From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) (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 5BD4628F3 for ; Tue, 4 Apr 2023 16:50:23 +0000 (UTC) Received: from lhrpeml100003.china.huawei.com (unknown [172.18.147.206]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4PrYYg44rVz67d2y; Wed, 5 Apr 2023 00:46:15 +0800 (CST) Received: from lhrpeml500005.china.huawei.com (7.191.163.240) by lhrpeml100003.china.huawei.com (7.191.160.210) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.23; Tue, 4 Apr 2023 17:50:14 +0100 Received: from lhrpeml500005.china.huawei.com ([7.191.163.240]) by lhrpeml500005.china.huawei.com ([7.191.163.240]) with mapi id 15.01.2507.023; Tue, 4 Apr 2023 17:50:14 +0100 From: Shameerali Kolothum Thodi To: Jason Gunthorpe , Nicolin Chen CC: Robin Murphy , "kevin.tian@intel.com" , "yi.l.liu@intel.com" , "eric.auger@redhat.com" , "baolu.lu@linux.intel.com" , "jean-philippe@linaro.org" , "iommu@lists.linux.dev" , Zhangfei Gao Subject: RE: Cache Invalidation Solution for Nested IOMMU Thread-Topic: Cache Invalidation Solution for Nested IOMMU Thread-Index: AQHZZcP9AmBGSPvPIkC4mL7SORjVE68ZjzWAgAAMCQCAAEmlgIAAUDeAgAERN4CAABdCsA== Date: Tue, 4 Apr 2023 16:50:14 +0000 Message-ID: References: In-Reply-To: Accept-Language: en-GB, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.48.155.16] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Precedence: bulk X-Mailing-List: iommu@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-CFilter-Loop: Reflected > -----Original Message----- > From: Jason Gunthorpe [mailto:jgg@nvidia.com] > Sent: 04 April 2023 17:20 > To: Nicolin Chen > Cc: Robin Murphy ; kevin.tian@intel.com; > yi.l.liu@intel.com; eric.auger@redhat.com; baolu.lu@linux.intel.com; > Shameerali Kolothum Thodi ; > jean-philippe@linaro.org; iommu@lists.linux.dev > Subject: Re: Cache Invalidation Solution for Nested IOMMU >=20 > On Mon, Apr 03, 2023 at 05:02:09PM -0700, Nicolin Chen wrote: >=20 > > My preference is to have a mmap'd page, so the interface can > > be reused later by VCMDQ too. Performance-wise, it should be > > good enough, since it does batching, IMHO. >=20 > You can't reuse mmaping the queue page with vcmdq, so it doesn't seem > meaningful to me. >=20 > There should be no mmap on the SW path. If you need a half step > between an ioctl as a batch and a full vhost-like queue scheme then > using iouring with pre-registered memory would be appropriate. >=20 > I feel like this is a topic Shameerali should share some insight with > since the Huawei implementation will rely on this SW path. So far the tests we have done are mainly using IOCTL method without batching and I don't have any numbers to compare against the batched method yet. [+Zhangfei] Zhangfei, do you think we can run some UADK/vSVA tests with different=20 Invalidation solutions discussed here and compare?=20 Thanks, Shameer=20