | 21 +++---------------
 4 files changed, 68 insertions(+), 38 deletions(-)
 create mode 100644 arch/x86/boot/compressed/sev-common.c
 create mode 100644 arch/x86/kernel/sev-common-shared.c

diff --git a/arch/x86/boot/compressed/sev-common.c b/arch/x86/boot/compressed/sev-common.c
new file mode 100644
index 000000000000..d81ff7a3a67d
--- /dev/null
+++ b/arch/x86/boot/compressed/sev-common.c
@@ -0,0 +1,32 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * AMD Encrypted Register State Support
+ *
+ * Author: Brijesh Singh <brijesh.singh@xxxxxxx>
+ *
+ * Copyright (C) 2021 Advanced Micro Devices, Inc.
+ *
+ * This file is not compiled stand-alone. It is includes directly in the
+ * sev-es.c and sev-snp.c.
+ */
+
+static inline u64 sev_es_rd_ghcb_msr(void)
+{
+	unsigned long low, high;
+
+	asm volatile("rdmsr" : "=a" (low), "=d" (high) :
+			"c" (MSR_AMD64_SEV_ES_GHCB));
+
+	return ((high << 32) | low);
+}
+
+static inline void sev_es_wr_ghcb_msr(u64 val)
+{
+	u32 low, high;
+
+	low  = val & 0xffffffffUL;
+	high = val >> 32;
+
+	asm volatile("wrmsr" : : "c" (MSR_AMD64_SEV_ES_GHCB),
+			"a"(low), "d" (high) : "memory");
+}
diff --git a/arch/x86/boot/compressed/sev-es.c b/arch/x86/boot/compressed/sev-es.c
index 27826c265aab..58b15b7c1aa7 100644
--- a/arch/x86/boot/compressed/sev-es.c
+++ b/arch/x86/boot/compressed/sev-es.c
@@ -54,26 +54,8 @@ static unsigned long insn_get_seg_base(struct pt_regs *regs, int seg_reg_idx)
 	return 0UL;
 }
 
-static inline u64 sev_es_rd_ghcb_msr(void)
-{
-	unsigned long low, high;
-
-	asm volatile("rdmsr" : "=a" (low), "=d" (high) :
-			"c" (MSR_AMD64_SEV_ES_GHCB));
-
-	return ((high << 32) | low);
-}
-
-static inline void sev_es_wr_ghcb_msr(u64 val)
-{
-	u32 low, high;
-
-	low  = val & 0xffffffffUL;
-	high = val >> 32;
-
-	asm volatile("wrmsr" : : "c" (MSR_AMD64_SEV_ES_GHCB),
-			"a"(low), "d" (high) : "memory");
-}
+/* Provides sev_es_{wr,rd}_ghcb_msr() */
+#include "sev-common.c"
 
 static enum es_result vc_decode_insn(struct es_em_ctxt *ctxt)
 {
diff --git a/arch/x86/kernel/sev-common-shared.c b/arch/x86/kernel/sev-common-shared.c
new file mode 100644
index 000000000000..6229566add6f
--- /dev/null
+++ b/arch/x86/kernel/sev-common-shared.c
@@ -0,0 +1,31 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * AMD Encrypted Register State Support
+ *
+ * Author: Brijesh Singh <brijesh.singh@xxxxxxx>
+ *
+ * Copyright (C) 2021 Advanced Micro Devices, Inc.
+ *
+ * This file is not compiled stand-alone. It contains code shared
+ * between the pre-decompression boot code and the running Linux kernel
+ * and is included directly into both code-bases.
+ */
+
+static void sev_es_terminate(unsigned int reason)
+{
+	u64 val = GHCB_SEV_TERMINATE;
+
+	/*
+	 * Tell the hypervisor what went wrong - only reason-set 0 is
+	 * currently supported.
+	 */
+	val |= GHCB_SEV_TERMINATE_REASON(0, reason);
+
+	/* Request Guest Termination from Hypvervisor */
+	sev_es_wr_ghcb_msr(val);
+	VMGEXIT();
+
+	while (true)
+		asm volatile("hlt\n" : : : "memory");
+}
+
diff --git a/arch/x86/kernel/sev-es-shared.c b/arch/x86/kernel/sev-es-shared.c
index cdc04d091242..669e15678387 100644
--- a/arch/x86/kernel/sev-es-shared.c
+++ b/arch/x86/kernel/sev-es-shared.c
@@ -14,6 +14,9 @@
 #define has_cpuflag(f)	boot_cpu_has(f)
 #endif
 
+/* Provides sev_es_terminate() */
+#include "sev-common-shared.c"
+
 static bool __init sev_es_check_cpu_features(void)
 {
 	if (!has_cpuflag(X86_FEATURE_RDRAND)) {
@@ -24,24 +27,6 @@ static bool __init sev_es_check_cpu_features(void)
 	return true;
 }
 
-static void sev_es_terminate(unsigned int reason)
-{
-	u64 val = GHCB_SEV_TERMINATE;
-
-	/*
-	 * Tell the hypervisor what went wrong - only reason-set 0 is
-	 * currently supported.
-	 */
-	val |= GHCB_SEV_TERMINATE_REASON(0, reason);
-
-	/* Request Guest Termination from Hypvervisor */
-	sev_es_wr_ghcb_msr(val);
-	VMGEXIT();
-
-	while (true)
-		asm volatile("hlt\n" : : : "memory");
-}
-
 static bool sev_es_negotiate_protocol(void)
 {
 	u64 val;
-- 
2.17.1