#ifndef _VISOR_VMX_H_
#define _VISOR_VMX_H_

#include <stdint.h>

#define VM_ENTRY_CONTROLS      0x4012
#define VMCS_INSTRUCTION_ERROR 0x4400

struct VMXON {
	uint32_t revisionID;
	uint32_t abortIndicator;
	char     vmcsData[];
};

struct VMCS {
	uint32_t revisionID;
	/* Guest-state area */
	/* Host-state area */
	/* VM-execution control fields */
	/* VM-exit control fields */
	/* VM-entry control fields */
	/* VM-exit information fields */
};

static inline uint64_t
vmxon(void *region)
{
	uint64_t regionpa = (uint64_t)region;
	uint64_t flags;
	__asm__ volatile (
		"vmxon   %1\n\t"
		"pushf     \n\t"
		"pop     %0\n\t"
		: "=r"(flags) : "m"(regionpa));
	return flags;
}

static inline void
vmxoff(void)
{
	__asm__ volatile ("vmxoff\n\t" ::);
}

static inline uint64_t
vmptrld(void *region)
{
	uint64_t regionpa = (uint64_t)region;
	uint64_t flags;
	__asm__ volatile (
		"vmptrld %1\n\t"
		"pushf     \n\t"
		"pop     %0\n\t"
		: "=r"(flags) : "m"(regionpa));
	return flags;
}

static inline void
vmptrst(void *arg)
{
	__asm__ volatile ("vmptrst\n\t" ::);
}

static inline uint64_t
vmclear(void *region)
{
	uint64_t regionpa = (uint64_t)region;
	uint64_t flags;
	__asm__ volatile (
		"vmclear %1\n\t"
		"pushf     \n\t"
		"pop     %0\n\t"
		: "=r"(flags) : "m"(regionpa));
	return flags;
}

static inline uint64_t
vmlaunch(void)
{
	uint64_t flags;
	__asm__ volatile (
		"vmlaunch  \n\t"
		"pushf     \n\t"
		"pop     %0\n\t"
		: "=r"(flags));
	return flags;
}

static inline void
vmresume(void)
{
	__asm__ volatile ("vmresume\n\t" ::);
}

static inline uint64_t
vmread(uint64_t field)
{
	uint64_t value;
	__asm__ volatile ("vmread %0, %1\n\t" : "=rm"(value) : "r"(field));
	return value;
}

static inline uint64_t
vmwrite(uint64_t field, uint64_t value)
{
	uint64_t flags;
	__asm__ volatile (
		"vmwrite %1, %2\n\t"
		"pushf         \n\t"
		"pop     %0    \n\t"
		: "=r"(flags) : "rm"(value), "r"(field));
	return flags;
}

static inline void
vmcall()
{
	__asm__ volatile ("vmcall\n\t" ::);
}

static inline const char *
vmx_describe_error(uint32_t error)
{
	switch (error) {
	default: return "Unknown VMX Error";
	case  0: return NULL;

	case  1: return "VMCALL executed in VMX root operation";
	case  2: return "VMCLEAR with invalid physical address";
	case  3: return "VMCLEAR with VMXON pointer";
	case  4: return "VMLAUNCH with non-clear VMCS";
	case  5: return "VMRESUME with non-launched VMCS";
	case  6: return "VMRESUME after VMXOFF (VMXOFF and VMXON between VMLAUNCH and VMRESUME)";
	case  7: return "VM entry with invalid control field(s)";
	case  8: return "VM entry with invalid host-state field(s)";
	case  9: return "VMPTRLD with invalid physical address";
	case 10: return "VMPTRLD with VMXON pointer";
	case 11: return "VMPTRLD with incorrect VMCS revision identifier";
	case 12: return "VMREAD/VMWRITE from/to unsupported VMCS component";
	case 13: return "VMWRITE to read-only VMCS component";
	case 15: return "VMXON executed in VMX root operation";
	case 16: return "VM entry with invalid executive-VMCS pointer";
	case 17: return "VM entry with non-launched executive VMCS";
	case 18: return "VM entry with executive-VMCS pointer not VMXON pointer (when attempting to deactivate the dual-monitor treatment of SMIs and SMM)";
	case 19: return "VMCALL with non-clear VMCS (when attempting to activate the dual-monitor treatment of SMIs and SMM)";
	case 20: return "VMCALL with invalid VM-exit control fields";
	case 22: return "VMCALL with incorrect MSEG revision identifier (when attempting to activate the dual-monitor treatment of SMIs and SMM)";
	case 23: return "VMXOFF under dual-monitor treatment of SMIs and SMM";
	case 24: return "VMCALL with invalid SMM-monitor features (when attempting to activate the dual-monitor treatment of SMIs and SMM)";
	case 25: return "VM entry with invalid VM-execution control fields in executive VMCS (when attempting to return from SMM)";
	case 26: return "VM entry with events blocked by MOV SS";
	case 28: return "Invalid operand to INVEPT/INVVPID";
	}
}

static inline const char *
vmcs_describe_error(void)
{
	uint32_t error = vmread(VMCS_INSTRUCTION_ERROR) & 0xffffffff;
	return vmx_describe_error(error);
}

#endif