From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.14]) (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 B037133BBD7 for ; Tue, 8 Sep 2026 04:44:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.14 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788842648; cv=none; b=Da46HlkleII6k5Onl4fk2VZm3E5Q3NWvbMdr+POzgCkELFjTYa5QoPst+vlnWzmR3bkdEVvZ8YB8z8fxOk/FTQuCxOGau5ImcsA8GBJVIcG2dv5NL9ibVgpHvaeY7zwZZLkOXpdtopms5pxMqFG7qOKJuGPLptIiayHn4DOG2aM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788842648; c=relaxed/simple; bh=N93yy2cSnalyHr04bMOVeqR8AIr0fIg+uFBrS273sM4=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=I/I5BkwQhPlPvNAX4v8RuzTtefWB7/v9lOk51rz6KUj6OTmOePxV0QR46OPOHdPS3rNpATV7dbCJsTBAqf/qQNVK5HibF8hxyfytnIREiE+nNvrf1k4p5CWBdeKyX8/9icHDUDHEvvjwkYBwuYs5xC0XjPowowdc7L6FUtqOCu8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=pass smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=UeWcE9T6; arc=none smtp.client-ip=192.198.163.14 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="UeWcE9T6" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1788842647; x=1820378647; h=date:from:to:cc:subject:message-id:references: mime-version:content-transfer-encoding:in-reply-to; bh=N93yy2cSnalyHr04bMOVeqR8AIr0fIg+uFBrS273sM4=; b=UeWcE9T62pzdr5n+F5iGCeiF9M8e4KhJUimjKWJbibt+Fcf9XtklVbSE wHcAsN+2IH57kL6TDLZXEldzcQF3iFDDcf/usi+RWAWegfO4fVfUPSQ8K SerGo3QsrTfykM3rptO5u2hc2JiwjR3bkIMhChIvTgtuH160brUBSisJF a0WeDw+GRF/RfGw5YH+1Edb8eyVwwWFnUlaf8gk0DvJ4GW8SyubJmfY1R RCKTtV/+McmDXzKp6Qwhb0UTzXqDRqG20s1AOqIxM1T9mUzaFMWCRgrzQ 0zfQS06cRreo38414zpdjom+qqkHjMW8/ng2yCZOMBaYWqcS0QD6+O8Vn A==; X-CSE-ConnectionGUID: TiQdRRMnQE6GEIsKqiDAxA== X-CSE-MsgGUID: OVirn0/ATsWd3PvEwWhFkA== X-IronPort-AV: E=McAfee;i="6800,10657,11899"; a="89252794" X-IronPort-AV: E=Sophos;i="6.25,268,1779174000"; d="scan'208";a="89252794" Received: from orviesa007.jf.intel.com ([10.64.159.147]) by fmvoesa108.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Sep 2026 21:44:06 -0700 X-CSE-ConnectionGUID: FV5WqCjlQsukkPCCvegyAg== X-CSE-MsgGUID: lvYpswhFSBCI8BohBu3mwA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.25,268,1779174000"; d="scan'208";a="270843380" Received: from bradocaj-mobl.ger.corp.intel.com (HELO localhost) ([10.245.246.90]) by orviesa007-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Sep 2026 21:43:58 -0700 Date: Tue, 8 Sep 2026 07:43:54 +0300 From: Tony Lindgren To: Artem Bityutskiy Cc: =?iso-8859-1?Q?J=F6rg_R=F6del?= , Paolo Bonzini , Sean Christopherson , Peter Xu , Fabiano Rosas , Jon Grimm , Pankaj Gupta , Tom Lendacky , Marc Zyngier , Oliver Upton , Steven Price , Anup Patel , Samuel Ortiz , Jakub =?utf-8?B?UsWvxb5pxI1rYQ==?= , Vishal Annapurve , Elena Reshetova , Kai Huang , Kishen Maloor , Mika Westerberg , Peter Fang , Rick Edgecombe , Xiaoyao Li , Xu Yilun , kvm@vger.kernel.org Subject: Re: [RFC PATCH v2 2/4] KVM: x86: Add optional KVM_CAP_LIVE_MIGRATION and KVM_MIGRATE_CMD Message-ID: References: <20260831071304.762939-1-tony.lindgren@linux.intel.com> <20260831071304.762939-3-tony.lindgren@linux.intel.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=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: On Mon, Sep 07, 2026 at 04:32:33PM +0300, Artem Bityutskiy wrote: > On Mon, 2026-09-07 at 15:15 +0200, Jörg Rödel wrote: > > The direction is always the same over a single live migration session, right? > > So it could be a setup flag, on the other hand having separate KVM_EXPORT_CMD > > and KVM_IMPORT_CMD seems to be a cleaner ABI. OK > Yes, the source stays the source, and the destination stays the destination > for the entire session. > > This is a special case of a broader question I keep coming back to: > > ** How much state should KVM keep about a migration session? ** > > For direction specifically, we could pass it to KVM on every call and let > KVM stay stateless about it, or KVM could record it once and remember it for > the rest of the session. Yes the "record and remember" is another option, it could be a sub-command something like KVM_MIGRATE_DIRECTION.