[PATCH 17/21] KVM: SEV: use mutex guard in sev_mem_enc_ioctl()

[Sean Christopherson <seanjc@google.com>]

From: Carlos López <clopez@suse.de>

Simplify the error paths in sev_mem_enc_ioctl() by using a mutex guard,
allowing early return instead of using gotos.

Signed-off-by: Carlos López <clopez@suse.de>
Link: https://patch.msgid.link/20260120201013.3931334-5-clopez@suse.de
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 arch/x86/kvm/svm/sev.c | 25 ++++++++-----------------
 1 file changed, 8 insertions(+), 17 deletions(-)

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index b559d7141ae9..d71241e8de95 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -2637,30 +2637,24 @@ int sev_mem_enc_ioctl(struct kvm *kvm, void __user *argp)
 	if (copy_from_user(&sev_cmd, argp, sizeof(struct kvm_sev_cmd)))
 		return -EFAULT;
 
-	mutex_lock(&kvm->lock);
+	guard(mutex)(&kvm->lock);
 
 	/* Only the enc_context_owner handles some memory enc operations. */
 	if (is_mirroring_enc_context(kvm) &&
-	    !is_cmd_allowed_from_mirror(sev_cmd.id)) {
-		r = -EINVAL;
-		goto out;
-	}
+	    !is_cmd_allowed_from_mirror(sev_cmd.id))
+		return -EINVAL;
 
 	/*
 	 * Once KVM_SEV_INIT2 initializes a KVM instance as an SNP guest, only
 	 * allow the use of SNP-specific commands.
 	 */
-	if (sev_snp_guest(kvm) && sev_cmd.id < KVM_SEV_SNP_LAUNCH_START) {
-		r = -EPERM;
-		goto out;
-	}
+	if (sev_snp_guest(kvm) && sev_cmd.id < KVM_SEV_SNP_LAUNCH_START)
+		return -EPERM;
 
 	switch (sev_cmd.id) {
 	case KVM_SEV_ES_INIT:
-		if (!sev_es_enabled) {
-			r = -ENOTTY;
-			goto out;
-		}
+		if (!sev_es_enabled)
+			return -ENOTTY;
 		fallthrough;
 	case KVM_SEV_INIT:
 		r = sev_guest_init(kvm, &sev_cmd);
@@ -2732,15 +2726,12 @@ int sev_mem_enc_ioctl(struct kvm *kvm, void __user *argp)
 		r = snp_enable_certs(kvm);
 		break;
 	default:
-		r = -EINVAL;
-		goto out;
+		return -EINVAL;
 	}
 
 	if (copy_to_user(argp, &sev_cmd, sizeof(struct kvm_sev_cmd)))
 		r = -EFAULT;
 
-out:
-	mutex_unlock(&kvm->lock);
 	return r;
 }
 
-- 
2.53.0.473.g4a7958ca14-goog