Function vtd_init

freebsd/amd64/vmm/intel/vtd.c:306–397

}

static int
vtd_init(void)
{
	int i, units, remaining, tmp;
	struct vtdmap *vtdmap;
	vm_paddr_t ctx_paddr;
	char *end, envname[32];
	unsigned long mapaddr;
	ACPI_STATUS status;
	ACPI_TABLE_DMAR *dmar;
	ACPI_DMAR_HEADER *hdr;
	ACPI_DMAR_HARDWARE_UNIT *drhd;

	/*
	 * Allow the user to override the ACPI DMAR table by specifying the
	 * physical address of each remapping unit.
	 *
	 * The following example specifies two remapping units at
	 * physical addresses 0xfed90000 and 0xfeda0000 respectively.
	 * set vtd.regmap.0.addr=0xfed90000
	 * set vtd.regmap.1.addr=0xfeda0000
	 */
	for (units = 0; units < DRHD_MAX_UNITS; units++) {
		snprintf(envname, sizeof(envname), "vtd.regmap.%d.addr", units);
		if (getenv_ulong(envname, &mapaddr) == 0)
			break;
		vtdmaps[units] = (struct vtdmap *)PHYS_TO_DMAP(mapaddr);
	}

	if (units > 0)
		goto skip_dmar;

	/* Search for DMAR table. */
	status = AcpiGetTable(ACPI_SIG_DMAR, 0, (ACPI_TABLE_HEADER **)&dmar);
	if (ACPI_FAILURE(status))
		return (ENXIO);

	end = (char *)dmar + dmar->Header.Length;
	remaining = dmar->Header.Length - sizeof(ACPI_TABLE_DMAR);
	while (remaining > sizeof(ACPI_DMAR_HEADER)) {
		hdr = (ACPI_DMAR_HEADER *)(end - remaining);
		if (hdr->Length > remaining)
			break;
		/*
		 * From Intel VT-d arch spec, version 1.3:
		 * BIOS implementations must report mapping structures
		 * in numerical order, i.e. All remapping structures of
		 * type 0 (DRHD) enumerated before remapping structures of
		 * type 1 (RMRR) and so forth.
		 */
		if (hdr->Type != ACPI_DMAR_TYPE_HARDWARE_UNIT)
			break;

		drhd = (ACPI_DMAR_HARDWARE_UNIT *)hdr;
		drhds[units] = drhd;
		vtdmaps[units] = (struct vtdmap *)PHYS_TO_DMAP(drhd->Address);
		if (++units >= DRHD_MAX_UNITS)
			break;