From: John Garry <john.garry@huawei.com>
To: Lu Baolu <baolu.lu@linux.intel.com>, <joro@8bytes.org>,
<will@kernel.org>, <dwmw2@infradead.org>, <robin.murphy@arm.com>,
<corbet@lwn.net>
Cc: <linux-kernel@vger.kernel.org>,
<iommu@lists.linux-foundation.org>, <linuxarm@huawei.com>,
<thunder.leizhen@huawei.com>, <chenxiang66@hisilicon.com>,
<linux-doc@vger.kernel.org>
Subject: Re: [PATCH v13 4/6] iommu/vt-d: Add support for IOMMU default DMA mode build options
Date: Fri, 18 Jun 2021 08:31:05 +0100 [thread overview]
Message-ID: <b654480e-d5ac-9e4c-1074-1158cccc5806@huawei.com> (raw)
In-Reply-To: <d53a6472-4628-313e-30a5-f76e016c9cb9@linux.intel.com>
On 18/06/2021 02:46, Lu Baolu wrote:
Hi baolu,
>> I need to change that. How about this:
>>
>> bool print_warning = false;
>>
>> for_each_active_iommu(iommu, drhd) {
>> /*
>> * The flush queue implementation does not perform
>> * page-selective invalidations that are required for efficient
>> * TLB flushes in virtual environments. The benefit of batching
>> * is likely to be much lower than the overhead of synchronizing
>> * the virtual and physical IOMMU page-tables.
>> */
>> if (!print_warning && cap_caching_mode(iommu->cap)) {
>> pr_warn("IOMMU batching disallowed due to virtualization\n");
>> iommu_set_dma_strict(true);
>> print_warning = true;
>> }
>> ...
>> }
>>
>> or use pr_warn_once().
>
> From my p.o.v, pr_xxxx_once() is better.
>
> How about using a pr_info_once()? I don't think it's a warning, it's
> just a policy choice in VM environment.
ok, I can go with that, which Robin mostly agrees with.
Thanks,
John
next prev parent reply other threads:[~2021-06-18 7:37 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-16 11:03 [PATCH v13 0/6] iommu: Enhance IOMMU default DMA mode build options John Garry
2021-06-16 11:03 ` [PATCH v13 1/6] iommu: Deprecate Intel and AMD cmdline methods to enable strict mode John Garry
2021-06-17 19:01 ` Robin Murphy
2021-06-18 7:43 ` John Garry
2021-06-16 11:03 ` [PATCH v13 2/6] iommu: Print strict or lazy mode at init time John Garry
2021-06-16 11:03 ` [PATCH v13 3/6] iommu: Enhance IOMMU default DMA mode build options John Garry
2021-06-16 11:03 ` [PATCH v13 4/6] iommu/vt-d: Add support for " John Garry
2021-06-17 7:32 ` Lu Baolu
2021-06-17 8:00 ` John Garry
2021-06-17 19:03 ` Robin Murphy
2021-06-18 1:46 ` Lu Baolu
2021-06-18 7:31 ` John Garry [this message]
2021-06-16 11:03 ` [PATCH v13 5/6] iommu/amd: " John Garry
2021-06-16 11:03 ` [PATCH v13 6/6] iommu: Remove mode argument from iommu_set_dma_strict() John Garry
2021-06-17 7:36 ` Lu Baolu
2021-06-17 7:41 ` John Garry
2021-06-18 1:52 ` Lu Baolu
2021-06-17 18:56 ` Robin Murphy
2021-06-18 1:51 ` Lu Baolu
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