From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pf1-f200.google.com (mail-pf1-f200.google.com [209.85.210.200]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id ECF5C4A64E6 for ; Wed, 2 Sep 2026 18:20:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.200 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788373229; cv=none; b=RmWwJ0Ca0duBoMNuNrwxXMTwDocXHHevl3K4WU8vGN8HrnsbG4x2w9Esp8OpoU7MXbdbOg2DMM8dRSsxjvc2p3YJd4cgQmL9Kcr1Amb+dMHdmnYgBVrvhmmVanzJyQ0ZOgdXbfPBEjLSUAAOyYrv4c28VUjG7Qm707yFFxxvOuw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788373229; c=relaxed/simple; bh=R/K5UWhNFqj3ZcM4cwx3BkSTRdQNwDAHdg7ioV3umQ0=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=NTjBDekT6E0PsnYU8w1jEzWWWno1NAIffX2RkKkpdUC7DSABsN7jiT/cL9/t1YttSVEL1tp79euf8hdPssM6pTtNrcx2bAIZDiCu0G+Cszzk5qN15BoHx9+latNsoKNippQkxSA6sUdByNUuvioYpjvOLqGj6ExEC/5cw9vWJQo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=PYeP9zHg; arc=none smtp.client-ip=209.85.210.200 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="PYeP9zHg" Received: by mail-pf1-f200.google.com with SMTP id d2e1a72fcca58-8485d853b08so2185065b3a.1 for ; Wed, 02 Sep 2026 11:20:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1788373227; x=1788978027; darn=vger.kernel.org; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:reply-to:from:to:cc:subject:date:message-id :reply-to:content-type; bh=ER0xLmEoKu3WiTJI8f5zgte0kZ2FP3/FFPxtMYpTVLw=; b=PYeP9zHgSsv3a8T64C2MCHn4cgmAEXPMMuCjxTxwRMY16GG355/xmzjZC+0LRkPQqf lq5ed/mQAUvKCSladaFzm1vkvHkarhcqIgXycYR3s7FikiwCbzrZPoyBaauuAc7W3wKc KNF4ByVrakx35n9uPIAm/+MHvUwG0QDPajl8uV55vKOm8zZoQxyXWCm2t/39CTYj54BV LuuAPRViZf3tz2dcBELGhBOjHcMw23OIR21gf3v6f24DT7g42SCAio61HMlTtc1bs8YB +b9SxDzgN4Pdhm9zY6sUUCRuZ3+YgaJbS6dYRMzz0hin8eY+j37pQLPOz2Nm68n82RtW 060g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1788373227; x=1788978027; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:reply-to:x-gm-message-state:from:to:cc:subject :date:message-id:reply-to:content-type; bh=ER0xLmEoKu3WiTJI8f5zgte0kZ2FP3/FFPxtMYpTVLw=; b=lztZ2ZPPPcHTxSk0c1qsyTCdDYo94KITsPqWZ/vRReKwM7YyJl7dChCWO0caNww/nn dmcj4C8z0FT4Apa9CMzlyvZw3G+XuzP53qYnyEvU6DbYWSZWHfemgNgKtXkGg4NkNRuA 7dcVh/HlOkvoA2EkEW2ch2KfFUXsWiEMddxvrGp+NSXe1uIremTWdzAXOr8SQWFSGB2V N8rmqvCD2lK6UI5IPp9U4x5RhD9fK38fqz3zGAbDBfA5MLXUGAE+VxUI9EDGiz3A6CPh iRg/OsDtx02IbisoOgyv8WtuK3uik2lXY1DhIbYu97dLTH4DqmnE5tlrpsZGcrzD9Lf3 CpkQ== X-Forwarded-Encrypted: i=1; AKwUvBzsevSX6NgFZ85l7RdsfFoF0bPjdTT9N1KpQRf6hZeOxYo0NYtlbFv8jucNU5UTE+mT63M=@vger.kernel.org X-Gm-Message-State: AFuF++mhR10B2ZtSUD64/CBptYLukkSKGhjwxazdf4EkIlmUQZUKjLue z/aNusx6wwUCCj7e8QtRuw9zDs+LyvwYErYUN/d5EThfbd1/IheFzUDLIEAFXJluMwGdyoDRzop Tj5iglQ== X-Received: from pfbfb9.prod.google.com ([2002:a05:6a00:2d89:b0:85f:34bc:42ef]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a00:9295:b0:837:e9cc:d474 with SMTP id d2e1a72fcca58-85ed1d07a02mr9437959b3a.2.1788373226909; Wed, 02 Sep 2026 11:20:26 -0700 (PDT) Reply-To: Sean Christopherson Date: Wed, 2 Sep 2026 11:20:20 -0700 In-Reply-To: <20260902182020.2615443-1-seanjc@google.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260902182020.2615443-1-seanjc@google.com> X-Mailer: git-send-email 2.55.0.970.g62bdec98f9-goog Message-ID: <20260902182020.2615443-5-seanjc@google.com> Subject: [PATCH v2 4/4] KVM: guest_memfd: Drop superfluous WRITE_ONCE() when binding a memslot From: Sean Christopherson To: Sean Christopherson , Paolo Bonzini Cc: David Hildenbrand , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Stefan Teodorescu , Dennis Tighe , Sashiko Bot , Yan Zhao Content-Type: text/plain; charset="UTF-8" Drop the superfluous WRITE_ONCE() when setting a memslot's guest_memfd file during initial binding, as the memslot *must* be inactive and unreachable. The superfluous WRITE_ONCE() was added by commit 67b43038ce14 ("KVM: guest_memfd: Remove RCU-protected attribute from slot->gmem.file") to maintain rough "parity" with the existing rcu_assign_pointer(), not realizing that the only reason rcu_assign_pointer() was used was to make sparse and other checkers happy. Cc: Yan Zhao Signed-off-by: Sean Christopherson --- virt/kvm/guest_memfd.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c index 2c8d8735de5f..323159c9b5f3 100644 --- a/virt/kvm/guest_memfd.c +++ b/virt/kvm/guest_memfd.c @@ -653,7 +653,7 @@ int kvm_gmem_bind(struct kvm *kvm, struct kvm_memory_slot *slot, * kvm_gmem_bind() must occur on a new memslot. Because the memslot * is not visible yet, kvm_gmem_get_pfn() is guaranteed to see the file. */ - WRITE_ONCE(slot->gmem.file, file); + slot->gmem.file = file; slot->gmem.pgoff = start; if (kvm_gmem_supports_mmap(inode)) slot->flags |= KVM_MEMSLOT_GMEM_ONLY; -- 2.55.0.970.g62bdec98f9-goog