Commit 432727f1 authored by Sean Christopherson's avatar Sean Christopherson
Browse files

KVM: VMX: Always inline to_vmx() and to_kvm_vmx() 



Tag to_vmx() and to_kvm_vmx() __always_inline as they both just reflect
the passed in pointer (the embedded struct is the first field in the
container), and drop the @vmx param from vmx_vcpu_enter_exit(), which
likely existed purely to make noinstr validation happy.

Amusingly, when the compiler decides to not inline the helpers, e.g. for
KASAN builds, to_vmx() and to_kvm_vmx() may end up pointing at the same
symbol, which generates very confusing objtool warnings.  E.g. the use of
to_vmx() in a future patch led to objtool complaining about to_kvm_vmx(),
and only once all use of to_kvm_vmx() was commented out did to_vmx() pop
up in the obj tool report.

  vmlinux.o: warning: objtool: vmx_vcpu_enter_exit+0x160: call to to_kvm_vmx()
                               leaves .noinstr.text section

Acked-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20221213060912.654668-5-seanjc@google.com


Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
parent 11633f69

arch/x86/kvm/vmx/vmx.c

+3 −2
Original line number Diff line number Diff line
@@ -7171,9 +7171,10 @@ static fastpath_t vmx_exit_handlers_fastpath(struct kvm_vcpu *vcpu) 
}



static noinstr void vmx_vcpu_enter_exit(struct kvm_vcpu *vcpu,

					struct vcpu_vmx *vmx,

					unsigned int flags)

{

	struct vcpu_vmx *vmx = to_vmx(vcpu);



	guest_state_enter_irqoff();



	/* L1D Flush includes CPU buffer clear to mitigate MDS */
@@ -7291,7 +7292,7 @@ static fastpath_t vmx_vcpu_run(struct kvm_vcpu *vcpu) 
	kvm_wait_lapic_expire(vcpu);



	/* The actual VMENTER/EXIT is in the .noinstr.text section. */

	vmx_vcpu_enter_exit(vcpu, vmx, __vmx_vcpu_run_flags(vmx));

	vmx_vcpu_enter_exit(vcpu, __vmx_vcpu_run_flags(vmx));



	/* All fields are clean at this point */

	if (static_branch_unlikely(&enable_evmcs)) {

arch/x86/kvm/vmx/vmx.h

+2 −2
Original line number Diff line number Diff line
@@ -640,12 +640,12 @@ BUILD_CONTROLS_SHADOW(tertiary_exec, TERTIARY_VM_EXEC_CONTROL, 64) 
				(1 << VCPU_EXREG_EXIT_INFO_1) | \

				(1 << VCPU_EXREG_EXIT_INFO_2))



static inline struct kvm_vmx *to_kvm_vmx(struct kvm *kvm)

static __always_inline struct kvm_vmx *to_kvm_vmx(struct kvm *kvm)

{

	return container_of(kvm, struct kvm_vmx, kvm);

}



static inline struct vcpu_vmx *to_vmx(struct kvm_vcpu *vcpu)

static __always_inline struct vcpu_vmx *to_vmx(struct kvm_vcpu *vcpu)

{

	return container_of(vcpu, struct vcpu_vmx, vcpu);

}