Re: [Qemu-devel] [PATCH v5 05/10] ACPI: Add Virtual Machine Generation ID support

["Michael S. Tsirkin" <mst@redhat.com>]

On Tue, Feb 07, 2017 at 02:48:22PM +0100, Igor Mammedov wrote:
> On Sun,  5 Feb 2017 01:12:00 -0800
> ben@skyportsystems.com wrote:
> 
> > From: Ben Warren <ben@skyportsystems.com>
> > 
> > This implements the VM Generation ID feature by passing a 128-bit
> > GUID to the guest via a fw_cfg blob.
> > Any time the GUID changes, an ACPI notify event is sent to the guest
> > 
> > The user interface is a simple device with one parameter:
> >  - guid (string, must be "auto" or in UUID format
> >    xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx)
> > 
> > Signed-off-by: Ben Warren <ben@skyportsystems.com>
> > ---
> >  default-configs/i386-softmmu.mak     |   1 +
> >  default-configs/x86_64-softmmu.mak   |   1 +
> >  hw/acpi/Makefile.objs                |   1 +
> >  hw/acpi/vmgenid.c                    | 206 +++++++++++++++++++++++++++++++++++
> >  hw/i386/acpi-build.c                 |  10 ++
> >  include/hw/acpi/acpi_dev_interface.h |   1 +
> >  include/hw/acpi/vmgenid.h            |  37 +++++++
> >  7 files changed, 257 insertions(+)
> >  create mode 100644 hw/acpi/vmgenid.c
> >  create mode 100644 include/hw/acpi/vmgenid.h
> > 
> > diff --git a/default-configs/i386-softmmu.mak b/default-configs/i386-softmmu.mak
> > index 384cefb..1a43542 100644
> > --- a/default-configs/i386-softmmu.mak
> > +++ b/default-configs/i386-softmmu.mak
> > @@ -58,3 +58,4 @@ CONFIG_I82801B11=y
> >  CONFIG_SMBIOS=y
> >  CONFIG_HYPERV_TESTDEV=$(CONFIG_KVM)
> >  CONFIG_PXB=y
> > +CONFIG_ACPI_VMGENID=y
> > diff --git a/default-configs/x86_64-softmmu.mak b/default-configs/x86_64-softmmu.mak
> > index 491a191..aee8b08 100644
> > --- a/default-configs/x86_64-softmmu.mak
> > +++ b/default-configs/x86_64-softmmu.mak
> > @@ -58,3 +58,4 @@ CONFIG_I82801B11=y
> >  CONFIG_SMBIOS=y
> >  CONFIG_HYPERV_TESTDEV=$(CONFIG_KVM)
> >  CONFIG_PXB=y
> > +CONFIG_ACPI_VMGENID=y
> > diff --git a/hw/acpi/Makefile.objs b/hw/acpi/Makefile.objs
> > index 6acf798..11c35bc 100644
> > --- a/hw/acpi/Makefile.objs
> > +++ b/hw/acpi/Makefile.objs
> > @@ -5,6 +5,7 @@ common-obj-$(CONFIG_ACPI_CPU_HOTPLUG) += cpu_hotplug.o
> >  common-obj-$(CONFIG_ACPI_MEMORY_HOTPLUG) += memory_hotplug.o
> >  common-obj-$(CONFIG_ACPI_CPU_HOTPLUG) += cpu.o
> >  common-obj-$(CONFIG_ACPI_NVDIMM) += nvdimm.o
> > +common-obj-$(CONFIG_ACPI_VMGENID) += vmgenid.o
> >  common-obj-$(call lnot,$(CONFIG_ACPI_X86)) += acpi-stub.o
> >  
> >  common-obj-y += acpi_interface.o
> > diff --git a/hw/acpi/vmgenid.c b/hw/acpi/vmgenid.c
> > new file mode 100644
> > index 0000000..6c9ecfd
> > --- /dev/null
> > +++ b/hw/acpi/vmgenid.c
> > @@ -0,0 +1,206 @@
> > +/*
> > + *  Virtual Machine Generation ID Device
> > + *
> > + *  Copyright (C) 2017 Skyport Systems.
> > + *
> > + *  Author: Ben Warren <ben@skyportsystems.com>
> > + *
> > + * This work is licensed under the terms of the GNU GPL, version 2 or later.
> > + * See the COPYING file in the top-level directory.
> > + *
> > + */
> > +
> > +#include "qemu/osdep.h"
> > +#include "qmp-commands.h"
> > +#include "hw/acpi/acpi.h"
> > +#include "hw/acpi/aml-build.h"
> > +#include "hw/acpi/vmgenid.h"
> > +#include "hw/nvram/fw_cfg.h"
> > +#include "sysemu/sysemu.h"
> > +
> > +void vmgenid_build_acpi(GArray *table_data, GArray *guid, BIOSLinker *linker)
> > +{
> > +    Object *obj;
> > +    VmGenIdState *s;
> > +    Aml *ssdt, *dev, *scope, *method, *addr, *if_ctx;
> > +    uint32_t vgia_offset;
> > +
> > +    obj = find_vmgenid_dev(NULL);
> get obj from caller
> 
> > +    assert(obj);
> > +    s = VMGENID(obj);
> > +
> > +    /* Fill in the GUID values */
> > +    if (guid->len != VMGENID_FW_CFG_SIZE) {
> > +        g_array_set_size(guid, VMGENID_FW_CFG_SIZE);
> does it have to be conditional?
> 
> > +    }
> > +    g_array_insert_vals(guid, VMGENID_GUID_OFFSET, s->guid.data, 16);
> > +
> > +    /* Put this in a separate SSDT table */
> > +    ssdt = init_aml_allocator();
> > +
> > +    /* Reserve space for header */
> > +    acpi_data_push(ssdt->buf, sizeof(AcpiTableHeader));
> > +
> > +    /* Storage for the GUID address */
> > +    vgia_offset = table_data->len +
> > +        build_append_named_dword(ssdt->buf, "VGIA");
> > +    scope = aml_scope("\\_SB");
> > +    dev = aml_device("VGEN");
> > +    aml_append(dev, aml_name_decl("_HID", aml_string("QEMUVGID")));
> > +    aml_append(dev, aml_name_decl("_CID", aml_string("VM_Gen_Counter")));
> > +    aml_append(dev, aml_name_decl("_DDN", aml_string("VM_Gen_Counter")));
> > +
> > +    /* Simple status method to check that address is linked and non-zero */
> > +    method = aml_method("_STA", 0, AML_NOTSERIALIZED);
> > +    addr = aml_local(0);
> > +    aml_append(method, aml_store(aml_int(0xf), addr));
> > +    if_ctx = aml_if(aml_equal(aml_name("VGIA"), aml_int(0)));
> > +    aml_append(if_ctx, aml_store(aml_int(0), addr));
> > +    aml_append(method, if_ctx);
> > +    aml_append(method, aml_return(addr));
> > +    aml_append(dev, method);
> > +
> > +    /* the ADDR method returns two 32-bit words representing the lower and
> > +     * upper halves * of the physical address of the fw_cfg blob
> > +     * (holding the GUID) */
> > +    method = aml_method("ADDR", 0, AML_NOTSERIALIZED);
> > +
> > +    addr = aml_local(0);
> > +    aml_append(method, aml_store(aml_package(2), addr));
> > +
> > +    aml_append(method, aml_store(aml_add(aml_name("VGIA"),
> > +                                         aml_int(VMGENID_GUID_OFFSET), NULL),
> > +                                 aml_index(addr, aml_int(0))));
> > +    aml_append(method, aml_store(aml_int(0), aml_index(addr, aml_int(1))));
> I'd rather have "VGIA" patched wit address to GUID and not the blob start,
> see next comment about how.
> 
> Also usage aml_index() looks a bit confusing, how about:
> 
> pkg = aml_local(0)
> aml_store(aml_package(2), pkg)
> aml_append(pkg, aml_name("VGIA"))
> aml_append(pkg, aml_int(0))
> 
> > +    aml_append(method, aml_return(addr));
> > +
> > +    aml_append(dev, method);
> > +    aml_append(scope, dev);
> > +    aml_append(ssdt, scope);
> > +
> > +    /* attach an ACPI notify */
> > +    method = aml_method("\\_GPE._E05", 0, AML_NOTSERIALIZED);
> > +    aml_append(method, aml_notify(aml_name("\\_SB.VGEN"), aml_int(0x80)));
> > +    aml_append(ssdt, method);
> > +
> > +    g_array_append_vals(table_data, ssdt->buf->data, ssdt->buf->len);
> > +
> > +    /* Allocate guest memory for the Data fw_cfg blob */
> > +    bios_linker_loader_alloc(linker, VMGENID_GUID_FW_CFG_FILE, guid, 4096,
> > +                             false /* page boundary, high memory */);
> does it guaranties that blob will be allocated in cacheable page?
> (SeaBIOS/OVMF)

Reserving it from guest. Pretty much, yes.

> > +
> > +    /* Patch address of GUID fw_cfg blob into the ADDR fw_cfg blob */
> > +    bios_linker_loader_add_pointer(linker,
> > +        VMGENID_ADDR_FW_CFG_FILE, 0, sizeof(uint32_t),
> > +        VMGENID_GUID_FW_CFG_FILE, 0, true);
> > +
> > +    /* Patch address of GUID fw_cfg blob into the AML */
> > +    bios_linker_loader_add_pointer(linker,
> > +        ACPI_BUILD_TABLE_FILE, vgia_offset, sizeof(uint32_t),
> > +        VMGENID_GUID_FW_CFG_FILE, 0, false);
> see @src_offset argument description,
> putting VMGENID_GUID_OFFSET would make patched place point directly to GUID
> 
> > +
> > +    build_header(linker, table_data,
> > +        (void *)(table_data->data + table_data->len - ssdt->buf->len),
> > +        "SSDT", ssdt->buf->len, 1, NULL, "VMGENID");
> > +    free_aml_allocator();
> > +}
> > +
> > +void vmgenid_add_fw_cfg(FWCfgState *s, GArray *guid)
> > +{
> > +    Object *obj = find_vmgenid_dev(NULL);
> > +    assert(obj);
> > +    VmGenIdState *vms = VMGENID(obj);
> > +
> > +    /* Create a read-only fw_cfg file for GUID */
> > +    fw_cfg_add_file(s, VMGENID_GUID_FW_CFG_FILE, guid->data,
> > +                    VMGENID_FW_CFG_SIZE);
> > +    /* Create a read-write fw_cfg file for Address */
> > +    fw_cfg_add_file_callback(s, VMGENID_ADDR_FW_CFG_FILE, NULL, NULL,
> > +                             vms->vgia_le, sizeof(uint32_t), false);
> > +}
> > +
> > +static void vmgenid_update_guest(VmGenIdState *s)
> > +{
> > +    Object *obj = object_resolve_path_type("", TYPE_ACPI_DEVICE_IF, NULL);
> > +    uint32_t vgia;
> > +
> > +    if (obj) {
> > +        /* Write the GUID to guest memory */
> > +        memcpy(&vgia, s->vgia_le, sizeof(vgia));
> > +        vgia = le32_to_cpu(vgia);
> > +        if (vgia) {
> > +            cpu_physical_memory_write(vgia + VMGENID_GUID_OFFSET,
> > +                                      s->guid.data, sizeof(s->guid.data));
> > +            /* Send _GPE.E05 event */
> > +            acpi_send_event(DEVICE(obj), ACPI_VMGENID_CHANGE_STATUS);
> > +        }
> > +    }
> > +}
> > +
> > +static void vmgenid_set_guid(Object *obj, const char *value, Error **errp)
> > +{
> > +    VmGenIdState *s = VMGENID(obj);
> > +
> > +    if (!strncmp(value, "auto", 4)) {
> > +        qemu_uuid_generate(&s->guid);
> > +    } else if (qemu_uuid_parse(value, &s->guid) < 0) {
> > +        error_setg(errp, "'%s. %s': Failed to parse GUID string: %s",
> > +                   object_get_typename(OBJECT(s)), VMGENID_GUID, value);
> > +        return;
> > +    }
> > +    /* QemuUUID has the first three words as big-endian, and expect that any
> > +     * GUIDs passed in will always be BE.  The guest, however will expect
> > +     * the fields to be little-endian, so store that way internally.  Make
> > +     * sure to swap back whenever reporting via monitor */
> > +    qemu_uuid_bswap(&s->guid);
> > +
> > +    /* Send the ACPI notify */
> > +    vmgenid_update_guest(s);
> > +}
> > +
> > +/* After restoring an image, we need to update the guest memory and notify
> > + * it of a potential change to VM Generation ID */
> > +static int vmgenid_post_load(void *opaque, int version_id)
> > +{
> > +    VmGenIdState *s = opaque;
> > +    vmgenid_update_guest(s);
> > +    return 0;
> > +}
> > +
> > +static const VMStateDescription vmstate_vmgenid = {
> > +    .name = "vmgenid",
> > +    .version_id = 1,
> > +    .minimum_version_id = 1,
> > +    .post_load = vmgenid_post_load,
> > +    .fields = (VMStateField[]) {
> > +        VMSTATE_UINT8_ARRAY(vgia_le, VmGenIdState, sizeof(uint32_t)),
> file with address could be memory region and migrated automatically,
> ex: rsdp_mr + acpi_add_rom_blob + acpi_ram_update
> 
> > +        VMSTATE_END_OF_LIST()
> > +    },
> > +};
> > +
> > +static void vmgenid_initfn(Object *obj)
> > +{
> > +    object_property_add_str(obj, VMGENID_GUID, NULL, vmgenid_set_guid, NULL);
> > +}
> > +
> > +static void vmgenid_device_class_init(ObjectClass *klass, void *data)
> > +{
> > +    DeviceClass *dc = DEVICE_CLASS(klass);
> > +
> > +    dc->vmsd = &vmstate_vmgenid;
> > +}
> > +
> > +static const TypeInfo vmgenid_device_info = {
> > +    .name          = VMGENID_DEVICE,
> > +    .parent        = TYPE_SYS_BUS_DEVICE,
> > +    .instance_size = sizeof(VmGenIdState),
> > +    .instance_init = vmgenid_initfn,
> > +    .class_init    = vmgenid_device_class_init,
> > +};
> > +
> > +static void vmgenid_register_types(void)
> > +{
> > +    type_register_static(&vmgenid_device_info);
> > +}
> > +
> > +type_init(vmgenid_register_types)
> > diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
> > index 78a1d84..4c40f76 100644
> > --- a/hw/i386/acpi-build.c
> > +++ b/hw/i386/acpi-build.c
> > @@ -42,6 +42,7 @@
> >  #include "hw/acpi/memory_hotplug.h"
> >  #include "sysemu/tpm.h"
> >  #include "hw/acpi/tpm.h"
> > +#include "hw/acpi/vmgenid.h"
> >  #include "sysemu/tpm_backend.h"
> >  #include "hw/timer/mc146818rtc_regs.h"
> >  #include "sysemu/numa.h"
> > @@ -2653,6 +2654,11 @@ void acpi_build(AcpiBuildTables *tables, MachineState *machine)
> >      acpi_add_table(table_offsets, tables_blob);
> >      build_madt(tables_blob, tables->linker, pcms);
> >  
> > +    if (find_vmgenid_dev(NULL)) {
> > +        acpi_add_table(table_offsets, tables_blob);
> > +        vmgenid_build_acpi(tables_blob, tables->vmgenid, tables->linker);
> pass find_vmgenid_dev(NULL) result as an argument to vmgenid_build_acpi()
> so it won't have to do lookup again.
> 
> > +    }
> > +
> >      if (misc.has_hpet) {
> >          acpi_add_table(table_offsets, tables_blob);
> >          build_hpet(tables_blob, tables->linker);
> > @@ -2859,6 +2865,10 @@ void acpi_setup(void)
> >      fw_cfg_add_file(pcms->fw_cfg, ACPI_BUILD_TPMLOG_FILE,
> >                      tables.tcpalog->data, acpi_data_len(tables.tcpalog));
> >  
> > +    if (find_vmgenid_dev(NULL)) {
> it's second lookup, cache result of the 1st call and reuse it here
> 
> > +        vmgenid_add_fw_cfg(pcms->fw_cfg, tables.vmgenid);
> > +    }
> > +
> >      if (!pcmc->rsdp_in_ram) {
> >          /*
> >           * Keep for compatibility with old machine types.
> > diff --git a/include/hw/acpi/acpi_dev_interface.h b/include/hw/acpi/acpi_dev_interface.h
> > index 71d3c48..3c2e4e9 100644
> > --- a/include/hw/acpi/acpi_dev_interface.h
> > +++ b/include/hw/acpi/acpi_dev_interface.h
> > @@ -11,6 +11,7 @@ typedef enum {
> >      ACPI_CPU_HOTPLUG_STATUS = 4,
> >      ACPI_MEMORY_HOTPLUG_STATUS = 8,
> >      ACPI_NVDIMM_HOTPLUG_STATUS = 16,
> > +    ACPI_VMGENID_CHANGE_STATUS = 32,
> >  } AcpiEventStatusBits;
> >  
> >  #define TYPE_ACPI_DEVICE_IF "acpi-device-interface"
> > diff --git a/include/hw/acpi/vmgenid.h b/include/hw/acpi/vmgenid.h
> > new file mode 100644
> > index 0000000..b60437a
> > --- /dev/null
> > +++ b/include/hw/acpi/vmgenid.h
> > @@ -0,0 +1,37 @@
> > +#ifndef ACPI_VMGENID_H
> > +#define ACPI_VMGENID_H
> > +
> > +#include "hw/acpi/bios-linker-loader.h"
> > +#include "hw/sysbus.h"
> > +#include "qemu/uuid.h"
> > +
> > +#define VMGENID_DEVICE           "vmgenid"
> > +#define VMGENID_GUID             "guid"
> > +#define VMGENID_GUID_FW_CFG_FILE      "etc/vmgenid"
> > +#define VMGENID_ADDR_FW_CFG_FILE      "etc/vmgenid_addr"
> > +
> > +#define VMGENID_FW_CFG_SIZE      4096 /* Occupy a page of memory */
> > +#define VMGENID_GUID_OFFSET      40   /* allow space for
> > +                                       * OVMF SDT Header Probe Supressor */
> > +
> > +void vmgenid_add_fw_cfg(FWCfgState *s, GArray *guid);
> > +void vmgenid_build_acpi(GArray *table_data, GArray *guid, BIOSLinker *linker);
> > +
> > +#define VMGENID(obj) OBJECT_CHECK(VmGenIdState, (obj), VMGENID_DEVICE)
> > +
> > +typedef struct VmGenIdState {
> > +    SysBusDevice parent_obj;
> Could it work with just plain Device parent?
> If it works then you can drop patch:
>   [PATCH v5 08/10] PC: Support dynamic sysbus on pc_i440fx
> 
> > +    QemuUUID guid;
> > +    uint8_t vgia_le[4];
> > +} VmGenIdState;
> > +
> > +static Object *find_vmgenid_dev(Error **errp)
> > +{
> > +    Object *obj = object_resolve_path_type("", VMGENID_DEVICE, NULL);
> > +    if (!obj && errp) {
> all callers pass NULL as errp, I'd just drop errp altogether.
> 
> > +        error_setg(errp, "%s is not found", VMGENID_DEVICE);
> > +    }
> > +    return obj;
> > +}
> > +
> > +#endif