> On Jan 25, 2017, at 4:48 PM, Laszlo Ersek <[email protected]> wrote: > > On 01/25/17 19:35, Michael S. Tsirkin wrote: >> On Wed, Jan 25, 2017 at 09:36:52AM -0800, Ben Warren wrote: >>> Hi Laszlo, >>> >>> >>> On Jan 24, 2017, at 7:55 PM, Laszlo Ersek <[email protected]> wrote: >>> >>> Hi Ben, >>> >>> sorry about being late to reviewing this series. I hope I can now spend >>> more time on it. >>> >>> - Please do not try to address my comments immediately. It's very >>> possible (even likely) that Igor, MST and myself could have different >>> opinions on things, so first please await agreement between your >>> reviewers. >>> >>> >>> Thanks for the very detailed review. I’ll give it a couple of days and then >>> start work on the suggested changes. >>> >>> >>> - I think you should have CC'd Igor and Michael directly. I'm adding >>> them to this reply; hopefully that will be enough for them to monitor >>> this series. >>> >>> - I'll likely be unable to review everything with 100% coverage; so >>> addressing (or sufficiently refuting) my comments might not guarantee >>> that the next version will be merged at once. >>> >>> With all that said: >>> >>> On 01/25/17 02:43, [email protected] wrote: >>> >>> From: Ben Warren <[email protected]> >>> >>> This is initially used to patch a 64-bit address into the VM >>> Generation >>> ID SSDT >>> >>> >>> (1) I think this commit message line is overlong; I think we wrap at 74 >>> chars or so. Not critical, but worth mentioning. >>> >>> >>> >>> Signed-off-by: Ben Warren <[email protected]> >>> --- >>> hw/acpi/aml-build.c | 28 ++++++++++++++++++++++++++++ >>> include/hw/acpi/aml-build.h | 4 ++++ >>> 2 files changed, 32 insertions(+) >>> >>> diff --git a/hw/acpi/aml-build.c b/hw/acpi/aml-build.c >>> index b2a1e40..dc4edc2 100644 >>> --- a/hw/acpi/aml-build.c >>> +++ b/hw/acpi/aml-build.c >>> @@ -285,6 +285,34 @@ build_append_named_dword(GArray *array, const >>> char >>> *name_format, ...) >>> return offset; >>> } >>> >>> +/* >>> + * Build NAME(XXXX, 0x00000000) where 0x00000000 is encoded as a >>> qword, >>> + * and return the offset to 0x00000000 for runtime patching. >>> + * >>> + * Warning: runtime patching is best avoided. Only use this as >>> + * a replacement for DataTableRegion (for guests that don't >>> + * support it). >>> + */ >> >> only one comment: QWords first appeared in ACPI 2.0 and >> XP does not like them. Not strictly a blocker as people can >> avoid using the feature, but nice to have. > > Does XP have a driver for VMGENID? > > If not, then I'd prefer to stick with the qword VGIA. > >> Will either UEFI or seabios allocate >> memory outside 4G range? If not you do not need a qword. > > Good point (assuming XP has a driver for VMGENID). > > OVMF keeps all such allocations (i.e., for COMMAND_ALLOCATE and the > upcoming COMMAND_ALLOCATE_RETURN_ADDR) under 4GB, so as far as OVMF is > concerned, using a dword for the VGIA named object should be fine. > Accordingly, a 4-byte wide ADD_POINTER command should be used for > patching VGIA. > > Considering the fw_cfg file that receives the address, and > COMMAND_ALLOCATE_RETURN_ADDR more generally, I'd still prefer if those > stayed 8-byte wide, regardless of XP's support for VMGENID. > > > Hm... It looks like VMGENID *can* be consumed on Windows XP SP3, as long > as "Hyper-V integration services" are installed: > > https://msdn.microsoft.com/en-us/library/jj643357(v=vs.85).aspx > <https://msdn.microsoft.com/en-us/library/jj643357(v=vs.85).aspx> > > The virtual machine must be running a guest operating system that > has support for the virtual machine generation identifier. > Currently, these are the following. > The following operating systems have native support for the virtual > machine generation identifier. > [...] > > The following operating can be used as the guest operating system > if the Hyper-V integration services from Windows 8 or Windows > Server 2012 are installed. > > [...] > * Windows XP with Service Pack 3 (SP3) > > Additionally, under > <https://technet.microsoft.com/en-us/library/dn792027(v=ws.11).aspx > <https://technet.microsoft.com/en-us/library/dn792027(v=ws.11).aspx>>: > > Supported Windows client guest operating systems > > Windows XP with [...] Install the integration [...] > Service Pack 3 (SP3) services after you set > up the operating system > in the virtual machine. > > This seems to be consistent with the VMGENID spec requirement that the > ADDR method return a package of two 32-bit integers, not a single 64-bit > one. > > So, I agree with using a dword for VGIA (and a matching 4-byte wide > ADD_POINTER command). > > But, again, I'd like to keep COMMAND_ALLOCATE_RETURN_ADDR 8-byte wide. > In the future we might introduce more allocation hints (for the "zone" > field) that would enable the firmware to allocate from the full 64-bit > address space. > > NB, I didn't check SeaBIOS (should be easy for Ben); AFAIR it only uses > 16-bit and 32-bit modes. > Right, it appears that the allocated address will always fit in 32 bits. As mentioned, XP should be OK since the ADDR method returns a package of two 32-bit numbers.
I propose to still include this patch but touch up the comments as requested by
Laszlo. This way it will be in the toolbox for future users and has been
tested. I will also change VGIA to dword and hard code the AML to return
ADDR[1] = 0.
FYI: here’s an iasl dump from Windows 2012 Hyper-V in case you haven’t seen it.
Note that Microsoft uses E00 and violates the HID name length spec:
Scope (\_SB)
{
Device (GENC)
{
Name (_CID, "VM_Gen_Counter") // _CID: Compatible ID
Name (_HID, "Hyper_V_Gen_Counter_V1") // _HID: Hardware ID
Name (_UID, 0x00) // _UID: Unique ID
Name (_DDN, "VM_Gen_Counter") // _DDN: DOS Device Name
Method (ADDR, 0, NotSerialized)
{
Name (LPKG, Package (0x02)
{
0x00,
0x00
})
LPKG [0x00] = GCAL /* \GCAL */
LPKG [0x01] = GCAH /* \GCAH */
Return (LPKG) /* \_SB_.GENC.ADDR.LPKG */
}
}
}
Scope (\_GPE)
{
Method (_E00, 0, NotSerialized) // _Exx: Edge-Triggered GPE
{
Notify (\_SB.GENC, 0x80) // Status Change
}
}
> Thanks!
> Laszlo
>
>>
>>
>>
>>
>>>
>>> (2) Since we're adding a qword (8-byte integer), the hexadecimal
>>> constant should have 16 nibbles: 0x0000000000000000. (After copying the
>>> comment from build_append_named_dword(), it should be actualized.)
>>>
>>> (3) Normally the functions in this file that create AML operators carry
>>> a note about the ACPI spec version and exact location that defines the
>>> operator. I see that commit f20354910893 ("acpi: add
>>> build_append_named_dword, returning an offset in buffer", 2016-03-01)
>>> missed that too.
>>>
>>> Unless this tradition has been willfully abandoned, I suggest that you
>>> add the right reference here, and also (in retrospect) to
>>> build_append_named_dword().
>>>
>>>
>>> +int
>>> +build_append_named_qword(GArray *array, const char *name_format,
>>> ...)
>>> +{
>>> + int offset;
>>> + va_list ap;
>>> +
>>> + build_append_byte(array, 0x08); /* NameOp */
>>> + va_start(ap, name_format);
>>> + build_append_namestringv(array, name_format, ap);
>>> + va_end(ap);
>>> +
>>> + build_append_byte(array, 0x0E); /* QWordPrefix */
>>> +
>>> + offset = array->len;
>>> + build_append_int_noprefix(array, 0x00000000, 8);
>>>
>>>
>>> (4) I guess the constant should be updated here too, for consistency
>>> with the comment.
>>>
>>> The rest looks okay. (I didn't verify 0x0E == QWordPrefix specifically,
>>> because an error there would break the functionality immediately, and
>>> you'd notice.)
>>>
>>> Thanks!
>>> Laszlo
>>>
>>>
>>> + assert(array->len == offset + 8);
>>> +
>>> + return offset;
>>> +}
>>> +
>>> static GPtrArray *alloc_list;
>>>
>>> static Aml *aml_alloc(void)
>>> diff --git a/include/hw/acpi/aml-build.h
>>> b/include/hw/acpi/aml-build.h
>>> index 559326c..dbf63cf 100644
>>> --- a/include/hw/acpi/aml-build.h
>>> +++ b/include/hw/acpi/aml-build.h
>>> @@ -385,6 +385,10 @@ int
>>> build_append_named_dword(GArray *array, const char *name_format, ...)
>>> GCC_FMT_ATTR(2, 3);
>>>
>>> +int
>>> +build_append_named_qword(GArray *array, const char *name_format,
>>> ...)
>>> +GCC_FMT_ATTR(2, 3);
>>> +
>>> void build_srat_memory(AcpiSratMemoryAffinity *numamem, uint64_t
>>> base,
>>> uint64_t len, int node, MemoryAffinityFlags
>>> flags);
>>>
>>>
>>> —Ben
smime.p7s
Description: S/MIME cryptographic signature
