On Wed, 2021-10-27 at 17:10 +0300, Maxim Levitsky wrote:

On Fri, 2021-10-08 at 19:12 -0700, Sean Christopherson wrote:

quoted

Rename a variety of HLT-related helpers to free up the function name
"kvm_vcpu_halt" for future use in generic KVM code, e.g. to differentiate
between "block" and "halt".

No functional change intended.

Reviewed-by: David Matlack <dmatlack@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 arch/x86/include/asm/kvm_host.h |  2 +-
 arch/x86/kvm/vmx/nested.c       |  2 +-
 arch/x86/kvm/vmx/vmx.c          |  4 ++--
 arch/x86/kvm/x86.c              | 13 +++++++------
 4 files changed, 11 insertions(+), 10 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 7aafc27ce7a9..328103a520d3 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h

@@ -1689,7 +1689,7 @@ int kvm_emulate_monitor(struct kvm_vcpu *vcpu);
 int kvm_fast_pio(struct kvm_vcpu *vcpu, int size, unsigned short port, int in);
 int kvm_emulate_cpuid(struct kvm_vcpu *vcpu);
 int kvm_emulate_halt(struct kvm_vcpu *vcpu);
-int kvm_vcpu_halt(struct kvm_vcpu *vcpu);
+int kvm_emulate_halt_noskip(struct kvm_vcpu *vcpu);
 int kvm_emulate_ap_reset_hold(struct kvm_vcpu *vcpu);
 int kvm_emulate_wbinvd(struct kvm_vcpu *vcpu);
 

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index af1bbb73430a..d0237a441feb 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c

@@ -3619,7 +3619,7 @@ static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch)
 		    !(nested_cpu_has(vmcs12, CPU_BASED_INTR_WINDOW_EXITING) &&
 		      (vmcs12->guest_rflags & X86_EFLAGS_IF))) {
 			vmx->nested.nested_run_pending = 0;
-			return kvm_vcpu_halt(vcpu);
+			return kvm_emulate_halt_noskip(vcpu);
 		}
 		break;
 	case GUEST_ACTIVITY_WAIT_SIPI:

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 1c8b2b6e7ed9..5517893f12fc 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c

@@ -4741,7 +4741,7 @@ static int handle_rmode_exception(struct kvm_vcpu *vcpu,
 		if (kvm_emulate_instruction(vcpu, 0)) {
 			if (vcpu->arch.halt_request) {
 				vcpu->arch.halt_request = 0;
-				return kvm_vcpu_halt(vcpu);
+				return kvm_emulate_halt_noskip(vcpu);

Could you elaborate on why you choose _noskip suffix? 
 
As far as I see, kvm_vcpu_halt just calls __kvm_vcpu_halt with new VCPU run state/exit reason,
which is used only when local apic is not in the kernel (which is these days not that
supported configuration).

Other user of __kvm_vcpu_halt is something SEV related.
 
Best regards,
	Maxim Levitsky

quoted

 			}
 			return 1;
 		}

@@ -5415,7 +5415,7 @@ static int handle_invalid_guest_state(struct kvm_vcpu *vcpu)
 
 		if (vcpu->arch.halt_request) {
 			vcpu->arch.halt_request = 0;
-			return kvm_vcpu_halt(vcpu);
+			return kvm_emulate_halt_noskip(vcpu);
 		}
 
 		/*

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 4a52a08707de..9c23ae1d483d 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c

@@ -8649,7 +8649,7 @@ void kvm_arch_exit(void)
 #endif
 }
 
-static int __kvm_vcpu_halt(struct kvm_vcpu *vcpu, int state, int reason)
+static int __kvm_emulate_halt(struct kvm_vcpu *vcpu, int state, int reason)
 {
 	++vcpu->stat.halt_exits;
 	if (lapic_in_kernel(vcpu)) {

@@ -8661,11 +8661,11 @@ static int __kvm_vcpu_halt(struct kvm_vcpu *vcpu, int state, int reason)
 	}
 }
 
-int kvm_vcpu_halt(struct kvm_vcpu *vcpu)
+int kvm_emulate_halt_noskip(struct kvm_vcpu *vcpu)
 {
-	return __kvm_vcpu_halt(vcpu, KVM_MP_STATE_HALTED, KVM_EXIT_HLT);
+	return __kvm_emulate_halt(vcpu, KVM_MP_STATE_HALTED, KVM_EXIT_HLT);
 }
-EXPORT_SYMBOL_GPL(kvm_vcpu_halt);
+EXPORT_SYMBOL_GPL(kvm_emulate_halt_noskip);
 
 int kvm_emulate_halt(struct kvm_vcpu *vcpu)
 {

@@ -8674,7 +8674,7 @@ int kvm_emulate_halt(struct kvm_vcpu *vcpu)
 	 * TODO: we might be squashing a GUESTDBG_SINGLESTEP-triggered
 	 * KVM_EXIT_DEBUG here.
 	 */
-	return kvm_vcpu_halt(vcpu) && ret;
+	return kvm_emulate_halt_noskip(vcpu) && ret;
 }
 EXPORT_SYMBOL_GPL(kvm_emulate_halt);
 

@@ -8682,7 +8682,8 @@ int kvm_emulate_ap_reset_hold(struct kvm_vcpu *vcpu)
 {
 	int ret = kvm_skip_emulated_instruction(vcpu);
 
-	return __kvm_vcpu_halt(vcpu, KVM_MP_STATE_AP_RESET_HOLD, KVM_EXIT_AP_RESET_HOLD) && ret;
+	return __kvm_emulate_halt(vcpu, KVM_MP_STATE_AP_RESET_HOLD,
+					KVM_EXIT_AP_RESET_HOLD) && ret;
 }
 EXPORT_SYMBOL_GPL(kvm_emulate_ap_reset_hold);
 

Also while at it, why not to use say '__kvm_emulate_hlt' ('hlt' instead of 'halt') to 
put emphasis on the fact that we are emulating a cpu instruction?

Best regards,
	Maxim Levitsky