linux-kernel - [PATCH 6/6] KVM: SEV: use scoped mutex guard in sev_asid

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Message-ID: <20251219114238.3797364-7-clopez@suse.de>
Date: Fri, 19 Dec 2025 12:42:01 +0100
From: Carlos López <clopez@...e.de>
To: kvm@...r.kernel.org,
	seanjc@...gle.com,
	pbonzini@...hat.com
Cc: tglx@...utronix.de,
	mingo@...hat.com,
	bp@...en8.de,
	dave.hansen@...ux.intel.com,
	x86@...nel.org,
	hpa@...or.com,
	linux-kernel@...r.kernel.org,
	Carlos López <clopez@...e.de>
Subject: [PATCH 6/6] KVM: SEV: use scoped mutex guard in sev_asid_new()

Simplify the lock management in sev_asid_new() by using a mutex guard,
automatically releasing the mutex when following the goto.

Signed-off-by: Carlos López <clopez@...e.de>
---
 arch/x86/kvm/svm/sev.c | 24 ++++++++++--------------
 1 file changed, 10 insertions(+), 14 deletions(-)

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 5f46b7f073b0..95430d456a6f 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -232,24 +232,20 @@ static int sev_asid_new(struct kvm_sev_info *sev, unsigned long vm_type)
 		return ret;
 	}
 
-	mutex_lock(&sev_bitmap_lock);
-
+	scoped_guard(mutex, &sev_bitmap_lock) {
 again:
-	asid = find_next_zero_bit(sev_asid_bitmap, max_asid + 1, min_asid);
-	if (asid > max_asid) {
-		if (retry && __sev_recycle_asids(min_asid, max_asid)) {
-			retry = false;
-			goto again;
+		asid = find_next_zero_bit(sev_asid_bitmap, max_asid + 1, min_asid);
+		if (asid > max_asid) {
+			if (retry && __sev_recycle_asids(min_asid, max_asid)) {
+				retry = false;
+				goto again;
+			}
+			ret = -EBUSY;
+			goto e_uncharge;
 		}
-		mutex_unlock(&sev_bitmap_lock);
-		ret = -EBUSY;
-		goto e_uncharge;
+		__set_bit(asid, sev_asid_bitmap);
 	}
 
-	__set_bit(asid, sev_asid_bitmap);
-
-	mutex_unlock(&sev_bitmap_lock);
-
 	sev->asid = asid;
 	return 0;
 e_uncharge:
-- 
2.51.0