From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BBED4288B1; Mon, 27 Jul 2026 08:57:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.19 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785142622; cv=none; b=Iycpgf7z7X83aEwwRbMTtXOsvin0+zzx+cwcHmbKLZ5OxeHN+xdVwWN3YFtxyYIXdLITkb7rlGDn8amg5eGfdYCM79BPy90B/kTI5uAKzalRabNWkaLwhvOgMR8Cy9BIgm+4/Tg2Vk29a8iLRf2AloLuBfoBwle/+UxsbE9ZhSM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785142622; c=relaxed/simple; bh=lMpIU/V66aytLPGUR/j5WZxaR63Djlk3lIVk2ujNTsM=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=NFeR+DTjmkzzHWRJS1TiGXyzymTdKqBJwAyYkvQ82ucbTkW7i+FYOtJgLD+dbkGF9XnHP14o0vvMMbI7z5nEmZ6jldVSOOj1rM1CsgX+lpXKSmccRBEHEgAuNVXJFBGOzzivVpOYYUUIvke2vgNdXdS57Bu8nozLB3kFHl3Eb78= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=Vd/B5lE1; arc=none smtp.client-ip=198.175.65.19 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="Vd/B5lE1" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1785142621; x=1816678621; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=lMpIU/V66aytLPGUR/j5WZxaR63Djlk3lIVk2ujNTsM=; b=Vd/B5lE1Ym4isKwuzUUv6ssKZJcX9Y3KxZ5lKTfgdwI+4BJPuGm24W4M PmVze8K8XoOBauA1nGnahZhP0llLQEkk8hFNsQ3dFj1GLCzVx3O9xa31F rTt5ej9Dzxoqe49+lXI5TlXdHjsD0QOBqRGJFPGsa9Kq1gn7YnvESrsmt hGR8Y1ndZTUMkeMmW1djv2T2Buv5tux+OT13lTD9ba9K9bzE++0iCDofg FIOS1cKByuH50ryJRBzPN/D95juaPkNY4PE9a3O6uu7gF/oW8Pcp6pdDA +xnhbpwg9ct+W623nxjVuWRbUmkLymx55+Uy8zu7mnrSByPGXaT8FqSdq A==; X-CSE-ConnectionGUID: wnTTwDm3RNiAYr2sJbHwqA== X-CSE-MsgGUID: EfcmmF7PRBWoEmOibJQuuw== X-IronPort-AV: E=McAfee;i="6800,10657,11857"; a="85650634" X-IronPort-AV: E=Sophos;i="6.25,188,1779174000"; d="scan'208";a="85650634" Received: from fmviesa004.fm.intel.com ([10.60.135.144]) by orvoesa111.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Jul 2026 01:56:46 -0700 X-CSE-ConnectionGUID: bCMhkf+yQb2QvXpI2EQz5Q== X-CSE-MsgGUID: k0pmQHftQiuyGJF1mR6S1g== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.25,188,1779174000"; d="scan'208";a="261321213" Received: from xiaoyaol-hp-g830.ccr.corp.intel.com (HELO [10.238.208.132]) ([10.238.208.132]) by fmviesa004-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Jul 2026 01:56:43 -0700 Message-ID: <0a800681-40da-4d45-b0f0-ee8aa84ec942@intel.com> Date: Mon, 27 Jul 2026 16:56:40 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v6 6/9] KVM: guest_memfd: Only "prepare" folios for private pages To: Sean Christopherson , Paolo Bonzini Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Fuad Tabba , Ackerley Tng , Michael Roth , Fuad Tabba References: <20260723210811.72720-1-seanjc@google.com> <20260723210811.72720-7-seanjc@google.com> Content-Language: en-US From: Xiaoyao Li In-Reply-To: <20260723210811.72720-7-seanjc@google.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 7/24/2026 5:08 AM, Sean Christopherson wrote: > From: Ackerley Tng > > When getting a guest_memfd pfn, prepare the folio, i.e. convert its pages > to private, if and only if the page is actually private. The misnamed > prepare() hook exists specifically to allow x86's SNP to assign pages to > the owning VM in the RMP when mapping private memory into a guest. > > Guarding the call will allow renaming the prepare() hook to better reflect > its role, without creating a semantic mess, and will become a hard > requirement once in-place conversion is supported, i.e. when CoCo VMs > support SHARED guest_memfd pages. > > For all intents, no functional change intended (the sole arch hook is a nop > for SHARED memory). > > Suggested-by: Michael Roth > Reviewed-by: Fuad Tabba > [sean: rewrite changelog to fit the context] > Signed-off-by: Ackerley Tng The rewritten the changelog read better and clearer! Reviewed-by: Xiaoyao Li > --- > virt/kvm/guest_memfd.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c > index e9d61410e5fb..f64cd87ec8b0 100644 > --- a/virt/kvm/guest_memfd.c > +++ b/virt/kvm/guest_memfd.c > @@ -814,7 +814,8 @@ int kvm_gmem_get_pfn(struct kvm *kvm, struct kvm_memory_slot *slot, > folio_mark_uptodate(folio); > } > > - r = kvm_gmem_prepare_folio(kvm, slot, gfn, folio); > + if (kvm_gmem_is_private_mem(file_inode(file), index)) > + r = kvm_gmem_prepare_folio(kvm, slot, gfn, folio); > > folio_unlock(folio); >