Re: [Qemu-devel] KVM call agenda for 2013-06-11
On Tue, Jun 04, 2013 at 04:24:31PM +0300, Michael S. Tsirkin wrote: Juan is not available now, and Anthony asked for agenda to be sent early. So here comes: Agenda for the meeting Tue, June 11: - Generating acpi tables, redux Not so much notes as a quick summary of the call: There are the following reasons to generate ACPI tables in QEMU: - sharing code with e.g. ovmf Anthony thinks this is not a valid argument - so we can make tables more dynamic and move away from iasl Anthony thinks this is not a valid reason too, since qemu and seabios have access to same info MST noted several info not accessible to bios. Anthony said they can be added, e.g. by exposing QOM to the bios. - even though most tables are static, hardcoded they are likely to change over time Anthony sees this as justified To summarize, there's a concensus now that generating ACPI tables in QEMU is a good idea. Two issues that need to be addressed: - original patches break cross-version migration. Need to fix that. - Anthony requested that patchset is merged together with some new feature. I'm not sure the reasoning is clear: current a version intentionally generates tables that are bug for bug compatible with seabios, to simplify testing. It seems clear we have users for this such as hotplug of devices behind pci bridges, so why keep the infrastructure out of tree? Looking for something additional, smaller as the hotplug patch is a bit big, so might delay merging. Going forward - would we want to move smbios as well? Everyone seems to think it's a good idea. -- MST
Re: [Qemu-devel] KVM call agenda for 2013-06-11
On 06/11/13 17:45, Michael S. Tsirkin wrote: To summarize, there's a concensus now that generating ACPI tables in QEMU is a good idea. Two issues that need to be addressed: - original patches break cross-version migration. Need to fix that. - Anthony requested that patchset is merged together with some new feature. I'm not sure the reasoning is clear: current a version intentionally generates tables that are bug for bug compatible with seabios, to simplify testing. Sorry about not following the series more closely -- is there now a qemu interface available that allows any firmware just take the tables, maybe to fix them up blindly / algorithmically, and to install them? IOW, is the interface at such a point that in OVMF we could start looking throwing out specific code, in favor of implementing the generic fw-side algorithm? It seems clear we have users for this such as hotplug of devices behind pci bridges, so why keep the infrastructure out of tree? Looking for something additional, smaller as the hotplug patch is a bit big, so might delay merging. Going forward - would we want to move smbios as well? Everyone seems to think it's a good idea. I think the current fw_cfg interface for SMBIOS tables is already good enough to save a lot of work in OVMF. Namely, if all required tables were generated (table template + field-wise patching) in qemu, and then all exported over fw_cfg as verbatim tables, my SMBIOS series currently pending for OVMF should be able to install them. This would save OVMF the coding of templates (and any necessary patching) for types 3, 4 (especially nasty), 9, 16, 17, 19, and 32. (Basically all except type 0 and type 1, which are already implemented (but verbatim tables from qemu would take priority even for type 0 and type 1). Type 7 can be left out apparently; IIRC dmidecode doesn't report it even under SeaBIOS.) I'm not implying anyone should start working on this (myself included :)), but yeah, moving SMBIOS would save work in OVMF. (Provided there was any reason to support said SMBIOS tables in OVMF :)) Thanks, Laszlo
Re: [Qemu-devel] KVM call agenda for 2013-06-11
Michael S. Tsirkin m...@redhat.com writes: On Tue, Jun 04, 2013 at 04:24:31PM +0300, Michael S. Tsirkin wrote: Juan is not available now, and Anthony asked for agenda to be sent early. So here comes: Agenda for the meeting Tue, June 11: - Generating acpi tables, redux Not so much notes as a quick summary of the call: There are the following reasons to generate ACPI tables in QEMU: - sharing code with e.g. ovmf Anthony thinks this is not a valid argument - so we can make tables more dynamic and move away from iasl Anthony thinks this is not a valid reason too, since qemu and seabios have access to same info MST noted several info not accessible to bios. Anthony said they can be added, e.g. by exposing QOM to the bios. - even though most tables are static, hardcoded they are likely to change over time Anthony sees this as justified To summarize, there's a concensus now that generating ACPI tables in QEMU is a good idea. I would say best worst idea ;-) I am deeply concerned about the complexity it introduces but I don't see many other options. Two issues that need to be addressed: - original patches break cross-version migration. Need to fix that. - Anthony requested that patchset is merged together with some new feature. I'm not sure the reasoning is clear: current a version intentionally generates tables that are bug for bug compatible with seabios, to simplify testing. I expect that there will be additional issues that need to be worked out and want to see a feature that actually uses the infrastructure before we add it. It seems clear we have users for this such as hotplug of devices behind pci bridges, so why keep the infrastructure out of tree? It's hard to evaluate the infrastructure without a user. Looking for something additional, smaller as the hotplug patch is a bit big, so might delay merging. Going forward - would we want to move smbios as well? Everyone seems to think it's a good idea. Yes, independent of ACPI, I think QEMU should be generating the SMBIOS tables. Regards, Anthony Liguori -- MST
Re: [Qemu-devel] KVM call agenda for 2013-06-11
On Tue, Jun 11, 2013 at 08:06:15PM +0200, Laszlo Ersek wrote: On 06/11/13 17:45, Michael S. Tsirkin wrote: To summarize, there's a concensus now that generating ACPI tables in QEMU is a good idea. Two issues that need to be addressed: - original patches break cross-version migration. Need to fix that. - Anthony requested that patchset is merged together with some new feature. I'm not sure the reasoning is clear: current a version intentionally generates tables that are bug for bug compatible with seabios, to simplify testing. Sorry about not following the series more closely -- is there now a qemu interface available that allows any firmware just take the tables, maybe to fix them up blindly / algorithmically, and to install them? Yes. IOW, is the interface at such a point that in OVMF we could start looking throwing out specific code, in favor of implementing the generic fw-side algorithm? It seems clear we have users for this such as hotplug of devices behind pci bridges, so why keep the infrastructure out of tree? Looking for something additional, smaller as the hotplug patch is a bit big, so might delay merging. Going forward - would we want to move smbios as well? Everyone seems to think it's a good idea. I think the current fw_cfg interface for SMBIOS tables is already good enough to save a lot of work in OVMF. Namely, if all required tables were generated (table template + field-wise patching) in qemu, and then all exported over fw_cfg as verbatim tables, my SMBIOS series currently pending for OVMF should be able to install them. This would save OVMF the coding of templates (and any necessary patching) for types 3, 4 (especially nasty), 9, 16, 17, 19, and 32. (Basically all except type 0 and type 1, which are already implemented (but verbatim tables from qemu would take priority even for type 0 and type 1). Type 7 can be left out apparently; IIRC dmidecode doesn't report it even under SeaBIOS.) I'm not implying anyone should start working on this (myself included :)), but yeah, moving SMBIOS would save work in OVMF. (Provided there was any reason to support said SMBIOS tables in OVMF :)) Thanks, Laszlo
Re: [Qemu-devel] KVM call agenda for 2013-06-11
On Tue, Jun 11, 2013 at 01:38:11PM -0500, Anthony Liguori wrote: Michael S. Tsirkin m...@redhat.com writes: On Tue, Jun 04, 2013 at 04:24:31PM +0300, Michael S. Tsirkin wrote: Juan is not available now, and Anthony asked for agenda to be sent early. So here comes: Agenda for the meeting Tue, June 11: - Generating acpi tables, redux Not so much notes as a quick summary of the call: There are the following reasons to generate ACPI tables in QEMU: - sharing code with e.g. ovmf Anthony thinks this is not a valid argument - so we can make tables more dynamic and move away from iasl Anthony thinks this is not a valid reason too, since qemu and seabios have access to same info MST noted several info not accessible to bios. Anthony said they can be added, e.g. by exposing QOM to the bios. - even though most tables are static, hardcoded they are likely to change over time Anthony sees this as justified To summarize, there's a concensus now that generating ACPI tables in QEMU is a good idea. I would say best worst idea ;-) I am deeply concerned about the complexity it introduces but I don't see many other options. Two issues that need to be addressed: - original patches break cross-version migration. Need to fix that. - Anthony requested that patchset is merged together with some new feature. I'm not sure the reasoning is clear: current a version intentionally generates tables that are bug for bug compatible with seabios, to simplify testing. I expect that there will be additional issues that need to be worked out and want to see a feature that actually uses the infrastructure before we add it. So please look at it, that code has been posted. See: [PATCH] qemu: piix: PCI bridge ACPI hotplug support it does not seem to show any major issues to work out besides the cross-version migration issue that we know about. It seems clear we have users for this such as hotplug of devices behind pci bridges, so why keep the infrastructure out of tree? It's hard to evaluate the infrastructure without a user. But the user has been posted, even if there are still issues to work out with it, that should be enough to evaluate the infrastructure - the user itself does not need to be merged for this. So please evaluate and give feedback. Looking for something additional, smaller as the hotplug patch is a bit big, so might delay merging. Going forward - would we want to move smbios as well? Everyone seems to think it's a good idea. Yes, independent of ACPI, I think QEMU should be generating the SMBIOS tables. Regards, Anthony Liguori -- MST
Re: [Qemu-devel] KVM call agenda for 2013-06-11
On Tue, Jun 04, 2013 at 04:24:31PM +0300, Michael S. Tsirkin wrote: Juan is not available now, and Anthony asked for agenda to be sent early. So here comes: Agenda for the meeting Tue, June 11: - Generating acpi tables, redux I've just posted a proof of concept patch on list, as promised. Since Anthony (apparently, alone?) is objecting to this on principle I don't think there's need to spend time testing it at this stage: I'd like to use the meeting to discuss the requirements coming from ACPI spec and how this patch addresses them, and how generating the SSDT table in qemu makes life easier, and would be awkward in the bios. Also, to address comments raised on the previous conf call. I hope that at the end of the meeting we'll be able to arrive at concensus opinion re the usefulness of supplying ACPI tables to guests (on PC only). Please, send any topic that you are interested in covering. Thanks, MST -- MST
[Qemu-devel] KVM call agenda for 2013-06-11
Juan is not available now, and Anthony asked for agenda to be sent early. So here comes: Agenda for the meeting Tue, June 11: - Generating acpi tables, redux Please, send any topic that you are interested in covering. Thanks, MST -- MST
