diff options
| -rw-r--r-- | docs/system/arm/virt.rst | 8 | ||||
| -rw-r--r-- | hw/arm/virt.c | 32 | ||||
| -rw-r--r-- | include/hw/arm/virt.h | 1 |
3 files changed, 39 insertions, 2 deletions
diff --git a/docs/system/arm/virt.rst b/docs/system/arm/virt.rst index 8507874..1544632 100644 --- a/docs/system/arm/virt.rst +++ b/docs/system/arm/virt.rst @@ -121,6 +121,14 @@ ras Set ``on``/``off`` to enable/disable reporting host memory errors to a guest using ACPI and guest external abort exceptions. The default is off. +dtb-kaslr-seed + Set ``on``/``off`` to pass a random seed via the guest dtb + kaslr-seed node (in both "/chosen" and /secure-chosen) to use + for features like address space randomisation. The default is + ``on``. You will want to disable it if your trusted boot chain will + verify the DTB it is passed. It would be the responsibility of the + firmware to come up with a seed and pass it on if it wants to. + Linux guest kernel configuration """""""""""""""""""""""""""""""" diff --git a/hw/arm/virt.c b/hw/arm/virt.c index b45b52c..84c2444 100644 --- a/hw/arm/virt.c +++ b/hw/arm/virt.c @@ -247,11 +247,15 @@ static void create_fdt(VirtMachineState *vms) /* /chosen must exist for load_dtb to fill in necessary properties later */ qemu_fdt_add_subnode(fdt, "/chosen"); - create_kaslr_seed(ms, "/chosen"); + if (vms->dtb_kaslr_seed) { + create_kaslr_seed(ms, "/chosen"); + } if (vms->secure) { qemu_fdt_add_subnode(fdt, "/secure-chosen"); - create_kaslr_seed(ms, "/secure-chosen"); + if (vms->dtb_kaslr_seed) { + create_kaslr_seed(ms, "/secure-chosen"); + } } /* Clock node, for the benefit of the UART. The kernel device tree @@ -2235,6 +2239,20 @@ static void virt_set_its(Object *obj, bool value, Error **errp) vms->its = value; } +static bool virt_get_dtb_kaslr_seed(Object *obj, Error **errp) +{ + VirtMachineState *vms = VIRT_MACHINE(obj); + + return vms->dtb_kaslr_seed; +} + +static void virt_set_dtb_kaslr_seed(Object *obj, bool value, Error **errp) +{ + VirtMachineState *vms = VIRT_MACHINE(obj); + + vms->dtb_kaslr_seed = value; +} + static char *virt_get_oem_id(Object *obj, Error **errp) { VirtMachineState *vms = VIRT_MACHINE(obj); @@ -2764,6 +2782,13 @@ static void virt_machine_class_init(ObjectClass *oc, void *data) "Set on/off to enable/disable " "ITS instantiation"); + object_class_property_add_bool(oc, "dtb-kaslr-seed", + virt_get_dtb_kaslr_seed, + virt_set_dtb_kaslr_seed); + object_class_property_set_description(oc, "dtb-kaslr-seed", + "Set off to disable passing of kaslr-seed " + "dtb node to guest"); + object_class_property_add_str(oc, "x-oem-id", virt_get_oem_id, virt_set_oem_id); @@ -2828,6 +2853,9 @@ static void virt_instance_init(Object *obj) /* MTE is disabled by default. */ vms->mte = false; + /* Supply a kaslr-seed by default */ + vms->dtb_kaslr_seed = true; + vms->irqmap = a15irqmap; virt_flash_create(vms); diff --git a/include/hw/arm/virt.h b/include/hw/arm/virt.h index dc6b66f..be05346 100644 --- a/include/hw/arm/virt.h +++ b/include/hw/arm/virt.h @@ -148,6 +148,7 @@ struct VirtMachineState { bool virt; bool ras; bool mte; + bool dtb_kaslr_seed; OnOffAuto acpi; VirtGICType gic_version; VirtIOMMUType iommu; |