From: hch@lst.de (Christoph Hellwig)
Subject: Requirement to get BAR pci_bus_address in user space
Date: Thu, 14 Jun 2018 16:59:42 +0200 [thread overview]
Message-ID: <20180614145942.GA4885@lst.de> (raw)
In-Reply-To: <20180614085015.3f39b367@w520.home>
On Thu, Jun 14, 2018@08:50:15AM -0600, Alex Williamson wrote:
> I don't understand the CQ vs CMB, but I think I gather that there's some
> sort of buffer that's allocated from within the devices MMIO BAR and
> some programming of the device needs to reference that buffer.
> Wouldn't you therefore use the vfio type1 IOMMU MAP_DMA ioctl to map
> the BAR into the IOVA address space and you can then use the IOVA +
> offset into the BAR for the device to reference the buffer? It seems
> this is the same way we'd setup a peer-to-peer mapping, but we're using
> it for the device to reference itself effectively. Thanks,
That's exactly what I meant..
WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch@lst.de>
To: Alex Williamson <alex.williamson@redhat.com>
Cc: linux-pci-owner@vger.kernel.org,
Abhishek Shah <abhishek.shah@broadcom.com>,
kvm@vger.kernel.org, linux-pci@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org,
Vikram Prakash <vikram.prakash@broadcom.com>,
Sinan Kaya <okaya@codeaurora.org>,
Srinath Mannam <srinath.mannam@broadcom.com>,
Bjorn Helgaas <bhelgaas@google.com>,
Christoph Hellwig <hch@lst.de>
Subject: Re: Requirement to get BAR pci_bus_address in user space
Date: Thu, 14 Jun 2018 16:59:42 +0200 [thread overview]
Message-ID: <20180614145942.GA4885@lst.de> (raw)
In-Reply-To: <20180614085015.3f39b367@w520.home>
On Thu, Jun 14, 2018 at 08:50:15AM -0600, Alex Williamson wrote:
> I don't understand the CQ vs CMB, but I think I gather that there's some
> sort of buffer that's allocated from within the devices MMIO BAR and
> some programming of the device needs to reference that buffer.
> Wouldn't you therefore use the vfio type1 IOMMU MAP_DMA ioctl to map
> the BAR into the IOVA address space and you can then use the IOVA +
> offset into the BAR for the device to reference the buffer? It seems
> this is the same way we'd setup a peer-to-peer mapping, but we're using
> it for the device to reference itself effectively. Thanks,
That's exactly what I meant..
_______________________________________________
Linux-nvme mailing list
Linux-nvme@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-nvme
WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch@lst.de>
To: Alex Williamson <alex.williamson@redhat.com>
Cc: Srinath Mannam <srinath.mannam@broadcom.com>,
Sinan Kaya <okaya@codeaurora.org>, Christoph Hellwig <hch@lst.de>,
Bjorn Helgaas <bhelgaas@google.com>,
Abhishek Shah <abhishek.shah@broadcom.com>,
Vikram Prakash <vikram.prakash@broadcom.com>,
linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-nvme@lists.infradead.org, kvm@vger.kernel.org,
linux-pci-owner@vger.kernel.org
Subject: Re: Requirement to get BAR pci_bus_address in user space
Date: Thu, 14 Jun 2018 16:59:42 +0200 [thread overview]
Message-ID: <20180614145942.GA4885@lst.de> (raw)
In-Reply-To: <20180614085015.3f39b367@w520.home>
On Thu, Jun 14, 2018 at 08:50:15AM -0600, Alex Williamson wrote:
> I don't understand the CQ vs CMB, but I think I gather that there's some
> sort of buffer that's allocated from within the devices MMIO BAR and
> some programming of the device needs to reference that buffer.
> Wouldn't you therefore use the vfio type1 IOMMU MAP_DMA ioctl to map
> the BAR into the IOVA address space and you can then use the IOVA +
> offset into the BAR for the device to reference the buffer? It seems
> this is the same way we'd setup a peer-to-peer mapping, but we're using
> it for the device to reference itself effectively. Thanks,
That's exactly what I meant..
next prev parent reply other threads:[~2018-06-14 14:59 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-14 10:07 Requirement to get BAR pci_bus_address in user space Srinath Mannam
2018-06-14 10:07 ` Srinath Mannam
2018-06-14 10:07 ` Srinath Mannam
2018-06-14 10:20 ` Christoph Hellwig
2018-06-14 10:20 ` Christoph Hellwig
2018-06-14 10:20 ` Christoph Hellwig
2018-06-14 10:29 ` Srinath Mannam
2018-06-14 10:29 ` Srinath Mannam
2018-06-14 10:29 ` Srinath Mannam
2018-06-14 10:33 ` okaya
2018-06-14 10:33 ` okaya
2018-06-14 10:33 ` okaya
2018-06-14 10:48 ` Srinath Mannam
2018-06-14 10:48 ` Srinath Mannam
2018-06-14 14:42 ` Keith Busch
2018-06-14 14:42 ` Keith Busch
2018-06-14 14:42 ` Keith Busch
2018-06-14 14:50 ` Alex Williamson
2018-06-14 14:50 ` Alex Williamson
2018-06-14 14:50 ` Alex Williamson
2018-06-14 14:59 ` Christoph Hellwig [this message]
2018-06-14 14:59 ` Christoph Hellwig
2018-06-14 14:59 ` Christoph Hellwig
2018-06-14 20:04 ` Walker, Benjamin
2018-06-14 20:04 ` Walker, Benjamin
2018-06-14 20:04 ` Walker, Benjamin
2018-06-15 6:11 ` Srinath Mannam
2018-06-15 6:11 ` Srinath Mannam
2018-06-15 6:11 ` Srinath Mannam
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20180614145942.GA4885@lst.de \
--to=hch@lst.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.