From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pf1-f201.google.com (mail-pf1-f201.google.com [209.85.210.201]) (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 AE718340DB8 for ; Wed, 24 Jun 2026 17:32:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782322371; cv=none; b=eopmllZGkKZ25d4c+5HgDkoAU+AHkpw7WFh6tumPoVzpZmezU+2Hxf34/GFKazlLlMEfWwdU434UAydmqCbBmU9BY/+gclY04b/c7JMiY5vb3u6tiIYORWc3Usizlsl4u+PtDzcedwVxXgkjwyAYYF4ohAPo010VJ0eiWYYwn7A= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782322371; c=relaxed/simple; bh=iikYRdViwRtzh9V9/K4oM7wLc4TMqwuuo3WzFq6sMBI=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=TLTpFKRAOnhRjbfl8DTwMKNQlTa5E3o/C8F63lai+LcqJDyn4QPTyA+Nh4SMIviPA7kcozgoS57TOgceaQHfQMd2p8El/rJwgd3eGAPnLK3wxwBaFsHLDmJpIAVVan+w2mHBM70i9Zp6/SZ8u8mtB+LBsCh3ZNxxEFj6lxO2FM0= 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=YV0alfNh; arc=none smtp.client-ip=209.85.210.201 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="YV0alfNh" Received: by mail-pf1-f201.google.com with SMTP id d2e1a72fcca58-8423efbfb61so996473b3a.0 for ; Wed, 24 Jun 2026 10:32:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1782322370; x=1782927170; darn=lists.linux.dev; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=NuCvG+ANEtYYDDfdrUYBmspYw8vstGpW69KsCXQmcQ4=; b=YV0alfNhH2idIGNgU+GJmWeaOU6BJ2tyC7fYARTn6fW1IWCiZ4IexUUA/hpM+S9hMk rq1spdbDZ/hQ6KZJURLXd4Evq86syFhP6ihP4yh8U8qLy7qnDIbbc1z1BRoKJkuM0+LS oScPDP4vyt2DDb8RFs8cT/jDqe6E5rBTN+inNcq6Qqf0sRymsdBQVOm7ZvnZqw42BF1s s2FNvCsFc2y/5fFArgUgGVusUPH583ujVoUBb9lo0CeXyHeQtl++58SnYNIC9RK08FO+ o3NArCoDJBXY5rs04DVUo5O0XTL3XvyMub0jlzZHmVGr4xVuvdqQd+EVf6+bT2wAmVVf 4isg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1782322370; x=1782927170; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=NuCvG+ANEtYYDDfdrUYBmspYw8vstGpW69KsCXQmcQ4=; b=iNB3vibYp8QOUbp64MFe82Pa0a/9ln9u7Zq5ROmI0fNCAKfAapTYn7DbQvZWu1xtyF Zrt8emjimouRZ4rbF2OOu6Fr/dldwIfq1GSnNRV/Ie5FhCxJULFJQkJfZUYIkWPLQWP2 iJfJIxsqg0KPtzNbeN23w+35KytZv6/2frEmHD+8q2kngG/EumZepLdIZz0mNJlGhKYp pOyuuY+02xx7ZcQZ9774PPB+0IVT9HLWis7NQ/vShlMDKIr8/OSQCpimrsfVjl2JdqbB cEMHPTliAd63ku+X3WRmdusD9+flO6sC0K1aYNVgxv5T+gpVsAG28gTJKInK1mMqO9AD 2p9A== X-Forwarded-Encrypted: i=1; AFNElJ+dg9AB3AcRJWL2c1GM2dKFjskfFcT5dwykiYkv8nwnUvoXebrqW5myFrO+FnuvHQ99Bllybds=@lists.linux.dev X-Gm-Message-State: AOJu0YwWWQZdkBv2iwvrAFLev+X5Y/n2pvkj9VmrKAgIP9XxmTiu5c/N BkxIKoyNRb8AC3ezyNCvRIV4NOG558+f8c4Rg2vkqj8V9z1UGDDoIl4JB7xxhq/VjeWFJ+XgTGH BZcdpGg== X-Received: from pfih1.prod.google.com ([2002:a05:6a00:2181:b0:842:9550:318a]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a00:450f:b0:83a:ebec:452f with SMTP id d2e1a72fcca58-845a28d4650mr5767948b3a.42.1782322369734; Wed, 24 Jun 2026 10:32:49 -0700 (PDT) Date: Wed, 24 Jun 2026 10:32:49 -0700 In-Reply-To: Precedence: bulk X-Mailing-List: kvmarm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260615155244.183044-1-alexandru.elisei@arm.com> <20260615160901.9A1A61F000E9@smtp.kernel.org> Message-ID: Subject: Re: [RFC PATCH] KVM: Ignore MMU notifiers for guest_memfd-only memslots From: Sean Christopherson To: Ackerley Tng Cc: Alexandru Elisei , sashiko-reviews@lists.linux.dev, Marc Zyngier , kvm@vger.kernel.org, kvmarm@lists.linux.dev, Oliver Upton Content-Type: text/plain; charset="us-ascii" On Tue, Jun 23, 2026, Ackerley Tng wrote: > Sean Christopherson writes: > > and purposes, we're conceptually treating conversions as free()+re-alloc(). So > > while the page might still be in the page cache, it's effectively been "freed". > > So in that case, KVM really does need to ensure it handles mmu_notifier events > > correctly to avoid UAF. > > Just making sure: "handle mmu_notifier events" here refers to > gfn_to_pfn_cache and other parts of KVM that works with memory. Yes. > There's no issue with a UAF between mmu_notifier invalidations and > conversions, right? Right.