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Mon, 30 Mar 2020 05:19:40 -0400 IronPort-SDR: EG+R3Df6GiOgyL0eBq2IdMQv/RmK5EjzWiyVyWcILgQDyKh5gHMihgFTpkymFRfgUx5KK8gEZJ KFnT8pBGckiw== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 30 Mar 2020 02:19:39 -0700 IronPort-SDR: nenw0c/QYlIZ+ezEmcT5mgKIqnKGs22ulwDq4iiQrlDz09QVb1KJ4hVKUKGASuz06B4unSR/pN l+oGwnoJ9HDg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.72,323,1580803200"; d="scan'208";a="294534776" Received: from fmsmsx103.amr.corp.intel.com ([10.18.124.201]) by FMSMGA003.fm.intel.com with ESMTP; 30 Mar 2020 02:19:38 -0700 Received: from fmsmsx156.amr.corp.intel.com (10.18.116.74) by FMSMSX103.amr.corp.intel.com (10.18.124.201) with Microsoft SMTP Server (TLS) id 14.3.439.0; Mon, 30 Mar 2020 02:19:38 -0700 Received: from shsmsx152.ccr.corp.intel.com (10.239.6.52) by fmsmsx156.amr.corp.intel.com (10.18.116.74) with Microsoft SMTP Server (TLS) id 14.3.439.0; Mon, 30 Mar 2020 02:19:38 -0700 Received: from shsmsx104.ccr.corp.intel.com ([169.254.5.225]) by SHSMSX152.ccr.corp.intel.com ([169.254.6.209]) with mapi id 14.03.0439.000; Mon, 30 Mar 2020 17:19:34 +0800 From: "Tian, Kevin" To: "Liu, Yi L" , "alex.williamson@redhat.com" , "eric.auger@redhat.com" CC: "jacob.jun.pan@linux.intel.com" , "joro@8bytes.org" , "Raj, Ashok" , "Tian, Jun J" , "Sun, Yi Y" , "jean-philippe@linaro.org" , "peterx@redhat.com" , "iommu@lists.linux-foundation.org" , "kvm@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "Wu, Hao" Subject: RE: [PATCH v1 2/8] vfio/type1: Add vfio_iommu_type1 parameter for quota tuning Thread-Topic: [PATCH v1 2/8] vfio/type1: Add vfio_iommu_type1 parameter for quota tuning Thread-Index: AQHWAEUbX2o9koiJmUSoQpAjbhigyahg28IA//9+x4CAAI0HsA== Date: Mon, 30 Mar 2020 09:19:33 +0000 Message-ID: References: <1584880325-10561-1-git-send-email-yi.l.liu@intel.com> <1584880325-10561-3-git-send-email-yi.l.liu@intel.com> In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: dlp-product: dlpe-windows dlp-version: 11.2.0.6 dlp-reaction: no-action x-originating-ip: [10.239.127.40] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > From: Liu, Yi L > Sent: Monday, March 30, 2020 4:53 PM > > > From: Tian, Kevin > > Sent: Monday, March 30, 2020 4:41 PM > > To: Liu, Yi L ; alex.williamson@redhat.com; > > Subject: RE: [PATCH v1 2/8] vfio/type1: Add vfio_iommu_type1 parameter > for quota > > tuning > > > > > From: Liu, Yi L > > > Sent: Sunday, March 22, 2020 8:32 PM > > > > > > From: Liu Yi L > > > > > > This patch adds a module option to make the PASID quota tunable by > > > administrator. > > > > > > TODO: needs to think more on how to make the tuning to be per-process. > > > > > > Previous discussions: > > > https://patchwork.kernel.org/patch/11209429/ > > > > > > Cc: Kevin Tian > > > CC: Jacob Pan > > > Cc: Alex Williamson > > > Cc: Eric Auger > > > Cc: Jean-Philippe Brucker > > > Signed-off-by: Liu Yi L > > > --- > > > drivers/vfio/vfio.c | 8 +++++++- > > > drivers/vfio/vfio_iommu_type1.c | 7 ++++++- > > > include/linux/vfio.h | 3 ++- > > > 3 files changed, 15 insertions(+), 3 deletions(-) > > > > > > diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c > > > index d13b483..020a792 100644 > > > --- a/drivers/vfio/vfio.c > > > +++ b/drivers/vfio/vfio.c > > > @@ -2217,13 +2217,19 @@ struct vfio_mm > *vfio_mm_get_from_task(struct > > > task_struct *task) > > > } > > > EXPORT_SYMBOL_GPL(vfio_mm_get_from_task); > > > > > > -int vfio_mm_pasid_alloc(struct vfio_mm *vmm, int min, int max) > > > +int vfio_mm_pasid_alloc(struct vfio_mm *vmm, int quota, int min, int > max) > > > { > > > ioasid_t pasid; > > > int ret = -ENOSPC; > > > > > > mutex_lock(&vmm->pasid_lock); > > > > > > + /* update quota as it is tunable by admin */ > > > + if (vmm->pasid_quota != quota) { > > > + vmm->pasid_quota = quota; > > > + ioasid_adjust_set(vmm->ioasid_sid, quota); > > > + } > > > + > > > > It's a bit weird to have quota adjusted in the alloc path, since the latter > might > > be initiated by non-privileged users. Why not doing the simple math in > vfio_ > > create_mm to set the quota when the ioasid set is created? even in the > future > > you may allow per-process quota setting, that should come from separate > > privileged path instead of thru alloc.. > > The reason is the kernel parameter modification has no event which > can be used to adjust the quota. So I chose to adjust it in pasid_alloc > path. If it's not good, how about adding one more IOCTL to let user- > space trigger a quota adjustment event? Then even non-privileged > user could trigger quota adjustment, the quota is actually controlled > by privileged user. How about your opinion? > why do you need an event to adjust? As I said, you can set the quota when the set is created in vfio_create_mm... Thanks Kevin