Re: [Xen-devel] [PATCH v3 6/8] hvmloader: Load large devices into high MMIO space as needed

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

On Thu, 20 Jun 2013, George Dunlap wrote:
> Keep track of how much mmio space is left total, as well as the amount
> of "low" MMIO space (<4GiB), and only load devices into high memory
> if there is not enough low memory for the rest of the devices to fit.
> 
> Because devices are processed by size in order from large to small,
> this should preferentially relocate devices with large BARs to 64-bit
> space.
> 
> v3:
>  - Just use mmio_total rather than introducing a new variable.
>  - Port to using mem_resource directly rather than low_mmio_left
> 
> Signed-off-by: George Dunlap <george.dunlap@xxxxxxxxxxxxx>
> CC: Ian Jackson <ian.jackson@xxxxxxxxxx>
> CC: Ian Campbell <ian.campbell@xxxxxxxxxx>
> CC: Stefano Stabellini <stefano.stabellini@xxxxxxxxxx>
> CC: Hanweidong <hanweidong@xxxxxxxxxx>
> CC: Keir Fraser <keir@xxxxxxx>


Acked-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>

>  tools/firmware/hvmloader/pci.c |    7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/tools/firmware/hvmloader/pci.c b/tools/firmware/hvmloader/pci.c
> index 606ccca..ac55d3e 100644
> --- a/tools/firmware/hvmloader/pci.c
> +++ b/tools/firmware/hvmloader/pci.c
> @@ -264,8 +264,12 @@ void pci_setup(void)
>          bar_reg = bars[i].bar_reg;
>          bar_sz  = bars[i].bar_sz;
>  
> +        /* Relocate to high memory if the total amount of MMIO needed
> +         * is more than the low MMIO available.  Because devices are
> +         * processed in order of bar_sz, this will preferentially
> +         * relocate larger devices to high memory first. */
>          using_64bar = bars[i].is_64bar && bar64_relocate
> -            && (bar_sz > (mem_resource.max - mem_resource.base));
> +            && (mmio_total > (mem_resource.max - mem_resource.base));
>          bar_data = pci_readl(devfn, bar_reg);
>  
>          if ( (bar_data & PCI_BASE_ADDRESS_SPACE) ==
> @@ -287,6 +291,7 @@ void pci_setup(void)
>                  resource = &mem_resource;
>                  bar_data &= ~PCI_BASE_ADDRESS_MEM_MASK;
>              }
> +            mmio_total -= bar_sz;
>          }
>          else
>          {
> -- 
> 1.7.9.5
> 

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