On 7/21/21 4:59 PM, Igor Mammedov wrote:
> On Tue, 20 Jul 2021 14:56:06 +0200
> Laurent Vivier <[email protected]> wrote:
>> On 20/07/2021 13:38, Laurent Vivier wrote:
>>> On 16/07/2021 17:15, Michael S. Tsirkin wrote:
>>>> From: Julia Suvorova <[email protected]>
>>>>
>>>> Q35 has three different types of PCI devices hot-plug: PCIe Native,
>>>> SHPC Native and ACPI hot-plug. This patch changes the default choice
>>>> for cold-plugged bridges from PCIe Native to ACPI Hot-plug with
>>>> ability to use SHPC and PCIe Native for hot-plugged bridges.
>>>>
>>>> This is a list of the PCIe Native hot-plug issues that led to this
>>>> change:
>>>> * no racy behavior during boot (see 110c477c2ed)
>>>> * 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:
>>>> * https://bugzilla.redhat.com/show_bug.cgi?id=1752465
>>>> * https://bugzilla.redhat.com/show_bug.cgi?id=1690256
>>>>
>>>> To return to PCIe Native hot-plug:
>>>> -global ICH9-LPC.acpi-pci-hotplug-with-bridge-support=off
>>>>
>>>> Known issue: older linux guests need the following flag
>>>> to allow hotplugged pci express devices to use io:
>>>> -device pcie-root-port,io-reserve=4096.
>>>> io is unusual for pci express so this seems minor.
>>>> We'll fix this by a follow up patch.
>>>>
>>>> Signed-off-by: Julia Suvorova <[email protected]>
>>>> Reviewed-by: Igor Mammedov <[email protected]>
>>>> Message-Id: <[email protected]>
>>>> Reviewed-by: Michael S. Tsirkin <[email protected]>
>>>> Signed-off-by: Michael S. Tsirkin <[email protected]>
>>>> Reviewed-by: David Gibson <[email protected]>
>>>> ---
>> It also happens with non-VFIO device like e1000e:
>>
>> ...
>> -device e1000e,bus=pcie-root-port-1,addr=0x0,id=hostdev0 \
> ^^^^^^^^^^^^^
> ACPI hotplug operates on slot level, so functions greater than 0 are not
> considered,
> hence unexpected ACPI error. For above CLI, setting 'addr' on root-ports to
> dedicated slots
> should fix issue.
>
> The same will happen on PC machine if you assign bridge to any function other
> than 0.
>
> Following should fix ACPI error:
>
> diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
> index 17836149fe..e2345bd7d0 100644
> --- a/hw/i386/acpi-build.c
> +++ b/hw/i386/acpi-build.c
> @@ -527,7 +527,7 @@ static void build_append_pci_bus_devices(Aml
> *parent_scope, PCIBus *bus,
> QLIST_FOREACH(sec, &bus->child, sibling) {
> int32_t devfn = sec->parent_dev->devfn;
>
> - if (pci_bus_is_root(sec)) {
> + if (pci_bus_is_root(sec) || PCI_FUNC(devfn)) {
> continue;
> }
>
> but unplug request will stay ignored if root port/bridge is not on function 0.
Shouldn't we emit a warning/error if a such config is used?
