x86/vmware: Introduce VMware hypercall API

Introduce a vmware_hypercall family of functions. It is a common implementation
to be used by the VMware guest code and virtual device drivers in architecture
independent manner.

The API consists of vmware_hypercallX and vmware_hypercall_hb_{out,in}
set of functions analogous to KVM's hypercall API. Architecture-specific
implementation is hidden inside.

It will simplify future enhancements in VMware hypercalls such as SEV-ES and
TDX related changes without needs to modify a caller in device drivers code.

Current implementation extends an idea from

  bac7b4e84323 ("x86/vmware: Update platform detection code for VMCALL/VMMCALL hypercalls")

to have a slow, but safe path vmware_hypercall_slow() earlier during the boot
when alternatives are not yet applied.  The code inherits VMWARE_CMD logic from
the commit mentioned above.

Move common macros from vmware.c to vmware.h.

  [ bp: Fold in a fix:
    https://lore.kernel.org/r/20240625083348.2299-1-alexey.makhalov@broadcom.com ]

Signed-off-by: Alexey Makhalov <alexey.makhalov@broadcom.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20240613191650.9913-2-alexey.makhalov@broadcom.com

1 files changed, 62 insertions, 8 deletions

diff --git a/arch/x86/kernel/cpu/vmware.c b/arch/x86/kernel/cpu/vmware.c
index 11f83d07925e..faf706879515 100644
--- a/arch/x86/kernel/cpu/vmware.c
+++ b/arch/x86/kernel/cpu/vmware.c
@@ -41,17 +41,9 @@
 
 #define CPUID_VMWARE_INFO_LEAF               0x40000000
 #define CPUID_VMWARE_FEATURES_LEAF           0x40000010
-#define CPUID_VMWARE_FEATURES_ECX_VMMCALL    BIT(0)
-#define CPUID_VMWARE_FEATURES_ECX_VMCALL     BIT(1)
 
-#define VMWARE_HYPERVISOR_MAGIC	0x564D5868
-
-#define VMWARE_CMD_GETVERSION    10
-#define VMWARE_CMD_GETHZ         45
-#define VMWARE_CMD_GETVCPU_INFO  68
 #define VMWARE_CMD_LEGACY_X2APIC  3
 #define VMWARE_CMD_VCPU_RESERVED 31
-#define VMWARE_CMD_STEALCLOCK    91
 
 #define STEALCLOCK_NOT_AVAILABLE (-1)
 #define STEALCLOCK_DISABLED        0
@@ -110,6 +102,68 @@ struct vmware_steal_time {
 static unsigned long vmware_tsc_khz __ro_after_init;
 static u8 vmware_hypercall_mode     __ro_after_init;
 
+unsigned long vmware_hypercall_slow(unsigned long cmd,
+				    unsigned long in1, unsigned long in3,
+				    unsigned long in4, unsigned long in5,
+				    u32 *out1, u32 *out2, u32 *out3,
+				    u32 *out4, u32 *out5)
+{
+	unsigned long out0, rbx, rcx, rdx, rsi, rdi;
+
+	switch (vmware_hypercall_mode) {
+	case CPUID_VMWARE_FEATURES_ECX_VMCALL:
+		asm_inline volatile ("vmcall"
+				: "=a" (out0), "=b" (rbx), "=c" (rcx),
+				"=d" (rdx), "=S" (rsi), "=D" (rdi)
+				: "a" (VMWARE_HYPERVISOR_MAGIC),
+				"b" (in1),
+				"c" (cmd),
+				"d" (in3),
+				"S" (in4),
+				"D" (in5)
+				: "cc", "memory");
+		break;
+	case CPUID_VMWARE_FEATURES_ECX_VMMCALL:
+		asm_inline volatile ("vmmcall"
+				: "=a" (out0), "=b" (rbx), "=c" (rcx),
+				"=d" (rdx), "=S" (rsi), "=D" (rdi)
+				: "a" (VMWARE_HYPERVISOR_MAGIC),
+				"b" (in1),
+				"c" (cmd),
+				"d" (in3),
+				"S" (in4),
+				"D" (in5)
+				: "cc", "memory");
+		break;
+	default:
+		asm_inline volatile ("movw %[port], %%dx; inl (%%dx), %%eax"
+				: "=a" (out0), "=b" (rbx), "=c" (rcx),
+				"=d" (rdx), "=S" (rsi), "=D" (rdi)
+				: [port] "i" (VMWARE_HYPERVISOR_PORT),
+				"a" (VMWARE_HYPERVISOR_MAGIC),
+				"b" (in1),
+				"c" (cmd),
+				"d" (in3),
+				"S" (in4),
+				"D" (in5)
+				: "cc", "memory");
+		break;
+	}
+
+	if (out1)
+		*out1 = rbx;
+	if (out2)
+		*out2 = rcx;
+	if (out3)
+		*out3 = rdx;
+	if (out4)
+		*out4 = rsi;
+	if (out5)
+		*out5 = rdi;
+
+	return out0;
+}
+
 static inline int __vmware_platform(void)
 {
 	uint32_t eax, ebx, ecx, edx;