From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pf1-f198.google.com (mail-pf1-f198.google.com [209.85.210.198]) (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 C1CDE42C4F0 for ; Wed, 26 Aug 2026 16:52:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.198 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787763140; cv=none; b=d6zcoh8AeqUYYQFmB7Wwz/S/KypIphCkRX8ZRqQThSmYE1uHxm9itEbAJ7LErySUhn4vJFqMj7NzTUhiDyxgn8FlKRjH5TR5A1O0ST+MMWmn7KZ1qFbq85n8YC8+f9bSqdMnV2ucYVJL20fdfW5KgqQnFmdg7PVJMKexz4JfXTk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787763140; c=relaxed/simple; bh=iqbnxW81PVZ4JrYasvYkpNsH6AAm6QU/fKSXBKEPVe0=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=SJ75x6hxwOPpAuVJ7J20A9vSx9DlB/qhNRHIhBPSi+xIeQu++esqC7/V/4AK2q0l9TfUAyjjgyO2uDvou1NKuylON21cjUc1WoDHKfHCMbkYBVOZ8ZMJxpYMyBrkQBzuM4MVRhr7QRACxmbK3WxTIVdWVjGdCKKxPjE7MCEC/Q0= 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=KNOy833R; arc=none smtp.client-ip=209.85.210.198 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="KNOy833R" Received: by mail-pf1-f198.google.com with SMTP id d2e1a72fcca58-8544b721ce9so654213b3a.1 for ; Wed, 26 Aug 2026 09:52:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1787763119; x=1788367919; 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=3KxgdA9C3Q2gUzH0EONwpXAO6HVPxwiye0akeJiAgZM=; b=KNOy833Rl39bZ5UcNb2FEd8yrlC7sivTNJXlFgwDBN70iodGd/QBWp7OtJvxbPuJdS TT6dKdYUxR/ta3Ahvi6KaCUikuAoxNSmg+ECDXT8tNfw03AAGgWOcEsDizBrNMW4Zwel tAQs/+6aGUGVUOUxRfkjtJA1TZP55bNGsgVF4F9Lw53hgwjSj4q4JBzlJaGG+a4TE2ud Nb8pXdvRlkikVY55fIqkzSrf2PG2zOywP7KPmsN/3eGwptzh5Vz62lzkzbnwYXrKOgFN X7Jt6RmDpa3PZlNsbX3ZU5OKwDQ9cgG4wDRNtCWhqJthMu7vi365IYe3x9BpfdJBQ/Sz ShIg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1787763119; x=1788367919; 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=3KxgdA9C3Q2gUzH0EONwpXAO6HVPxwiye0akeJiAgZM=; b=LaHk7Ch2wJRUrvUeGeiyi9vfKglwIIKecAV9HIj1Gml2v7vQqfBf9aeu8fkFQJjS6h tryg5O7pKqj0LtPG+Cq68axJ44bEES0ZV2Tv6IRfFWozOrkKCCfPXE+v+xXOX1i4XBMh RfmOMLSLErJbmYfimqTdndQGA/ISlLrjJC7lwJ0Ggh96zgUzVRpw5TPgXwEn18qEvq4g mvX2BusZWsV1tW4soE6s8L87PO/Af+cj5gyisTej86wvH6zpynZhuRWSX+E0t1UV8vNO GcdIUm4H7l2KGKHIB43lvp7j/j5hUWeU/vNNEpLYIAVLltFQTmgW6ZthU89YKmH453wz TpOQ== X-Forwarded-Encrypted: i=1; AHgh+RpVH8Z65DBmB4JYT9e6cYO20eraXetZjTDLgvjkxBUe82hHN/YNqDh7EU4U00TWUKKhrp8=@vger.kernel.org X-Gm-Message-State: AFuF++nr40sWbVNhD2D0T3eHlJnjW9PmlexnaVRMpKlVzs5Xmhhj7WEz 81WH2/JjUyXXiddCIeBqre4hmJgEVjg+FpknRgwdGHEtknUNxizR6yahq2EWiHKlBq6furs38aQ Yer92Wg== X-Received: from pfbfw4.prod.google.com ([2002:a05:6a00:61c4:b0:848:487e:d23c]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a00:2e08:b0:853:6571:9567 with SMTP id d2e1a72fcca58-853720af96dmr14899043b3a.4.1787763118618; Wed, 26 Aug 2026 09:51:58 -0700 (PDT) Reply-To: Sean Christopherson Date: Wed, 26 Aug 2026 09:51:54 -0700 In-Reply-To: <20260826165154.766699-1-seanjc@google.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260826165154.766699-1-seanjc@google.com> X-Mailer: git-send-email 2.55.0.887.g758fc8c411-goog Message-ID: <20260826165154.766699-3-seanjc@google.com> Subject: [PATCH 2/2] KVM: guest_memfd: Drop superfluous WRITE_ONCE() when binding a memslot From: Sean Christopherson To: Paolo Bonzini , Sean Christopherson 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 1ef9e2916423..1d2de9a1bc3f 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; -- 2.55.0.887.g758fc8c411-goog