search for: css0

On Wed, 10 Apr 2019 17:31:48 +0200 Halil Pasic <pasic at linux.ibm.com> wrote: > On Tue, 9 Apr 2019 19:14:53 +0200 > Cornelia Huck <cohuck at redhat.com> wrote: > > [..] > > > > > At this point, you're always going via the css0 device. I'm > > > > wondering whether you should pass in the cssid here and use > > > > css_by_id(cssid) to make this future proof. But then, I'm not > > > > quite clear from which context this will be called. > > > > > > As said...

...; buffers addressed by MIDA vs IDA vs direct). > > Virtio uses the DMA properties of the parent, that is in our case the > struct device embedded in struct ccw_device. > > The previous version (RFC) used to allocate all the cio DMA stuff from > this global cio_dma_pool using the css0.dev for the DMA API > interactions. And we set *css0.dev.dma_mask == DMA_BIT_MASK(31) so > e.g. the allocated ccws are 31 bit addressable. > > But I was asked to change this so that when I allocate DMA memory for a > channel program of particular ccw device, a struct device of that...

...; buffers addressed by MIDA vs IDA vs direct). > > Virtio uses the DMA properties of the parent, that is in our case the > struct device embedded in struct ccw_device. > > The previous version (RFC) used to allocate all the cio DMA stuff from > this global cio_dma_pool using the css0.dev for the DMA API > interactions. And we set *css0.dev.dma_mask == DMA_BIT_MASK(31) so > e.g. the allocated ccws are 31 bit addressable. > > But I was asked to change this so that when I allocate DMA memory for a > channel program of particular ccw device, a struct device of that...

...GES 1 > +static struct gen_pool *cio_dma_pool; > +/* Currently cio supports only a single css */ > +static struct device *cio_dma_css; That global variable feels wrong, especially if you plan to support MCSS-E in the future. (Do you? :) If yes, should the dma pool be global or per-css? As css0 currently is the root device for the channel subsystem stuff, you'd either need a new parent to hang this off from or size this with the number of css images.) For now, just grab channel_subsystems[0]->device directly? > +static gfp_t cio_dma_flags; > + > +static void __init cio_...

...IDA vs direct). > > > > Virtio uses the DMA properties of the parent, that is in our case the > > struct device embedded in struct ccw_device. > > > > The previous version (RFC) used to allocate all the cio DMA stuff > > from this global cio_dma_pool using the css0.dev for the DMA API > > interactions. And we set *css0.dev.dma_mask == DMA_BIT_MASK(31) so > > e.g. the allocated ccws are 31 bit addressable. > > > > But I was asked to change this so that when I allocate DMA memory > > for a channel program of particular ccw device,...

...cio_dma_css; > > > > That global variable feels wrong, especially if you plan to support > > MCSS-E in the future. (Do you? :) > > Not that I'm aware of any plans to add support MCSS-E. > > > If yes, should the dma pool be global > > or per-css? As css0 currently is the root device for the channel > > subsystem stuff, you'd either need a new parent to hang this off from > > or size this with the number of css images.) > > > > For now, just grab channel_subsystems[0]->device directly? > > > > Patch 6...

...e going to use the memory (e.g. buffers addressed by MIDA vs IDA vs direct). Virtio uses the DMA properties of the parent, that is in our case the struct device embedded in struct ccw_device. The previous version (RFC) used to allocate all the cio DMA stuff from this global cio_dma_pool using the css0.dev for the DMA API interactions. And we set *css0.dev.dma_mask == DMA_BIT_MASK(31) so e.g. the allocated ccws are 31 bit addressable. But I was asked to change this so that when I allocate DMA memory for a channel program of particular ccw device, a struct device of that ccw device is used as the...

On Fri, 26 Apr 2019 20:32:41 +0200 Halil Pasic <pasic at linux.ibm.com> wrote: > As virtio-ccw devices are channel devices, we need to use the dma area > for any communication with the hypervisor. > > This patch addresses the most basic stuff (mostly what is required for > virtio-ccw), and does take care of QDIO or any devices. "does not take care of QDIO",

On Fri, 26 Apr 2019 20:32:41 +0200 Halil Pasic <pasic at linux.ibm.com> wrote: > As virtio-ccw devices are channel devices, we need to use the dma area > for any communication with the hypervisor. > > This patch addresses the most basic stuff (mostly what is required for > virtio-ccw), and does take care of QDIO or any devices. "does not take care of QDIO",