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Re: [Qemu-devel] [PATCH v2 0/4] Fix device listener interface for PCI to
From: |
Michael S. Tsirkin |
Subject: |
Re: [Qemu-devel] [PATCH v2 0/4] Fix device listener interface for PCI to PCI bridges |
Date: |
Tue, 9 Jun 2015 11:13:11 +0200 |
On Mon, Jun 08, 2015 at 05:18:48PM -0400, Don Slutz wrote:
> changes v1 to v2:
> Split v1 patch into 3.
>
> Added a BUG FIX patch (#1: "exec: Do not use MemoryRegion after
> free").
>
> Technically this bug fix should be a separate patch, however this
> issue only seems to reproduce when this patch set is applied.
>
>
> Michael S. Tsirkin:
> "You need some other API that makes sense, probably PCI specific."
> This is basically patch #2: "Extend device listener interface..."
>
> "This is relying on undocumented assumptions and how specific
> firmware works. There's nothing special about bus number 255,
> and 0 is not very special either (except it happens to be the
> reset value)."
> Dropped all checking of 0 and 255.
>
>
> Open question by Michael S. Tsirkin:
>
> >>>> On Thu, May 28, 2015 at 07:25:50AM -0400, Don Slutz wrote:
> ...
> >>>> It is not clear to me that the complexity of tracking bus
> >>>> visibility make sense. Clearly you do.
> >>> Well what was the point of the change?
> >
> > To get config cycles that are valid that you do not get today.
> >
> >>> If you don't care that we get irrelevant config cycles why not
> >>> just send them all to QEMU?
> >>>
> >
> > That would need to be answered by Paul Durrant and/or other people (see
> > below)
> >
>
> We could broadcast config space ioreqs to all emulators, the problem
> is how do we know (in the case of a read) which emulator is actually
> the one supplying the data? At some level Xen needs to know who is
> implementing what.
>
> Paul Durrant
Can irrelevant emulators all respond with some kind of nack?
Xen would pick the one that did respond correctly.
> So this patch set just adjusts Xen to correctly know the current set
> of PCI devices and their bus, device, and function.
>
> It does not attempt to calculate the visibility of the PCI devices.
So non-visible devices will appear with invalid bus number values,
conflicting with the visible devices.
Seems wrong.
>
> v1:
>
> Note: Right now hvmloader in Xen does not handle PCI to PCI bridges
> and so SeaBIOS does not have access to PCI device(s) on secondary
> buses. How ever domU can setup the secondary bus(es) and this patch
> will restore access to these PCI devices.
>
>
> Don Slutz (4):
> exec: Do not use MemoryRegion after free
> Extend device listener interface for PCI to PCI bridges
> xen: Add usage of device listener interface for PCI to PCI bridges
> xen: Fix map/unmap of pcidev to ioreq server
>
> exec.c | 8 ++++--
> hw/core/qdev.c | 7 ++++++
> hw/pci/pci_bridge.c | 18 +++++++++++++
> include/hw/qdev-core.h | 3 +++
> include/hw/xen/xen_common.h | 61
> ++++++++++++++++++++++++++++++++++-----------
> trace-events | 6 +++--
> xen-hvm.c | 20 +++++++++++++--
> 7 files changed, 102 insertions(+), 21 deletions(-)
>
> --
> 1.8.4
- Re: [Qemu-devel] [PATCH v2 2/4] Extend device listener interface for PCI to PCI bridges, (continued)
[Qemu-devel] [PATCH v2 4/4] xen: Fix map/unmap of pcidev to ioreq server, Don Slutz, 2015/06/08
- Re: [Qemu-devel] [PATCH v2 4/4] xen: Fix map/unmap of pcidev to ioreq server, Paul Durrant, 2015/06/09
- Re: [Qemu-devel] [PATCH v2 4/4] xen: Fix map/unmap of pcidev to ioreq server, Don Slutz, 2015/06/09
- Re: [Qemu-devel] [PATCH v2 4/4] xen: Fix map/unmap of pcidev to ioreq server, Paul Durrant, 2015/06/09
- Re: [Qemu-devel] [PATCH v2 4/4] xen: Fix map/unmap of pcidev to ioreq server, Don Slutz, 2015/06/09
- Re: [Qemu-devel] [PATCH v2 4/4] xen: Fix map/unmap of pcidev to ioreq server, Paul Durrant, 2015/06/09
- Re: [Qemu-devel] [PATCH v2 4/4] xen: Fix map/unmap of pcidev to ioreq server, Don Slutz, 2015/06/09
Re: [Qemu-devel] [PATCH v2 0/4] Fix device listener interface for PCI to PCI bridges,
Michael S. Tsirkin <=
- Re: [Qemu-devel] [PATCH v2 0/4] Fix device listener interface for PCI to PCI bridges, Paul Durrant, 2015/06/09
- Re: [Qemu-devel] [PATCH v2 0/4] Fix device listener interface for PCI to PCI bridges, Michael S. Tsirkin, 2015/06/09
- Re: [Qemu-devel] [PATCH v2 0/4] Fix device listener interface for PCI to PCI bridges, Paul Durrant, 2015/06/09
- Re: [Qemu-devel] [PATCH v2 0/4] Fix device listener interface for PCI to PCI bridges, Michael S. Tsirkin, 2015/06/09
- Re: [Qemu-devel] [PATCH v2 0/4] Fix device listener interface for PCI to PCI bridges, Paul Durrant, 2015/06/09
- Re: [Qemu-devel] [PATCH v2 0/4] Fix device listener interface for PCI to PCI bridges, Michael S. Tsirkin, 2015/06/09
- Re: [Qemu-devel] [PATCH v2 0/4] Fix device listener interface for PCI to PCI bridges, Don Slutz, 2015/06/09