linux-kernel - [PATCH v4 10/19] x86/virt: KVM: Move VMXOFF helpers into KVM VMX

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Date:   Fri, 21 Jul 2023 13:18:50 -0700
From:   Sean Christopherson <seanjc@...gle.com>
To:     Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        Dave Hansen <dave.hansen@...ux.intel.com>, x86@...nel.org,
        Sean Christopherson <seanjc@...gle.com>,
        Paolo Bonzini <pbonzini@...hat.com>
Cc:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
        Andrew Cooper <Andrew.Cooper3@...rix.com>,
        Kai Huang <kai.huang@...el.com>, Chao Gao <chao.gao@...el.com>
Subject: [PATCH v4 10/19] x86/virt: KVM: Move VMXOFF helpers into KVM VMX

Now that VMX is disabled in emergencies via the virt callbacks, move the
VMXOFF helpers into KVM, the only remaining user.

No functional change intended.

Reviewed-by: Kai Huang <kai.huang@...el.com>
Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 arch/x86/include/asm/virtext.h | 42 ----------------------------------
 arch/x86/kvm/vmx/vmx.c         | 29 ++++++++++++++++++++---
 2 files changed, 26 insertions(+), 45 deletions(-)

diff --git a/arch/x86/include/asm/virtext.h b/arch/x86/include/asm/virtext.h
index b1171a5ad452..a27801f2bc71 100644
--- a/arch/x86/include/asm/virtext.h
+++ b/arch/x86/include/asm/virtext.h
@@ -19,48 +19,6 @@
 #include <asm/svm.h>
 #include <asm/tlbflush.h>
 
-/*
- * VMX functions:
- */
-/**
- * cpu_vmxoff() - Disable VMX on the current CPU
- *
- * Disable VMX and clear CR4.VMXE (even if VMXOFF faults)
- *
- * Note, VMXOFF causes a #UD if the CPU is !post-VMXON, but it's impossible to
- * atomically track post-VMXON state, e.g. this may be called in NMI context.
- * Eat all faults as all other faults on VMXOFF faults are mode related, i.e.
- * faults are guaranteed to be due to the !post-VMXON check unless the CPU is
- * magically in RM, VM86, compat mode, or at CPL>0.
- */
-static inline int cpu_vmxoff(void)
-{
-	asm_volatile_goto("1: vmxoff\n\t"
-			  _ASM_EXTABLE(1b, %l[fault])
-			  ::: "cc", "memory" : fault);
-
-	cr4_clear_bits(X86_CR4_VMXE);
-	return 0;
-
-fault:
-	cr4_clear_bits(X86_CR4_VMXE);
-	return -EIO;
-}
-
-static inline int cpu_vmx_enabled(void)
-{
-	return __read_cr4() & X86_CR4_VMXE;
-}
-
-/** Disable VMX if it is enabled on the current CPU
- */
-static inline void __cpu_emergency_vmxoff(void)
-{
-	if (cpu_vmx_enabled())
-		cpu_vmxoff();
-}
-
-
 /*
  * SVM functions:
  */
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 71571cd9adbb..6f4fcd82fa6e 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -47,7 +47,6 @@
 #include <asm/mshyperv.h>
 #include <asm/mwait.h>
 #include <asm/spec-ctrl.h>
-#include <asm/virtext.h>
 #include <asm/vmx.h>
 
 #include "capabilities.h"
@@ -744,6 +743,29 @@ static int vmx_set_guest_uret_msr(struct vcpu_vmx *vmx,
 	return ret;
 }
 
+/*
+ * Disable VMX and clear CR4.VMXE (even if VMXOFF faults)
+ *
+ * Note, VMXOFF causes a #UD if the CPU is !post-VMXON, but it's impossible to
+ * atomically track post-VMXON state, e.g. this may be called in NMI context.
+ * Eat all faults as all other faults on VMXOFF faults are mode related, i.e.
+ * faults are guaranteed to be due to the !post-VMXON check unless the CPU is
+ * magically in RM, VM86, compat mode, or at CPL>0.
+ */
+static int kvm_cpu_vmxoff(void)
+{
+	asm_volatile_goto("1: vmxoff\n\t"
+			  _ASM_EXTABLE(1b, %l[fault])
+			  ::: "cc", "memory" : fault);
+
+	cr4_clear_bits(X86_CR4_VMXE);
+	return 0;
+
+fault:
+	cr4_clear_bits(X86_CR4_VMXE);
+	return -EIO;
+}
+
 static void vmx_emergency_disable(void)
 {
 	int cpu = raw_smp_processor_id();
@@ -753,7 +775,8 @@ static void vmx_emergency_disable(void)
 			    loaded_vmcss_on_cpu_link)
 		vmcs_clear(v->vmcs);
 
-	__cpu_emergency_vmxoff();
+	if (__read_cr4() & X86_CR4_VMXE)
+		kvm_cpu_vmxoff();
 }
 
 static void __loaded_vmcs_clear(void *arg)
@@ -2818,7 +2841,7 @@ static void vmx_hardware_disable(void)
 {
 	vmclear_local_loaded_vmcss();
 
-	if (cpu_vmxoff())
+	if (kvm_cpu_vmxoff())
 		kvm_spurious_fault();
 
 	hv_reset_evmcs();
-- 
2.41.0.487.g6d72f3e995-goog