1390316 – PCIe: Add Generic PCIe Root Ports

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Bug 1390316 - PCIe: Add Generic PCIe Root Ports

Summary: PCIe: Add Generic PCIe Root Ports

Keywords:
Status:	CLOSED ERRATA
Alias:	None
Product:	Red Hat Enterprise Linux 7
Classification:	Red Hat
Component:	qemu-kvm-rhev
Sub Component:
Version:	7.4
Hardware:	All
OS:	Unspecified
Priority:	medium
Severity:	low
Target Milestone:	rc
Target Release:	7.4
Assignee:	Marcel Apfelbaum
QA Contact:	jingzhao
Docs Contact:
URL:
Whiteboard:
Depends On:
Blocks:	1173755 1395265 1408808 1410437 1410441 1422967
TreeView+	depends on / blocked

Reported:	2016-10-31 16:51 UTC by Marcel Apfelbaum
Modified:	2017-08-02 03:32 UTC (History)
CC List:	11 users (show)
Fixed In Version:	qemu-kvm-rhev-2.9.0-1.el7
Doc Type:	If docs needed, set a value
Doc Text:
Clone Of:
Clones:	1408808 (view as bug list)
Environment:
Last Closed:	2017-08-01 23:37:14 UTC
Target Upstream Version:
Embargoed:

Attachments	(Terms of Use)

Links
System	ID	Private	Priority	Status	Summary	Last Updated
Red Hat Bugzilla	1365623	0	low	CLOSED	[PCI] The default MMIO range reserved by firmware for PCI bridges is not enough to hotplug virtio-1 devices	2021-02-22 00:41:40 UTC
Red Hat Product Errata	RHSA-2017:2392	0	normal	SHIPPED_LIVE	Important: qemu-kvm-rhev security, bug fix, and enhancement update	2017-08-01 20:04:36 UTC

Internal Links: 1365623

Description Marcel Apfelbaum 2016-10-31 16:51:12 UTC

Two reasons:
1. Can be used by both x86 and ARM VMs
2. Add a vendor-specific pci capability to these ports,
   with recommended window sizes (io/mem/prefmem) for the firmware
   for more efficient resource allocation.

Comment 1 Marcel Apfelbaum 2017-01-01 11:24:12 UTC

Posted upstream:
https://lists.gnu.org/archive/html/qemu-devel/2016-11/msg04310.html

Comment 2 jingzhao 2017-02-16 03:12:09 UTC

Hi Marcel

  According to comment1, "Generic PCIe root ports" is the same with "ioh3420", what is the different between bz1390316 and bz1390329 ? I am not very clear about it.

Thanks
Jing Zhao

Comment 3 Marcel Apfelbaum 2017-02-16 13:55:57 UTC

(In reply to jingzhao from comment #2)
> Hi Marcel
> 
>   According to comment1, "Generic PCIe root ports" is the same with
> "ioh3420", what is the different between bz1390316 and bz1390329 ? I am not
> very clear about it.
> 
> Thanks
> Jing Zhao

Hi,

Generic PCIe Root ports exports the same functionality as IOH3420 indeed,
however bz1390329 refers to PCIe-PCI bridge that has other functionality, to allow legacy PCI devices (instead of the DMI-PCI bridge i82801b11)

Thanks,
Marcel

Comment 4 jingzhao 2017-02-17 01:40:05 UTC

> Hi,
> 
> Generic PCIe Root ports exports the same functionality as IOH3420 indeed,
> however bz1390329 refers to PCIe-PCI bridge that has other functionality, to
> allow legacy PCI devices (instead of the DMI-PCI bridge i82801b11)

Marcel, thanks very much firstly, and also following questions confused me

1. "bz1390329 allow legacy PCI devices", you mean instead of i82801b11 bridge, how about the connection PRL for the legacy PCI device? connect to the Generic PCIe-PCI bridge(bz1390329) or connect to the pcie.0, in other words, what's the common connection?

2. As QE known, i82801b11 bridge will be not used on rhel7.4, that means we will use the PCIe-PCI bridge that bz1390329 provided in qemu? qemu will provide Generic PCIe-PCI bridge all the time, never use the i82801b11 bridge?

3. the usage of the two bridge, are the following right?
  
   1) pcie.0  --- Generic PCIe Root Ports (/multifunction) -- pcie devices
   2) pcie.0  --- Generic PCIe-PCI bridge --- PCI devices


Thanks
Jing Zhao

Comment 5 Marcel Apfelbaum 2017-02-17 08:44:13 UTC

(In reply to jingzhao from comment #4)
> > Hi,
> > 
> > Generic PCIe Root ports exports the same functionality as IOH3420 indeed,
> > however bz1390329 refers to PCIe-PCI bridge that has other functionality, to
> > allow legacy PCI devices (instead of the DMI-PCI bridge i82801b11)
> 
> Marcel, thanks very much firstly, and also following questions confused me
> 
> 1. "bz1390329 allow legacy PCI devices", you mean instead of i82801b11
> bridge, how about the connection PRL for the legacy PCI device? connect to
> the Generic PCIe-PCI bridge(bz1390329) or connect to the pcie.0, in other
> words, what's the common connection?
> 

Yes, PCI devices  should be Integrated Endpoints (plugged into pcie.0) or connected to the new device - the PCIe-PCI bridge. We want to deprecate the i82801b11 bridge.

> 2. As QE known, i82801b11 bridge will be not used on rhel7.4, that means we
> will use the PCIe-PCI bridge that bz1390329 provided in qemu?

yes, but the new bridge will not be ready for 7.4 . on 7.4 PCI devices will be plugged only into pcie.0 bus.

 qemu will
> provide Generic PCIe-PCI bridge all the time, never use the i82801b11 bridge?
> 

once the device will be ready, it will completely replace the i82801b11

> 3. the usage of the two bridge, are the following right?
>   
>    1) pcie.0  --- Generic PCIe Root Ports (/multifunction) -- pcie devices
>    2) pcie.0  --- Generic PCIe-PCI bridge --- PCI devices
> 

Correct

and also:
     3) pcie.0 ---  PCI devices


Thanks,
Marcel

> 
> Thanks
> Jing Zhao

Comment 10 errata-xmlrpc 2017-08-01 23:37:14 UTC

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHSA-2017:2392

Comment 11 errata-xmlrpc 2017-08-02 01:14:54 UTC

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHSA-2017:2392

Comment 12 errata-xmlrpc 2017-08-02 02:06:52 UTC

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHSA-2017:2392

Comment 13 errata-xmlrpc 2017-08-02 02:47:39 UTC

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHSA-2017:2392

Comment 14 errata-xmlrpc 2017-08-02 03:12:20 UTC

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHSA-2017:2392

Comment 15 errata-xmlrpc 2017-08-02 03:32:30 UTC

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHSA-2017:2392

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