From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 904F02E821 for ; Wed, 20 Mar 2024 12:33:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710938002; cv=none; b=TcsLuTN88JwZAhE0id1BIbbzZvDzVeRp6qXmhFRBN6tf5vilqB0OTDrK5eVMhsk1brviadnb/XgXOp2RlFLbNjw0MfE10n2HKereugv8EKrvfZUbbc8BBEhKQMZoatVW6opntcCfW+CVsVdpoyBsZ3uHJhEB9MBW6pLKaRvnAf4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710938002; c=relaxed/simple; bh=032atrOwuW9yo3/SuiSJBmgyjzf3UfhiJ2p0uQEe5Jg=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=omFpdLuG8JkKfsBApS/W/FitIz1g0QEcC88kdDveITOQ7zCVha0RWtS3B0JCUsG9qrdEVMw7eXI7VsCf76wWQHyuB8hZaTM/hQ1/MmirVaFzjgxf91oFt4M9RPdG9oSHw7I/OnFeLeiu+AZUOgBfZWV/8s2Bm6rb8TtKXLb3R9U= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none 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=errFLGrk; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none 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="errFLGrk" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1710937999; h=from:from:reply-to: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=LI54pxdGKEWVTWxWzs7S5KmA8mpkqqZDrOFVx2kvCH0=; b=errFLGrk9a/DFXzl8iN0OgBALGDqDWjMK7PpOSOo+mpjbLi4m+jO8bWyXWHvLPykrfKaWs Le8i+sgZ28xwmJ3RSGt/GAIQ/yhDC0GpDz1VBsDuode3Fu2hee5YHVgPk4VsrnyUfkiZLF M7/ruA2Kr3sgTlwtDh2ZTNxp213QF3U= Received: from mimecast-mx02.redhat.com (mx-ext.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-220-URfAf05JNkG4lG_Pftr4Uw-1; Wed, 20 Mar 2024 08:33:17 -0400 X-MC-Unique: URfAf05JNkG4lG_Pftr4Uw-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (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 mimecast-mx02.redhat.com (Postfix) with ESMTPS id 2EE8F1C54460; Wed, 20 Mar 2024 12:33:17 +0000 (UTC) Received: from redhat.com (unknown [10.42.28.205]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 10A69112132A; Wed, 20 Mar 2024 12:33:15 +0000 (UTC) Date: Wed, 20 Mar 2024 12:33:10 +0000 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Michael Roth Cc: qemu-devel@nongnu.org, kvm@vger.kernel.org, Tom Lendacky , Paolo Bonzini , Markus Armbruster , Pankaj Gupta , Xiaoyao Li , Isaku Yamahata Subject: Re: [PATCH v3 29/49] i386/sev: Don't disable block discarding for SNP Message-ID: Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= References: <20240320083945.991426-1-michael.roth@amd.com> <20240320083945.991426-30-michael.roth@amd.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20240320083945.991426-30-michael.roth@amd.com> User-Agent: Mutt/2.2.12 (2023-09-09) X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.3 On Wed, Mar 20, 2024 at 03:39:25AM -0500, Michael Roth wrote: > SEV/SEV-ES rely on pinned memory to back guest RAM so discarding > isn't actually possible. With SNP, only guest_memfd pages are used > for private guest memory, so discarding of shared memory is still > possible, so only disable discard for SEV/SEV-ES. > > Signed-off-by: Michael Roth > --- > target/i386/sev.c | 16 ++++++++++++---- > 1 file changed, 12 insertions(+), 4 deletions(-) > > diff --git a/target/i386/sev.c b/target/i386/sev.c > index 134e8f7c22..43e6c0172f 100644 > --- a/target/i386/sev.c > +++ b/target/i386/sev.c > @@ -888,10 +888,18 @@ static int sev_kvm_init(ConfidentialGuestSupport *cgs, Error **errp) > uint32_t host_cbitpos; > struct sev_user_data_status status = {}; > > - ret = ram_block_discard_disable(true); > - if (ret) { > - error_report("%s: cannot disable RAM discard", __func__); > - return -1; > + /* > + * SEV/SEV-ES rely on pinned memory to back guest RAM so discarding > + * isn't actually possible. With SNP, only guest_memfd pages are used > + * for private guest memory, so discarding of shared memory is still > + * possible.. > + */ > + if (!sev_snp_enabled()) { > + ret = ram_block_discard_disable(true); > + if (ret) { > + error_report("%s: cannot disable RAM discard", __func__); > + return -1; > + } > } Pre-existing code bug, but this method must use 'error_setg' to fill the 'Error **errp' parameter. With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|