#include <efi.h>
#include <efilib.h>
#include <efiapi.h>

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

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

static struct VMXON *vmxon_region;

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;
}

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;
	}

	return true;
}

void
vintel_enable(void)
{
	Print(L"Set CR4 Bit\n");
	writecr4(readcr4() | CR4_VMXE);

#if 0
	Print(L"Enable in Feature Control\n");
	uint64_t fctl = rdmsr64(IA32_FEATURE_CONTROL);
	fctl |= (1 << 0);
	wrmsr64(IA32_FEATURE_CONTROL, fctl);
#endif

	Print(L"Allocating VMXON Page\n");
	uefi_call_wrapper(BS->AllocatePages, 4, AllocateAnyPages, EfiRuntimeServicesData, 1, &vmxon_region);

	Print(L"VMCS: %p\n", vmxon_region);
	vmxon_region->revisionID = rdmsr32(IA32_VMX_BASIC);
	Print(L"Set Revision ID.\n");

	uint64_t status = vmxon(vmxon_region);
	Print(L"VMXON Status: %p\n", (void *)status);
	if (status & (1 << 0)) {
		Print(L"Invalid VMCS Pointer\n");
	}
	if (status & (1 << 6)) {
		Print(L"Extended VMX Error\n");
	}
}

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