On Thu, Jun 17, 2021 at 09:07:32PM +0200, Julia Suvorova wrote:
> The patch set consists of two parts:
> patches 1-4: introduce new feature
> 'acpi-pci-hotplug-with-bridge-support' on Q35
> patches 5-7: make the feature default along with changes in ACPI tables
>
> With the feature disabled Q35 falls back to the native hot-plug.
>
> Pros
> * no racy behavior during boot (see 110c477c2ed)
> * eject is possible - according to PCIe spec, attention button
> press should lead to power off, and then the adapter should be
> removed manually. As there is no power down state exists in QEMU,
> we cannot distinguish between an eject and a power down
> request.
> * no delay during deleting - after the actual power off software
> must wait at least 1 second before indicating about it. This case
> is quite important for users, it even has its own bug:
> https://bugzilla.redhat.com/show_bug.cgi?id=1594168
> * no timer-based behavior - in addition to the previous example,
> the attention button has a 5-second waiting period, during which
> the operation can be canceled with a second press. While this
> looks fine for manual button control, automation will result in
> the need to queue or drop events, and the software receiving
> events in all sort of unspecified combinations of attention/power
> indicator states, which is racy and uppredictable.
> * fixes or reduces the likelihood of the bugs:
> * https://bugzilla.redhat.com/show_bug.cgi?id=1833187
> * https://bugzilla.redhat.com/show_bug.cgi?id=1657077
> * https://bugzilla.redhat.com/show_bug.cgi?id=1669931
> * https://bugzilla.redhat.com/show_bug.cgi?id=1678290
>
> Cons:
> * no access to possible features presented in slot capabilities
> (this is only surprise removal AFAIK)
This all looks quite nice to me.
Let's give people a bit of time for review, then I'll merge.
> v5:
> * make sugar property on TYPE_PCIE_SLOT
> instead of old TYPE_MACHINE property [Igor]
> * minor style changes
> v4:
> * regain per-port control over hot-plug
> * rebased over acpi-index changes
> * set property on machine type to
> make pci code more generic [Igor, Michael]
>
> v3:
> * drop change of _OSC to allow SHPC on hotplugged bridges
> * use 'acpi-root-pci-hotplug'
> * add migration states [Igor]
> * minor style changes
>
> v2:
> * new ioport range for acpiphp [Gerd]
> * drop find_pci_host() [Igor]
> * explain magic numbers in _OSC [Igor]
> * drop build_q35_pci_hotplug() wrapper [Igor]
>
> Julia Suvorova (7):
> hw/acpi/pcihp: Enhance acpi_pcihp_disable_root_bus() to support Q35
> hw/i386/acpi-build: Add ACPI PCI hot-plug methods to Q35
> hw/acpi/ich9: Enable ACPI PCI hot-plug
> hw/pci/pcie: Do not set HPC flag if acpihp is used
> bios-tables-test: Allow changes in DSDT ACPI tables
> hw/acpi/ich9: Set ACPI PCI hot-plug as default on Q35
> bios-tables-test: Update golden binaries
>
> hw/i386/acpi-build.h | 5 +++
> include/hw/acpi/ich9.h | 5 +++
> include/hw/acpi/pcihp.h | 3 +-
> include/hw/pci/pcie_port.h | 5 ++-
> hw/acpi/ich9.c | 67 ++++++++++++++++++++++++++++++
> hw/acpi/pcihp.c | 22 +++++++---
> hw/acpi/piix4.c | 4 +-
> hw/core/machine.c | 1 -
> hw/i386/acpi-build.c | 32 ++++++++------
> hw/i386/pc.c | 1 +
> hw/i386/pc_q35.c | 11 +++++
> hw/pci/pcie.c | 8 +++-
> hw/pci/pcie_port.c | 1 +
> tests/data/acpi/q35/DSDT | Bin 7859 -> 8289 bytes
> tests/data/acpi/q35/DSDT.acpihmat | Bin 9184 -> 9614 bytes
> tests/data/acpi/q35/DSDT.bridge | Bin 7877 -> 11003 bytes
> tests/data/acpi/q35/DSDT.cphp | Bin 8323 -> 8753 bytes
> tests/data/acpi/q35/DSDT.dimmpxm | Bin 9513 -> 9943 bytes
> tests/data/acpi/q35/DSDT.ipmibt | Bin 7934 -> 8364 bytes
> tests/data/acpi/q35/DSDT.memhp | Bin 9218 -> 9648 bytes
> tests/data/acpi/q35/DSDT.mmio64 | Bin 8990 -> 9419 bytes
> tests/data/acpi/q35/DSDT.nohpet | Bin 7717 -> 8147 bytes
> tests/data/acpi/q35/DSDT.numamem | Bin 7865 -> 8295 bytes
> tests/data/acpi/q35/DSDT.tis | Bin 8465 -> 8894 bytes
> 24 files changed, 143 insertions(+), 22 deletions(-)
>
> --
> 2.30.2