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RE: [Xen-devel] [PATCH] passthru: Fix pci bar remapping for passthru dev

To: Wei Wang2 <wei.wang2@xxxxxxx>, "xen-devel@xxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject: RE: [Xen-devel] [PATCH] passthru: Fix pci bar remapping for passthru devices
From: "Jiang, Yunhong" <yunhong.jiang@xxxxxxxxx>
Date: Mon, 20 Jul 2009 22:26:00 +0800
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Thread-topic: [Xen-devel] [PATCH] passthru: Fix pci bar remapping for passthru devices
I assume guest should disable the MMIO in PCI_COMMAND before writing all "1"s 
to bar register. Otherwise, what will happen on native if guest try to access 
And if we do update the P2M, will it cause trouble to Xen HV?

Yunhong Jiang

xen-devel-bounces@xxxxxxxxxxxxxxxxxxx wrote:
> Hi,
> When guest code tries to get the block size of mmio, it will write
> all "1"s into pci bar register and then qemu will return all "0"s to
> the don't care
> bits in the emulated bar register to indicate the block size
> to guest code.
> In this case, we should not create p2m mapping in
> pt_bar_reg_write() and
> pt_exp_rom_bar_reg_write(). Attached patch fixes this issue,
> additional comment can be found in the patch.
> Thanks,
> Wei
> Signed-off-by: Wei Wang <wei.wang2@xxxxxxx>
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