From mboxrd@z Thu Jan  1 00:00:00 1970
From: Andi Kleen <andi@firstfloor.org>
Subject: Re: [PATCH] KVM PV Guest: Implement paravirtualized DMA
Date: Tue, 29 Apr 2008 15:31:32 +0200
Message-ID: <87od7shjnv.fsf@basil.nowhere.org>
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Cc: kvm-devel@lists.sourceforge.net, chrisw@redhat.com,
	allen.m.kay@intel.com, linux-kernel@vger.kernel.org,
	gcosta@redhat.com, avi@qumranet.com,
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To: Amit Shah <amit.shah@qumranet.com>
Return-path: <linux-kernel-owner+glk-linux-kernel-3=40m.gmane.org-S1761648AbYD2Nby@vger.kernel.org>
In-Reply-To: <1209465451-3758-4-git-send-email-amit.shah@qumranet.com> (Amit Shah's message of "Tue, 29 Apr 2008 13:37:31 +0300")
Sender: linux-kernel-owner@vger.kernel.org
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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