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 AE6A63033FB 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=GjKHn9WOFsKB2L12QvhXw0SAzMVsy0UvkUBAVco9G1cEQHwqLbKTLdE2MRpovz6Mdrfk08Om8aaJ+jmK/Yu/S129GoKp4e5dx7Ypeim700upLJnTc/a9GTtJm9z5+zbl2nGj1lvmrGArGNuTk9nUB3YwdnCgY8s3YG20eWVHaps= 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=LFhdzk+2; 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="LFhdzk+2" Received: by mail-pf1-f201.google.com with SMTP id d2e1a72fcca58-84238e83851so990929b3a.1 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=vger.kernel.org; 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=LFhdzk+2Do8UQMJm5Y48bOFY4ViXc1bsi4f3edRXhS5k7rcIdAbK+9Qa0sh/j39D72 a0xKi8lwqe1wylHuSHz+MtI2uTSmsZNjIFIr3kLbSVNt0bkjzv4kOoYwqn2G0g7YIM0x 0wFTn5pBWj9bp1BnXaFxMydBlxe/4sVPKFNEmdIhBJwgbYGxoWjE9zGFGWrScpubmbvg a/SY1tuMxCQ9AdbZfI4QGpd9z0SpqehYjx6/9wrm2kPWfW/2a4pzVxJsCvKzQOrz1Xel G7f2g9csChThxzWE9N7c8+mdOEVSNgsm2gY5gIGfGZs57yRZ3Okiiinxv0xfytURO6rl IzEg== 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=ZAKdoWg6Su6jDWDo4jSmT+Eog8jjgQEtNf+3nagVcTldkeUDNyV+alkch5WOpeQQzA ua9cr2+IvQoZ++06oH4RIvwYgL9l9LGEz4rWTzzMQHVyhIa5Ze/PzGYRSBVbT+HV1jKR 3qTH4Hxwogt7eqIhtWEYvB8tHS/YP67ydoS0Re89O/NazEMlXZYPz3lPWaqNwFX5+IgZ 0Hf6Hfs1dvl6E9rVUPlwlMqX6YLgtuoDqncw3SSAb+VgXopylaNDIplpNQKUYa/aXHo1 SkCsK41NZMNBSw9+y/Udnqr5x13tHrsn4QiYqT/PAGa7zUlOeJ3LQE27kKkHk1aBUhhf 6+sA== X-Forwarded-Encrypted: i=1; AFNElJ/KrJxdzwOaUiJ6iSMYgUZR9O2c16kXsgd/Uc0/sVJheK0jTcS1jmmE0U0zONkq6RN9PzI=@vger.kernel.org X-Gm-Message-State: AOJu0Yz62rCdF2SXSULcfUSLZ+Befh9M+GgKR/ri6w7p9uVy0qcYdBgf R9Yz6G1j+jNeh0G1+Ah/7+RukBrexcR7UwmpcLbIoVOlS/ci51QYTfy08wThrpY9dd1txbSgGC3 7i+QILA== 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: kvm@vger.kernel.org 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.