Re: [Qemu-devel] [PATCH qemu v7 08/14] spapr_pci: Do complete reset of DMA config when resetting PHB

[David Gibson <david@gibson.dropbear.id.au>]

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On Sat, Apr 25, 2015 at 10:24:38PM +1000, Alexey Kardashevskiy wrote:
> On a system reset, DMA configuration has to reset too. At the moment
> it clears the table content. This is enough for the single table case
> but with DDW, we will also have to disable all DMA windows except
> the default one. Furthermore according to sPAPR, if the guest removed
> the default window and created a huge one at the same zero offset on
> a PCI bus, the reset handler has to recreate the default window with
> the default properties (2GB big, 4K pages).
> 
> This reworks SPAPR PHB code to disable the existing DMA window on reset
> and then configure and enable the default window.
> Without DDW that means that the same window will be disabled and then
> enabled with no other change in behaviour.
> 
> This changes the table creation to do it in one place in PHB (VFIO PHB
> just inherits the behaviour from PHB). The actual table allocation is
> done from the reset handler and this is where dma_init_window() is called.
> 
> This disables all DMA windows on a PHB reset. It does not make any
> difference now as there is just one DMA window but it will later with DDW
> patches.
> 
> This makes spapr_phb_dma_reset() and spapr_phb_dma_remove_window() public
> as these will be used in DDW RTAS "ibm,reset-pe-dma-window" and
> "ibm,remove-pe-dma-window" handlers later; the handlers will reside in
> hw/ppc/spapr_rtas_ddw.c.
> 
> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>

Reviewed-by: David Gibson <david@gibson.dropbear.id.au>

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
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http://www.ozlabs.org/~dgibson

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