Re: OVMF and PCI0 UID

Re: OVMF and PCI0 UID

[Laszlo Ersek]

Hi Vitaly,

adding Igor, Michael, Marcel, and qemu-devel.

On 07/20/20 11:06, vit9696 wrote:
> Hello,
>
> I discovered an issue with inconsistent QEMU/OVMF device paths, and
> while I am unsure whether directing this e-mail is appropriate to you,
> I believe that you likely have the contacts you could forward this
> e-mail to.
>
> macOS uses ACPI UIDs to build the DevicePath for NVRAM boot options,
> while OVMF firmware gets them via an internal channel through QEMU.
> Due to a bug in QEMU (or OVMF) currently UEFI firmware and ACPI have
> different values, and this makes the underlying operating system
> unable to report its boot option.
>
> The particular node in question is the primary PciRoot (PCI0 in ACPI),
> which for some reason gets assigned 1 in ACPI UID and 0 in the
> DevicePath. To me this looks like a bug here:
> https://github.com/qemu/qemu/blob/8f06f22/hw/i386/acpi-build.c#L1511-L1515
> Which does not correspond to the primary PCI identifier here:
> https://github.com/qemu/qemu/blob/5a79d10/hw/pci/pci.c#L160-L162
>
> Reference with the device paths, OVMF startup logs, and ACPI table
> dumps (SysReport):
> https://github.com/acidanthera/bugtracker/issues/1050
>
> Would you be able to forward this to the right people or perhaps keep
> an eye on the issue itself?

I think you are right.

In UEFI v2.8, section "10.4.2 Rules with ACPI _HID and _UID" ends with
the paragraph,

    Root PCI bridges will use the plug and play ID of PNP0A03, This will
    be stored in the ACPI Device Path _HID field, or in the Expanded
    ACPI Device Path _CID field to match the ACPI name space. The _UID
    in the ACPI Device Path structure must match the _UID in the ACPI
    name space.

(See especially the last sentence.)

Considering *extra* root bridges / root buses (with bus number > 0),
QEMU's ACPI generator actually does the right thing; since QEMU commit
c96d9286a6d7 ("i386/acpi-build: more traditional _UID and _HID for PXB
root buses", 2015-06-11).

However, the _UID values for root bridge zero (on both i440fx and q35)
have always been "wrong" (from UEFI perspective), going back in QEMU to
commit 74523b850189 ("i386: add ACPI table files from seabios",
2013-10-14).

Even in SeaBIOS, these _UID values have always been 1; see commit
a4d357638c57 ("Port rombios32 code from bochs-bios.", 2008-03-08) for
i440fx, and commit ecbe3fd61511 ("seabios: q35: add dsdt", 2012-12-01)
for q35.

Does the following patch work for you? (I can see you proposed the same
in
<https://github.com/acidanthera/bugtracker/issues/1050#issuecomment-660734139>)

> diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
> index b7bcbbbb2a35..7a5a8b3521b0 100644
> --- a/hw/i386/acpi-build.c
> +++ b/hw/i386/acpi-build.c
> @@ -1496,9 +1496,9 @@ build_dsdt(GArray *table_data, BIOSLinker *linker,
>          sb_scope = aml_scope("_SB");
>          dev = aml_device("PCI0");
>          aml_append(dev, aml_name_decl("_HID", aml_eisaid("PNP0A03")));
>          aml_append(dev, aml_name_decl("_ADR", aml_int(0)));
> -        aml_append(dev, aml_name_decl("_UID", aml_int(1)));
> +        aml_append(dev, aml_name_decl("_UID", aml_int(0)));
>          aml_append(sb_scope, dev);
>          aml_append(dsdt, sb_scope);
>
>          build_hpet_aml(dsdt);
> @@ -1511,9 +1511,9 @@ build_dsdt(GArray *table_data, BIOSLinker *linker,
>          dev = aml_device("PCI0");
>          aml_append(dev, aml_name_decl("_HID", aml_eisaid("PNP0A08")));
>          aml_append(dev, aml_name_decl("_CID", aml_eisaid("PNP0A03")));
>          aml_append(dev, aml_name_decl("_ADR", aml_int(0)));
> -        aml_append(dev, aml_name_decl("_UID", aml_int(1)));
> +        aml_append(dev, aml_name_decl("_UID", aml_int(0)));
>          aml_append(dev, build_q35_osc_method());
>          aml_append(sb_scope, dev);
>          aml_append(dsdt, sb_scope);

If it does, I suggest submitting the above patch to qemu-devel, and/or
filing a bug for upstream QEMU at <https://bugs.launchpad.net/qemu/>.

(Note: I didn't even compile the above change.)

Thanks
Laszlo

Re: OVMF and PCI0 UID

[Michael S. Tsirkin]

On Mon, Jul 20, 2020 at 11:25:58PM +0200, Laszlo Ersek wrote:
> Hi Vitaly,
> 
> adding Igor, Michael, Marcel, and qemu-devel.
> 
> On 07/20/20 11:06, vit9696 wrote:
> > Hello,
> >
> > I discovered an issue with inconsistent QEMU/OVMF device paths, and
> > while I am unsure whether directing this e-mail is appropriate to you,
> > I believe that you likely have the contacts you could forward this
> > e-mail to.
> >
> > macOS uses ACPI UIDs to build the DevicePath for NVRAM boot options,
> > while OVMF firmware gets them via an internal channel through QEMU.
> > Due to a bug in QEMU (or OVMF) currently UEFI firmware and ACPI have
> > different values, and this makes the underlying operating system
> > unable to report its boot option.
> >
> > The particular node in question is the primary PciRoot (PCI0 in ACPI),
> > which for some reason gets assigned 1 in ACPI UID and 0 in the
> > DevicePath. To me this looks like a bug here:
> > https://github.com/qemu/qemu/blob/8f06f22/hw/i386/acpi-build.c#L1511-L1515
> > Which does not correspond to the primary PCI identifier here:
> > https://github.com/qemu/qemu/blob/5a79d10/hw/pci/pci.c#L160-L162
> >
> > Reference with the device paths, OVMF startup logs, and ACPI table
> > dumps (SysReport):
> > https://github.com/acidanthera/bugtracker/issues/1050
> >
> > Would you be able to forward this to the right people or perhaps keep
> > an eye on the issue itself?
> 
> I think you are right.
> 
> In UEFI v2.8, section "10.4.2 Rules with ACPI _HID and _UID" ends with
> the paragraph,
> 
>     Root PCI bridges will use the plug and play ID of PNP0A03, This will
>     be stored in the ACPI Device Path _HID field, or in the Expanded
>     ACPI Device Path _CID field to match the ACPI name space. The _UID
>     in the ACPI Device Path structure must match the _UID in the ACPI
>     name space.
> 
> (See especially the last sentence.)
> 
> Considering *extra* root bridges / root buses (with bus number > 0),
> QEMU's ACPI generator actually does the right thing; since QEMU commit
> c96d9286a6d7 ("i386/acpi-build: more traditional _UID and _HID for PXB
> root buses", 2015-06-11).
> 
> However, the _UID values for root bridge zero (on both i440fx and q35)
> have always been "wrong" (from UEFI perspective), going back in QEMU to
> commit 74523b850189 ("i386: add ACPI table files from seabios",
> 2013-10-14).
> 
> Even in SeaBIOS, these _UID values have always been 1; see commit
> a4d357638c57 ("Port rombios32 code from bochs-bios.", 2008-03-08) for
> i440fx, and commit ecbe3fd61511 ("seabios: q35: add dsdt", 2012-12-01)
> for q35.
> 
> Does the following patch work for you? (I can see you proposed the same
> in
> <https://github.com/acidanthera/bugtracker/issues/1050#issuecomment-660734139>)
> 
> > diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
> > index b7bcbbbb2a35..7a5a8b3521b0 100644
> > --- a/hw/i386/acpi-build.c
> > +++ b/hw/i386/acpi-build.c
> > @@ -1496,9 +1496,9 @@ build_dsdt(GArray *table_data, BIOSLinker *linker,
> >          sb_scope = aml_scope("_SB");
> >          dev = aml_device("PCI0");
> >          aml_append(dev, aml_name_decl("_HID", aml_eisaid("PNP0A03")));
> >          aml_append(dev, aml_name_decl("_ADR", aml_int(0)));
> > -        aml_append(dev, aml_name_decl("_UID", aml_int(1)));
> > +        aml_append(dev, aml_name_decl("_UID", aml_int(0)));
> >          aml_append(sb_scope, dev);
> >          aml_append(dsdt, sb_scope);
> >
> >          build_hpet_aml(dsdt);
> > @@ -1511,9 +1511,9 @@ build_dsdt(GArray *table_data, BIOSLinker *linker,
> >          dev = aml_device("PCI0");
> >          aml_append(dev, aml_name_decl("_HID", aml_eisaid("PNP0A08")));
> >          aml_append(dev, aml_name_decl("_CID", aml_eisaid("PNP0A03")));
> >          aml_append(dev, aml_name_decl("_ADR", aml_int(0)));
> > -        aml_append(dev, aml_name_decl("_UID", aml_int(1)));
> > +        aml_append(dev, aml_name_decl("_UID", aml_int(0)));
> >          aml_append(dev, build_q35_osc_method());
> >          aml_append(sb_scope, dev);
> >          aml_append(dsdt, sb_scope);
> 
> If it does, I suggest submitting the above patch to qemu-devel, and/or
> filing a bug for upstream QEMU at <https://bugs.launchpad.net/qemu/>.

Or even just reporting whether the above helps you, we can
take it from there.

> (Note: I didn't even compile the above change.)
> 
> Thanks
> Laszlo

Re: OVMF and PCI0 UID

[vit9696]

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Thank you, we will provide an update whether this solves the problem.

Besides, this is not the only case where UIDs are wrong for the PCI bus. In hw/arm/virt-acpi-build.c there is the following code:

    Aml *dev = aml_device("%s", "PCI0");
    aml_append(dev, aml_name_decl("_HID", aml_string("PNP0A08")));
    aml_append(dev, aml_name_decl("_CID", aml_string("PNP0A03")));
    aml_append(dev, aml_name_decl("_SEG", aml_int(0)));
    aml_append(dev, aml_name_decl("_BBN", aml_int(0)));
    aml_append(dev, aml_name_decl("_ADR", aml_int(0)));
    aml_append(dev, aml_name_decl("_UID", aml_string("PCI0")));
    aml_append(dev, aml_name_decl("_STR", aml_unicode("PCIe 0 Device")));
    aml_append(dev, aml_name_decl("_CCA", aml_int(1)));

https://github.com/qemu/qemu/blob/2c1fb4d/hw/arm/virt-acpi-build.c#L168-L175 <https://github.com/qemu/qemu/blob/2c1fb4d/hw/arm/virt-acpi-build.c#L168-L175>

It makes UID on ARM builds a string, which is certainly not expected. We do not have ARM test setups, but I hope this can be useful too.

Best wishes,
Vitaly

> 21 июля 2020 г., в 09:58, Michael S. Tsirkin <mst@redhat.com> написал(а):
> 
> 
> On Mon, Jul 20, 2020 at 11:25:58PM +0200, Laszlo Ersek wrote:
>> Hi Vitaly,
>> 
>> adding Igor, Michael, Marcel, and qemu-devel.
>> 
>> On 07/20/20 11:06, vit9696 wrote:
>>> Hello,
>>> 
>>> I discovered an issue with inconsistent QEMU/OVMF device paths, and
>>> while I am unsure whether directing this e-mail is appropriate to you,
>>> I believe that you likely have the contacts you could forward this
>>> e-mail to.
>>> 
>>> macOS uses ACPI UIDs to build the DevicePath for NVRAM boot options,
>>> while OVMF firmware gets them via an internal channel through QEMU.
>>> Due to a bug in QEMU (or OVMF) currently UEFI firmware and ACPI have
>>> different values, and this makes the underlying operating system
>>> unable to report its boot option.
>>> 
>>> The particular node in question is the primary PciRoot (PCI0 in ACPI),
>>> which for some reason gets assigned 1 in ACPI UID and 0 in the
>>> DevicePath. To me this looks like a bug here:
>>> https://github.com/qemu/qemu/blob/8f06f22/hw/i386/acpi-build.c#L1511-L1515
>>> Which does not correspond to the primary PCI identifier here:
>>> https://github.com/qemu/qemu/blob/5a79d10/hw/pci/pci.c#L160-L162
>>> 
>>> Reference with the device paths, OVMF startup logs, and ACPI table
>>> dumps (SysReport):
>>> https://github.com/acidanthera/bugtracker/issues/1050
>>> 
>>> Would you be able to forward this to the right people or perhaps keep
>>> an eye on the issue itself?
>> 
>> I think you are right.
>> 
>> In UEFI v2.8, section "10.4.2 Rules with ACPI _HID and _UID" ends with
>> the paragraph,
>> 
>>    Root PCI bridges will use the plug and play ID of PNP0A03, This will
>>    be stored in the ACPI Device Path _HID field, or in the Expanded
>>    ACPI Device Path _CID field to match the ACPI name space. The _UID
>>    in the ACPI Device Path structure must match the _UID in the ACPI
>>    name space.
>> 
>> (See especially the last sentence.)
>> 
>> Considering *extra* root bridges / root buses (with bus number > 0),
>> QEMU's ACPI generator actually does the right thing; since QEMU commit
>> c96d9286a6d7 ("i386/acpi-build: more traditional _UID and _HID for PXB
>> root buses", 2015-06-11).
>> 
>> However, the _UID values for root bridge zero (on both i440fx and q35)
>> have always been "wrong" (from UEFI perspective), going back in QEMU to
>> commit 74523b850189 ("i386: add ACPI table files from seabios",
>> 2013-10-14).
>> 
>> Even in SeaBIOS, these _UID values have always been 1; see commit
>> a4d357638c57 ("Port rombios32 code from bochs-bios.", 2008-03-08) for
>> i440fx, and commit ecbe3fd61511 ("seabios: q35: add dsdt", 2012-12-01)
>> for q35.
>> 
>> Does the following patch work for you? (I can see you proposed the same
>> in
>> <https://github.com/acidanthera/bugtracker/issues/1050#issuecomment-660734139>)
>> 
>>> diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
>>> index b7bcbbbb2a35..7a5a8b3521b0 100644
>>> --- a/hw/i386/acpi-build.c
>>> +++ b/hw/i386/acpi-build.c
>>> @@ -1496,9 +1496,9 @@ build_dsdt(GArray *table_data, BIOSLinker *linker,
>>>         sb_scope = aml_scope("_SB");
>>>         dev = aml_device("PCI0");
>>>         aml_append(dev, aml_name_decl("_HID", aml_eisaid("PNP0A03")));
>>>         aml_append(dev, aml_name_decl("_ADR", aml_int(0)));
>>> -        aml_append(dev, aml_name_decl("_UID", aml_int(1)));
>>> +        aml_append(dev, aml_name_decl("_UID", aml_int(0)));
>>>         aml_append(sb_scope, dev);
>>>         aml_append(dsdt, sb_scope);
>>> 
>>>         build_hpet_aml(dsdt);
>>> @@ -1511,9 +1511,9 @@ build_dsdt(GArray *table_data, BIOSLinker *linker,
>>>         dev = aml_device("PCI0");
>>>         aml_append(dev, aml_name_decl("_HID", aml_eisaid("PNP0A08")));
>>>         aml_append(dev, aml_name_decl("_CID", aml_eisaid("PNP0A03")));
>>>         aml_append(dev, aml_name_decl("_ADR", aml_int(0)));
>>> -        aml_append(dev, aml_name_decl("_UID", aml_int(1)));
>>> +        aml_append(dev, aml_name_decl("_UID", aml_int(0)));
>>>         aml_append(dev, build_q35_osc_method());
>>>         aml_append(sb_scope, dev);
>>>         aml_append(dsdt, sb_scope);
>> 
>> If it does, I suggest submitting the above patch to qemu-devel, and/or
>> filing a bug for upstream QEMU at <https://bugs.launchpad.net/qemu/>.
> 
> Or even just reporting whether the above helps you, we can
> take it from there.
> 
>> (Note: I didn't even compile the above change.)
>> 
>> Thanks
>> Laszlo


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Re: OVMF and PCI0 UID

[vit9696 via]

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Re: OVMF and PCI0 UID

[Michael S. Tsirkin]

Thanks, I sent the patches on the list now!

On Wed, Jul 22, 2020 at 01:53:23PM +0000, vit9696 via wrote:
> Hello,
> 
> We can confirm that the suggested change to zero UIDs resolves the problem. It
> will be great if you could handle the rest as you see fit. Thank you!
> 
> Best regards,
> Vitaly
> 
> 
> В вт, июля 21, 2020 в 12:24, vit9696 <vit9696@protonmail.com> пишет:
> 
>     Thank you, we will provide an update whether this solves the problem.
> 
>     Besides, this is not the only case where UIDs are wrong for the PCI bus.
>     In hw/arm/virt-acpi-build.c there is the following code:
> 
>         Aml *dev = aml_device("%s", "PCI0");
>         aml_append(dev, aml_name_decl("_HID", aml_string("PNP0A08")));
>         aml_append(dev, aml_name_decl("_CID", aml_string("PNP0A03")));
>         aml_append(dev, aml_name_decl("_SEG", aml_int(0)));
>         aml_append(dev, aml_name_decl("_BBN", aml_int(0)));
>         aml_append(dev, aml_name_decl("_ADR", aml_int(0)));
>         aml_append(dev, aml_name_decl("_UID", aml_string("PCI0")));
>         aml_append(dev, aml_name_decl("_STR", aml_unicode("PCIe 0 Device")));
>         aml_append(dev, aml_name_decl("_CCA", aml_int(1)));
> 
>     https://github.com/qemu/qemu/blob/2c1fb4d/hw/arm/virt-acpi-build.c#
>     L168-L175
> 
>     It makes UID on ARM builds a string, which is certainly not expected. We do
>     not have ARM test setups, but I hope this can be useful too.
> 
>     Best wishes,
>     Vitaly
> 
> 
>         21 июля 2020 г., в 09:58, Michael S. Tsirkin <mst@redhat.com> написал
>         (а):
> 
> 
>         On Mon, Jul 20, 2020 at 11:25:58PM +0200, Laszlo Ersek wrote:
> 
>             Hi Vitaly,
> 
>             adding Igor, Michael, Marcel, and qemu-devel.
> 
>             On 07/20/20 11:06, vit9696 wrote:
> 
>                 Hello,
> 
>                 I discovered an issue with inconsistent QEMU/OVMF device paths,
>                 and
>                 while I am unsure whether directing this e-mail is appropriate
>                 to you,
>                 I believe that you likely have the contacts you could forward
>                 this
>                 e-mail to.
> 
>                 macOS uses ACPI UIDs to build the DevicePath for NVRAM boot
>                 options,
>                 while OVMF firmware gets them via an internal channel through
>                 QEMU.
>                 Due to a bug in QEMU (or OVMF) currently UEFI firmware and ACPI
>                 have
>                 different values, and this makes the underlying operating
>                 system
>                 unable to report its boot option.
> 
>                 The particular node in question is the primary PciRoot (PCI0 in
>                 ACPI),
>                 which for some reason gets assigned 1 in ACPI UID and 0 in the
>                 DevicePath. To me this looks like a bug here:
>                 https://github.com/qemu/qemu/blob/8f06f22/hw/i386/acpi-build.c#
>                 L1511-L1515
>                 Which does not correspond to the primary PCI identifier here:
>                 https://github.com/qemu/qemu/blob/5a79d10/hw/pci/pci.c#
>                 L160-L162
> 
>                 Reference with the device paths, OVMF startup logs, and ACPI
>                 table
>                 dumps (SysReport):
>                 https://github.com/acidanthera/bugtracker/issues/1050
> 
>                 Would you be able to forward this to the right people or
>                 perhaps keep
>                 an eye on the issue itself?
> 
> 
>             I think you are right.
> 
>             In UEFI v2.8, section "10.4.2 Rules with ACPI _HID and _UID" ends
>             with
>             the paragraph,
> 
>                Root PCI bridges will use the plug and play ID of PNP0A03, This
>             will
>                be stored in the ACPI Device Path _HID field, or in the Expanded
>                ACPI Device Path _CID field to match the ACPI name space. The
>             _UID
>                in the ACPI Device Path structure must match the _UID in the
>             ACPI
>                name space.
> 
>             (See especially the last sentence.)
> 
>             Considering *extra* root bridges / root buses (with bus number >
>             0),
>             QEMU's ACPI generator actually does the right thing; since QEMU
>             commit
>             c96d9286a6d7 ("i386/acpi-build: more traditional _UID and _HID for
>             PXB
>             root buses", 2015-06-11).
> 
>             However, the _UID values for root bridge zero (on both i440fx and
>             q35)
>             have always been "wrong" (from UEFI perspective), going back in
>             QEMU to
>             commit 74523b850189 ("i386: add ACPI table files from seabios",
>             2013-10-14).
> 
>             Even in SeaBIOS, these _UID values have always been 1; see commit
>             a4d357638c57 ("Port rombios32 code from bochs-bios.", 2008-03-08)
>             for
>             i440fx, and commit ecbe3fd61511 ("seabios: q35: add dsdt",
>             2012-12-01)
>             for q35.
> 
>             Does the following patch work for you? (I can see you proposed the
>             same
>             in
>             <https://github.com/acidanthera/bugtracker/issues/1050
>             issuecomment-660734139>)
> 
> 
>                 diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
>                 index b7bcbbbb2a35..7a5a8b3521b0 100644
>                 --- a/hw/i386/acpi-build.c
>                 +++ b/hw/i386/acpi-build.c
>                 @@ -1496,9 +1496,9 @@ build_dsdt(GArray *table_data, BIOSLinker
>                 *linker,
>                         sb_scope = aml_scope("_SB");
>                         dev = aml_device("PCI0");
>                         aml_append(dev, aml_name_decl("_HID", aml_eisaid
>                 ("PNP0A03")));
>                         aml_append(dev, aml_name_decl("_ADR", aml_int(0)));
>                 -        aml_append(dev, aml_name_decl("_UID", aml_int(1)));
>                 +        aml_append(dev, aml_name_decl("_UID", aml_int(0)));
>                         aml_append(sb_scope, dev);
>                         aml_append(dsdt, sb_scope);
> 
>                         build_hpet_aml(dsdt);
>                 @@ -1511,9 +1511,9 @@ build_dsdt(GArray *table_data, BIOSLinker
>                 *linker,
>                         dev = aml_device("PCI0");
>                         aml_append(dev, aml_name_decl("_HID", aml_eisaid
>                 ("PNP0A08")));
>                         aml_append(dev, aml_name_decl("_CID", aml_eisaid
>                 ("PNP0A03")));
>                         aml_append(dev, aml_name_decl("_ADR", aml_int(0)));
>                 -        aml_append(dev, aml_name_decl("_UID", aml_int(1)));
>                 +        aml_append(dev, aml_name_decl("_UID", aml_int(0)));
>                         aml_append(dev, build_q35_osc_method());
>                         aml_append(sb_scope, dev);
>                         aml_append(dsdt, sb_scope);
> 
> 
>             If it does, I suggest submitting the above patch to qemu-devel, and
>             /or
>             filing a bug for upstream QEMU at <https://bugs.launchpad.net/qemu/
>             >.
> 
> 
>         Or even just reporting whether the above helps you, we can
>         take it from there.
> 
> 
>             (Note: I didn't even compile the above change.)
> 
>             Thanks
>             Laszlo
> 
> 
> 
> 
>