hw/i386: make IOMMUs configurable via default-configs/

Allow distributions to disable the Intel and/or AMD IOMMU devices.

Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

default-configs/i386-softmmu.mak

@@ -63,3 +63,5 @@ CONFIG_PXB=y
 CONFIG_ACPI_VMGENID=y
 CONFIG_FW_CFG_DMA=y
 CONFIG_I2C=y
+CONFIG_VTD=y
+CONFIG_AMD_IOMMU=y

default-configs/x86_64-softmmu.mak

@@ -63,3 +63,5 @@ CONFIG_PXB=y
 CONFIG_ACPI_VMGENID=y
 CONFIG_FW_CFG_DMA=y
 CONFIG_I2C=y
+CONFIG_VTD=y
+CONFIG_AMD_IOMMU=y

hw/i386/Makefile.objs

@@ -2,8 +2,8 @@ obj-$(CONFIG_KVM) += kvm/
 obj-y += multiboot.o
 obj-y += pc.o pc_piix.o pc_q35.o
 obj-y += pc_sysfw.o
-obj-y += x86-iommu.o intel_iommu.o
-obj-y += amd_iommu.o
+obj-$(CONFIG_VTD) += x86-iommu.o intel_iommu.o
+obj-$(CONFIG_AMD_IOMMU) += x86-iommu.o amd_iommu.o
 obj-$(CONFIG_XEN) += ../xenpv/ xen/
 obj-$(CONFIG_VMPORT) += vmport.o
 obj-$(CONFIG_VMMOUSE) += vmmouse.o