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

["Ni, Ruiyu" <ruiyu.ni@intel.com>]

Jeff,
Thanks you for your comments!

How are you in Guiyang?

Thanks/Ray

From: Fan Jeff [mailto:vanjeff_919@hotmail.com]
Sent: Wednesday, November 1, 2017 10:43 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: 答复: [edk2] [PATCH] MdeModulePkg/PciBus: Disable BME of all devices when entering RT

Minimal comment: To use DEBUG_INFO instead of EFI_D_INFO for consistence in this patch.
+        DEBUG ((
+          EFI_D_INFO,"  %02x   %02x      %02x         %04x\n",
+          PciIoDevice->BusNumber, PciIoDevice->DeviceNumber, PciIoDevice->FunctionNumber,
+          Command
+          ));
发件人: Ruiyu Ni<mailto:ruiyu.ni@intel.com>
发送时间: 2017年10月31日 15:54
收件人: edk2-devel@lists.01.org<mailto:edk2-devel@lists.01.org>
抄送: Michael D Kinney<mailto:michael.d.kinney@intel.com>; Michael Turner<mailto:michael.turner@microsoft.com>; Jiewen Yao<mailto:jiewen.yao@intel.com>
主题: [edk2] [PATCH] MdeModulePkg/PciBus: Disable BME of all devices when entering RT

The patch assumes IOMMU protections are disabled after PciBus
disables the BMT bit in Command register.
It ensures all DMA transactions are protected by IOMMU.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Michael Turner <michael.turner@microsoft.com<mailto:michael.turner@microsoft.com>>
Signed-off-by: Ruiyu Ni <ruiyu.ni@intel.com<mailto:ruiyu.ni@intel.com>>
Cc: Michael D Kinney <michael.d.kinney@intel.com<mailto:michael.d.kinney@intel.com>>
Cc: Jiewen Yao <jiewen.yao@intel.com<mailto:jiewen.yao@intel.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..b5530a13d1 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 ((
+          EFI_D_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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