OvmfPkg/PlatformPei: take VCPU count from QEMU and configure MpInitLib

[mirror_edk2.git] / OvmfPkg / PlatformPei / Platform.c

diff --git a/OvmfPkg/PlatformPei/Platform.c b/OvmfPkg/PlatformPei/Platform.c
index c6e1106c9ed01ef790ad9947497e9192cf34dd5a..0be86722e548e0db6c1f259348f692c31faeb3d1 100644 (file)
--- a/OvmfPkg/PlatformPei/Platform.c
+++ b/OvmfPkg/PlatformPei/Platform.c
@@ -68,6 +68,7 @@ EFI_BOOT_MODE mBootMode = BOOT_WITH_FULL_CONFIGURATION;
 \r
 BOOLEAN mS3Supported = FALSE;\r
 \r
+UINT32 mMaxCpuCount;\r
 \r
 VOID\r
 AddIoMemoryBaseSizeHob (\r
@@ -567,6 +568,47 @@ S3Verification (
 }\r
 \r
 \r
+/**\r
+  Fetch the number of boot CPUs from QEMU and expose it to UefiCpuPkg modules.\r
+  Set the mMaxCpuCount variable.\r
+**/\r
+VOID\r
+MaxCpuCountInitialization (\r
+  VOID\r
+  )\r
+{\r
+  UINT16        ProcessorCount;\r
+  RETURN_STATUS PcdStatus;\r
+\r
+  QemuFwCfgSelectItem (QemuFwCfgItemSmpCpuCount);\r
+  ProcessorCount = QemuFwCfgRead16 ();\r
+  //\r
+  // If the fw_cfg key or fw_cfg entirely is unavailable, load mMaxCpuCount\r
+  // from the PCD default. No change to PCDs.\r
+  //\r
+  if (ProcessorCount == 0) {\r
+    mMaxCpuCount = PcdGet32 (PcdCpuMaxLogicalProcessorNumber);\r
+    return;\r
+  }\r
+  //\r
+  // Otherwise, set mMaxCpuCount to the value reported by QEMU.\r
+  //\r
+  mMaxCpuCount = ProcessorCount;\r
+  //\r
+  // Additionally, tell UefiCpuPkg modules (a) the exact number of VCPUs, (b)\r
+  // to wait, in the initial AP bringup, exactly as long as it takes for all of\r
+  // the APs to report in. For this, we set the longest representable timeout\r
+  // (approx. 71 minutes).\r
+  //\r
+  PcdStatus = PcdSet32S (PcdCpuMaxLogicalProcessorNumber, ProcessorCount);\r
+  ASSERT_RETURN_ERROR (PcdStatus);\r
+  PcdStatus = PcdSet32S (PcdCpuApInitTimeOutInMicroSeconds, MAX_UINT32);\r
+  ASSERT_RETURN_ERROR (PcdStatus);\r
+  DEBUG ((DEBUG_INFO, "%a: QEMU reports %d processor(s)\n", __FUNCTION__,\r
+    ProcessorCount));\r
+}\r
+\r
+\r
 /**\r
   Perform Platform PEI initialization.\r
 \r
@@ -601,6 +643,7 @@ InitializePlatform (
   S3Verification ();\r
   BootModeInitialization ();\r
   AddressWidthInitialization ();\r
+  MaxCpuCountInitialization ();\r
 \r
   PublishPeiMemory ();\r
 \r