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Re: OVMF and PCI0 UID
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From: |
Michael S. Tsirkin |
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Subject: |
Re: OVMF and PCI0 UID |
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Date: |
Thu, 30 Jul 2020 11:59:18 -0400 |
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
>
>
>
>
>