From f2a1ae45d8ec5ad494e66a9234499a2e0fbf4b40 Mon Sep 17 00:00:00 2001 From: Laszlo Ersek Date: Mon, 20 Mar 2017 18:05:56 +0100 Subject: [PATCH] hw/acpi/vmgenid: prevent device realization on pre-2.5 machine types The WRITE_POINTER linker/loader command that underlies VMGENID depends on commit baf2d5bfbac0 ("fw-cfg: support writeable blobs", 2017-01-12), which in turn depends on fw_cfg DMA. DMA for fw_cfg is enabled in 2.5+ machine types only (see commit e6915b5f3a87, "fw_cfg: unbreak migration compatibility for 2.4 and earlier machines", 2016-02-18). Cc: "Michael S. Tsirkin" Cc: Ben Warren Cc: Igor Mammedov Cc: Paolo Bonzini Signed-off-by: Laszlo Ersek Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin Reviewed-by: Ben Warren > Reviewed-by: Igor Mammedov --- hw/acpi/vmgenid.c | 14 ++++++++++++++ include/hw/acpi/vmgenid.h | 1 + include/hw/compat.h | 4 ++++ 3 files changed, 19 insertions(+) diff --git a/hw/acpi/vmgenid.c b/hw/acpi/vmgenid.c index 7a3ad17d66..c3ddcc8e7c 100644 --- a/hw/acpi/vmgenid.c +++ b/hw/acpi/vmgenid.c @@ -205,9 +205,22 @@ static void vmgenid_handle_reset(void *opaque) memset(vms->vmgenid_addr_le, 0, ARRAY_SIZE(vms->vmgenid_addr_le)); } +static Property vmgenid_properties[] = { + DEFINE_PROP_BOOL("x-write-pointer-available", VmGenIdState, + write_pointer_available, true), + DEFINE_PROP_END_OF_LIST(), +}; + static void vmgenid_realize(DeviceState *dev, Error **errp) { VmGenIdState *vms = VMGENID(dev); + + if (!vms->write_pointer_available) { + error_setg(errp, "%s requires DMA write support in fw_cfg, " + "which this machine type does not provide", VMGENID_DEVICE); + return; + } + qemu_register_reset(vmgenid_handle_reset, vms); } @@ -218,6 +231,7 @@ static void vmgenid_device_class_init(ObjectClass *klass, void *data) dc->vmsd = &vmstate_vmgenid; dc->realize = vmgenid_realize; dc->hotpluggable = false; + dc->props = vmgenid_properties; object_class_property_add_str(klass, VMGENID_GUID, NULL, vmgenid_set_guid, NULL); diff --git a/include/hw/acpi/vmgenid.h b/include/hw/acpi/vmgenid.h index db7fa0e633..8578476bae 100644 --- a/include/hw/acpi/vmgenid.h +++ b/include/hw/acpi/vmgenid.h @@ -21,6 +21,7 @@ typedef struct VmGenIdState { DeviceClass parent_obj; QemuUUID guid; /* The 128-bit GUID seen by the guest */ uint8_t vmgenid_addr_le[8]; /* Address of the GUID (little-endian) */ + bool write_pointer_available; } VmGenIdState; static inline Object *find_vmgenid_dev(void) diff --git a/include/hw/compat.h b/include/hw/compat.h index fc8c3e0600..5d5be91daf 100644 --- a/include/hw/compat.h +++ b/include/hw/compat.h @@ -131,6 +131,10 @@ .driver = "fw_cfg_io",\ .property = "dma_enabled",\ .value = "off",\ + },{\ + .driver = "vmgenid",\ + .property = "x-write-pointer-available",\ + .value = "off",\ }, #define HW_COMPAT_2_3 \ -- 2.39.2