From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pj1-f71.google.com (mail-pj1-f71.google.com [209.85.216.71]) (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 511D53EA96A for ; Fri, 31 Jul 2026 12:55:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.71 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785502502; cv=none; b=uqbCrEJRX6H4Om+1MVVlFS8STWDo8xs/3psduLyid9tcj4BIz0H3QAbfEkJhZ8JSk5nhjwSl/7SbS/Y09UFewtRTLSrwqPIa2E1xdR3vzznU00gzaHPHZkFTCxIwv+/LNk/oN/1wBBhOeJJVihn3NnjBhzu3C4IM9nfrwzaHY9I= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785502502; c=relaxed/simple; bh=VLoydqIVwuKUQXc9UhOoh5aUJw20KctFbJ47mghnEwQ=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=hkcUJaOA8vCFn5rQOzeyD91x+fgTok97Ldd7tBvsUcLJMcovn9cZd00lVgrGbKibY1o1aTrSRO+0gp5Fc3RAORspAi4Ne9JVLX0RA7/ftRA/Li+kBonj4wZ6D+8mh3GXKAVcCefUOB/RTVAdM3eeu5rmZh6Mhaselxj8VbkAx80= 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=DctK7RRk; arc=none smtp.client-ip=209.85.216.71 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="DctK7RRk" Received: by mail-pj1-f71.google.com with SMTP id 98e67ed59e1d1-38e7621655eso1760578a91.0 for ; Fri, 31 Jul 2026 05:55:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1785502501; x=1786107301; darn=vger.kernel.org; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:from:to:cc:subject:date:message-id:reply-to :content-type; bh=/YNbRRWBcnK55n/7Fk+h5EFRipryAvZ2dYj1AcH+cM4=; b=DctK7RRke0afxICUutbpKpHGLgLCjeaCp84HesdXcUtDslI2Ta9pF97c6DfuJtL+Mp Ybx3QxO2Uq+kavUPSjwyTV/4XdsVHgNqNd8RqynI88osWRhgeXgHjzA8puTAGwfbpnLu DRwemJvX9ciehiuhnGiDKej2iqbnX8uXfQOaCSJFfM/GbuPhrgQjwzoGztplD1TI8fvA 5BSBWKuTj7lxHHqSg5flvEtI3Xwcuu4B9WFIGM0LEjroqNZ+aHkoOMozIzFoEUN5draL 51CDYRTgPbPq6F16+gTcgpvP+uFyJyk7ouPgeORV/Fy6+sOSK60vIoi1oFuJSqA7/pLj c2ng== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1785502501; x=1786107301; h=content-type: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:content-type; bh=/YNbRRWBcnK55n/7Fk+h5EFRipryAvZ2dYj1AcH+cM4=; b=Ea4G0uJiOWHgWzNlk2c4aZEo8AWZGp7Uuo9n9SScSpbZS2IfeQKfPPRr94teI3w3Xv NE0hmmLQzrugcJqtU2qnmDvl6eCRpFNOmbMzUpKAKWFTB55UNd0r6btSoAeAfaG1N6pj H+u+IQSkRfVwIhWbQ8+MofQvG7pOO9gsbGXLGrX0ra4xwpdHA0+/6Qi9cRhcqTlOVGLy loiflSwWSSsaN+SZx0JFKKseJ0U5Hr36hq59Gsl31e5YoqRf6VzCwus562/ZRVVe4vjX CKHOdHdo1L40c5UgHNGhBzUDAU8m8QKCIunECyP4xAf0dhbVy2rOKdGaeOmho/y+FiNj y0uQ== X-Forwarded-Encrypted: i=1; AHgh+RoVbZM7lyzncDSd6VpYFZN76553cudu/r6crj41H3i+yDYm/Ptb2aG2XSM1fVm/Hy9u1yOOgydD0Ug=@vger.kernel.org X-Gm-Message-State: AOJu0YyxcfZp5lybTREVKPJL0Utq7AOWARevtdo9ROKKVO6Y4DfQCX1T c8LFH2TYa5occX/QZlAS3Y3wN9fG3F8fjiQB/WD2anI4g3iPBJjBbXgSlVuW2MfO2f38yra3wc9 +LN+tmA== X-Received: from pjbdb11.prod.google.com ([2002:a17:90a:d64b:b0:38e:bb71:b8c5]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a17:90b:3c81:b0:366:3517:1aa2 with SMTP id 98e67ed59e1d1-38fb0e858dcmr1811652a91.0.1785502500466; Fri, 31 Jul 2026 05:55:00 -0700 (PDT) Date: Fri, 31 Jul 2026 05:54:59 -0700 In-Reply-To: <20260731091708.2963414-1-flosch@nutanix.com> Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260731091708.2963414-1-flosch@nutanix.com> Message-ID: Subject: Re: [PATCH] kvm: add EVER_MAPPED ioctl and capability From: Sean Christopherson To: Florian Schmidt Cc: Paolo Bonzini , Jonathan Corbet , Shuah Khan , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , kvm@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org Content-Type: text/plain; charset="us-ascii" On Fri, Jul 31, 2026, Florian Schmidt wrote: > This allows a VMM to keep track of which pages were mapped by the guest > at any point. So does userfaultfd. Any performance concerns with UFFD should be addressed by KVM Userfault, which is on my todo list for this year. [*] https://lore.kernel.org/all/20250109204929.1106563-1-jthoughton@google.com