From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pf1-f199.google.com (mail-pf1-f199.google.com [209.85.210.199]) (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 F38B1478E3E for ; Wed, 2 Sep 2026 18:20:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.199 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788373230; cv=none; b=aYdyw6/3+Rj9iHrrzSNhMTS4kj0O/TlDNpZobmRPPdc1i+k0mdDiGttaLZxARyS0kpUFPrHfHWNR8hizNTk2SRJnwLV7w1bNn1JFHFpjTF/3g9LXzposQtpMwju3LPt0gZPlu324YHz1vCI0ZkLz0hSP8Sd8uFJuKZ8B+oV31b8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788373230; c=relaxed/simple; bh=R/K5UWhNFqj3ZcM4cwx3BkSTRdQNwDAHdg7ioV3umQ0=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=fVzEY07ZeuAaaiij10is1wQ3IFWsxORhNd3yh7lGalp/WfuSOMQBVuTdzs7roLszESeOUyasRI1mXzaaa3sg0EevGdjhagOhITLvrDnxJse759eRUM0P4gKCeHmsf+7x2DzyDOxgaB3Dne/t5OmMhW1lpe+IPplgJyV7xCG83C0= 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=209.85.210.199 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-f199.google.com with SMTP id d2e1a72fcca58-8535db07af9so722547b3a.2 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=S3yJ8okr02P6HwZAaqTa7+Oj6XuqToNS0gdwUA25O0RBlZNZKIcMZeAJzUkvARK3tC AAT38c9HLhQ7k6zkZcBWR5RR908oNHuCJtL3Of+m0kAHMVcCUiMFK3Bv7ieJDNZTJGVO MY+i9IlSIYGn/qzYF167TZe5++UplT4TT/gBwq1O43BKWvzNEI1PpBnXIFHv/VXhyFYT CKqfb3GIobegffpR+fwZzU8yJWbbta7g1l/X0PPC6dz2qxiobk8q9l2ZPSpcM89Nupar HjQhK+8hK/MccLXH0gwuudTfE3ElcWuRDz3kr/+2DUQ8HowSdK9p+q+6+0KvA6DcfyoA zNwQ== X-Forwarded-Encrypted: i=1; AKwUvBzmgO2YA/trrjONCN6d1uF93fILcnLhR6fzqHFOTHpza53pDNgO0QFpyr6jgJI4LhTDGfJE3BZDnJMK8+I=@vger.kernel.org X-Gm-Message-State: AFuF++k0lR6eUwhpOfrIoCxnlVFNhHyfqVq5rSPlowBh5W+JJG0UdxDA Ypy29s/te54zi9EkDfXYFEzSKW6l2HL0PwNPTI54lvMv7bJTFYFsV7zc7i6qYcKKGaMB1mCBmHt mbzHWkg== 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: linux-kernel@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