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Date: Wed, 28 Aug 2019 10:03:51 +0200
From: Thomas Hellström (VMware)
<thomas_os@...pmail.org>
To: linux-kernel@...r.kernel.org
Cc: pv-drivers@...are.com, linux-graphics-maintainer@...are.com,
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 v3 2/4] x86/vmware: Add a header file for hypercall definitions
From: Thomas Hellstrom <thellstrom@...are.com>
The new header is intended to be used by drivers using the backdoor.
Follow the KVM example using alternatives self-patching to
choose between vmcall, vmmcall and io instructions.
Also define two new CPU feature flags to indicate hypervisor support
for vmcall- and vmmcall instructions. The new XF86_FEATURE_VMW_VMMCALL
flag is needed because using XF86_FEATURE_VMMCALL might break QEMU/KVM
setups using the vmmouse driver. They rely on XF86_FEATURE_VMMCALL
on AMD to get the kvm_hypercall() right. But they do not yet implement
vmmcall for the VMware hypercall used by the vmmouse driver.
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 | 50 ++++++++++++++++++++++++++++++
arch/x86/kernel/cpu/vmware.c | 6 +++-
4 files changed, 58 insertions(+), 1 deletion(-)
create mode 100644 arch/x86/include/asm/vmware.h
diff --git a/MAINTAINERS b/MAINTAINERS
index c2d975da561f..5bf65a49fa19 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..55fa3b3f0bac 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_VMCALL ( 8*32+18) /* "" Hypervisor supports the VMCALL 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..478bbc05746d
--- /dev/null
+++ b/arch/x86/include/asm/vmware.h
@@ -0,0 +1,50 @@
+/* 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>
+
+/*
+ * The hypercall definitions differ in the low word of the %edx argument in
+ * the following way: The old port base interface uses the port number to
+ * distinguish between high- and low bandwidth versions. The new vmcall
+ * interface instead uses a set of flags to select bandwidth mode and
+ * transfer direction. The flags should be loaded into %dx by any user
+ * and are automatically replaced by the port number if the
+ * VMWARE_HYPERVISOR_PORT method is used. In short, New driver code should
+ * strictly use the new definition of %dx content.
+ */
+
+/* Old port-based version */
+#define VMWARE_HYPERVISOR_PORT "0x5658"
+#define VMWARE_HYPERVISOR_PORT_HB "0x5659"
+
+/* Current vmcall / vmmcall version */
+#define VMWARE_HYPERVISOR_HB BIT(0)
+#define VMWARE_HYPERVISOR_OUT BIT(1)
+
+/* The low bandwidth call. The low word of edx is presumed clear. */
+#define VMWARE_HYPERCALL \
+ ALTERNATIVE_2("movw $" VMWARE_HYPERVISOR_PORT ", %%dx; inl (%%dx)", \
+ "vmcall", X86_FEATURE_VMCALL, \
+ "vmmcall", X86_FEATURE_VMW_VMMCALL)
+
+/*
+ * The high bandwidth out call. The low word of edx is presumed to have the
+ * HB and OUT bits set.
+ */
+#define VMWARE_HYPERCALL_HB_OUT \
+ ALTERNATIVE_2("movw $" VMWARE_HYPERVISOR_PORT_HB ", %%dx; rep outsb", \
+ "vmcall", X86_FEATURE_VMCALL, \
+ "vmmcall", X86_FEATURE_VMW_VMMCALL)
+
+/*
+ * The high bandwidth in call. The low word of edx is presumed to have the
+ * HB bit set.
+ */
+#define VMWARE_HYPERCALL_HB_IN \
+ ALTERNATIVE_2("movw $" VMWARE_HYPERVISOR_PORT_HB ", %%dx; rep insb", \
+ "vmcall", X86_FEATURE_VMCALL, \
+ "vmmcall", X86_FEATURE_VMW_VMMCALL)
+#endif
diff --git a/arch/x86/kernel/cpu/vmware.c b/arch/x86/kernel/cpu/vmware.c
index 757dded223af..9735139cfdf8 100644
--- a/arch/x86/kernel/cpu/vmware.c
+++ b/arch/x86/kernel/cpu/vmware.c
@@ -30,6 +30,7 @@
#include <asm/hypervisor.h>
#include <asm/timer.h>
#include <asm/apic.h>
+#include <asm/vmware.h>
#undef pr_fmt
#define pr_fmt(fmt) "vmware: " fmt
@@ -40,7 +41,6 @@
#define CPUID_VMWARE_FEATURES_ECX_VMCALL BIT(1)
#define VMWARE_HYPERVISOR_MAGIC 0x564D5868
-#define VMWARE_HYPERVISOR_PORT 0x5658
#define VMWARE_CMD_GETVERSION 10
#define VMWARE_CMD_GETHZ 45
@@ -164,6 +164,10 @@ static void __init vmware_set_capabilities(void)
{
setup_force_cpu_cap(X86_FEATURE_CONSTANT_TSC);
setup_force_cpu_cap(X86_FEATURE_TSC_RELIABLE);
+ if (vmware_hypercall_mode == CPUID_VMWARE_FEATURES_ECX_VMCALL)
+ setup_force_cpu_cap(X86_FEATURE_VMCALL);
+ else if (vmware_hypercall_mode == CPUID_VMWARE_FEATURES_ECX_VMMCALL)
+ setup_force_cpu_cap(X86_FEATURE_VMW_VMMCALL);
}
static void __init vmware_platform_setup(void)
--
2.20.1
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