#include <cpuid.h>
#include <x86/msr.h>
#include <x86/cr.h>

#include "virt.h"
#include "std.h"

static bool
vintel_has_bios_support(void)
{
	uint64_t value = rdmsr64(IA32_FEATURE_CONTROL);
	return (value & 0x5) == 0x5;
}

static bool
vintel_has_cpu_support(void)
{
	unsigned info[4];
	__get_cpuid(0x1, &info[0], &info[1], &info[2], &info[3]);
	return (info[2] & (1 << 5)) != 0;
}

static bool
vintel_has_cr4_support(void)
{
	uint64_t value = readcr4();
	return (value & (1 << 13)) != 0;
}

bool
vintel_has_support(char *err, size_t errmax)
{
	if (!vintel_has_cpu_support()) {
		strlcpy(err, "CPU does not support VT-x.", errmax);
		return false;
	}

	if (!vintel_has_bios_support()) {
		strlcpy(err, "VT-x support is not enabled in BIOS.", errmax);
		return false;
	}

	if (!vintel_has_cr4_support()) {
		strlcpy(err, "VT-x enable bit is not set in CR4.", errmax);
		return false;
	}

	return true;
}

struct virt_vtable virt_vtable_intel = {
	.has_support = vintel_has_support,
};