From: "Tian, Kevin" <kevin.tian@intel.com>
To: Jacob Pan <jacob.jun.pan@linux.intel.com>,
LKML <linux-kernel@vger.kernel.org>,
"iommu@lists.linux.dev" <iommu@lists.linux.dev>,
Jason Gunthorpe <jgg@nvidia.com>,
Lu Baolu <baolu.lu@linux.intel.com>,
Joerg Roedel <joro@8bytes.org>,
"dmaengine@vger.kernel.org" <dmaengine@vger.kernel.org>,
"vkoul@kernel.org" <vkoul@kernel.org>
Cc: Robin Murphy <robin.murphy@arm.com>,
Will Deacon <will@kernel.org>,
"David Woodhouse" <dwmw2@infradead.org>,
"Raj, Ashok" <ashok.raj@intel.com>,
"Liu, Yi L" <yi.l.liu@intel.com>,
"Yu, Fenghua" <fenghua.yu@intel.com>,
"Jiang, Dave" <dave.jiang@intel.com>,
"Luck, Tony" <tony.luck@intel.com>,
"Zanussi, Tom" <tom.zanussi@intel.com>
Subject: RE: [PATCH v2 3/8] iommu/sva: Support reservation of global SVA PASIDs
Date: Tue, 28 Mar 2023 07:35:43 +0000 [thread overview]
Message-ID: <BN9PR11MB527652D88D15437F52FCE8268C889@BN9PR11MB5276.namprd11.prod.outlook.com> (raw)
In-Reply-To: <20230327232138.1490712-4-jacob.jun.pan@linux.intel.com>
> From: Jacob Pan <jacob.jun.pan@linux.intel.com>
> Sent: Tuesday, March 28, 2023 7:22 AM
>
> +/**
> + * @brief
> + * Reserve a PASID from the SVA global number space.
> + *
> + * @param min starting range, inclusive
> + * @param max ending range, inclusive
> + * @return The reserved PASID on success or IOMMU_PASID_INVALID on
> failure.
> + */
> +ioasid_t iommu_sva_reserve_pasid(ioasid_t min, ioasid_t max)
> +{
> + int ret;
> +
> + if (!pasid_valid(min) || !pasid_valid(max) ||
> + min == 0 || max < min)
> + return IOMMU_PASID_INVALID;
> +
> + ret = ida_alloc_range(&iommu_global_pasid_ida, min, max,
> GFP_KERNEL);
> + if (ret < 0)
> + return IOMMU_PASID_INVALID;
> +
> + return ret;
> +}
> +EXPORT_SYMBOL_GPL(iommu_sva_reserve_pasid);
> +
Look at this function. There is no single word about sva except
in the function name.
sva is just one user of global pasids.
when a driver supports sva it has to always use global pasids even
for non-sva usages like dma pasid.
but this doesn't mean that we should build the API around sva.
it's really about global pasids.
let's just call it clearly as iommu_alloc_global_pasid(min, max).
Then we can define a wrapper iommu_reserve_global_pasid(pasid)
as iommu_alloc_global_pasid(pasid, pasid).
for PASID#0 driver calls iommu_reserve_global_pasid(0).
for dma pasid driver calls iommu_alloc_global_pasid() to get a random
one instead of reserving pasid#1.
this would be future proof when the same driver starts to allocate
more pasids for other usages e..g siov.
next prev parent reply other threads:[~2023-03-28 7:37 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-27 23:21 [PATCH v2 0/8] Re-enable IDXD kernel workqueue under DMA API Jacob Pan
2023-03-27 23:21 ` [PATCH v2 1/8] iommu/vt-d: Use non-privileged mode for all PASIDs Jacob Pan
2023-03-28 4:55 ` Baolu Lu
2023-03-27 23:21 ` [PATCH v2 2/8] iommu/vt-d: Remove PASID supervisor request support Jacob Pan
2023-03-28 4:59 ` Baolu Lu
2023-03-27 23:21 ` [PATCH v2 3/8] iommu/sva: Support reservation of global SVA PASIDs Jacob Pan
2023-03-28 5:11 ` Baolu Lu
2023-03-28 15:21 ` Jacob Pan
2023-03-28 7:35 ` Tian, Kevin [this message]
2023-03-28 15:31 ` Jacob Pan
2023-03-28 15:55 ` Jason Gunthorpe
2023-03-28 16:32 ` Jacob Pan
2023-03-27 23:21 ` [PATCH v2 4/8] iommu/vt-d: Reserve RID_PASID from global SVA PASID space Jacob Pan
2023-03-28 5:20 ` Baolu Lu
2023-03-28 16:29 ` Jacob Pan
2023-03-28 20:52 ` Jacob Pan
2023-03-29 6:13 ` Baolu Lu
2023-03-29 8:20 ` Vasant Hegde
2023-03-27 23:21 ` [PATCH v2 5/8] iommu/vt-d: Make device pasid attachment explicit Jacob Pan
2023-03-28 5:49 ` Baolu Lu
2023-03-28 7:44 ` Tian, Kevin
2023-03-28 20:39 ` Jacob Pan
2023-03-29 6:18 ` Baolu Lu
2023-03-27 23:21 ` [PATCH v2 6/8] iommu/vt-d: Implement set_dev_pasid domain op Jacob Pan
2023-03-28 7:47 ` Tian, Kevin
2023-03-28 15:40 ` Jacob Pan
2023-03-29 3:04 ` Tian, Kevin
2023-03-29 6:22 ` Baolu Lu
2023-03-27 23:21 ` [PATCH v2 7/8] iommu: Export iommu_get_dma_domain Jacob Pan
2023-03-28 6:04 ` Baolu Lu
2023-03-28 7:52 ` Tian, Kevin
2023-03-28 15:48 ` Jacob Pan
2023-03-28 16:19 ` Jason Gunthorpe
2023-03-28 17:25 ` Jacob Pan
2023-03-28 15:48 ` Jacob Pan
2023-03-29 6:28 ` Baolu Lu
2023-03-27 23:21 ` [PATCH v2 8/8] dmaengine/idxd: Re-enable kernel workqueue under DMA API Jacob Pan
2023-03-28 18:16 ` Fenghua Yu
2023-03-28 20:23 ` Jacob Pan
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