Re: [PATCH] hw/pci: add comment explaining the reason for checking function 0 in hotplug

[Michael S. Tsirkin]

On Tue, Jun 20, 2023 at 07:55:51PM +0530, Ani Sinha wrote:
> This change is cosmetic. A comment is added explaining why we need to check 
> for
> the availability of function 0 when we hotplug a device.
> 
> CC: m...@redhat.com
> Signed-off-by: Ani Sinha 
> ---
>  hw/pci/pci.c | 5 +
>  1 file changed, 5 insertions(+)
> 
> diff --git a/hw/pci/pci.c b/hw/pci/pci.c
> index bf38905b7d..847e534f68 100644
> --- a/hw/pci/pci.c
> +++ b/hw/pci/pci.c
> @@ -1179,6 +1179,11 @@ static PCIDevice *do_pci_register_device(PCIDevice 
> *pci_dev,
> PCI_SLOT(devfn), PCI_FUNC(devfn), name,
> bus->devices[devfn]->name, bus->devices[devfn]->qdev.id);
>  return NULL;
> +/*
> + * Populating function 0 triggers a scan from the guest that
> + * exposes other non-zero functions. Hence we need to ensure that
> + * function 0 wasn't added yet.
> + */

bad place for the comment

>  }


stick the comment here

> else

or here

> if (dev->hotplugged &&
> !pci_is_vf(pci_dev) &&
> pci_get_function_0(pci_dev)) {
> -- 
> 2.39.1

[PATCH] hw/pci: add comment explaining the reason for checking function 0 in hotplug

[Ani Sinha]

This change is cosmetic. A comment is added explaining why we need to check for
the availability of function 0 when we hotplug a device.

CC: m...@redhat.com
Signed-off-by: Ani Sinha 
---
 hw/pci/pci.c | 5 +
 1 file changed, 5 insertions(+)

diff --git a/hw/pci/pci.c b/hw/pci/pci.c
index bf38905b7d..847e534f68 100644
--- a/hw/pci/pci.c
+++ b/hw/pci/pci.c
@@ -1179,6 +1179,11 @@ static PCIDevice *do_pci_register_device(PCIDevice 
*pci_dev,
PCI_SLOT(devfn), PCI_FUNC(devfn), name,
bus->devices[devfn]->name, bus->devices[devfn]->qdev.id);
 return NULL;
+/*
+ * Populating function 0 triggers a scan from the guest that
+ * exposes other non-zero functions. Hence we need to ensure that
+ * function 0 wasn't added yet.
+ */
 } else if (dev->hotplugged &&
!pci_is_vf(pci_dev) &&
pci_get_function_0(pci_dev)) {
-- 
2.39.1