On Mon, Feb 06, 2017 at 09:29:30AM -0800, Ben Warren wrote:
>
> On Feb 6, 2017, at 8:15 AM, Michael S. Tsirkin <m...@redhat.com> wrote:
>
> On Sun, Feb 05, 2017 at 01:12:00AM -0800, b...@skyportsystems.com wrote:
>
> From: Ben Warren <b...@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 <b...@skyportsystems.com>
>
>
>
> Thanks!
> I think it's mostly in a good shape.
> Comments inside.
>
>
> Thanks! Hopefully the next rev has everything you want.
>
>
>
> ---
> 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 <b...@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);
> + 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);
> + }
> + g_array_insert_vals(guid, VMGENID_GUID_OFFSET, s->guid.data, 16);
>
>
> ARRAY_SIZE(s->guid.data);
>
>
> OK
>
> +
> + /* 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) */
>
>
> /*
> * multiline comments
> * look like this
> */
>
>
> OK
>
> + 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))));
> + 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 */);
> +
> + /* Patch address of GUID fw_cfg blob into the ADDR fw_cfg blob */
>
>
> add ... so QEMU can write GUID there
>
>
> OK
>
> + 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 */
>
>
> add ... so OSPM can retrieve and read it
>
>
> OK
>
> + bios_linker_loader_add_pointer(linker,
> + ACPI_BUILD_TABLE_FILE, vgia_offset, sizeof(uint32_t),
> + VMGENID_GUID_FW_CFG_FILE, 0, false);
> +
> + 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,
>
>
> Seems wrong. What if guest updates the address after command line
> set it? You want a callback to copy guid there.
>
>
> Sure, I can do that. My understanding was that this is a read callback, but
> if
> it also is called upon a write, we should do what you suggest.
Hmm you are right. But we really need to call something
on write though - unlike read, it must be called after write.
Otherwise I don't see how it can work if you set gen id before
guest boots.
I guess this means we need yet another callback per file.
FWCfgWriteCallback ?
Can you implement this in hw/nvram/fw_cfg.c?
It's rather straight-forward to do.
>
>
> + vms->vgia_le, sizeof(uint32_t), false);
>
>
> Should be ARRAY_SIZE(vms->vgia_le).
>
> Also, I thought GUID is at an offset from the beginning
> in order to trick OVMF, isn't it?
>
>
> The offset is taken into account in the GUID fw_cfg file. The writing to
> guest
> memory, we add the offset to VGIA.
I keep forgetting it's the address. Really please rename it
using full words.
>
> +}
> +
> +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) {
>
>
> add a comment saying 0 means bios did not run yet.
>
> OK
>
>
>
> + cpu_physical_memory_write(vgia + VMGENID_GUID_OFFSET,
> + s->guid.data, sizeof(s->
> guid.data));
>
>
> Avoid this. You want dma.h APIs.
>
> I’ll have a look at those. This function was recommended to me in an earlier
> patch version.
>
>
>
> + /* 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)) {
>
>
> I'd use strcmp here.
>
> OK
>
>
>
> + 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.
>
>
> This makes my head spin. It's the actual guid, right? Only place we need
> it
> is when
> we copy it into guest memory. So swap there -
> and do it to a copy so you won't need these comments.
>
> I understand. I wanted to only do the swap at one place and decided to do it
> closest to the user interface, but can do it at the other end instead.
>
>
>
> Make
> + * sure to swap back whenever reporting via monitor */
>
>
> And what code does this swap back?
>
> A later patch where the QMP code is added. But I’ll remove that necessity.
>
>
>
> + 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)),
> + 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);
> + }
> +
> 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)) {
> + 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"
>
>
> Maybe vmgenid_guid ?
>
> Sure.
>
>
>
> +#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 */
>
>
> ACPI header size is 36 bytes. I'd expect just to use that.
> Where does 40 come from? I think it's an 8 bytes alignment requirement.
>
>
> The number 40 was asked for by Laszlo for the OVMF SDT Header Probe
> Suppressor,
> which I don’t know anything about.
I think I do though :)
> This GUID isn’t going in an ACPI table, so
> I’m not sure what you mean here. We allocate on a page boundary and 40 bytes
> in should be 8-byte aligned.
>
> So do QEMU_ALIGN_UP(sizeof(AcpiTableHeader), 8)
>
> Add a comment explaining that 8.
Laszlo could you suggest a comment explaining a bit about what
OVMF does here?
>
> +
> +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;
> + QemuUUID guid;
> + uint8_t vgia_le[4];
>
>
> Please give this fields a better name. Is this the address?
> Pls add comments, too.
>
>
> This variable name was suggested by Laszlo. the ‘a’ in ‘vgia’ refers to
> address, but I’ll add some comments.
vmgenid_addr_le?
> How about we make it 8 byte so it's future proof?
>
> I can do that, but a previous conversation we had made it clear that guests
> would never allocate above 4GB so 64 bits wasn’t necessary.
Right, it's just very painful to change once we make it 32 bit.
> alternatively put it in a ram block instead.
>
>
> +} VmGenIdState;
> +
> +static Object *find_vmgenid_dev(Error **errp)
> +{
> + Object *obj = object_resolve_path_type("", VMGENID_DEVICE, NULL);
> + if (!obj && errp) {
> + error_setg(errp, "%s is not found", VMGENID_DEVICE);
> + }
> + return obj;
> +}
> +
> +#endif
> --
> 2.7.4
>
>
