OvmfPkg/PlatformPei: take VCPU count from QEMU and configure MpInitLib
These settings will allow CpuMpPei and CpuDxe to wait for the initial AP
check-ins exactly as long as necessary.
It is safe to set PcdCpuMaxLogicalProcessorNumber and
PcdCpuApInitTimeOutInMicroSeconds in OvmfPkg/PlatformPei.
OvmfPkg/PlatformPei installs the permanent PEI RAM, producing
gEfiPeiMemoryDiscoveredPpiGuid, and UefiCpuPkg/CpuMpPei has a depex on
gEfiPeiMemoryDiscoveredPpiGuid.
It is safe to read the fw_cfg item QemuFwCfgItemSmpCpuCount (0x0005). It
was added to QEMU in 2008 as key FW_CFG_NB_CPUS, in commit 905fdcb5264c
("Add common keys to firmware configuration"). Even if the key is
unavailable (or if fw_cfg is entirely unavailable, for example on Xen),
QemuFwCfgRead16() will return 0, and then we stick with the current
behavior.
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Jeff Fan <jeff.fan@intel.com>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Michael Kinney <michael.d.kinney@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
diff --git a/OvmfPkg/OvmfPkgIa32.dsc b/OvmfPkg/OvmfPkgIa32.dsc
index ed43c45..d913030 100644
--- a/OvmfPkg/OvmfPkgIa32.dsc
+++ b/OvmfPkg/OvmfPkgIa32.dsc
@@ -488,6 +488,10 @@
gEfiMdeModulePkgTokenSpaceGuid.PcdSetNxForStack|FALSE
gEfiMdeModulePkgTokenSpaceGuid.PcdPropertiesTableEnable|FALSE
+ # UefiCpuPkg PCDs related to initial AP bringup and general AP management.
+ gUefiCpuPkgTokenSpaceGuid.PcdCpuMaxLogicalProcessorNumber|64
+ gUefiCpuPkgTokenSpaceGuid.PcdCpuApInitTimeOutInMicroSeconds|50000
+
################################################################################
#
# Components Section - list of all EDK II Modules needed by this Platform.
diff --git a/OvmfPkg/OvmfPkgIa32X64.dsc b/OvmfPkg/OvmfPkgIa32X64.dsc
index ccd156d..8143ea9 100644
--- a/OvmfPkg/OvmfPkgIa32X64.dsc
+++ b/OvmfPkg/OvmfPkgIa32X64.dsc
@@ -496,6 +496,10 @@
gEfiMdeModulePkgTokenSpaceGuid.PcdSetNxForStack|FALSE
gEfiMdeModulePkgTokenSpaceGuid.PcdPropertiesTableEnable|FALSE
+ # UefiCpuPkg PCDs related to initial AP bringup and general AP management.
+ gUefiCpuPkgTokenSpaceGuid.PcdCpuMaxLogicalProcessorNumber|64
+ gUefiCpuPkgTokenSpaceGuid.PcdCpuApInitTimeOutInMicroSeconds|50000
+
################################################################################
#
# Components Section - list of all EDK II Modules needed by this Platform.
diff --git a/OvmfPkg/OvmfPkgX64.dsc b/OvmfPkg/OvmfPkgX64.dsc
index 012ce85..d48d603 100644
--- a/OvmfPkg/OvmfPkgX64.dsc
+++ b/OvmfPkg/OvmfPkgX64.dsc
@@ -495,6 +495,10 @@
gEfiMdeModulePkgTokenSpaceGuid.PcdSetNxForStack|FALSE
gEfiMdeModulePkgTokenSpaceGuid.PcdPropertiesTableEnable|FALSE
+ # UefiCpuPkg PCDs related to initial AP bringup and general AP management.
+ gUefiCpuPkgTokenSpaceGuid.PcdCpuMaxLogicalProcessorNumber|64
+ gUefiCpuPkgTokenSpaceGuid.PcdCpuApInitTimeOutInMicroSeconds|50000
+
################################################################################
#
# Components Section - list of all EDK II Modules needed by this Platform.
diff --git a/OvmfPkg/PlatformPei/MemDetect.c b/OvmfPkg/PlatformPei/MemDetect.c
index d00a570..af96a04 100644
--- a/OvmfPkg/PlatformPei/MemDetect.c
+++ b/OvmfPkg/PlatformPei/MemDetect.c
@@ -358,7 +358,7 @@
//
if (mS3Supported) {
mS3AcpiReservedMemorySize = SIZE_512KB +
- PcdGet32 (PcdCpuMaxLogicalProcessorNumber) *
+ mMaxCpuCount *
PcdGet32 (PcdCpuApStackSize);
mS3AcpiReservedMemoryBase = LowerMemorySize - mS3AcpiReservedMemorySize;
LowerMemorySize = mS3AcpiReservedMemoryBase;
diff --git a/OvmfPkg/PlatformPei/Platform.c b/OvmfPkg/PlatformPei/Platform.c
index c6e1106..0be8672 100644
--- a/OvmfPkg/PlatformPei/Platform.c
+++ b/OvmfPkg/PlatformPei/Platform.c
@@ -68,6 +68,7 @@
BOOLEAN mS3Supported = FALSE;
+UINT32 mMaxCpuCount;
VOID
AddIoMemoryBaseSizeHob (
@@ -568,6 +569,47 @@
/**
+ Fetch the number of boot CPUs from QEMU and expose it to UefiCpuPkg modules.
+ Set the mMaxCpuCount variable.
+**/
+VOID
+MaxCpuCountInitialization (
+ VOID
+ )
+{
+ UINT16 ProcessorCount;
+ RETURN_STATUS PcdStatus;
+
+ QemuFwCfgSelectItem (QemuFwCfgItemSmpCpuCount);
+ ProcessorCount = QemuFwCfgRead16 ();
+ //
+ // If the fw_cfg key or fw_cfg entirely is unavailable, load mMaxCpuCount
+ // from the PCD default. No change to PCDs.
+ //
+ if (ProcessorCount == 0) {
+ mMaxCpuCount = PcdGet32 (PcdCpuMaxLogicalProcessorNumber);
+ return;
+ }
+ //
+ // Otherwise, set mMaxCpuCount to the value reported by QEMU.
+ //
+ mMaxCpuCount = ProcessorCount;
+ //
+ // Additionally, tell UefiCpuPkg modules (a) the exact number of VCPUs, (b)
+ // to wait, in the initial AP bringup, exactly as long as it takes for all of
+ // the APs to report in. For this, we set the longest representable timeout
+ // (approx. 71 minutes).
+ //
+ PcdStatus = PcdSet32S (PcdCpuMaxLogicalProcessorNumber, ProcessorCount);
+ ASSERT_RETURN_ERROR (PcdStatus);
+ PcdStatus = PcdSet32S (PcdCpuApInitTimeOutInMicroSeconds, MAX_UINT32);
+ ASSERT_RETURN_ERROR (PcdStatus);
+ DEBUG ((DEBUG_INFO, "%a: QEMU reports %d processor(s)\n", __FUNCTION__,
+ ProcessorCount));
+}
+
+
+/**
Perform Platform PEI initialization.
@param FileHandle Handle of the file being invoked.
@@ -601,6 +643,7 @@
S3Verification ();
BootModeInitialization ();
AddressWidthInitialization ();
+ MaxCpuCountInitialization ();
PublishPeiMemory ();
diff --git a/OvmfPkg/PlatformPei/Platform.h b/OvmfPkg/PlatformPei/Platform.h
index eda765b..18f42c3 100644
--- a/OvmfPkg/PlatformPei/Platform.h
+++ b/OvmfPkg/PlatformPei/Platform.h
@@ -101,4 +101,6 @@
extern UINT8 mPhysMemAddressWidth;
+extern UINT32 mMaxCpuCount;
+
#endif // _PLATFORM_PEI_H_INCLUDED_
diff --git a/OvmfPkg/PlatformPei/PlatformPei.inf b/OvmfPkg/PlatformPei/PlatformPei.inf
index 776a4ab..fbaed31 100644
--- a/OvmfPkg/PlatformPei/PlatformPei.inf
+++ b/OvmfPkg/PlatformPei/PlatformPei.inf
@@ -95,6 +95,7 @@
gEfiMdeModulePkgTokenSpaceGuid.PcdAcpiS3Enable
gUefiCpuPkgTokenSpaceGuid.PcdCpuLocalApicBaseAddress
gUefiCpuPkgTokenSpaceGuid.PcdCpuMaxLogicalProcessorNumber
+ gUefiCpuPkgTokenSpaceGuid.PcdCpuApInitTimeOutInMicroSeconds
gUefiCpuPkgTokenSpaceGuid.PcdCpuApStackSize
[FixedPcd]
