Re: [PATCH v11 1/2] virtio-pci: only reset pm state during resetting

[Chen, Jiqian]

Hi MST,

On 2024/6/6 18:22, Jiqian Chen wrote:
> Fix bug imported by 27ce0f3afc9dd ("fix Power Management Control Register for 
> PCI Express virtio devices"
> After this change, observe that QEMU may erroneously clear the power status 
> of the device,
> or may erroneously clear non writable registers, such as NO_SOFT_RESET, etc.
> 
> Only state of PM_CTRL is writable.
> Only when flag VIRTIO_PCI_FLAG_INIT_PM is set, need to reset state.
> 
> Fixes: 27ce0f3afc9dd ("fix Power Management Control Register for PCI Express 
> virtio devices"
> 
> Signed-off-by: Jiqian Chen <Jiqian.Chen@amd.com>
> ---
>  hw/virtio/virtio-pci.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
> index b1d02f4b3de0..1b63bcb3f15c 100644
> --- a/hw/virtio/virtio-pci.c
> +++ b/hw/virtio/virtio-pci.c
> @@ -2300,10 +2300,16 @@ static void virtio_pci_bus_reset_hold(Object *obj, 
> ResetType type)
>      virtio_pci_reset(qdev);
>  
>      if (pci_is_express(dev)) {
> +        VirtIOPCIProxy *proxy = VIRTIO_PCI(dev);
> +
>          pcie_cap_deverr_reset(dev);
>          pcie_cap_lnkctl_reset(dev);
>  
> -        pci_set_word(dev->config + dev->exp.pm_cap + PCI_PM_CTRL, 0);
> +        if (proxy->flags & VIRTIO_PCI_FLAG_INIT_PM) {
> +            pci_word_test_and_clear_mask(
> +                dev->config + dev->exp.pm_cap + PCI_PM_CTRL,
> +                PCI_PM_CTRL_STATE_MASK);
> +        }
>      }
>  }
>  
I noticed that you merged this patch into the staging before, but then reverted 
it. Do you still have any concerns?

-- 
Best regards,
Jiqian Chen.