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Re: [PATCH v6 3/6] failover: fix unplug pending detection
From: |
Ani Sinha |
Subject: |
Re: [PATCH v6 3/6] failover: fix unplug pending detection |
Date: |
Tue, 7 Dec 2021 09:43:28 +0530 (IST) |
User-agent: |
Alpine 2.22 (DEB 394 2020-01-19) |
On Mon, 6 Dec 2021, Laurent Vivier wrote:
> Failover needs to detect the end of the PCI unplug to start migration
> after the VFIO card has been unplugged.
>
> To do that, a flag is set in pcie_cap_slot_unplug_request_cb() and reset in
> pcie_unplug_device().
>
> But since
> 17858a169508 ("hw/acpi/ich9: Set ACPI PCI hot-plug as default on Q35")
> we have switched to ACPI unplug and these functions are not called anymore
> and the flag not set. So failover migration is not able to detect if card
> is really unplugged and acts as it's done as soon as it's started. So it
> doesn't wait the end of the unplug to start the migration. We don't see any
> problem when we test that because ACPI unplug is faster than PCIe native
> hotplug and when the migration really starts the unplug operation is
> already done.
>
> See c000a9bd06ea ("pci: mark device having guest unplug request pending")
> a99c4da9fc2a ("pci: mark devices partially unplugged")
>
This has already been merged upstream:
https://git.qemu.org/?p=qemu.git;a=commit;h=9323f892b39d133eb69b301484bf7b2f3f49737d
Not sure why you resent this one.
> Signed-off-by: Laurent Vivier <lvivier@redhat.com>
> Reviewed-by: Ani Sinha <ani@anisinha.ca>
> ---
> hw/acpi/pcihp.c | 30 +++++++++++++++++++++++++++---
> 1 file changed, 27 insertions(+), 3 deletions(-)
>
> diff --git a/hw/acpi/pcihp.c b/hw/acpi/pcihp.c
> index f610a25d2ef9..30405b5113d7 100644
> --- a/hw/acpi/pcihp.c
> +++ b/hw/acpi/pcihp.c
> @@ -222,9 +222,27 @@ static void acpi_pcihp_eject_slot(AcpiPciHpState *s,
> unsigned bsel, unsigned slo
> PCIDevice *dev = PCI_DEVICE(qdev);
> if (PCI_SLOT(dev->devfn) == slot) {
> if (!acpi_pcihp_pc_no_hotplug(s, dev)) {
> - hotplug_ctrl = qdev_get_hotplug_handler(qdev);
> - hotplug_handler_unplug(hotplug_ctrl, qdev, &error_abort);
> - object_unparent(OBJECT(qdev));
> + /*
> + * partially_hotplugged is used by virtio-net failover:
> + * failover has asked the guest OS to unplug the device
> + * but we need to keep some references to the device
> + * to be able to plug it back in case of failure so
> + * we don't execute hotplug_handler_unplug().
> + */
> + if (dev->partially_hotplugged) {
> + /*
> + * pending_deleted_event is set to true when
> + * virtio-net failover asks to unplug the device,
> + * and set to false here when the operation is done
> + * This is used by the migration loop to detect the
> + * end of the operation and really start the migration.
> + */
> + qdev->pending_deleted_event = false;
> + } else {
> + hotplug_ctrl = qdev_get_hotplug_handler(qdev);
> + hotplug_handler_unplug(hotplug_ctrl, qdev, &error_abort);
> + object_unparent(OBJECT(qdev));
> + }
> }
> }
> }
> @@ -396,6 +414,12 @@ void acpi_pcihp_device_unplug_request_cb(HotplugHandler
> *hotplug_dev,
> return;
> }
>
> + /*
> + * pending_deleted_event is used by virtio-net failover to detect the
> + * end of the unplug operation, the flag is set to false in
> + * acpi_pcihp_eject_slot() when the operation is completed.
> + */
> + pdev->qdev.pending_deleted_event = true;
> s->acpi_pcihp_pci_status[bsel].down |= (1U << slot);
> acpi_send_event(DEVICE(hotplug_dev), ACPI_PCI_HOTPLUG_STATUS);
> }
> --
> 2.33.1
>
>
- [PATCH v6 0/6] tests/qtest: add some tests for virtio-net failover, Laurent Vivier, 2021/12/06
- [PATCH v6 1/6] qtest/libqos: add a function to initialize secondary PCI buses, Laurent Vivier, 2021/12/06
- [PATCH v6 2/6] tests/qtest: add some tests for virtio-net failover, Laurent Vivier, 2021/12/06
- [PATCH v6 3/6] failover: fix unplug pending detection, Laurent Vivier, 2021/12/06
- Re: [PATCH v6 3/6] failover: fix unplug pending detection,
Ani Sinha <=
- [PATCH v6 4/6] tests/libqtest: update virtio-net failover test, Laurent Vivier, 2021/12/06
- [PATCH v6 5/6] test/libqtest: add some virtio-net failover migration cancelling tests, Laurent Vivier, 2021/12/06
- [PATCH v6 6/6] tests/libqtest: add a migration test with two couples of failover devices, Laurent Vivier, 2021/12/06