Re: [Qemu-devel] [PATCH] pcie: set link state inactive/active after hot unplug/plug

[Marcel Apfelbaum]

On 12/3/18 9:05 AM, Zheng Xiang wrote:
> When VM boots from the latest version of linux kernel, after
> hot-unpluging virtio-blk disks which are hotplugged into
> pcie-root-port, the VM's dmesg log shows:
>
> [  151.046242] pciehp 0000:00:05.0:pcie004: pending interrupts 0x0001 from Slot 
> Status
> [  151.046365] pciehp 0000:00:05.0:pcie004: Slot(0-3): Attention button pressed
> [  151.046369] pciehp 0000:00:05.0:pcie004: Slot(0-3): Powering off due to 
> button press
> [  151.046420] pciehp 0000:00:05.0:pcie004: pending interrupts 0x0010 from Slot 
> Status
> [  151.046425] pciehp 0000:00:05.0:pcie004: pciehp_green_led_blink: SLOTCTRL a8 
> write cmd 200
> [  151.046464] pciehp 0000:00:05.0:pcie004: pending interrupts 0x0010 from Slot 
> Status
> [  151.046468] pciehp 0000:00:05.0:pcie004: pciehp_set_attention_status: 
> SLOTCTRL a8 write cmd c0
> [  156.163421] pciehp 0000:00:05.0:pcie004: pciehp_get_power_status: SLOTCTRL 
> a8 value read 2f1
> [  156.163427] pciehp 0000:00:05.0:pcie004: pciehp_unconfigure_device: 
> domain:bus:dev = 0000:06:00
> [  156.198736] pciehp 0000:00:05.0:pcie004: pending interrupts 0x0010 from Slot 
> Status
> [  156.198772] pciehp 0000:00:05.0:pcie004: pciehp_power_off_slot: SLOTCTRL a8 
> write cmd 400
> [  157.224124] pciehp 0000:00:05.0:pcie004: pending interrupts 0x0018 from Slot 
> Status
> [  157.224194] pciehp 0000:00:05.0:pcie004: pciehp_green_led_off: SLOTCTRL a8 
> write cmd 300
> [  157.224220] pciehp 0000:00:05.0:pcie004: pciehp_check_link_active: 
> lnk_status = 2011
> [  157.224223] pciehp 0000:00:05.0:pcie004: Slot(0-3): Link Up
> [  157.224233] pciehp 0000:00:05.0:pcie004: pciehp_get_power_status: SLOTCTRL 
> a8 value read 7f1
> [  157.224281] pciehp 0000:00:05.0:pcie004: pending interrupts 0x0010 from Slot 
> Status
> [  157.224285] pciehp 0000:00:05.0:pcie004: pciehp_power_on_slot: SLOTCTRL a8 
> write cmd 0
> [  157.224300] pciehp 0000:00:05.0:pcie004: __pciehp_link_set: lnk_ctrl = 0
> [  157.224336] pciehp 0000:00:05.0:pcie004: pending interrupts 0x0010 from Slot 
> Status
> [  157.224339] pciehp 0000:00:05.0:pcie004: pciehp_green_led_blink: SLOTCTRL a8 
> write cmd 200
> [  159.739294] pci 0000:06:00.0 id reading try 50 times with interval 20 ms to 
> get ffffffff
> [  159.739315] pciehp 0000:00:05.0:pcie004: pciehp_check_link_status: 
> lnk_status = 2011
> [  159.739318] pciehp 0000:00:05.0:pcie004: Failed to check link status
> [  159.739371] pciehp 0000:00:05.0:pcie004: pending interrupts 0x0010 from Slot 
> Status
> [  159.739394] pciehp 0000:00:05.0:pcie004: pciehp_power_off_slot: SLOTCTRL a8 
> write cmd 400
> [  160.771426] pciehp 0000:00:05.0:pcie004: pending interrupts 0x0010 from Slot 
> Status
> [  160.771452] pciehp 0000:00:05.0:pcie004: pciehp_green_led_off: SLOTCTRL a8 
> write cmd 300
> [  160.771495] pciehp 0000:00:05.0:pcie004: pending interrupts 0x0010 from Slot 
> Status
> [  160.771499] pciehp 0000:00:05.0:pcie004: pciehp_set_attention_status: 
> SLOTCTRL a8 write cmd 40
> [  160.771535] pciehp 0000:00:05.0:pcie004: pending interrupts 0x0010 from Slot 
> Status
> [  160.771539] pciehp 0000:00:05.0:pcie004: pciehp_green_led_off: SLOTCTRL a8 
> write cmd 300
>
> After analyzing the log information, it seems that qemu doesn't
> change the Link Status from active to inactive after hot-unplug.
> This results in the abnormal log after the linux kernel commit
> d331710ea78fea merged.
>
> Furthermore, If I hotplug the same virtio-blk disk after hot-unplug,
> the virtio-blk would turn on and then back off.
>
> So this patch set the Link Status inactive after hot-unplug and
> active after hot-plug.
>
> Signed-off-by: Zheng Xiang <address@hidden>
> Signed-off-by: Zheng Xiang <address@hidden>
> Cc: Wang Haibin <address@hidden>
> ---
>   hw/pci/pcie.c | 12 ++++++++++++
>   1 file changed, 12 insertions(+)
>
> diff --git a/hw/pci/pcie.c b/hw/pci/pcie.c
> index 6c91bd4..66b73b8 100644
> --- a/hw/pci/pcie.c
> +++ b/hw/pci/pcie.c
> @@ -345,6 +345,10 @@ void pcie_cap_slot_hotplug_cb(HotplugHandler *hotplug_dev, 
> DeviceState *dev,
>       if (!dev->hotplugged) {
>           pci_word_test_and_set_mask(exp_cap + PCI_EXP_SLTSTA,
>                                      PCI_EXP_SLTSTA_PDS);
> +        if (pci_dev->cap_present & QEMU_PCIE_LNKSTA_DLLLA) {
> +            pci_word_test_and_set_mask(exp_cap + PCI_EXP_LNKSTA,
> +                                       PCI_EXP_LNKSTA_DLLLA);
> +        }
>           return;
>       }
>   
> @@ -355,6 +359,10 @@ void pcie_cap_slot_hotplug_cb(HotplugHandler *hotplug_dev, DeviceState *dev,
>       if (pci_get_function_0(pci_dev)) {
>           pci_word_test_and_set_mask(exp_cap + PCI_EXP_SLTSTA,
>                                      PCI_EXP_SLTSTA_PDS);
> +        if (pci_dev->cap_present & QEMU_PCIE_LNKSTA_DLLLA) {
> +            pci_word_test_and_set_mask(exp_cap + PCI_EXP_LNKSTA,
> +                                       PCI_EXP_LNKSTA_DLLLA);
> +        }
>           pcie_cap_slot_event(PCI_DEVICE(hotplug_dev),
>                               PCI_EXP_HP_EV_PDC | PCI_EXP_HP_EV_ABP);
>       }
> @@ -531,6 +539,10 @@ void pcie_cap_slot_write_config(PCIDevice *dev,
>   
>           pci_word_test_and_clear_mask(exp_cap + PCI_EXP_SLTSTA,
>                                        PCI_EXP_SLTSTA_PDS);
> +        if (dev->cap_present & QEMU_PCIE_LNKSTA_DLLLA) {
> +            pci_word_test_and_clear_mask(exp_cap + PCI_EXP_LNKSTA,
> +                                         PCI_EXP_LNKSTA_DLLLA);
> +        }
>           pci_word_test_and_set_mask(exp_cap + PCI_EXP_SLTSTA,
>                                          PCI_EXP_SLTSTA_PDC);
>       }

Looks good to me,

Reviewed-by: Marcel Apfelbaum<address@hidden>
Thanks,
Marcel