From: Jason Gunthorpe <jgg@nvidia.com>
To: Nicolin Chen <nicolinc@nvidia.com>
Cc: "robin.murphy@arm.com" <robin.murphy@arm.com>,
"Tian, Kevin" <kevin.tian@intel.com>,
"joro@8bytes.org" <joro@8bytes.org>,
"will@kernel.org" <will@kernel.org>,
"marcan@marcan.st" <marcan@marcan.st>,
"sven@svenpeter.dev" <sven@svenpeter.dev>,
"robdclark@gmail.com" <robdclark@gmail.com>,
"baolu.lu@linux.intel.com" <baolu.lu@linux.intel.com>,
"matthias.bgg@gmail.com" <matthias.bgg@gmail.com>,
"orsonzhai@gmail.com" <orsonzhai@gmail.com>,
"baolin.wang7@gmail.com" <baolin.wang7@gmail.com>,
"zhang.lyra@gmail.com" <zhang.lyra@gmail.com>,
"jean-philippe@linaro.org" <jean-philippe@linaro.org>,
"alex.williamson@redhat.com" <alex.williamson@redhat.com>,
"jordan@cosmicpenguin.net" <jordan@cosmicpenguin.net>,
"thierry.reding@gmail.com" <thierry.reding@gmail.com>,
"alyssa@rosenzweig.io" <alyssa@rosenzweig.io>,
"linux-s390@vger.kernel.org" <linux-s390@vger.kernel.org>,
"saiprakash.ranjan@codeaurora.org"
<saiprakash.ranjan@codeaurora.org>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"jonathanh@nvidia.com" <jonathanh@nvidia.com>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"yangyingliang@huawei.com" <yangyingliang@huawei.com>,
"gerald.schaefer@linux.ibm.com" <gerald.schaefer@linux.ibm.com>,
"linux-arm-msm@vger.kernel.org" <linux-arm-msm@vger.kernel.org>,
"christophe.jaillet@wanadoo.fr" <christophe.jaillet@wanadoo.fr>,
"linux-tegra@vger.kernel.org" <linux-tegra@vger.kernel.org>,
"tglx@linutronix.de" <tglx@linutronix.de>,
"virtualization@lists.linux-foundation.org"
<virtualization@lists.linux-foundation.org>,
"isaacm@codeaurora.org" <isaacm@codeaurora.org>,
"cohuck@redhat.com" <cohuck@redhat.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"iommu@lists.linux-foundation.org"
<iommu@lists.linux-foundation.org>,
"linux-mediatek@lists.infradead.org"
<linux-mediatek@lists.infradead.org>,
"dwmw2@infradead.org" <dwmw2@infradead.org>
Subject: Re: [PATCH v2 5/5] vfio/iommu_type1: Simplify group attachment
Date: Mon, 20 Jun 2022 01:03:17 -0300 [thread overview]
Message-ID: <20220620040317.GD5219@nvidia.com> (raw)
In-Reply-To: <Yq0JKBiQfTkWh4nq@Asurada-Nvidia>
On Fri, Jun 17, 2022 at 04:07:20PM -0700, Nicolin Chen wrote:
> > > > > + vfio_iommu_aper_expand(iommu, &iova_copy);
> > > >
> > > > but now it's done for every group detach. The aperture is decided
> > > > by domain geometry which is not affected by attached groups.
> > >
> > > Yea, I've noticed this part. Actually Jason did this change for
> > > simplicity, and I think it'd be safe to do so?
> >
> > Perhaps detach_destroy() can return a Boolean to indicate whether
> > a domain is destroyed.
>
> It could be a solution but doesn't feel that common for a clean
> function to have a return value indicating a special case. Maybe
> passing in "&domain" so that we can check if it's NULL after?
It is harmless to do every time, it just burns a few CPU cycles on a
slow path. We don't need complexity to optmize it.
Jason
WARNING: multiple messages have this Message-ID (diff)
From: Jason Gunthorpe via iommu <iommu@lists.linux-foundation.org>
To: Nicolin Chen <nicolinc@nvidia.com>
Cc: "cohuck@redhat.com" <cohuck@redhat.com>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"jordan@cosmicpenguin.net" <jordan@cosmicpenguin.net>,
"linux-tegra@vger.kernel.org" <linux-tegra@vger.kernel.org>,
"thierry.reding@gmail.com" <thierry.reding@gmail.com>,
"will@kernel.org" <will@kernel.org>,
"alyssa@rosenzweig.io" <alyssa@rosenzweig.io>,
"jean-philippe@linaro.org" <jean-philippe@linaro.org>,
"saiprakash.ranjan@codeaurora.org"
<saiprakash.ranjan@codeaurora.org>,
"zhang.lyra@gmail.com" <zhang.lyra@gmail.com>,
"iommu@lists.linux-foundation.org"
<iommu@lists.linux-foundation.org>,
"jonathanh@nvidia.com" <jonathanh@nvidia.com>,
"yangyingliang@huawei.com" <yangyingliang@huawei.com>,
"orsonzhai@gmail.com" <orsonzhai@gmail.com>,
"gerald.schaefer@linux.ibm.com" <gerald.schaefer@linux.ibm.com>,
"dwmw2@infradead.org" <dwmw2@infradead.org>,
"Tian, Kevin" <kevin.tian@intel.com>,
"linux-arm-msm@vger.kernel.org" <linux-arm-msm@vger.kernel.org>,
"alex.williamson@redhat.com" <alex.williamson@redhat.com>,
"christophe.jaillet@wanadoo.fr" <christophe.jaillet@wanadoo.fr>,
"matthias.bgg@gmail.com" <matthias.bgg@gmail.com>,
"tglx@linutronix.de" <tglx@linutronix.de>,
"virtualization@lists.linux-foundation.org"
<virtualization@lists.linux-foundation.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"isaacm@codeaurora.org" <isaacm@codeaurora.org>,
"linux-s390@vger.kernel.org" <linux-s390@vger.kernel.org>,
"marcan@marcan.st" <marcan@marcan.st>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"baolin.wang7@gmail.com" <baolin.wang7@gmail.com>,
"linux-mediatek@lists.infradead.org"
<linux-mediatek@lists.infradead.org>,
"robin.murphy@arm.com" <robin.murphy@arm.com>
Subject: Re: [PATCH v2 5/5] vfio/iommu_type1: Simplify group attachment
Date: Mon, 20 Jun 2022 01:03:17 -0300 [thread overview]
Message-ID: <20220620040317.GD5219@nvidia.com> (raw)
In-Reply-To: <Yq0JKBiQfTkWh4nq@Asurada-Nvidia>
On Fri, Jun 17, 2022 at 04:07:20PM -0700, Nicolin Chen wrote:
> > > > > + vfio_iommu_aper_expand(iommu, &iova_copy);
> > > >
> > > > but now it's done for every group detach. The aperture is decided
> > > > by domain geometry which is not affected by attached groups.
> > >
> > > Yea, I've noticed this part. Actually Jason did this change for
> > > simplicity, and I think it'd be safe to do so?
> >
> > Perhaps detach_destroy() can return a Boolean to indicate whether
> > a domain is destroyed.
>
> It could be a solution but doesn't feel that common for a clean
> function to have a return value indicating a special case. Maybe
> passing in "&domain" so that we can check if it's NULL after?
It is harmless to do every time, it just burns a few CPU cycles on a
slow path. We don't need complexity to optmize it.
Jason
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu
WARNING: multiple messages have this Message-ID (diff)
From: Jason Gunthorpe <jgg@nvidia.com>
To: Nicolin Chen <nicolinc@nvidia.com>
Cc: "robin.murphy@arm.com" <robin.murphy@arm.com>,
"Tian, Kevin" <kevin.tian@intel.com>,
"joro@8bytes.org" <joro@8bytes.org>,
"will@kernel.org" <will@kernel.org>,
"marcan@marcan.st" <marcan@marcan.st>,
"sven@svenpeter.dev" <sven@svenpeter.dev>,
"robdclark@gmail.com" <robdclark@gmail.com>,
"baolu.lu@linux.intel.com" <baolu.lu@linux.intel.com>,
"matthias.bgg@gmail.com" <matthias.bgg@gmail.com>,
"orsonzhai@gmail.com" <orsonzhai@gmail.com>,
"baolin.wang7@gmail.com" <baolin.wang7@gmail.com>,
"zhang.lyra@gmail.com" <zhang.lyra@gmail.com>,
"jean-philippe@linaro.org" <jean-philippe@linaro.org>,
"alex.williamson@redhat.com" <alex.williamson@redhat.com>,
"jordan@cosmicpenguin.net" <jordan@cosmicpenguin.net>,
"thierry.reding@gmail.com" <thierry.reding@gmail.com>,
"alyssa@rosenzweig.io" <alyssa@rosenzweig.io>,
"linux-s390@vger.kernel.org" <linux-s390@vger.kernel.org>,
"saiprakash.ranjan@codeaurora.org"
<saiprakash.ranjan@codeaurora.org>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"jonathanh@nvidia.com" <jonathanh@nvidia.com>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"yangyingliang@huawei.com" <yangyingliang@huawei.com>,
"gerald.schaefer@linux.ibm.com" <gerald.schaefer@linux.ibm.com>,
"linux-arm-msm@vger.kernel.org" <linux-arm-msm@vger.kernel.org>,
"christophe.jaillet@wanadoo.fr" <christophe.jaillet@wanadoo.fr>,
"linux-tegra@vger.kernel.org" <linux-tegra@vger.kernel.org>,
"tglx@linutronix.de" <tglx@linutronix.de>,
"virtualization@lists.linux-foundation.org"
<virtualization@lists.linux-foundation.org>,
"isaacm@codeaurora.org" <isaacm@codeaurora.org>,
"cohuck@redhat.com" <cohuck@redhat.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"iommu@lists.linux-foundation.org"
<iommu@lists.linux-foundation.org>,
"linux-mediatek@lists.infradead.org"
<linux-mediatek@lists.infradead.org>,
"dwmw2@infradead.org" <dwmw2@infradead.org>
Subject: Re: [PATCH v2 5/5] vfio/iommu_type1: Simplify group attachment
Date: Mon, 20 Jun 2022 01:03:17 -0300 [thread overview]
Message-ID: <20220620040317.GD5219@nvidia.com> (raw)
In-Reply-To: <Yq0JKBiQfTkWh4nq@Asurada-Nvidia>
On Fri, Jun 17, 2022 at 04:07:20PM -0700, Nicolin Chen wrote:
> > > > > + vfio_iommu_aper_expand(iommu, &iova_copy);
> > > >
> > > > but now it's done for every group detach. The aperture is decided
> > > > by domain geometry which is not affected by attached groups.
> > >
> > > Yea, I've noticed this part. Actually Jason did this change for
> > > simplicity, and I think it'd be safe to do so?
> >
> > Perhaps detach_destroy() can return a Boolean to indicate whether
> > a domain is destroyed.
>
> It could be a solution but doesn't feel that common for a clean
> function to have a return value indicating a special case. Maybe
> passing in "&domain" so that we can check if it's NULL after?
It is harmless to do every time, it just burns a few CPU cycles on a
slow path. We don't need complexity to optmize it.
Jason
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2022-06-20 4:03 UTC|newest]
Thread overview: 101+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-16 0:02 [PATCH v2 0/5] Simplify vfio_iommu_type1 attach/detach routine Nicolin Chen
2022-06-16 0:02 ` Nicolin Chen
2022-06-16 0:02 ` Nicolin Chen via iommu
2022-06-16 0:03 ` [PATCH v2 1/5] iommu: Return -EMEDIUMTYPE for incompatible domain and device/group Nicolin Chen
2022-06-16 0:03 ` Nicolin Chen
2022-06-16 0:03 ` Nicolin Chen via iommu
2022-06-16 2:09 ` Baolu Lu
2022-06-16 2:09 ` Baolu Lu
2022-06-16 2:09 ` Baolu Lu
2022-06-16 2:40 ` Nicolin Chen
2022-06-16 2:40 ` Nicolin Chen
2022-06-16 2:40 ` Nicolin Chen via iommu
2022-06-16 6:28 ` Tian, Kevin
2022-06-16 6:28 ` Tian, Kevin
2022-06-16 6:28 ` Tian, Kevin
2022-06-16 6:28 ` Tian, Kevin
2022-06-16 0:03 ` [PATCH v2 2/5] vfio/iommu_type1: Prefer to reuse domains vs match enforced cache coherency Nicolin Chen
2022-06-16 0:03 ` Nicolin Chen
2022-06-16 0:03 ` Nicolin Chen via iommu
2022-06-16 6:29 ` Tian, Kevin
2022-06-16 6:29 ` Tian, Kevin
2022-06-16 6:29 ` Tian, Kevin
2022-06-16 6:29 ` Tian, Kevin
2022-06-21 22:46 ` Alex Williamson
2022-06-21 22:46 ` Alex Williamson
2022-06-21 22:46 ` Alex Williamson
2022-06-21 22:46 ` Alex Williamson
2022-06-21 23:47 ` Nicolin Chen
2022-06-21 23:47 ` Nicolin Chen
2022-06-21 23:47 ` Nicolin Chen via iommu
2022-06-16 0:03 ` [PATCH v2 3/5] vfio/iommu_type1: Remove the domain->ops comparison Nicolin Chen
2022-06-16 0:03 ` Nicolin Chen
2022-06-16 0:03 ` Nicolin Chen via iommu
2022-06-16 6:40 ` Tian, Kevin
2022-06-16 6:40 ` Tian, Kevin
2022-06-16 6:40 ` Tian, Kevin
2022-06-16 6:40 ` Tian, Kevin
2022-06-16 22:23 ` Nicolin Chen
2022-06-16 22:23 ` Nicolin Chen
2022-06-16 22:23 ` Nicolin Chen via iommu
2022-06-22 7:54 ` Robin Murphy
2022-06-22 7:54 ` Robin Murphy
2022-06-22 7:54 ` Robin Murphy
2022-06-22 7:54 ` Robin Murphy
2022-06-23 3:50 ` Tian, Kevin
2022-06-23 3:50 ` Tian, Kevin
2022-06-23 3:50 ` Tian, Kevin
2022-06-23 3:50 ` Tian, Kevin
2022-06-23 7:47 ` Nicolin Chen
2022-06-23 7:47 ` Nicolin Chen
2022-06-23 7:47 ` Nicolin Chen via iommu
2022-06-24 13:16 ` Jason Gunthorpe
2022-06-24 13:16 ` Jason Gunthorpe
2022-06-24 13:16 ` Jason Gunthorpe via iommu
2022-06-24 18:31 ` Robin Murphy
2022-06-24 18:31 ` Robin Murphy
2022-06-24 18:31 ` Robin Murphy
2022-06-24 18:31 ` Robin Murphy
2022-06-24 18:46 ` Jason Gunthorpe
2022-06-24 18:46 ` Jason Gunthorpe
2022-06-24 18:46 ` Jason Gunthorpe via iommu
2022-06-16 0:03 ` [PATCH v2 4/5] vfio/iommu_type1: Clean up update_dirty_scope in detach_group() Nicolin Chen
2022-06-16 0:03 ` Nicolin Chen
2022-06-16 0:03 ` Nicolin Chen via iommu
2022-06-16 6:45 ` Tian, Kevin
2022-06-16 6:45 ` Tian, Kevin
2022-06-16 6:45 ` Tian, Kevin
2022-06-16 6:45 ` Tian, Kevin
2022-06-16 22:26 ` Nicolin Chen
2022-06-16 22:26 ` Nicolin Chen
2022-06-16 22:26 ` Nicolin Chen via iommu
2022-06-16 0:03 ` [PATCH v2 5/5] vfio/iommu_type1: Simplify group attachment Nicolin Chen
2022-06-16 0:03 ` Nicolin Chen
2022-06-16 0:03 ` Nicolin Chen via iommu
2022-06-16 7:08 ` Tian, Kevin
2022-06-16 7:08 ` Tian, Kevin
2022-06-16 7:08 ` Tian, Kevin
2022-06-16 7:08 ` Tian, Kevin
2022-06-16 22:40 ` Nicolin Chen
2022-06-16 22:40 ` Nicolin Chen
2022-06-16 22:40 ` Nicolin Chen via iommu
2022-06-17 2:53 ` Tian, Kevin
2022-06-17 2:53 ` Tian, Kevin
2022-06-17 2:53 ` Tian, Kevin
2022-06-17 2:53 ` Tian, Kevin
2022-06-17 23:07 ` Nicolin Chen
2022-06-17 23:07 ` Nicolin Chen
2022-06-17 23:07 ` Nicolin Chen via iommu
2022-06-20 4:03 ` Jason Gunthorpe [this message]
2022-06-20 4:03 ` Jason Gunthorpe
2022-06-20 4:03 ` Jason Gunthorpe via iommu
2022-06-21 20:59 ` Nicolin Chen via iommu
2022-06-21 20:59 ` Nicolin Chen
2022-06-21 20:59 ` Nicolin Chen
2022-06-20 10:11 ` Robin Murphy
2022-06-20 10:11 ` Robin Murphy
2022-06-20 10:11 ` Robin Murphy
2022-06-20 10:11 ` Robin Murphy
2022-06-21 21:08 ` Nicolin Chen via iommu
2022-06-21 21:08 ` Nicolin Chen
2022-06-21 21:08 ` Nicolin Chen
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