OvmfPkg/CpuHotplugSmm: complete root MMI handler for CPU hotplug

With the help of the Post-SMM Pen and the SMBASE relocation functions
added in the previous patches, we can now complete the root MMI handler
for CPU hotplug.

In the driver's entry point function:

- allocate the pen (in a reserved page in normal RAM),

- install the default ("first") SMI handler for hot-added CPUs (which
  includes priming the exchange area between the MM Monarch and the
  hot-added CPUs, i.e., shutting the APIC ID gate).

In the root MMI handler, for each hot-added CPU:

- record the APIC ID of the new CPU in CPU_HOT_PLUG_DATA,

- relocate the SMBASE of the new CPU,

- inform PiSmmCpuDxeSmm by calling
  EFI_SMM_CPU_SERVICE_PROTOCOL.AddProcessor().

Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Michael Kinney <michael.d.kinney@intel.com>
Cc: Philippe Mathieu-Daudé <philmd@redhat.com>
Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=1512
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Message-Id: <20200226221156.29589-14-lersek@redhat.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Tested-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>

1 files changed, 95 insertions, 2 deletions

diff --git a/OvmfPkg/CpuHotplugSmm/CpuHotplug.c b/OvmfPkg/CpuHotplugSmm/CpuHotplug.c
index 42e023cb85..20e6bec04f 100644
--- a/OvmfPkg/CpuHotplugSmm/CpuHotplug.c
+++ b/OvmfPkg/CpuHotplugSmm/CpuHotplug.c
@@ -20,6 +20,7 @@
 

 #include "ApicId.h"                          // APIC_ID

 #include "QemuCpuhp.h"                       // QemuCpuhpWriteCpuSelector()

+#include "Smbase.h"                          // SmbaseAllocatePostSmmPen()

 

 //

 // We use this protocol for accessing IO Ports.

@@ -52,6 +53,11 @@ STATIC CPU_HOT_PLUG_DATA *mCpuHotPlugData;
 STATIC APIC_ID *mPluggedApicIds;

 STATIC APIC_ID *mToUnplugApicIds;

 //

+// Address of the non-SMRAM reserved memory page that contains the Post-SMM Pen

+// for hot-added CPUs.

+//

+STATIC UINT32 mPostSmmPenAddress;

+//

 // Represents the registration of the CPU Hotplug MMI handler.

 //

 STATIC EFI_HANDLE mDispatchHandle;

@@ -116,6 +122,8 @@ CpuHotplugMmi (
   UINT8      ApmControl;

   UINT32     PluggedCount;

   UINT32     ToUnplugCount;

+  UINT32     PluggedIdx;

+  UINT32     NewSlot;

 

   //

   // Assert that we are entering this function due to our root MMI handler

@@ -172,10 +180,77 @@ CpuHotplugMmi (
   }

 

   //

+  // Process hot-added CPUs.

+  //

+  // The Post-SMM Pen need not be reinstalled multiple times within a single

+  // root MMI handling. Even reinstalling once per root MMI is only prudence;

+  // in theory installing the pen in the driver's entry point function should

+  // suffice.

+  //

+  SmbaseReinstallPostSmmPen (mPostSmmPenAddress);

+

+  PluggedIdx = 0;

+  NewSlot = 0;

+  while (PluggedIdx < PluggedCount) {

+    APIC_ID NewApicId;

+    UINTN   NewProcessorNumberByProtocol;

+

+    NewApicId = mPluggedApicIds[PluggedIdx];

+    //

+    // Find the first empty slot in CPU_HOT_PLUG_DATA.

+    //

+    while (NewSlot < mCpuHotPlugData->ArrayLength &&

+           mCpuHotPlugData->ApicId[NewSlot] != MAX_UINT64) {

+      NewSlot++;

+    }

+    if (NewSlot == mCpuHotPlugData->ArrayLength) {

+      DEBUG ((DEBUG_ERROR, "%a: no room for APIC ID " FMT_APIC_ID "\n",

+        __FUNCTION__, NewApicId));

+      goto Fatal;

+    }

+

+    //

+    // Store the APIC ID of the new processor to the slot.

+    //

+    mCpuHotPlugData->ApicId[NewSlot] = NewApicId;

+

+    //

+    // Relocate the SMBASE of the new CPU.

+    //

+    Status = SmbaseRelocate (NewApicId, mCpuHotPlugData->SmBase[NewSlot],

+               mPostSmmPenAddress);

+    if (EFI_ERROR (Status)) {

+      goto RevokeNewSlot;

+    }

+

+    //

+    // Add the new CPU with EFI_SMM_CPU_SERVICE_PROTOCOL.

+    //

+    Status = mMmCpuService->AddProcessor (mMmCpuService, NewApicId,

+                              &NewProcessorNumberByProtocol);

+    if (EFI_ERROR (Status)) {

+      DEBUG ((DEBUG_ERROR, "%a: AddProcessor(" FMT_APIC_ID "): %r\n",

+        __FUNCTION__, NewApicId, Status));

+      goto RevokeNewSlot;

+    }

+

+    DEBUG ((DEBUG_INFO, "%a: hot-added APIC ID " FMT_APIC_ID ", SMBASE 0x%Lx, "

+      "EFI_SMM_CPU_SERVICE_PROTOCOL assigned number %Lu\n", __FUNCTION__,

+      NewApicId, (UINT64)mCpuHotPlugData->SmBase[NewSlot],

+      (UINT64)NewProcessorNumberByProtocol));

+

+    NewSlot++;

+    PluggedIdx++;

+  }

+

+  //

   // We've handled this MMI.

   //

   return EFI_SUCCESS;

 

+RevokeNewSlot:

+  mCpuHotPlugData->ApicId[NewSlot] = MAX_UINT64;

+

 Fatal:

   ASSERT (FALSE);

   CpuDeadLoop ();

@@ -271,6 +346,15 @@ CpuHotplugEntry (
   }

 

   //

+  // Allocate the Post-SMM Pen for hot-added CPUs.

+  //

+  Status = SmbaseAllocatePostSmmPen (&mPostSmmPenAddress,

+             SystemTable->BootServices);

+  if (EFI_ERROR (Status)) {

+    goto ReleaseToUnplugApicIds;

+  }

+

+  //

   // Sanity-check the CPU hotplug interface.

   //

   // Both of the following features are part of QEMU 5.0, introduced primarily

@@ -299,7 +383,7 @@ CpuHotplugEntry (
     Status = EFI_NOT_FOUND;

     DEBUG ((DEBUG_ERROR, "%a: modern CPU hotplug interface: %r\n",

       __FUNCTION__, Status));

-    goto ReleaseToUnplugApicIds;

+    goto ReleasePostSmmPen;

   }

 

   //

@@ -313,11 +397,20 @@ CpuHotplugEntry (
   if (EFI_ERROR (Status)) {

     DEBUG ((DEBUG_ERROR, "%a: MmiHandlerRegister(): %r\n", __FUNCTION__,

       Status));

-    goto ReleaseToUnplugApicIds;

+    goto ReleasePostSmmPen;

   }

 

+  //

+  // Install the handler for the hot-added CPUs' first SMI.

+  //

+  SmbaseInstallFirstSmiHandler ();

+

   return EFI_SUCCESS;

 

+ReleasePostSmmPen:

+  SmbaseReleasePostSmmPen (mPostSmmPenAddress, SystemTable->BootServices);

+  mPostSmmPenAddress = 0;

+

 ReleaseToUnplugApicIds:

   gMmst->MmFreePool (mToUnplugApicIds);

   mToUnplugApicIds = NULL;