linux-kernel - [PATCH v2 06/10] KVM: SVM: Simplify request+kick logic in SNP AP Creation handling

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Message-ID: <20250227012541.3234589-7-seanjc@google.com>
Date: Wed, 26 Feb 2025 17:25:37 -0800
From: Sean Christopherson <seanjc@...gle.com>
To: Sean Christopherson <seanjc@...gle.com>, Paolo Bonzini <pbonzini@...hat.com>
Cc: kvm@...r.kernel.org, linux-kernel@...r.kernel.org, 
	Naveen N Rao <naveen@...nel.org>, Kim Phillips <kim.phillips@....com>, 
	Tom Lendacky <thomas.lendacky@....com>, Alexey Kardashevskiy <aik@....com>, 
	Pankaj Gupta <pankaj.gupta@....com>
Subject: [PATCH v2 06/10] KVM: SVM: Simplify request+kick logic in SNP AP
 Creation handling

Drop the local "kick" variable and the unnecessary "fallthrough" logic
from sev_snp_ap_creation(), and simply pivot on the request when deciding
whether or not to immediate force a state update on the target vCPU.

No functional change intended.

Reviewed-by: Pankaj Gupta <pankaj.gupta@....com>
Reviewed-by: Tom Lendacky <thomas.lendacky@....com>
Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 arch/x86/kvm/svm/sev.c | 15 +++++----------
 1 file changed, 5 insertions(+), 10 deletions(-)

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index bad5834ec143..ccac840ee7be 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -3938,7 +3938,6 @@ static int sev_snp_ap_creation(struct vcpu_svm *svm)
 	struct vcpu_svm *target_svm;
 	unsigned int request;
 	unsigned int apic_id;
-	bool kick;
 	int ret;
 
 	request = lower_32_bits(svm->vmcb->control.exit_info_1);
@@ -3956,18 +3955,10 @@ static int sev_snp_ap_creation(struct vcpu_svm *svm)
 
 	target_svm = to_svm(target_vcpu);
 
-	/*
-	 * The target vCPU is valid, so the vCPU will be kicked unless the
-	 * request is for CREATE_ON_INIT.
-	 */
-	kick = true;
-
 	mutex_lock(&target_svm->sev_es.snp_vmsa_mutex);
 
 	switch (request) {
 	case SVM_VMGEXIT_AP_CREATE_ON_INIT:
-		kick = false;
-		fallthrough;
 	case SVM_VMGEXIT_AP_CREATE:
 		if (vcpu->arch.regs[VCPU_REGS_RAX] != sev->vmsa_features) {
 			vcpu_unimpl(vcpu, "vmgexit: mismatched AP sev_features [%#lx] != [%#llx] from guest\n",
@@ -4012,7 +4003,11 @@ static int sev_snp_ap_creation(struct vcpu_svm *svm)
 
 	target_svm->sev_es.snp_ap_waiting_for_reset = true;
 
-	if (kick) {
+	/*
+	 * Unless Creation is deferred until INIT, signal the vCPU to update
+	 * its state.
+	 */
+	if (request != SVM_VMGEXIT_AP_CREATE_ON_INIT) {
 		kvm_make_request(KVM_REQ_UPDATE_PROTECTED_GUEST_STATE, target_vcpu);
 		kvm_vcpu_kick(target_vcpu);
 	}
-- 
2.48.1.711.g2feabab25a-goog