From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 D16D32DCBE3 for ; Tue, 2 Jun 2026 08:23:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780388632; cv=none; b=XeHxILooGycflFmIBWe/fdx0ieNURymatgXrs6wMVn664AJ2Lj+jND6evd6kEZRw3g/pLstV9DMHPsmJ/tVft/K0tycZLSUMZIjpZjjj2ZBqdyRqJDlZFH8CCgMSN6uC1ALMPEMzs2bt5SmIlcRm3pFp7rSr7T80cRm3ApxGT1M= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780388632; c=relaxed/simple; bh=JE/i4PI7L0h9y3u1kiQUkOY2mSU/MdfBnJplzJU0hzg=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=ku4WWY734GqSmtYem4fhjuiQHwTvsf8fzSKfVzNECLsiTQU15/Z9NOXExsS7nBQlr5oGyAUSHK2R83ak9gWW1OhUq8dYRSsaCOMhTnjEDfgcqJE6pZ3lHsvFTEv1MIumK8GDdTeYSh+itN8DN0Vg7HSqR4axBob7IZsm2oOJXPQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=Rch8OcJL; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Rch8OcJL" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1780388629; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=JzEx/djjiKdSQ43hJspteLYFDK5pHtfMy3ITMuebRHU=; b=Rch8OcJLwZK7H/n1vekoZoPnIA7jvjFLszrySUiSkJA248fMHYBC+FXZbVi5v89WRJ1AxY 7Zw+NOBGH21EYZQjVCqufY0GUqzjcUlBc3O/+7urtpKSgBsYdvEXGUXDa0zy/4+vued2h/ +56wqutE8bvTaQuFK+Kk3GRFh8uiNEU= Received: from mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-677-sU4JCvHpM2G4-w1R1dkwvw-1; Tue, 02 Jun 2026 04:23:45 -0400 X-MC-Unique: sU4JCvHpM2G4-w1R1dkwvw-1 X-Mimecast-MFC-AGG-ID: sU4JCvHpM2G4-w1R1dkwvw_1780388623 Received: from mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.111]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 4AA39195606C; Tue, 2 Jun 2026 08:23:43 +0000 (UTC) Received: from blackfin.pond.sub.org (unknown [10.44.22.2]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id E40461800352; Tue, 2 Jun 2026 08:23:42 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id 87D1721E6A01; Tue, 02 Jun 2026 10:23:40 +0200 (CEST) From: Markus Armbruster To: Michael Roth Cc: , , , , , , , , , , Subject: Re: [PATCH RFC 04/12] accel/kvm: Add CGS option to control in-place conversion support In-Reply-To: <20260528000416.8161-5-michael.roth@amd.com> (Michael Roth's message of "Wed, 27 May 2026 19:03:29 -0500") References: <20260528000416.8161-1-michael.roth@amd.com> <20260528000416.8161-5-michael.roth@amd.com> Date: Tue, 02 Jun 2026 10:23:40 +0200 Message-ID: <87wlwh5p0z.fsf@pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 Michael Roth writes: > For confidential guests, guest_memfd is currently used only for private > guest memory, and normal guest memory comes from the configured memory > backend just as it does for a non-confidential guest. It is now possible > to use the same physical memory to back a particular GPA regardless of > whether it is in a shared or private state. This avoids the need to > rely on discarding memory between shared/private conversions (to avoid > doubled memory usage), and is intended to be the primary mode of using > guest_memfd for confidential guests moving forward, and future features > like hugepage support will likely require it. > > Add an option to enable this support. Since ConfidentialGuestSupport is > already used to track some guest_memfd-related functionality (e.g. > whether it is required for the configured machine), similarly introduce > this option as a property of ConfidentialGuestSupport. > > Also add the KVM-specific checks to enable this support, but leave the > option disabled until other required changes are implemented for > CGS variants that intend to make use of KVM's in-place conversion > support. > > Signed-off-by: Michael Roth [...] > diff --git a/qapi/qom.json b/qapi/qom.json > index 502fafeb15..037c078799 100644 > --- a/qapi/qom.json > +++ b/qapi/qom.json > @@ -1014,6 +1014,21 @@ > 'if': 'CONFIG_IGVM', > 'data': { 'file': 'str' } } > > +## > +# @ConfidentialGuestSupportProperties: > +# > +# Properties for ConfidentialGuestSupport base class. > +# > +# @convert-in-place: If true, the same physical pages are reused > +# when memory is converted between shared and private states. > +# If false (default), separate allocations are used depending > +# on whether the page is private or shared. > +# > +# Since: 11.1 > +## > +{ 'struct': 'ConfidentialGuestSupportProperties', > + 'data': { '*convert-in-place': 'bool' } } > + > ## > # @SevCommonProperties: > # > @@ -1038,6 +1053,7 @@ > # Since: 9.1 > ## > { 'struct': 'SevCommonProperties', > + 'base': 'ConfidentialGuestSupportProperties', > 'data': { '*sev-device': 'str', > '*cbitpos': 'uint32', > 'reduced-phys-bits': 'uint32', Why use a base type instead of simply adding @convert-in-place to SevCommonProperties?