Re: [edk2-devel] [PATCH 1/1] MdeModulePkg: Handle InitialVFs=0 case for SR-IOV

["Ni, Ray" <ray.ni@intel.com>]

Reviewed-by: Ray Ni <ray.ni@intel.com>

> -----Original Message-----
> From: devel@edk2.groups.io <devel@edk2.groups.io> On Behalf Of Foster Nong
> Sent: Thursday, September 29, 2022 5:20 PM
> To: devel@edk2.groups.io
> Cc: Nong, Foster <foster.nong@intel.com>
> Subject: [edk2-devel] [PATCH 1/1] MdeModulePkg: Handle InitialVFs=0 case for SR-IOV
> 
> Per the section 3.3.5 SR-IOV spec v1.1, InitialVFs (0ch).
> InitialVFs indicates to SR-PCIM the number of VFs that are initially associated with the PF.
> The minimum value of InitialVFs is 0.
> 
> Below code is used to calculate SR-IOV reserved bus number,
> if InitialVFs =0, it maybe calculate the wrong bus number in this case.
>   LastVF = PFRid + FirstVFOffset + (PciIoDevice->InitialVFs - 1) * VFStride
> 
> we can fix it with below code:
>  if (PciIoDevice->InitialVFs == 0) {
>  PciIoDevice->ReservedBusNum = 0;
> } else {
> PFRid  = EFI_PCI_RID (Bus, Device, Func);
>  LastVF = PFRid + FirstVFOffset + (PciIoDevice->InitialVFs - 1) * VFStride;
> //
> // Calculate ReservedBusNum for this PF
> //
> PciIoDevice->ReservedBusNum = (UINT16)(EFI_PCI_BUS_OF_RID (LastVF) - Bus + 1);
> //
>  // Calculate ReservedBusNum for this PF
> //
>  PciIoDevice->ReservedBusNum = (UINT16)(EFI_PCI_BUS_OF_RID (LastVF) - Bus + 1);
> }
> 
> https://bugzilla.tianocore.org/show_bug.cgi?id=4069
> 
> Signed-off-by: Foster Nong <foster.nong@intel.com>
> ---
>  .../Bus/Pci/PciBusDxe/PciEnumeratorSupport.c     | 16 ++++++++++------
>  1 file changed, 10 insertions(+), 6 deletions(-)
> 
> diff --git a/MdeModulePkg/Bus/Pci/PciBusDxe/PciEnumeratorSupport.c
> b/MdeModulePkg/Bus/Pci/PciBusDxe/PciEnumeratorSupport.c
> index 509f828b621d..eb250f6f7b62 100644
> --- a/MdeModulePkg/Bus/Pci/PciBusDxe/PciEnumeratorSupport.c
> +++ b/MdeModulePkg/Bus/Pci/PciBusDxe/PciEnumeratorSupport.c
> @@ -2416,13 +2416,17 @@ CreatePciIoDevice (
>        //
>        // Calculate LastVF
>        //
> -      PFRid  = EFI_PCI_RID (Bus, Device, Func);
> -      LastVF = PFRid + FirstVFOffset + (PciIoDevice->InitialVFs - 1) * VFStride;
> +      if (PciIoDevice->InitialVFs == 0) {
> +        PciIoDevice->ReservedBusNum = 0;
> +      } else {
> +        PFRid  = EFI_PCI_RID (Bus, Device, Func);
> +        LastVF = PFRid + FirstVFOffset + (PciIoDevice->InitialVFs - 1) * VFStride;
> 
> -      //
> -      // Calculate ReservedBusNum for this PF
> -      //
> -      PciIoDevice->ReservedBusNum = (UINT16)(EFI_PCI_BUS_OF_RID (LastVF) - Bus + 1);
> +        //
> +        // Calculate ReservedBusNum for this PF
> +        //
> +        PciIoDevice->ReservedBusNum = (UINT16)(EFI_PCI_BUS_OF_RID (LastVF) - Bus + 1);
> +      }
> 
>        DEBUG ((
>          DEBUG_INFO,
> --
> 2.37.1.windows.1
> 
> 
> 
> 
>