Re: [Qemu-devel] [PATCH v5 03/10] docs: VM Generation ID device description
On 02/05/17 10:11, b...@skyportsystems.com wrote: > +Or to change guid in runtime use: > + > + set-vm-generation-id guid=124e6eaf-d1d1-4bf6-bf41-b9bb6c91fb87 > + set-vm-generation-id guid=auto > Please drop the "guid=" prefix from the examples; the HMP command doesn't need it / chokes on it. It only takes "auto" or a UUID. Thanks Laszlo
Re: [Qemu-devel] [PATCH v5 03/10] docs: VM Generation ID device description
On 02/05/17 10:11, b...@skyportsystems.com wrote:
> From: Ben Warren
>
> This patch is based off an earlier version by
> Gal Hammer (gham...@redhat.com)
>
> Requirements section, ASCII diagrams and overall help
> provided by Laszlo Ersek (ler...@redhat.com)
>
> Signed-off-by: Gal Hammer
> Signed-off-by: Ben Warren
> ---
> docs/specs/vmgenid.txt | 239
> +
> 1 file changed, 239 insertions(+)
> create mode 100644 docs/specs/vmgenid.txt
>
> diff --git a/docs/specs/vmgenid.txt b/docs/specs/vmgenid.txt
> new file mode 100644
> index 000..d36f8bd
> --- /dev/null
> +++ b/docs/specs/vmgenid.txt
> @@ -0,0 +1,239 @@
> +VIRTUAL MACHINE GENERATION ID
> +=
> +
> +Copyright (C) 2016 Red Hat, Inc.
> +Copyright (C) 2017 Skyport Systems, Inc.
> +
> +This work is licensed under the terms of the GNU GPL, version 2 or later.
> +See the COPYING file in the top-level directory.
> +
> +===
> +
> +The VM generation ID (vmgenid) device is an emulated device which
> +exposes a 128-bit, cryptographically random, integer value identifier,
> +referred to as a Globally Unique Identifier, or GUID.
> +
> +This allows management applications (e.g. libvirt) to notify the guest
> +operating system when the virtual machine is executed with a different
> +configuration (e.g. snapshot execution or creation from a template). The
> +guest operating system notices the change, and is then able to react as
> +appropriate by marking its copies of distributed databases as dirty,
> +re-initializing its random number generator etc.
> +
> +
> +Requirements
> +
> +
> +These requirements are extracted from the "How to implement virtual machine
> +generation ID support in a virtualization platform" section of the
> +specification, dated August 1, 2012.
> +
> +
> +The document may be found on the web at:
> + http://go.microsoft.com/fwlink/?LinkId=260709
> +
> +R1a. The generation ID shall live in an 8-byte aligned buffer.
> +
> +R1b. The buffer holding the generation ID shall be in guest RAM, ROM, or
> device
> + MMIO range.
> +
> +R1c. The buffer holding the generation ID shall be kept separate from areas
> + used by the operating system.
> +
> +R1d. The buffer shall not be covered by an AddressRangeMemory or
> + AddressRangeACPI entry in the E820 or UEFI memory map.
> +
> +R1e. The generation ID shall not live in a page frame that could be mapped
> with
> + caching disabled. (In other words, regardless of whether the generation
> ID
> + lives in RAM, ROM or MMIO, it shall only be mapped as cacheable.)
> +
> +R2 to R5. [These AML requirements are isolated well enough in the Microsoft
> + specification for us to simply refer to them here.]
> +
> +R6. The hypervisor shall expose a _HID (hardware identifier) object in the
> +VMGenId device's scope that is unique to the hypervisor vendor.
> +
> +
> +QEMU Implementation
> +---
> +
> +The above-mentioned specification does not dictate which ACPI descriptor
> table
> +will contain the VM Generation ID device. Other implementations (Hyper-V and
> +Xen) put it in the main descriptor table (Differentiated System Description
> +Table or DSDT). For ease of debugging and implementation, we have decided to
> +put it in its own Secondary System Description Table, or SSDT.
> +
> +The following is a dump of the contents from a running system:
> +
> +# iasl -p ./SSDT -d /sys/firmware/acpi/tables/SSDT
> +
> +Intel ACPI Component Architecture
> +ASL+ Optimizing Compiler version 20150717-64
> +Copyright (c) 2000 - 2015 Intel Corporation
> +
> +Reading ACPI table from file /sys/firmware/acpi/tables/SSDT - Length
> +0198 (0xC6)
> +ACPI: SSDT 0x C6 (v01 BOCHS VMGENID 0001 BXPC
> +0001)
> +Acpi table [SSDT] successfully installed and loaded
> +Pass 1 parse of [SSDT]
> +Pass 2 parse of [SSDT]
> +Parsing Deferred Opcodes (Methods/Buffers/Packages/Regions)
> +
> +Parsing completed
> +Disassembly completed
> +ASL Output:./SSDT.dsl - 1631 bytes
> +# cat SSDT.dsl
> +/*
> + * Intel ACPI Component Architecture
> + * AML/ASL+ Disassembler version 20150717-64
> + * Copyright (c) 2000 - 2015 Intel Corporation
> + *
> + * Disassembling to symbolic ASL+ operators
> + *
> + * Disassembly of /sys/firmware/acpi/tables/SSDT, Sun Feb 5 00:19:37 2017
> + *
> + * Original Table Header:
> + * Signature"SSDT"
> + * Length 0x00CA (202)
> + * Revision 0x01
> + * Checksum 0x4B
> + * OEM ID "BOCHS "
> + * OEM Table ID "VMGENID"
> + * OEM Revision 0x0001 (1)
> + * Compiler ID "BXPC"
> + * Compiler Version 0x0001 (1)
> + */
> +DefinitionBlock ("/sys/firmware/acpi/tables/SSDT.aml", "SSDT", 1, "BOCHS ",
> +"VMGENID", 0x0001)
> +{
> +Name (VGIA, 0x07FFF000)
> +Scope (\_SB)
> +{
> +Device (VGEN)
> +{
> +Name (_HID, "Q
Re: [Qemu-devel] [PATCH v5 03/10] docs: VM Generation ID device description
On 02/05/2017 03:11 AM, b...@skyportsystems.com wrote: > From: Ben Warren > > This patch is based off an earlier version by > Gal Hammer (gham...@redhat.com) > > Requirements section, ASCII diagrams and overall help > provided by Laszlo Ersek (ler...@redhat.com) > > Signed-off-by: Gal Hammer > Signed-off-by: Ben Warren > --- > docs/specs/vmgenid.txt | 239 > + > 1 file changed, 239 insertions(+) > create mode 100644 docs/specs/vmgenid.txt > > + > + > +Design Details: > +--- > + > +Requirements R1a through R1e dicate that the memory holding the s/dicate/dictate/ > +VM Generation ID must be allocated and owned by the guest operating system, > + > +GUID Storage Format: > + > + > +In order to work with OVMF "SDT Header Probe Supressor", the contents of s/Supressor/Suppressor/ > +the vmgenid fw_cfg blob are not simply a 128-bit GUID. There is also > +significant padding in order to align and fill a memory page, as shown in the > +following diagram: > + > ++--+ > +| SSDT with OEM Table ID = VMGENID | > ++--+ > +| ... | TOP OF PAGE > +| VGIA dword object ---|-> +---+ > +| ... | | fw-allocated array for| > +| _STA method referring to VGIA| | "etc/vmgenid"| Inconsistent whitespace -- Eric Blake eblake redhat com+1-919-301-3266 Libvirt virtualization library http://libvirt.org signature.asc Description: OpenPGP digital signature
[Qemu-devel] [PATCH v5 03/10] docs: VM Generation ID device description
From: Ben Warren
This patch is based off an earlier version by
Gal Hammer (gham...@redhat.com)
Requirements section, ASCII diagrams and overall help
provided by Laszlo Ersek (ler...@redhat.com)
Signed-off-by: Gal Hammer
Signed-off-by: Ben Warren
---
docs/specs/vmgenid.txt | 239 +
1 file changed, 239 insertions(+)
create mode 100644 docs/specs/vmgenid.txt
diff --git a/docs/specs/vmgenid.txt b/docs/specs/vmgenid.txt
new file mode 100644
index 000..d36f8bd
--- /dev/null
+++ b/docs/specs/vmgenid.txt
@@ -0,0 +1,239 @@
+VIRTUAL MACHINE GENERATION ID
+=
+
+Copyright (C) 2016 Red Hat, Inc.
+Copyright (C) 2017 Skyport Systems, Inc.
+
+This work is licensed under the terms of the GNU GPL, version 2 or later.
+See the COPYING file in the top-level directory.
+
+===
+
+The VM generation ID (vmgenid) device is an emulated device which
+exposes a 128-bit, cryptographically random, integer value identifier,
+referred to as a Globally Unique Identifier, or GUID.
+
+This allows management applications (e.g. libvirt) to notify the guest
+operating system when the virtual machine is executed with a different
+configuration (e.g. snapshot execution or creation from a template). The
+guest operating system notices the change, and is then able to react as
+appropriate by marking its copies of distributed databases as dirty,
+re-initializing its random number generator etc.
+
+
+Requirements
+
+
+These requirements are extracted from the "How to implement virtual machine
+generation ID support in a virtualization platform" section of the
+specification, dated August 1, 2012.
+
+
+The document may be found on the web at:
+ http://go.microsoft.com/fwlink/?LinkId=260709
+
+R1a. The generation ID shall live in an 8-byte aligned buffer.
+
+R1b. The buffer holding the generation ID shall be in guest RAM, ROM, or device
+ MMIO range.
+
+R1c. The buffer holding the generation ID shall be kept separate from areas
+ used by the operating system.
+
+R1d. The buffer shall not be covered by an AddressRangeMemory or
+ AddressRangeACPI entry in the E820 or UEFI memory map.
+
+R1e. The generation ID shall not live in a page frame that could be mapped with
+ caching disabled. (In other words, regardless of whether the generation ID
+ lives in RAM, ROM or MMIO, it shall only be mapped as cacheable.)
+
+R2 to R5. [These AML requirements are isolated well enough in the Microsoft
+ specification for us to simply refer to them here.]
+
+R6. The hypervisor shall expose a _HID (hardware identifier) object in the
+VMGenId device's scope that is unique to the hypervisor vendor.
+
+
+QEMU Implementation
+---
+
+The above-mentioned specification does not dictate which ACPI descriptor table
+will contain the VM Generation ID device. Other implementations (Hyper-V and
+Xen) put it in the main descriptor table (Differentiated System Description
+Table or DSDT). For ease of debugging and implementation, we have decided to
+put it in its own Secondary System Description Table, or SSDT.
+
+The following is a dump of the contents from a running system:
+
+# iasl -p ./SSDT -d /sys/firmware/acpi/tables/SSDT
+
+Intel ACPI Component Architecture
+ASL+ Optimizing Compiler version 20150717-64
+Copyright (c) 2000 - 2015 Intel Corporation
+
+Reading ACPI table from file /sys/firmware/acpi/tables/SSDT - Length
+0198 (0xC6)
+ACPI: SSDT 0x C6 (v01 BOCHS VMGENID 0001 BXPC
+0001)
+Acpi table [SSDT] successfully installed and loaded
+Pass 1 parse of [SSDT]
+Pass 2 parse of [SSDT]
+Parsing Deferred Opcodes (Methods/Buffers/Packages/Regions)
+
+Parsing completed
+Disassembly completed
+ASL Output:./SSDT.dsl - 1631 bytes
+# cat SSDT.dsl
+/*
+ * Intel ACPI Component Architecture
+ * AML/ASL+ Disassembler version 20150717-64
+ * Copyright (c) 2000 - 2015 Intel Corporation
+ *
+ * Disassembling to symbolic ASL+ operators
+ *
+ * Disassembly of /sys/firmware/acpi/tables/SSDT, Sun Feb 5 00:19:37 2017
+ *
+ * Original Table Header:
+ * Signature"SSDT"
+ * Length 0x00CA (202)
+ * Revision 0x01
+ * Checksum 0x4B
+ * OEM ID "BOCHS "
+ * OEM Table ID "VMGENID"
+ * OEM Revision 0x0001 (1)
+ * Compiler ID "BXPC"
+ * Compiler Version 0x0001 (1)
+ */
+DefinitionBlock ("/sys/firmware/acpi/tables/SSDT.aml", "SSDT", 1, "BOCHS ",
+"VMGENID", 0x0001)
+{
+Name (VGIA, 0x07FFF000)
+Scope (\_SB)
+{
+Device (VGEN)
+{
+Name (_HID, "QEMUVGID") // _HID: Hardware ID
+Name (_CID, "VM_Gen_Counter") // _CID: Compatible ID
+Name (_DDN, "VM_Gen_Counter") // _DDN: DOS Device Name
+Method (_STA, 0, NotSerialized) // _STA: Status
+{
+Local0 = 0x0F
+If ((VGIA == Zero))
+{
+
