From: Anshuman Khandual <khandual@linux.vnet.ibm.com>
To: Ram Pai <linuxram@us.ibm.com>, "Michael S. Tsirkin" <mst@redhat.com>
Cc: robh@kernel.org, aik@ozlabs.ru, jasowang@redhat.com,
linux-kernel@vger.kernel.org,
virtualization@lists.linux-foundation.org, hch@infradead.org,
joe@perches.com, linuxppc-dev@lists.ozlabs.org,
elfring@users.sourceforge.net, david@gibson.dropbear.id.au
Subject: Re: [RFC V2] virtio: Add platform specific DMA API translation for virito devices
Date: Thu, 31 May 2018 09:09:24 +0530 [thread overview]
Message-ID: <0c508eb2-08df-3f76-c260-90cf7137af80@linux.vnet.ibm.com> (raw)
In-Reply-To: <20180524072104.GD6139@ram.oc3035372033.ibm.com>
On 05/24/2018 12:51 PM, Ram Pai wrote:
> On Wed, May 23, 2018 at 09:50:02PM +0300, Michael S. Tsirkin wrote:
>> subj: s/virito/virtio/
>>
> ..snip..
>>> machine_subsys_initcall_sync(pseries, tce_iommu_bus_notifier_init);
>>> +
>>> +bool platform_forces_virtio_dma(struct virtio_device *vdev)
>>> +{
>>> + /*
>>> + * On protected guest platforms, force virtio core to use DMA
>>> + * MAP API for all virtio devices. But there can also be some
>>> + * exceptions for individual devices like virtio balloon.
>>> + */
>>> + return (of_find_compatible_node(NULL, NULL, "ibm,ultravisor") != NULL);
>>> +}
>>
>> Isn't this kind of slow? vring_use_dma_api is on
>> data path and supposed to be very fast.
>
> Yes it is slow and not ideal. This won't be the final code. The final
> code will cache the information in some global variable and used
> in this function.
Right this will be a simple check based on a global variable.
next prev parent reply other threads:[~2018-05-31 3:39 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-22 6:33 [RFC V2] virtio: Add platform specific DMA API translation for virito devices Anshuman Khandual
2018-05-23 18:50 ` Michael S. Tsirkin
2018-05-23 22:27 ` Benjamin Herrenschmidt
2018-05-24 7:17 ` Christoph Hellwig
2018-05-25 17:45 ` Michael S. Tsirkin
2018-05-28 23:48 ` Benjamin Herrenschmidt
2018-05-28 23:56 ` Benjamin Herrenschmidt
2018-05-29 14:03 ` Christoph Hellwig
2018-05-29 22:13 ` Benjamin Herrenschmidt
2018-06-04 8:57 ` David Gibson
2018-06-04 9:48 ` Benjamin Herrenschmidt
2018-06-04 12:50 ` Michael S. Tsirkin
2018-06-05 1:52 ` David Gibson
2018-06-04 12:43 ` Michael S. Tsirkin
2018-06-04 12:55 ` Christoph Hellwig
2018-06-04 13:14 ` Benjamin Herrenschmidt
2018-06-04 16:34 ` Michael S. Tsirkin
2018-06-04 13:11 ` Benjamin Herrenschmidt
2018-06-04 16:21 ` Michael S. Tsirkin
2018-06-04 23:26 ` Benjamin Herrenschmidt
2018-06-05 1:25 ` Michael S. Tsirkin
2018-06-05 4:52 ` Christoph Hellwig
2018-05-24 7:21 ` Ram Pai
2018-05-31 3:39 ` Anshuman Khandual [this message]
2018-05-31 17:43 ` Michael S. Tsirkin
2018-06-07 5:23 ` Christoph Hellwig
2018-06-07 16:28 ` Michael S. Tsirkin
2018-06-08 6:36 ` Christoph Hellwig
2018-06-13 13:49 ` Michael S. Tsirkin
2018-06-11 2:39 ` Ram Pai
2018-06-11 3:28 ` Michael S. Tsirkin
2018-06-11 3:34 ` Benjamin Herrenschmidt
2018-06-13 14:23 ` Michael S. Tsirkin
2018-06-11 3:29 ` Benjamin Herrenschmidt
2018-06-13 7:41 ` Christoph Hellwig
2018-06-13 12:25 ` Benjamin Herrenschmidt
2018-06-13 13:11 ` Benjamin Herrenschmidt
2018-06-15 9:16 ` Christoph Hellwig
2018-06-16 1:07 ` Benjamin Herrenschmidt
2018-06-13 13:59 ` Michael S. Tsirkin
2018-06-13 14:03 ` Michael S. Tsirkin
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