Re: [PATCH v2] MdeModulePkg/PciBus: Disable BME of all devices when entering RT

["Yao, Jiewen" <jiewen.yao@intel.com>]

Looks good.
Reviewed-by: Jiewen.yao@intel.com

> -----Original Message-----
> From: Ni, Ruiyu
> Sent: Tuesday, November 7, 2017 10:40 AM
> To: Ni, Ruiyu <ruiyu.ni@intel.com>; edk2-devel@lists.01.org
> Cc: Kinney, Michael D <michael.d.kinney@intel.com>; Michael Turner
> <michael.turner@microsoft.com>; Yao, Jiewen <jiewen.yao@intel.com>
> Subject: RE: [edk2] [PATCH v2] MdeModulePkg/PciBus: Disable BME of all devices
> when entering RT
> 
> Jiewen,
> Any comments?
> 
> Thanks/Ray
> 
> > -----Original Message-----
> > From: edk2-devel [mailto:edk2-devel-bounces@lists.01.org] On Behalf Of
> > Ruiyu Ni
> > Sent: Wednesday, November 1, 2017 12:49 PM
> > To: edk2-devel@lists.01.org
> > Cc: Kinney, Michael D <michael.d.kinney@intel.com>; Michael Turner
> > <michael.turner@microsoft.com>; Yao, Jiewen <jiewen.yao@intel.com>
> > Subject: [edk2] [PATCH v2] MdeModulePkg/PciBus: Disable BME of all
> > devices when entering RT
> >
> > The patch ensures all DMA transactions are blocked after ExitBootService.
> > If a platform enables IOMMU before and needs disable IOMMU after
> > ExitBootService, the IOMMU should be disabled after PCI bus driver disables
> > BME.
> >
> > Contributed-under: TianoCore Contribution Agreement 1.1
> > Signed-off-by: Michael Turner <michael.turner@microsoft.com>
> > Signed-off-by: Ruiyu Ni <ruiyu.ni@intel.com>
> > Cc: Michael D Kinney <michael.d.kinney@intel.com>
> > Cc: Jiewen Yao <jiewen.yao@intel.com>
> > Cc: Jeff Fan <vanjeff_919@hotmail.com>
> > ---
> >  MdeModulePkg/Bus/Pci/PciBusDxe/PciBus.h           |  2 +
> >  MdeModulePkg/Bus/Pci/PciBusDxe/PciBusDxe.inf      |  3 +
> >  MdeModulePkg/Bus/Pci/PciBusDxe/PciDeviceSupport.c | 86
> > +++++++++++++++++++++++
> >  3 files changed, 91 insertions(+)
> >
> > diff --git a/MdeModulePkg/Bus/Pci/PciBusDxe/PciBus.h
> > b/MdeModulePkg/Bus/Pci/PciBusDxe/PciBus.h
> > index 55eb3a5a80..79b5b71082 100644
> > --- a/MdeModulePkg/Bus/Pci/PciBusDxe/PciBus.h
> > +++ b/MdeModulePkg/Bus/Pci/PciBusDxe/PciBus.h
> > @@ -18,6 +18,8 @@ WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY
> > KIND, EITHER EXPRESS OR IMPLIED.
> >
> >  #include <PiDxe.h>
> >
> > +#include <Guid/EventGroup.h>
> > +
> >  #include <Protocol/LoadedImage.h>
> >  #include <Protocol/PciHostBridgeResourceAllocation.h>
> >  #include <Protocol/PciIo.h>
> > diff --git a/MdeModulePkg/Bus/Pci/PciBusDxe/PciBusDxe.inf
> > b/MdeModulePkg/Bus/Pci/PciBusDxe/PciBusDxe.inf
> > index 97608bfcf2..d5b8fab3ca 100644
> > --- a/MdeModulePkg/Bus/Pci/PciBusDxe/PciBusDxe.inf
> > +++ b/MdeModulePkg/Bus/Pci/PciBusDxe/PciBusDxe.inf
> > @@ -80,6 +80,9 @@ [LibraryClasses]
> >    DebugLib
> >    PeCoffLib
> >
> > +[Guids]
> > +  gEfiEventExitBootServicesGuid                   ##
> SOMETIMES_CONSUMES ##
> > Event
> > +
> >  [Protocols]
> >    gEfiPciHotPlugRequestProtocolGuid               ##
> SOMETIMES_PRODUCES
> >    gEfiPciIoProtocolGuid                           ## BY_START
> > diff --git a/MdeModulePkg/Bus/Pci/PciBusDxe/PciDeviceSupport.c
> > b/MdeModulePkg/Bus/Pci/PciBusDxe/PciDeviceSupport.c
> > index 97bb971a59..004f2a3b5b 100644
> > --- a/MdeModulePkg/Bus/Pci/PciBusDxe/PciDeviceSupport.c
> > +++ b/MdeModulePkg/Bus/Pci/PciBusDxe/PciDeviceSupport.c
> > @@ -21,6 +21,72 @@ WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY
> > KIND, EITHER EXPRESS OR IMPLIED.
> >  LIST_ENTRY  mPciDevicePool;
> >
> >  /**
> > + Disable Bus Master Enable bit in all devices in the list.
> > +
> > + @param Devices  A device list.
> > +**/
> > +VOID
> > +DisableBmeOnTree (
> > +  IN LIST_ENTRY      *Devices
> > +  )
> > +{
> > +  LIST_ENTRY      *Link;
> > +  PCI_IO_DEVICE   *PciIoDevice;
> > +  UINT16           Command;
> > +
> > +  for ( Link = GetFirstNode (Devices)
> > +      ; !IsNull (Devices, Link)
> > +      ; Link = GetNextNode (Devices, Link)
> > +      ) {
> > +    PciIoDevice = PCI_IO_DEVICE_FROM_LINK (Link);
> > +    //
> > +    // Turn off all children's Bus Master, if any
> > +    //
> > +    DisableBmeOnTree (&PciIoDevice->ChildList);
> > +
> > +    //
> > +    // If this is a device that supports BME, disable BME on this device.
> > +    //
> > +    if ((PciIoDevice->Supports & EFI_PCI_IO_ATTRIBUTE_BUS_MASTER) != 0)
> > {
> > +      PCI_READ_COMMAND_REGISTER(PciIoDevice, &Command);
> > +      if ((Command & EFI_PCI_COMMAND_BUS_MASTER) != 0) {
> > +        Command &= ~EFI_PCI_COMMAND_BUS_MASTER;
> > +        PCI_SET_COMMAND_REGISTER (PciIoDevice, Command);
> > +        DEBUG ((
> > +          DEBUG_INFO,"  %02x   %02x      %02x         %04x\n",
> > +          PciIoDevice->BusNumber, PciIoDevice->DeviceNumber,
> PciIoDevice-
> > >FunctionNumber,
> > +          Command
> > +          ));
> > +      }
> > +    }
> > +  }
> > +}
> > +
> > +/**
> > +  Exit Boot Services Event notification handler.
> > +
> > +  Disable Bus Master on any that were enabled during BDS.
> > +
> > +  @param[in]  Event     Event whose notification function is being
> invoked.
> > +  @param[in]  Context   Pointer to the notification function's context.
> > +
> > +**/
> > +VOID
> > +EFIAPI
> > +OnExitBootServices (
> > +  IN      EFI_EVENT                 Event,
> > +  IN      VOID                      *Context
> > +  )
> > +{
> > +  DEBUG ((
> > +    DEBUG_INFO,
> > +    "PciBus: Disable Bus Master of all devices...\n"
> > +    "  Bus# Device# Function#  NewCommand\n"
> > +    ));
> > +  DisableBmeOnTree(&mPciDevicePool);
> > +}
> > +
> > +/**
> >    Initialize the PCI devices pool.
> >
> >  **/
> > @@ -29,7 +95,27 @@ InitializePciDevicePool (
> >    VOID
> >    )
> >  {
> > +  EFI_EVENT   ExitBootServicesEvent;
> > +  EFI_STATUS  Status;
> > +
> >    InitializeListHead (&mPciDevicePool);
> > +
> > +  //
> > +  // DisableBME on ExitBootServices should be synchonized with any
> > IOMMU ExitBootServices routine.
> > +  // DisableBME should be run before the IOMMU protections are disabled.
> > +  // One way to do this is to ensure that the IOMMU ExitBootServices
> > callback runs at TPL_CALLBACK.
> > +  //
> > +  Status = gBS->CreateEventEx (
> > +                  EVT_NOTIFY_SIGNAL,
> > +                  TPL_NOTIFY,
> > +                  OnExitBootServices,
> > +                  NULL,
> > +                  &gEfiEventExitBootServicesGuid,
> > +                  &ExitBootServicesEvent
> > +                  );
> > +  if (EFI_ERROR (Status)) {
> > +    DEBUG ((DEBUG_ERROR, "PciBus: Unable to hook ExitBootServices event
> > + - %r\n", Status));  }
> >  }
> >
> >  /**
> > --
> > 2.12.2.windows.2
> >
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