[PATCH v3 03/16] KVM: x86: Move "kvm_rebooting" to kernel as "virt_rebooting"

[Sean Christopherson <seanjc@google.com>]

Move "kvm_rebooting" to the kernel, exported for KVM, as one of many steps
towards extracting the innermost VMXON and EFER.SVME management logic out
of KVM and into to core x86.

For lack of a better name, call the new file "hw.c", to yield "virt
hardware" when combined with its parent directory.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 arch/x86/include/asm/virt.h | 11 +++++++++++
 arch/x86/kvm/svm/svm.c      |  3 ++-
 arch/x86/kvm/svm/vmenter.S  | 10 +++++-----
 arch/x86/kvm/vmx/tdx.c      |  3 ++-
 arch/x86/kvm/vmx/vmenter.S  |  2 +-
 arch/x86/kvm/vmx/vmx.c      |  5 +++--
 arch/x86/kvm/x86.c          | 17 ++++++++---------
 arch/x86/kvm/x86.h          |  1 -
 arch/x86/virt/Makefile      |  2 ++
 arch/x86/virt/hw.c          |  7 +++++++
 10 files changed, 41 insertions(+), 20 deletions(-)
 create mode 100644 arch/x86/include/asm/virt.h
 create mode 100644 arch/x86/virt/hw.c

diff --git a/arch/x86/include/asm/virt.h b/arch/x86/include/asm/virt.h
new file mode 100644
index 000000000000..131b9bf9ef3c
--- /dev/null
+++ b/arch/x86/include/asm/virt.h
@@ -0,0 +1,11 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef _ASM_X86_VIRT_H
+#define _ASM_X86_VIRT_H
+
+#include <linux/types.h>
+
+#if IS_ENABLED(CONFIG_KVM_X86)
+extern bool virt_rebooting;
+#endif
+
+#endif /* _ASM_X86_VIRT_H */
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 8f8bc863e214..0ae66c770ebc 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -44,6 +44,7 @@
 #include <asm/traps.h>
 #include <asm/reboot.h>
 #include <asm/fpu/api.h>
+#include <asm/virt.h>
 
 #include <trace/events/ipi.h>
 
@@ -495,7 +496,7 @@ static inline void kvm_cpu_svm_disable(void)
 
 static void svm_emergency_disable_virtualization_cpu(void)
 {
-	kvm_rebooting = true;
+	virt_rebooting = true;
 
 	kvm_cpu_svm_disable();
 }
diff --git a/arch/x86/kvm/svm/vmenter.S b/arch/x86/kvm/svm/vmenter.S
index 3392bcadfb89..d47c5c93c991 100644
--- a/arch/x86/kvm/svm/vmenter.S
+++ b/arch/x86/kvm/svm/vmenter.S
@@ -298,16 +298,16 @@ SYM_FUNC_START(__svm_vcpu_run)
 	RESTORE_GUEST_SPEC_CTRL_BODY
 	RESTORE_HOST_SPEC_CTRL_BODY (%_ASM_SP)
 
-10:	cmpb $0, _ASM_RIP(kvm_rebooting)
+10:	cmpb $0, _ASM_RIP(virt_rebooting)
 	jne 2b
 	ud2
-30:	cmpb $0, _ASM_RIP(kvm_rebooting)
+30:	cmpb $0, _ASM_RIP(virt_rebooting)
 	jne 4b
 	ud2
-50:	cmpb $0, _ASM_RIP(kvm_rebooting)
+50:	cmpb $0, _ASM_RIP(virt_rebooting)
 	jne 6b
 	ud2
-70:	cmpb $0, _ASM_RIP(kvm_rebooting)
+70:	cmpb $0, _ASM_RIP(virt_rebooting)
 	jne 8b
 	ud2
 
@@ -394,7 +394,7 @@ SYM_FUNC_START(__svm_sev_es_vcpu_run)
 	RESTORE_GUEST_SPEC_CTRL_BODY
 	RESTORE_HOST_SPEC_CTRL_BODY %sil
 
-3:	cmpb $0, kvm_rebooting(%rip)
+3:	cmpb $0, virt_rebooting(%rip)
 	jne 2b
 	ud2
 
diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
index 5df9d32d2058..0c790eb0bfa6 100644
--- a/arch/x86/kvm/vmx/tdx.c
+++ b/arch/x86/kvm/vmx/tdx.c
@@ -6,6 +6,7 @@
 #include <linux/misc_cgroup.h>
 #include <linux/mmu_context.h>
 #include <asm/tdx.h>
+#include <asm/virt.h>
 #include "capabilities.h"
 #include "mmu.h"
 #include "x86_ops.h"
@@ -1994,7 +1995,7 @@ int tdx_handle_exit(struct kvm_vcpu *vcpu, fastpath_t fastpath)
 	 * TDX_SEAMCALL_VMFAILINVALID.
 	 */
 	if (unlikely((vp_enter_ret & TDX_SW_ERROR) == TDX_SW_ERROR)) {
-		KVM_BUG_ON(!kvm_rebooting, vcpu->kvm);
+		KVM_BUG_ON(!virt_rebooting, vcpu->kvm);
 		goto unhandled_exit;
 	}
 
diff --git a/arch/x86/kvm/vmx/vmenter.S b/arch/x86/kvm/vmx/vmenter.S
index 4426d34811fc..8a481dae9cae 100644
--- a/arch/x86/kvm/vmx/vmenter.S
+++ b/arch/x86/kvm/vmx/vmenter.S
@@ -310,7 +310,7 @@ SYM_INNER_LABEL_ALIGN(vmx_vmexit, SYM_L_GLOBAL)
 	RET
 
 .Lfixup:
-	cmpb $0, _ASM_RIP(kvm_rebooting)
+	cmpb $0, _ASM_RIP(virt_rebooting)
 	jne .Lvmfail
 	ud2
 .Lvmfail:
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 967b58a8ab9d..fc6e3b620866 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -48,6 +48,7 @@
 #include <asm/msr.h>
 #include <asm/mwait.h>
 #include <asm/spec-ctrl.h>
+#include <asm/virt.h>
 #include <asm/vmx.h>
 
 #include <trace/events/ipi.h>
@@ -814,13 +815,13 @@ void vmx_emergency_disable_virtualization_cpu(void)
 	int cpu = raw_smp_processor_id();
 	struct loaded_vmcs *v;
 
-	kvm_rebooting = true;
+	virt_rebooting = true;
 
 	/*
 	 * Note, CR4.VMXE can be _cleared_ in NMI context, but it can only be
 	 * set in task context.  If this races with VMX is disabled by an NMI,
 	 * VMCLEAR and VMXOFF may #UD, but KVM will eat those faults due to
-	 * kvm_rebooting set.
+	 * virt_rebooting set.
 	 */
 	if (!(__read_cr4() & X86_CR4_VMXE))
 		return;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 77edc24f8309..69937d14f5e1 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -83,6 +83,8 @@
 #include <asm/intel_pt.h>
 #include <asm/emulate_prefix.h>
 #include <asm/sgx.h>
+#include <asm/virt.h>
+
 #include <clocksource/hyperv_timer.h>
 
 #define CREATE_TRACE_POINTS
@@ -700,9 +702,6 @@ static void drop_user_return_notifiers(void)
 		kvm_on_user_return(&msrs->urn);
 }
 
-__visible bool kvm_rebooting;
-EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_rebooting);
-
 /*
  * Handle a fault on a hardware virtualization (VMX or SVM) instruction.
  *
@@ -713,7 +712,7 @@ EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_rebooting);
 noinstr void kvm_spurious_fault(void)
 {
 	/* Fault while not rebooting.  We want the trace. */
-	BUG_ON(!kvm_rebooting);
+	BUG_ON(!virt_rebooting);
 }
 EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_spurious_fault);
 
@@ -13184,16 +13183,16 @@ int kvm_arch_enable_virtualization_cpu(void)
 void kvm_arch_shutdown(void)
 {
 	/*
-	 * Set kvm_rebooting to indicate that KVM has asynchronously disabled
+	 * Set virt_rebooting to indicate that KVM has asynchronously disabled
 	 * hardware virtualization, i.e. that errors and/or exceptions on SVM
 	 * and VMX instructions are expected and should be ignored.
 	 */
-	kvm_rebooting = true;
+	virt_rebooting = true;
 
 	/*
-	 * Ensure kvm_rebooting is visible before IPIs are sent to other CPUs
+	 * Ensure virt_rebooting is visible before IPIs are sent to other CPUs
 	 * to disable virtualization.  Effectively pairs with the reception of
-	 * the IPI (kvm_rebooting is read in task/exception context, but only
+	 * the IPI (virt_rebooting is read in task/exception context, but only
 	 * _needs_ to be read as %true after the IPI function callback disables
 	 * virtualization).
 	 */
@@ -13214,7 +13213,7 @@ void kvm_arch_disable_virtualization_cpu(void)
 	 * disable virtualization arrives.  Handle the extreme edge case here
 	 * instead of trying to account for it in the normal flows.
 	 */
-	if (in_task() || WARN_ON_ONCE(!kvm_rebooting))
+	if (in_task() || WARN_ON_ONCE(!virt_rebooting))
 		drop_user_return_notifiers();
 	else
 		__module_get(THIS_MODULE);
diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h
index b314649e5c02..94d4f07aaaa0 100644
--- a/arch/x86/kvm/x86.h
+++ b/arch/x86/kvm/x86.h
@@ -54,7 +54,6 @@ struct kvm_host_values {
 	u64 arch_capabilities;
 };
 
-extern bool kvm_rebooting;
 void kvm_spurious_fault(void);
 
 #define SIZE_OF_MEMSLOTS_HASHTABLE \
diff --git a/arch/x86/virt/Makefile b/arch/x86/virt/Makefile
index ea343fc392dc..6e485751650c 100644
--- a/arch/x86/virt/Makefile
+++ b/arch/x86/virt/Makefile
@@ -1,2 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0-only
 obj-y	+= svm/ vmx/
+
+obj-$(subst m,y,$(CONFIG_KVM_X86)) += hw.o
\ No newline at end of file
diff --git a/arch/x86/virt/hw.c b/arch/x86/virt/hw.c
new file mode 100644
index 000000000000..df3dc18d19b4
--- /dev/null
+++ b/arch/x86/virt/hw.c
@@ -0,0 +1,7 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/kvm_types.h>
+
+#include <asm/virt.h>
+
+__visible bool virt_rebooting;
+EXPORT_SYMBOL_FOR_KVM(virt_rebooting);
-- 
2.53.0.310.g728cabbaf7-goog