From: Alex Williamson <alex.williamson@redhat.com>
To: Thanos Makatos <thanos.makatos@nutanix.com>
Cc: "qemu-devel@nongnu.org" <qemu-devel@nongnu.org>,
Swapnil Ingle <swapnil.ingle@nutanix.com>,
Felipe Franciosi <felipe@nutanix.com>
Subject: Re: [Qemu-devel] QEMU tries to register to VFIO memory that is not RAM
Date: Fri, 31 May 2019 08:37:32 -0600 [thread overview]
Message-ID: <20190531083732.37ecbb1e@x1.home> (raw)
In-Reply-To: <MN2PR02MB62053CE40CA6B4A97B32FA048B190@MN2PR02MB6205.namprd02.prod.outlook.com>
On Fri, 31 May 2019 13:32:29 +0000
Thanos Makatos <thanos.makatos@nutanix.com> wrote:
> When configuring device pass-through via VFIO to a VM, I noticed that
> QEMU tries to register (DMA_MAP) all memory regions of a guest (not
> only RAM). That includes firmware regions like "pc.rom". Would a
> physical device ever need access to those?
Probably not, but are those things not in the address space of the
device on a physical system?
> Am I missing something?
Does this cause a problem? It's not always easy to identify regions
that should not be mapped to a device, clearly we're not going to
create a whitelist based on the name of the region. Thanks,
Alex
next prev parent reply other threads:[~2019-05-31 14:39 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-31 13:32 [Qemu-devel] QEMU tries to register to VFIO memory that is not RAM Thanos Makatos
2019-05-31 14:37 ` Alex Williamson [this message]
2019-05-31 15:28 ` Thanos Makatos
2019-05-31 15:40 ` Alex Williamson
2019-06-04 16:08 ` Thanos Makatos
2019-06-14 15:56 ` Thanos Makatos
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