From: Baolu Lu <baolu.lu@linux.intel.com>
To: Jason Gunthorpe <jgg@ziepe.ca>
Cc: baolu.lu@linux.intel.com, Joerg Roedel <joro@8bytes.org>,
Will Deacon <will@kernel.org>,
Robin Murphy <robin.murphy@arm.com>,
Kevin Tian <kevin.tian@intel.com>,
iommu@lists.linux.dev, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 1/6] iommu/vt-d: Setup scalable mode context entry in probe path
Date: Tue, 12 Dec 2023 13:34:19 +0800 [thread overview]
Message-ID: <11b4b1db-2fde-413c-a203-0734bc18f4f7@linux.intel.com> (raw)
In-Reply-To: <20231211173826.GE1489931@ziepe.ca>
On 12/12/23 1:38 AM, Jason Gunthorpe wrote:
> On Tue, Dec 05, 2023 at 09:21:58AM +0800, Lu Baolu wrote:
>> +/*
>> + * Get the PASID directory size for scalable mode context entry.
>> + * Value of X in the PDTS field of a scalable mode context entry
>> + * indicates PASID directory with 2^(X + 7) entries.
>> + */
>> +static unsigned long context_get_sm_pds(struct pasid_table *table)
>> +{
>> + unsigned long pds, max_pde;
>> +
>> + max_pde = table->max_pasid >> PASID_PDE_SHIFT;
>> + pds = find_first_bit(&max_pde, MAX_NR_PASID_BITS);
>> + if (pds < 7)
>> + return 0;
>> +
>> + return pds - 7;
> This seems like a convoluted way to write
> max(ilog2(table-max_pasid) - 7,0)
>
> ?
Yes. :-)
Something like,
max(ilog2(table->max_pasid >> PASID_PDE_SHIFT) - 7, 0)
Best regards,
baolu
next prev parent reply other threads:[~2023-12-12 5:39 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-05 1:21 [PATCH v2 0/6] iommu/vt-d: Convert to use static identity domain Lu Baolu
2023-12-05 1:21 ` [PATCH v2 1/6] iommu/vt-d: Setup scalable mode context entry in probe path Lu Baolu
2023-12-08 8:50 ` Tian, Kevin
2023-12-09 7:52 ` Baolu Lu
2023-12-11 4:06 ` Tian, Kevin
2023-12-11 17:38 ` Jason Gunthorpe
2023-12-12 5:34 ` Baolu Lu [this message]
2023-12-05 1:21 ` [PATCH v2 2/6] iommu/vt-d: Remove scalable mode context entry setup from attach_dev Lu Baolu
2023-12-08 8:56 ` Tian, Kevin
2023-12-09 7:57 ` Baolu Lu
2023-12-05 1:22 ` [PATCH v2 3/6] iommu/vt-d: Refactor domain_context_mapping_one() to be reusable Lu Baolu
2023-12-05 1:22 ` [PATCH v2 4/6] iommu/vt-d: Remove 1:1 mappings from identity domain Lu Baolu
2023-12-08 9:09 ` Tian, Kevin
2023-12-08 12:45 ` Baolu Lu
2023-12-11 3:58 ` Tian, Kevin
2023-12-12 6:20 ` Baolu Lu
2023-12-13 2:20 ` Tian, Kevin
2023-12-13 2:43 ` Baolu Lu
2023-12-13 3:04 ` Tian, Kevin
2023-12-13 3:02 ` Baolu Lu
2023-12-05 1:22 ` [PATCH v2 5/6] iommu/vt-d: Add support for static " Lu Baolu
2023-12-05 1:22 ` [PATCH v2 6/6] iommu/vt-d: Cleanup si_domain Lu Baolu
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