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[92.22.18.152]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-485268859f1sm743165e9.2.2026.03.05.15.28.47 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 05 Mar 2026 15:28:47 -0800 (PST) X-Outflank-Mailman: Message body and most headers restored to incoming version X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 102f392a-18eb-11f1-b164-2bf370ae4941 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=citrix.com; s=google; t=1772753328; x=1773358128; darn=lists.xenproject.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=4vF9oHZvcy9raonXFUwX0+3Jx8cqQFifTNwFvrPALvY=; b=rnYxs1W+0C0cJAv7EsqchVOGrK2ziULp0JeZwBMXUqu67tTfSeXtwMKWOuYF12dHCy Of4T4+ESXcWR+TX1KvvsVOnbAGmKWPR95v9iRArydxUCU98ik0qVr+8/GMwjUDhD6adH qlOyQfePib5eDoHwN/lD5d8pGt/4cq5N9xck8= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1772753328; x=1773358128; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=4vF9oHZvcy9raonXFUwX0+3Jx8cqQFifTNwFvrPALvY=; b=fx55aDh/dueL76CzoIIp/Uhmx56qh3yc67l9AALL6xySg1V4R72F1QCgoP1G1vyx3H CTz2fw6uW87RuROcy65kk+1QMwCq4w+0KKctHL5N9uOjBehCFbzewqXWqf9H8Q3C4GH8 BjuNv15F3Q62/PuzTnbWgxo9pc0GKSwzg/YNiqI3lXDH6jVNP82BfTNmymkMu2JGwJOQ /ie6/b1xDGuaKfbx0DA/OmxEq61YOz4gq5njQ6TSPIMWfXRhMYNcuSftJlVVvJ+0XPwU HfPvJXJbXXBPQV4dqMj/TLDJSs8Cj2dk588nAUN/7Ouo84+iHRGwFjYP5ZuyNHTQWF+l pAKQ== X-Gm-Message-State: AOJu0YxEhkhdLicd8TD3+rge2vBwfmGLlDIbOkU+1sGa8ou8eRt4x48e 5rt18TjJnJhsAXQDH1lS88aU7wx0aMEakAqnjT8vr+yF7/owBtxxu5Os/fGjEImC6NV/ObKv5WD 5sNaD X-Gm-Gg: ATEYQzwGl/LO9TlhCO/lH08jV/hdP7n5VFVWXmM0yH01NTrrwm/xhr5FzsGWJ4zCgDL yEOJuZf54+SwrxD5RY7HDwcLdxAO2hERQRrGt0elrgSKyFaQrl8aLOhN99Ky9KecDHcyo2e7TvU TjZiUnL8Bxlh/fl8PIas6nJMKm9HbUxe4EMOiUIRrArCsmrHgRMjITPjGHD8ELbhhMBgYNdb9km +mTtYykFq99iVlAQMHiNR4aMXBGEkGNRbAPm7zV28kTQSOZk8blRMWZz1Vl9m2vB5Y9tggw3GcO r9F1SLcBLzlDak+eOPC0iJc9d6PYEgerFdphWgLj8OAJezgMCdpMXp4GpvceH7tSwnCElvxTma9 gmwjZkEJ7dNQuS+Vi+ZjqdbR5eKY+XcbUE4trUMYYBMK8IWVQS6MkMMuynJnBlAo6OCVcBHIIsW 38awS84V0oAjNQxkUjQYDbGNdca4WS7AyzzbWxwaYxKzmWXxNVMP+fDPu11mrHjmd7PrXjwY4= X-Received: by 2002:a05:600c:3b07:b0:483:43da:6c87 with SMTP id 5b1f17b1804b1-4852697965dmr80705e9.33.1772753328227; Thu, 05 Mar 2026 15:28:48 -0800 (PST) From: Andrew Cooper To: Xen-devel Cc: Andrew Cooper , Stefano Stabellini , Julien Grall , Volodymyr Babchuk , Bertrand Marquis , Michal Orzel , Jan Beulich , =?UTF-8?q?Roger=20Pau=20Monn=C3=A9?= , Ayan Kumar Halder Subject: [PATCH] ARM/vgic: Use for_each_set_bit() in vgic_sync_from_lrs() Date: Thu, 5 Mar 2026 23:28:45 +0000 Message-Id: <20260305232845.62024-1-andrew.cooper3@citrix.com> X-Mailer: git-send-email 2.39.5 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable X-ZohoMail-DKIM: pass (identity @citrix.com) X-ZM-MESSAGEID: 1772753362525158500 lr_mask doesn't have bits set beyond the hardware limit, with the upper bits remaining zero. Therefore, for_each_set_bit() is a better option. For ARM64, bloat-o-meter reports: Function old new delta vgic_sync_from_lrs 208 168 -40 but this doesn't highlight that it also removes a call to find_next_bit() f= rom each loop iteration. No functional change. Signed-off-by: Andrew Cooper Acked-by: Julien Grall Reviewed-by: Michal Orzel --- CC: Stefano Stabellini CC: Julien Grall CC: Volodymyr Babchuk CC: Bertrand Marquis CC: Michal Orzel CC: Jan Beulich CC: Roger Pau Monn=C3=A9 CC: Ayan Kumar Halder RFC. This form also doesn't suffer an OoB read when lr_mask changes type. --- xen/arch/arm/gic-vgic.c | 7 +------ 1 file changed, 1 insertion(+), 6 deletions(-) diff --git a/xen/arch/arm/gic-vgic.c b/xen/arch/arm/gic-vgic.c index ea48c5375a91..fae80e6cd293 100644 --- a/xen/arch/arm/gic-vgic.c +++ b/xen/arch/arm/gic-vgic.c @@ -241,9 +241,7 @@ static void gic_update_one_lr(struct vcpu *v, int i) =20 void vgic_sync_from_lrs(struct vcpu *v) { - int i =3D 0; unsigned long flags; - unsigned int nr_lrs =3D gic_get_nr_lrs(); =20 /* The idle domain has no LRs to be cleared. Since gic_restore_state * doesn't write any LR registers for the idle domain they could be @@ -255,11 +253,8 @@ void vgic_sync_from_lrs(struct vcpu *v) =20 spin_lock_irqsave(&v->arch.vgic.lock, flags); =20 - while ((i =3D find_next_bit((const unsigned long *) &this_cpu(lr_mask), - nr_lrs, i)) < nr_lrs ) { + for_each_set_bit ( i, this_cpu(lr_mask) ) gic_update_one_lr(v, i); - i++; - } =20 spin_unlock_irqrestore(&v->arch.vgic.lock, flags); } base-commit: bdd49cc2f61510797a47ad81486be653633ab3ee --=20 2.39.5