OvmfPkg/CpuHotplugSmm: define the QEMU_CPUHP_CMD_GET_ARCH_ID macro

[mirror_edk2.git] / OvmfPkg / CpuHotplugSmm / CpuHotplug.c

diff --git a/OvmfPkg/CpuHotplugSmm/CpuHotplug.c b/OvmfPkg/CpuHotplugSmm/CpuHotplug.c
index fd09403eabf3693da15a0ac7595360b943d7fb0c..5df8c689c63aac0ed4d4b3810d790c113bde5722 100644 (file)
--- a/OvmfPkg/CpuHotplugSmm/CpuHotplug.c
+++ b/OvmfPkg/CpuHotplugSmm/CpuHotplug.c
@@ -7,6 +7,7 @@
 **/\r
 \r
 #include <IndustryStandard/Q35MchIch9.h>     // ICH9_APM_CNT\r
+#include <IndustryStandard/QemuCpuHotplug.h> // QEMU_CPUHP_CMD_GET_PENDING\r
 #include <Library/BaseLib.h>                 // CpuDeadLoop()\r
 #include <Library/DebugLib.h>                // ASSERT()\r
 #include <Library/MmServicesTableLib.h>      // gMmst\r
@@ -14,6 +15,8 @@
 #include <Protocol/MmCpuIo.h>                // EFI_MM_CPU_IO_PROTOCOL\r
 #include <Uefi/UefiBaseType.h>               // EFI_STATUS\r
 \r
+#include "QemuCpuhp.h"                       // QemuCpuhpWriteCpuSelector()\r
+\r
 //\r
 // We use this protocol for accessing IO Ports.\r
 //\r
@@ -168,6 +171,38 @@ CpuHotplugEntry (
     goto Fatal;\r
   }\r
 \r
+  //\r
+  // Sanity-check the CPU hotplug interface.\r
+  //\r
+  // Both of the following features are part of QEMU 5.0, introduced primarily\r
+  // in commit range 3e08b2b9cb64..3a61c8db9d25:\r
+  //\r
+  // (a) the QEMU_CPUHP_CMD_GET_ARCH_ID command of the modern CPU hotplug\r
+  //     interface,\r
+  //\r
+  // (b) the "SMRAM at default SMBASE" feature.\r
+  //\r
+  // From these, (b) is restricted to 5.0+ machine type versions, while (a)\r
+  // does not depend on machine type version. Because we ensured the stricter\r
+  // condition (b) through PcdQ35SmramAtDefaultSmbase above, the (a)\r
+  // QEMU_CPUHP_CMD_GET_ARCH_ID command must now be available too. While we\r
+  // can't verify the presence of precisely that command, we can still verify\r
+  // (sanity-check) that the modern interface is active, at least.\r
+  //\r
+  // Consult the "Typical usecases | Detecting and enabling modern CPU hotplug\r
+  // interface" section in QEMU's "docs/specs/acpi_cpu_hotplug.txt", on the\r
+  // following.\r
+  //\r
+  QemuCpuhpWriteCpuSelector (mMmCpuIo, 0);\r
+  QemuCpuhpWriteCpuSelector (mMmCpuIo, 0);\r
+  QemuCpuhpWriteCommand (mMmCpuIo, QEMU_CPUHP_CMD_GET_PENDING);\r
+  if (QemuCpuhpReadCommandData2 (mMmCpuIo) != 0) {\r
+    Status = EFI_NOT_FOUND;\r
+    DEBUG ((DEBUG_ERROR, "%a: modern CPU hotplug interface: %r\n",\r
+      __FUNCTION__, Status));\r
+    goto Fatal;\r
+  }\r
+\r
   //\r
   // Register the handler for the CPU Hotplug MMI.\r
   //\r