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From: "Xin Li (Intel)" <xin@zytor.com>
To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
	linux-doc@vger.kernel.org
Cc: pbonzini@redhat.com, seanjc@google.com, corbet@lwn.net,
	tglx@linutronix.de, mingo@redhat.com, bp@alien8.de,
	dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com,
	xin@zytor.com, luto@kernel.org, peterz@infradead.org,
	andrew.cooper3@citrix.com, chao.gao@intel.com, hch@infradead.org
Subject: [PATCH v5 02/23] KVM: VMX: Initialize VM entry/exit FRED controls in vmcs_config
Date: Wed, 23 Jul 2025 10:53:20 -0700	[thread overview]
Message-ID: <20250723175341.1284463-3-xin@zytor.com> (raw)
In-Reply-To: <20250723175341.1284463-1-xin@zytor.com>

From: Xin Li <xin3.li@intel.com>

Setup VM entry/exit FRED controls in the global vmcs_config for proper
FRED VMCS fields management:
  1) load guest FRED state upon VM entry.
  2) save guest FRED state during VM exit.
  3) load host FRED state during VM exit.

Also add FRED control consistency checks to the existing VM entry/exit
consistency check framework.

Signed-off-by: Xin Li <xin3.li@intel.com>
Signed-off-by: Xin Li (Intel) <xin@zytor.com>
Tested-by: Shan Kang <shan.kang@intel.com>
Tested-by: Xuelian Guo <xuelian.guo@intel.com>
Reviewed-by: Chao Gao <chao.gao@intel.com>
---

Change in v5:
* Remove the pair VM_ENTRY_LOAD_IA32_FRED/VM_EXIT_ACTIVATE_SECONDARY_CONTROLS,
  since the secondary VM exit controls are unconditionally enabled anyway, and
  there are features other than FRED needing it (Chao Gao).
* Add TB from Xuelian Guo.

Change in v4:
* Do VM exit/entry consistency checks using the new macro from Sean
  Christopherson.

Changes in v3:
* Add FRED control consistency checks to the existing VM entry/exit
  consistency check framework (Sean Christopherson).
* Just do the unnecessary FRED state load/store on every VM entry/exit
  (Sean Christopherson).
---
 arch/x86/include/asm/vmx.h | 4 ++++
 arch/x86/kvm/vmx/vmx.c     | 2 ++
 arch/x86/kvm/vmx/vmx.h     | 7 +++++--
 3 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/vmx.h b/arch/x86/include/asm/vmx.h
index 97f7e0545534..1879de94457d 100644
--- a/arch/x86/include/asm/vmx.h
+++ b/arch/x86/include/asm/vmx.h
@@ -108,6 +108,9 @@
 #define VM_EXIT_CLEAR_IA32_RTIT_CTL		0x02000000
 #define VM_EXIT_ACTIVATE_SECONDARY_CONTROLS	0x80000000
 
+#define SECONDARY_VM_EXIT_SAVE_IA32_FRED	BIT_ULL(0)
+#define SECONDARY_VM_EXIT_LOAD_IA32_FRED	BIT_ULL(1)
+
 #define VM_EXIT_ALWAYSON_WITHOUT_TRUE_MSR	0x00036dff
 
 #define VM_ENTRY_LOAD_DEBUG_CONTROLS            0x00000004
@@ -120,6 +123,7 @@
 #define VM_ENTRY_LOAD_BNDCFGS                   0x00010000
 #define VM_ENTRY_PT_CONCEAL_PIP			0x00020000
 #define VM_ENTRY_LOAD_IA32_RTIT_CTL		0x00040000
+#define VM_ENTRY_LOAD_IA32_FRED			0x00800000
 
 #define VM_ENTRY_ALWAYSON_WITHOUT_TRUE_MSR	0x000011ff
 
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 85632de1dddb..463fc4a65788 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -2591,6 +2591,8 @@ static int setup_vmcs_config(struct vmcs_config *vmcs_conf,
 		u32 entry_control;
 		u64 exit_control;
 	} const vmcs_entry_exit2_pairs[] = {
+		{ VM_ENTRY_LOAD_IA32_FRED,
+			SECONDARY_VM_EXIT_SAVE_IA32_FRED | SECONDARY_VM_EXIT_LOAD_IA32_FRED },
 	};
 
 	memset(vmcs_conf, 0, sizeof(*vmcs_conf));
diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h
index 20194412bed3..32829f98af2f 100644
--- a/arch/x86/kvm/vmx/vmx.h
+++ b/arch/x86/kvm/vmx/vmx.h
@@ -484,7 +484,8 @@ static inline u8 vmx_get_rvi(void)
 	 VM_ENTRY_LOAD_IA32_EFER |					\
 	 VM_ENTRY_LOAD_BNDCFGS |					\
 	 VM_ENTRY_PT_CONCEAL_PIP |					\
-	 VM_ENTRY_LOAD_IA32_RTIT_CTL)
+	 VM_ENTRY_LOAD_IA32_RTIT_CTL |					\
+	 VM_ENTRY_LOAD_IA32_FRED)
 
 #define __KVM_REQUIRED_VMX_VM_EXIT_CONTROLS				\
 	(VM_EXIT_SAVE_DEBUG_CONTROLS |					\
@@ -510,7 +511,9 @@ static inline u8 vmx_get_rvi(void)
 	       VM_EXIT_ACTIVATE_SECONDARY_CONTROLS)
 
 #define KVM_REQUIRED_VMX_SECONDARY_VM_EXIT_CONTROLS (0)
-#define KVM_OPTIONAL_VMX_SECONDARY_VM_EXIT_CONTROLS (0)
+#define KVM_OPTIONAL_VMX_SECONDARY_VM_EXIT_CONTROLS			\
+	     (SECONDARY_VM_EXIT_SAVE_IA32_FRED |			\
+	      SECONDARY_VM_EXIT_LOAD_IA32_FRED)
 
 #define KVM_REQUIRED_VMX_PIN_BASED_VM_EXEC_CONTROL			\
 	(PIN_BASED_EXT_INTR_MASK |					\
-- 
2.50.1


  parent reply	other threads:[~2025-07-23 17:54 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-07-23 17:53 [PATCH v5 00/23] Enable FRED with KVM VMX Xin Li (Intel)
2025-07-23 17:53 ` [PATCH v5 01/23] KVM: VMX: Add support for the secondary VM exit controls Xin Li (Intel)
2025-07-23 17:53 ` Xin Li (Intel) [this message]
2025-07-23 17:53 ` [PATCH v5 03/23] KVM: VMX: Disable FRED if FRED consistency checks fail Xin Li (Intel)
2025-07-23 17:53 ` [PATCH v5 04/23] x86/cea: Export an API to get per CPU exception stacks for KVM to use Xin Li (Intel)
2025-07-23 17:53 ` [PATCH v5 05/23] KVM: VMX: Fix an indentation Xin Li (Intel)
2025-07-23 17:53 ` [PATCH v5 06/23] KVM: VMX: Initialize VMCS FRED fields Xin Li (Intel)
2025-07-23 17:53 ` [PATCH v5 07/23] KVM: VMX: Set FRED MSR intercepts Xin Li (Intel)
2025-07-23 17:53 ` [PATCH v5 08/23] KVM: VMX: Save/restore guest FRED RSP0 Xin Li (Intel)
2025-07-23 17:53 ` [PATCH v5 09/23] KVM: VMX: Add host MSR read/write helpers to streamline preemption logic Xin Li (Intel)
2025-07-23 17:53 ` [PATCH v5 10/23] KVM: VMX: Add support for FRED context save/restore Xin Li (Intel)
2025-07-24  5:35   ` Chao Gao
2025-07-24 18:01     ` Xin Li
2025-08-02 17:15     ` [PATCH v5A " Xin Li (Intel)
2025-07-23 17:53 ` [PATCH v5 11/23] KVM: x86: Add a helper to detect if FRED is enabled for a vCPU Xin Li (Intel)
2025-07-23 17:53 ` [PATCH v5 12/23] KVM: VMX: Virtualize FRED event_data Xin Li (Intel)
2025-07-23 17:53 ` [PATCH v5 13/23] KVM: VMX: Virtualize FRED nested exception tracking Xin Li (Intel)
2025-07-23 17:53 ` [PATCH v5 14/23] Documentation: kvm: Fix a section number typo Xin Li (Intel)
2025-07-23 17:53 ` [PATCH v5 15/23] KVM: x86: Save/restore the nested flag of an exception Xin Li (Intel)
2025-07-23 17:53 ` [PATCH v5 16/23] KVM: x86: Mark CR4.FRED as not reserved Xin Li (Intel)
2025-07-23 17:53 ` [PATCH v5 17/23] KVM: VMX: Dump FRED context in dump_vmcs() Xin Li (Intel)
2025-07-23 17:53 ` [PATCH v5 18/23] KVM: x86: Advertise support for FRED Xin Li (Intel)
2025-07-23 17:53 ` [PATCH v5 19/23] KVM: nVMX: Add support for the secondary VM exit controls Xin Li (Intel)
2025-07-23 17:53 ` [PATCH v5 20/23] KVM: nVMX: Add FRED VMCS fields to nested VMX context handling Xin Li (Intel)
2025-07-24  6:50   ` Chao Gao
2025-07-31  7:24     ` Xin Li
2025-08-02 17:17     ` [PATCH v5A " Xin Li (Intel)
2025-08-02 17:33       ` Xin Li
2025-08-04  6:03         ` Xin Li
2025-07-23 17:53 ` [PATCH v5 21/23] KVM: nVMX: Add FRED-related VMCS field checks Xin Li (Intel)
2025-07-23 17:53 ` [PATCH v5 22/23] KVM: nVMX: Allow VMX FRED controls Xin Li (Intel)
2025-07-23 17:53 ` [PATCH v5 23/23] KVM: nVMX: Add prerequisites to SHADOW_FIELD_R[OW] macros Xin Li (Intel)

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