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 C3A77298CAB for ; Tue, 22 Sep 2026 00:13:42 +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=1790036032; cv=none; b=fdNlwY7nO3X+SBsPeW0HTU4MDjUctgyGFr2uLbZYFOrgs8EsCghUFEp6f9lj9qWAW+3ihuwjECUNkchBuQ003AN7C7maHXkKJkvFPbO6GTapde/jeMDe34pTI53GNFznV/PXZy/9Vz5paBEJPnXbLeYfdvKu01w0Cp9VYNbxsFM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790036032; c=relaxed/simple; bh=8hkynfdu3qiULMUVYcyhuzcTSpgySEmn1WUnJFWpxKs=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=MTRV4nzu1FgYcrBA3FnFQSoVB/Q7E3kuSo4nMgYzBrnnHguW5v1ESxUKrgIBYpQyiEy4VmAY5+4VFy3GT4BdRNB4FC1w7sIcQMDtNel9JkO6NbrTpMVtZh9RsRfHjs7oYcKWFZI2gnrlQ6M5wvGMKC63TqEQ1/P5hXyMhhdGgFQ= 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=g8uyAqky; 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="g8uyAqky" Received: by mail-pf1-f199.google.com with SMTP id d2e1a72fcca58-8716b158692so1617431b3a.3 for ; Mon, 21 Sep 2026 17:13:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1790036022; x=1790640822; 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=1abdFyW8+E6I798OukP3jAN+Bgv2ctuNheDkfba7TQA=; b=g8uyAqkyWWiQJgFx4Rns0exupjnv4x0BzODcp08OS9B3FJEGuOYZQTLDYWUYX5VP3C KYcPH5Uyx/uxsPu3z7Ncex8VrYqhkYm59fmFhGFL7w8aNbAUo/w/7cjHpa+Xm+IS1nNG lNuATo2v1zpbfwgqJYJI+iaLxJLh0ViVAFJLiIgh9PqM7d6OnteEkDD1cQIQbxNxZ/ku 7lKHoxHetSC5nAaLtRYq+RemwmwpPKbvVRHv0wFuqRFkdNtuDxtI95wYa854BH/+LO7J B080GjKcALqpBAxLIEldnuOycpgWGE7JKDGJZff2oDwUjf0v6hL9YDc0JNHZBF0iXb9z NVEA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1790036022; x=1790640822; 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=1abdFyW8+E6I798OukP3jAN+Bgv2ctuNheDkfba7TQA=; b=xzNVRtZpZH6g0ExB2Xv8foJxKwkcYV1+Am+xMZqqi3+KlV1nLTY8eIfyDDoFZwSVrX 71eJk7Gz7RZGH5fbQbHdeLKS6s54/kS5vURHZGcEqKmp2zzikGWy8wGuTYdUHz1n5ZcZ 2l9+r9zNjvrzOHhO0PYc/WPVBK0tL7K/yeJpNrQGP1237YBl2R9LTzVcTslcW2v13fbz 1SnBs5wWZ6xPrumVTzQDsWyWfJ1wy2+8oEz2pf+x24EvCPu3dEd/Xsz6r0NKiBuEMTrv /G7aDdquDIqYL6qoiRYgUfd6mBvPFwJdluVDCOdcUDjU683Ov8ebV6u+9+SFuR5ISWUy aUMw== X-Forwarded-Encrypted: i=1; AKwUvBzcOUA5gWZM5LHrkPPi2N5cF+/00DOVKCc3BeQ9ilCStLwQ8sY97hEQ1k2aaxXm7eGezDk=@vger.kernel.org X-Gm-Message-State: AFuF++mXkU9hzqqJrMzIhFHY91Wvzs5V3AWqkwSPcMACmMvn8rXTjbxJ Z4rWn0D4RW82OQx9YLSXcn2NPOTwqgHrSZQ1a/zhHSrKtSSW3RievObDjfgYPgaUty/2bNFPxY6 n1X3lZw== X-Received: from pfbdl2.prod.google.com ([2002:a05:6a00:4902:b0:870:7bb4:8565]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a00:288a:b0:87b:784b:455c with SMTP id d2e1a72fcca58-87b784b5205mr2503863b3a.56.1790036021541; Mon, 21 Sep 2026 17:13:41 -0700 (PDT) Reply-To: Sean Christopherson Date: Mon, 21 Sep 2026 17:13:32 -0700 In-Reply-To: <20260922001332.1121266-1-seanjc@google.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260922001332.1121266-1-seanjc@google.com> X-Mailer: git-send-email 2.55.0.1082.g2b9226bbc0-goog Message-ID: <20260922001332.1121266-7-seanjc@google.com> Subject: [PATCH v5 6/6] 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 , Ackerley Tng , 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 Reviewed-by: David Hildenbrand (Arm) Reviewed-by: Ackerley Tng 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 80932f4ec4a3..826d26036926 100644 --- a/virt/kvm/guest_memfd.c +++ b/virt/kvm/guest_memfd.c @@ -677,7 +677,7 @@ int kvm_gmem_prepare_memory_region(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 = offset >> PAGE_SHIFT; if (kvm_gmem_supports_mmap(inode)) slot->flags |= KVM_MEMSLOT_GMEM_ONLY; -- 2.55.0.1082.g2b9226bbc0-goog