x86/vmware: Add a header file for hypercall definitions

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.

 [ bp: reflow hypercall %edx usage explanation comment. ]

Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Doug Covelli <dcovelli@vmware.com>
Cc: Aaron Lewis <aaronlewis@google.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: linux-graphics-maintainer@vmware.com
Cc: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Cc: Nicolas Ferre <nicolas.ferre@microchip.com>
Cc: Robert Hoo <robert.hu@linux.intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: virtualization@lists.linux-foundation.org
Cc: <pv-drivers@vmware.com>
Cc: x86-ml <x86@kernel.org>
Link: https://lkml.kernel.org/r/20190828080353.12658-3-thomas_os@shipmail.org

diff --git a/MAINTAINERS b/MAINTAINERS
index 9cbcf167bdd08f94bfeb80aa7424c5893224555c..47efc1b47d4c132fe4c9aebecfb44b9992258d21 100644 (file)
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -17206,6 +17206,7 @@ M:      "VMware, Inc." <pv-drivers@vmware.com>
 L:     virtualization@lists.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@vmware.com>

diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index e880f2408e29d5e56bb659d851ccb254cc9a148e..aaeae2fa49a5fc4874306b41ce78b1ea96a23344 100644 (file)
--- 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 (file)
index 0000000..e00c9e8
--- /dev/null
+++ b/arch/x86/include/asm/vmware.h
@@ -0,0 +1,53 @@
+/* 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 757dded223af42348df5bbeb3a6a937f80702ea3..9735139cfdf86bcdaee7ea29a3ba7ab9a6d99270 100644 (file)
--- 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)