linux-kernel - [PATCH 2/4] x86/vmware: Add a header file for hypercall definitions

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Message-Id: <20190818143316.4906-3-thomas_os@shipmail.org>
Date:   Sun, 18 Aug 2019 16:33:14 +0200
From:   Thomas Hellström (VMware) 
        <thomas_os@...pmail.org>
To:     linux-kernel@...r.kernel.org, pv-drivers@...are.com
Cc:     Thomas Hellstrom <thellstrom@...are.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        "H. Peter Anvin" <hpa@...or.com>, x86@...nel.org,
        Doug Covelli <dcovelli@...are.com>
Subject: [PATCH 2/4] x86/vmware: Add a header file for hypercall definitions

From: Thomas Hellstrom <thellstrom@...are.com>

This is intended to be used by drivers using the backdoor, and
we follow the kvm example using alternatives self-patching to
choose between vmcall, vmmcall and inl instructions.

This patch defines two new x86 cpu feature flags.

Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Ingo Molnar <mingo@...hat.com>
Cc: Borislav Petkov <bp@...en8.de>
Cc: "H. Peter Anvin" <hpa@...or.com>
Cc: <x86@...nel.org>
Signed-off-by: Thomas Hellstrom <thellstrom@...are.com>
Reviewed-by: Doug Covelli <dcovelli@...are.com>
---
 MAINTAINERS                        |  1 +
 arch/x86/include/asm/cpufeatures.h |  2 ++
 arch/x86/include/asm/vmware.h      | 13 +++++++++++++
 3 files changed, 16 insertions(+)
 create mode 100644 arch/x86/include/asm/vmware.h

diff --git a/MAINTAINERS b/MAINTAINERS
index 1bd7b9c2d146..412206747270 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -17203,6 +17203,7 @@ M:	"VMware, Inc." <pv-drivers@...are.com>
 L:	virtualization@...ts.linux-foundation.org
 S:	Supported
 F:	arch/x86/kernel/cpu/vmware.c
+F:	arch/x86/include/asm/vmware.h
 
 VMWARE PVRDMA DRIVER
 M:	Adit Ranadive <aditr@...are.com>
diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index 998c2cc08363..69cecc3bc9cb 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -232,6 +232,8 @@
 #define X86_FEATURE_VMMCALL		( 8*32+15) /* Prefer VMMCALL to VMCALL */
 #define X86_FEATURE_XENPV		( 8*32+16) /* "" Xen paravirtual guest */
 #define X86_FEATURE_EPT_AD		( 8*32+17) /* Intel Extended Page Table access-dirty bit */
+#define X86_FEATURE_VMW_VMCALL		( 8*32+18) /* VMware prefers VMCALL hypercall instruction */
+#define X86_FEATURE_VMW_VMMCALL		( 8*32+19) /* VMware prefers VMMCALL hypercall instruction */
 
 /* Intel-defined CPU features, CPUID level 0x00000007:0 (EBX), word 9 */
 #define X86_FEATURE_FSGSBASE		( 9*32+ 0) /* RDFSBASE, WRFSBASE, RDGSBASE, WRGSBASE instructions*/
diff --git a/arch/x86/include/asm/vmware.h b/arch/x86/include/asm/vmware.h
new file mode 100644
index 000000000000..22d2dbfba90f
--- /dev/null
+++ b/arch/x86/include/asm/vmware.h
@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: GPL-2.0 or MIT */
+#ifndef _ASM_X86_VMWARE_H
+#define _ASM_X86_VMWARE_H
+
+#include <asm/cpufeatures.h>
+#include <asm/alternative.h>
+
+#define VMWARE_HYPERCALL \
+	ALTERNATIVE_2(".byte 0xed", \
+		      ".byte 0x0f, 0x01, 0xc1", X86_FEATURE_VMW_VMCALL,	\
+		      ".byte 0x0f, 0x01, 0xd9", X86_FEATURE_VMW_VMMCALL)
+
+#endif
-- 
2.20.1