From a5efebddb858c739d4a67865a4f8d836ba989d30 Mon Sep 17 00:00:00 2001 From: Laszlo Ersek Date: Tue, 14 Jul 2020 20:43:05 +0200 Subject: OvmfPkg/SmmControl2Dxe: negotiate ICH9_LPC_SMI_F_CPU_HOTPLUG MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit RH-Author: Laszlo Ersek (lersek) RH-MergeRequest: 1: [RHEL-8.4.0] complete the "VCPU hotplug with SMI" OVMF feature RH-Commit: [1/3] 33d820d43a1be2ece09044b0cf105275f3fcc9ce (lersek/edk2) RH-Bugzilla: 1849177 The ICH9_LPC_SMI_F_BROADCAST and ICH9_LPC_SMI_F_CPU_HOTPLUG feature flags cause QEMU to behave as follows: BROADCAST CPU_HOTPLUG use case / behavior --------- ----------- ------------------------------------------------ clear clear OVMF built without SMM_REQUIRE; or very old OVMF (from before commit a316d7ac91d3 / 2017-02-07). QEMU permits CPU hotplug operations, and does not cause the OS to inject an SMI upon hotplug. Firmware is not expected to be aware of hotplug events. clear set Invalid feature set; QEMU rejects the feature negotiation. set clear OVMF after a316d7ac91d3 / 2017-02-07, built with SMM_REQUIRE, but no support for CPU hotplug. QEMU gracefully refuses hotplug operations. set set OVMF after a316d7ac91d3 / 2017-02-07, built with SMM_REQUIRE, and supporting CPU hotplug. QEMU permits CPU hotplug operations, and causes the OS to inject an SMI upon hotplug. Firmware is expected to deal with hotplug events. Negotiate ICH9_LPC_SMI_F_CPU_HOTPLUG -- but only if SEV is disabled, as OvmfPkg/CpuHotplugSmm can't deal with SEV yet. Cc: Ard Biesheuvel Cc: Boris Ostrovsky Cc: Igor Mammedov Cc: Jordan Justen Cc: Liran Alon Cc: Philippe Mathieu-Daudé Signed-off-by: Laszlo Ersek Message-Id: <20200714184305.9814-1-lersek@redhat.com> Acked-by: Ard Biesheuvel Reviewed-by: Philippe Mathieu-Daudé (cherry picked from commit 5ba203b54e5953572e279e5505cd65e4cc360e34) Signed-off-by: Laszlo Ersek --- OvmfPkg/SmmControl2Dxe/SmiFeatures.c | 26 +++++++++++++++++++++-- OvmfPkg/SmmControl2Dxe/SmmControl2Dxe.inf | 1 + 2 files changed, 25 insertions(+), 2 deletions(-) diff --git a/OvmfPkg/SmmControl2Dxe/SmiFeatures.c b/OvmfPkg/SmmControl2Dxe/SmiFeatures.c index 6210b7515e..c9d8755432 100644 --- a/OvmfPkg/SmmControl2Dxe/SmiFeatures.c +++ b/OvmfPkg/SmmControl2Dxe/SmiFeatures.c @@ -9,6 +9,7 @@ #include #include +#include #include #include #include @@ -21,6 +22,12 @@ // "etc/smi/supported-features" and "etc/smi/requested-features" fw_cfg files. // #define ICH9_LPC_SMI_F_BROADCAST BIT0 +// +// The following bit value stands for "enable CPU hotplug, and inject an SMI +// with control value ICH9_APM_CNT_CPU_HOTPLUG upon hotplug", in the +// "etc/smi/supported-features" and "etc/smi/requested-features" fw_cfg files. +// +#define ICH9_LPC_SMI_F_CPU_HOTPLUG BIT1 // // Provides a scratch buffer (allocated in EfiReservedMemoryType type memory) @@ -67,6 +74,7 @@ NegotiateSmiFeatures ( UINTN SupportedFeaturesSize; UINTN RequestedFeaturesSize; UINTN FeaturesOkSize; + UINT64 RequestedFeaturesMask; // // Look up the fw_cfg files used for feature negotiation. The selector keys @@ -104,9 +112,16 @@ NegotiateSmiFeatures ( QemuFwCfgReadBytes (sizeof mSmiFeatures, &mSmiFeatures); // - // We want broadcast SMI and nothing else. + // We want broadcast SMI, SMI on CPU hotplug, and nothing else. // - mSmiFeatures &= ICH9_LPC_SMI_F_BROADCAST; + RequestedFeaturesMask = ICH9_LPC_SMI_F_BROADCAST; + if (!MemEncryptSevIsEnabled ()) { + // + // For now, we only support hotplug with SEV disabled. + // + RequestedFeaturesMask |= ICH9_LPC_SMI_F_CPU_HOTPLUG; + } + mSmiFeatures &= RequestedFeaturesMask; QemuFwCfgSelectItem (mRequestedFeaturesItem); QemuFwCfgWriteBytes (sizeof mSmiFeatures, &mSmiFeatures); @@ -144,6 +159,13 @@ NegotiateSmiFeatures ( DEBUG ((DEBUG_INFO, "%a: using SMI broadcast\n", __FUNCTION__)); } + if ((mSmiFeatures & ICH9_LPC_SMI_F_CPU_HOTPLUG) == 0) { + DEBUG ((DEBUG_INFO, "%a: CPU hotplug not negotiated\n", __FUNCTION__)); + } else { + DEBUG ((DEBUG_INFO, "%a: CPU hotplug with SMI negotiated\n", + __FUNCTION__)); + } + // // Negotiation successful (although we may not have gotten the optimal // feature set). diff --git a/OvmfPkg/SmmControl2Dxe/SmmControl2Dxe.inf b/OvmfPkg/SmmControl2Dxe/SmmControl2Dxe.inf index 3abed141e6..b8fdea8deb 100644 --- a/OvmfPkg/SmmControl2Dxe/SmmControl2Dxe.inf +++ b/OvmfPkg/SmmControl2Dxe/SmmControl2Dxe.inf @@ -46,6 +46,7 @@ BaseLib DebugLib IoLib + MemEncryptSevLib MemoryAllocationLib PcdLib PciLib -- 2.18.4