From: Christoph Hellwig <hch@lst.de>
To: Tianyu Lan <ltykernel@gmail.com>
Cc: Christoph Hellwig <hch@lst.de>,
kys@microsoft.com, haiyangz@microsoft.com,
sthemmin@microsoft.com, wei.liu@kernel.org, decui@microsoft.com,
tglx@linutronix.de, mingo@redhat.com, bp@alien8.de,
dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com,
hch@infradead.org, m.szyprowski@samsung.com,
robin.murphy@arm.com, michael.h.kelley@microsoft.com,
Tianyu Lan <Tianyu.Lan@microsoft.com>,
iommu@lists.linux-foundation.org, linux-hyperv@vger.kernel.org,
linux-kernel@vger.kernel.org, vkuznets@redhat.com,
brijesh.singh@amd.com, konrad.wilk@oracle.com,
parri.andrea@gmail.com, thomas.lendacky@amd.com
Subject: Re: [PATCH V2 1/2] Swiotlb: Add swiotlb_alloc_from_low_pages switch
Date: Mon, 14 Feb 2022 14:58:34 +0100 [thread overview]
Message-ID: <20220214135834.GA30150@lst.de> (raw)
In-Reply-To: <4f433f07-05be-f81f-43e8-55c3f1af23b3@gmail.com>
On Mon, Feb 14, 2022 at 07:28:40PM +0800, Tianyu Lan wrote:
> On 2/14/2022 4:19 PM, Christoph Hellwig wrote:
>> Adding a function to set the flag doesn't really change much. As Robin
>> pointed out last time you should fine a way to just call
>> swiotlb_init_with_tbl directly with the memory allocated the way you
>> like it. Or given that we have quite a few of these trusted hypervisor
>> schemes maybe add an argument to swiotlb_init that specifies how to
>> allocate the memory.
>
> Thanks for your suggestion. I will try the first approach first approach.
Take a look at the SWIOTLB_ANY flag in this WIP branch:
http://git.infradead.org/users/hch/misc.git/shortlog/refs/heads/swiotlb-init-cleanup
That being said I'm not sure that either this flag or the existing powerpc
code iѕ actually the right thing to do. We still need the 4G limited
buffer to support devices with addressing limitations. So I think we need
an additional io_tlb_mem instance for the devices without addressing
limitations instead.
next prev parent reply other threads:[~2022-02-14 13:58 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-09 12:23 [PATCH V2 0/2] x86/hyperv/Swiotlb: Add swiotlb_set_alloc_from_low_pages() switch function Tianyu Lan
2022-02-09 12:23 ` [PATCH V2 1/2] Swiotlb: Add swiotlb_alloc_from_low_pages switch Tianyu Lan
2022-02-14 8:19 ` Christoph Hellwig
2022-02-14 11:28 ` Tianyu Lan
2022-02-14 13:58 ` Christoph Hellwig [this message]
2022-02-15 15:32 ` Tianyu Lan
2022-02-21 15:14 ` Tianyu Lan
2022-02-22 8:05 ` Christoph Hellwig
2022-02-22 15:07 ` Tianyu Lan
2022-02-22 16:00 ` Christoph Hellwig
2022-02-23 9:46 ` Tianyu Lan
2022-02-25 14:28 ` Tianyu Lan
2022-03-01 11:53 ` Christoph Hellwig
2022-03-01 14:01 ` Tianyu Lan
2022-02-09 12:23 ` [PATCH V2 2/2] x86/hyperv: Make swiotlb bounce buffer allocation not just from low pages Tianyu Lan
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