OvmfPkg/SmmControl2Dxe: negotiate CPU hot-unplug

Advertise OVMF support for CPU hot-unplug and negotiate it
if QEMU requests the feature.

Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Ard Biesheuvel <ard.biesheuvel@arm.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Aaron Young <aaron.young@oracle.com>
Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=3132
Signed-off-by: Ankur Arora <ankur.a.arora@oracle.com>
Message-Id: <20210312062656.2477515-11-ankur.a.arora@oracle.com>
[lersek@redhat.com: preserve the empty line between the ICH9_LPC_SMI_F_*
 group of macro definitions and the SCRATCH_BUFFER type definition]
Reviewed-by: Laszlo Ersek <lersek@redhat.com>

1 files changed, 16 insertions, 1 deletions

diff --git a/OvmfPkg/SmmControl2Dxe/SmiFeatures.c b/OvmfPkg/SmmControl2Dxe/SmiFeatures.c
index c9d8755432..bd0653e6b1 100644
--- a/OvmfPkg/SmmControl2Dxe/SmiFeatures.c
+++ b/OvmfPkg/SmmControl2Dxe/SmiFeatures.c
@@ -28,6 +28,12 @@
 // "etc/smi/supported-features" and "etc/smi/requested-features" fw_cfg files.

 //

 #define ICH9_LPC_SMI_F_CPU_HOTPLUG BIT1

+//

+// The following bit value stands for "enable CPU hot-unplug, and inject an SMI

+// with control value ICH9_APM_CNT_CPU_HOTPLUG upon hot-unplug", in the

+// "etc/smi/supported-features" and "etc/smi/requested-features" fw_cfg files.

+//

+#define ICH9_LPC_SMI_F_CPU_HOT_UNPLUG BIT2

 

 //

 // Provides a scratch buffer (allocated in EfiReservedMemoryType type memory)

@@ -112,7 +118,8 @@ NegotiateSmiFeatures (
   QemuFwCfgReadBytes (sizeof mSmiFeatures, &mSmiFeatures);

 

   //

-  // We want broadcast SMI, SMI on CPU hotplug, and nothing else.

+  // We want broadcast SMI, SMI on CPU hotplug, SMI on CPU hot-unplug

+  // and nothing else.

   //

   RequestedFeaturesMask = ICH9_LPC_SMI_F_BROADCAST;

   if (!MemEncryptSevIsEnabled ()) {

@@ -120,6 +127,7 @@ NegotiateSmiFeatures (
     // For now, we only support hotplug with SEV disabled.

     //

     RequestedFeaturesMask |= ICH9_LPC_SMI_F_CPU_HOTPLUG;

+    RequestedFeaturesMask |= ICH9_LPC_SMI_F_CPU_HOT_UNPLUG;

   }

   mSmiFeatures &= RequestedFeaturesMask;

   QemuFwCfgSelectItem (mRequestedFeaturesItem);

@@ -166,6 +174,13 @@ NegotiateSmiFeatures (
       __FUNCTION__));

   }

 

+  if ((mSmiFeatures & ICH9_LPC_SMI_F_CPU_HOT_UNPLUG) == 0) {

+    DEBUG ((DEBUG_INFO, "%a: CPU hot-unplug not negotiated\n", __FUNCTION__));

+  } else {

+    DEBUG ((DEBUG_INFO, "%a: CPU hot-unplug with SMI negotiated\n",

+      __FUNCTION__));

+  }

+

   //

   // Negotiation successful (although we may not have gotten the optimal

   // feature set).