Re: [PATCH] KVM PV Guest: Implement paravirtualized DMA

[Andi Kleen <andi@firstfloor.org>]

Amit Shah <amit.shah@qumranet.com> writes:
> +
> +static struct page *page;
> +static unsigned long page_gfn;
Bad variable names

> +
> +const struct dma_mapping_ops *orig_dma_ops;

I suspect real dma ops stacking will need some further thought than
your simple hacks
> +
> +	match = find_matching_pt_dev(&pt_devs_head, &pv_pci_info);
> +	if (match) {
> +		r = match->is_pv;
> +		goto out;
> +	}
> +
> +	memcpy(page_address(page), &pv_pci_info, sizeof(pv_pci_info));

Note that on 32bit page_address() might be not mapped.


> +
> +	npages = get_order(size) + 1;

Are you sure that's correct? It looks quite bogus. order is a 2 logarithm,
normally npages = 1 << order

if you want  npages from order the correct  need 1 << order

Haven't read further, but to be honest the code doesn't seem to be anywhere
near merging quality.

-Andi