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Date: Tue, 3 Oct 2017 09:06:49 -0600
From: Keith Busch <keith.busch@intel.com>
To: Abhishek Shah <abhishek.shah@broadcom.com>
Cc: Jens Axboe <axboe@fb.com>, Christoph Hellwig <hch@lst.de>,
        Sagi Grimberg <sagi@grimberg.me>,
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        open list <linux-kernel@vger.kernel.org>,
        BCM Kernel Feedback <bcm-kernel-feedback-list@broadcom.com>,
        stable@vger.kernel.org
Subject: Re: [PATCH] nvme-pci: Use PCI bus address for data/queues in CMB
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On Sat, Sep 30, 2017 at 02:30:16PM +0530, Abhishek Shah wrote:
> > On a similar note, we also break CMB usage in virutalization with direct
> > assigned devices: the guest doesn't know the host physical bus address,
> > so it sets the CMB queue address incorrectly there, too. I don't know of
> > a way to fix that other than disabling CMB.
> 
> I don't have much idea on CMB usage in virtualization... will let
> someone else comment on this.

It's okay, I think it's a gap in the NVMe specification that would allow
such usage.