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Date:   Tue, 27 Jun 2023 17:48:02 +0200
From:   Christoph Hellwig <hch@lst.de>
To:     Petr =?utf-8?B?VGVzYcWZw61r?= <petr@tesarici.cz>
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Subject: Re: [PATCH v3 1/7] swiotlb: make io_tlb_default_mem local to
 swiotlb.c
Message-ID: <20230627154802.GA29567@lst.de>
References: <cover.1687859323.git.petr.tesarik.ext@huawei.com> <a1ef6eeab8b64fac817b9734da4a056f05a68d01.1687859323.git.petr.tesarik.ext@huawei.com> <2023062745-routing-palace-d0b4@gregkh> <73f11258-1562-17c1-969e-b134dcb5f35c@arm.com> <20230627133006.16ee11af@meshulam.tesarici.cz>
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On Tue, Jun 27, 2023 at 01:30:06PM +0200, Petr Tesařík wrote:
> Xen is the only user of an "is SWIOTLB present" interface. IIUC Xen
> needs bounce buffers for the PCI frontend driver, but if there is no
> other reason to have a SWIOTLB, the system does not set up one at boot.

Please take a look at my "unexport swiotlb_active v2" series that
unfortunately missed the 6.5 merge window waiting for reviews.