KVM: x86: Check kvm_rebooting in kvm_spurious_fault() (4b526de5) · Commits · 戴 / test

Explicitly check kvm_rebooting in kvm_spurious_fault() prior to invoking BUG(), as opposed to assuming the caller has already done so. Letting kvm_spurious_fault() be called "directly" will allow VMX to better optimize its low level assembly flows. As a happy side effect, kvm_spurious_fault() no longer needs to be marked as a dead end since it doesn't unconditionally BUG(). Acked-by:

Paolo Bonzini <pbonzini@redhat.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by:

Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by:

Paolo Bonzini <pbonzini@redhat.com>

arch/x86/include/asm/kvm_host.h

+1 −1

Original line number	Diff line number	Diff line
		@@ -1534,7 +1534,7 @@ enum {
		#define kvm_arch_vcpu_memslots_id(vcpu) ((vcpu)->arch.hflags & HF_SMM_MASK ? 1 : 0)
		#define kvm_memslots_for_spte_role(kvm, role) __kvm_memslots(kvm, (role).smm)

		asmlinkage void __noreturn kvm_spurious_fault(void);
		asmlinkage void kvm_spurious_fault(void);

		/*
		* Hardware virtualization extension instructions may fault if a

arch/x86/kvm/x86.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -360,6 +360,7 @@ EXPORT_SYMBOL_GPL(kvm_set_apic_base);
		asmlinkage __visible void kvm_spurious_fault(void)
		{
		/* Fault while not rebooting. We want the trace. */
		if (!kvm_rebooting)
		BUG();
		}
		EXPORT_SYMBOL_GPL(kvm_spurious_fault);

tools/objtool/check.c

+0 −1

Original line number	Diff line number	Diff line
		@@ -138,7 +138,6 @@ static bool __dead_end_function(struct objtool_file file, struct symbol func,
		"do_task_dead",
		"__module_put_and_exit",
		"complete_and_exit",
		"kvm_spurious_fault",
		"__reiserfs_panic",
		"lbug_with_loc",
		"fortify_panic",

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