On Wed, Aug 02, 2017 at 12:23:46AM +0200, Laszlo Ersek wrote:
On 08/01/17 23:39, Michael S. Tsirkin wrote:
On Wed, Aug 02, 2017 at 12:33:12AM +0300, Alexander Bezzubikov wrote:
2017-08-01 23:31 GMT+03:00 Laszlo Ersek lersek@redhat.com:
(Whenever my comments conflict with Michael's or Marcel's, I defer to them.)
On 07/29/17 01:37, Aleksandr Bezzubikov wrote:
Signed-off-by: Aleksandr Bezzubikov zuban32s@gmail.com
docs/pcie.txt | 46 ++++++++++-------- docs/pcie_pci_bridge.txt | 121 +++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 147 insertions(+), 20 deletions(-) create mode 100644 docs/pcie_pci_bridge.txt
diff --git a/docs/pcie.txt b/docs/pcie.txt index 5bada24..338b50e 100644 --- a/docs/pcie.txt +++ b/docs/pcie.txt @@ -46,7 +46,7 @@ Place only the following kinds of devices directly on the Root Complex: (2) PCI Express Root Ports (ioh3420), for starting exclusively PCI Express hierarchies.
- (3) DMI-PCI Bridges (i82801b11-bridge), for starting legacy PCI
(3) PCIE-PCI Bridge (pcie-pci-bridge), for starting legacy PCI hierarchies.
(4) Extra Root Complexes (pxb-pcie), if multiple PCI Express Root Buses
When reviewing previous patches modifying / adding this file, I requested that we spell out "PCI Express" every single time. I'd like to see the same in this patch, if possible.
OK, I didn't know it.
@@ -55,18 +55,18 @@ Place only the following kinds of devices directly on the Root Complex: pcie.0 bus ---------------------------------------------------------------------------- | | | |
- | PCI Dev | | PCIe Root Port | | DMI-PCI Bridge | | pxb-pcie |
- | PCI Dev | | PCIe Root Port | | PCIE-PCI Bridge | | pxb-pcie |
2.1.1 To plug a device into pcie.0 as a Root Complex Integrated Endpoint use: -device <dev>[,bus=pcie.0] 2.1.2 To expose a new PCI Express Root Bus use: -device pxb-pcie,id=pcie.1,bus_nr=x[,numa_node=y][,addr=z]
Only PCI Express Root Ports and DMI-PCI bridges can be connected
Only PCI Express Root Ports, PCIE-PCI bridges and DMI-PCI bridges can be connectedIt would be nice if we could keep the flowing text wrapped to 80 chars.
Also, here you add the "PCI Express-PCI" bridge to the list of allowed controllers (and you keep DMI-PCI as permitted), but above DMI was replaced. I think these should be made consistent -- we should make up our minds if we continue to recommend the DMI-PCI bridge or not. If not, then we should eradicate all traces of it. If we want to keep it at least for compatibility, then it should remain as fully documented as it is now.
Now I'm beginning to think that we shouldn't keep the DMI-PCI bridge even for compatibility and may want to use a new PCIE-PCI bridge everywhere (of course, except some cases when users are sure they need exactly DMI-PCI bridge for some reason)
Can dmi-pci support shpc? why doesn't it? For compatibility?
I don't know why, but the fact that it doesn't is the reason libvirt settled on auto-creating a dmi-pci bridge and a pci-pci bridge under that for Q35. The reasoning was (IIRC Laine's words correctly) that the dmi-pci bridge cannot receive hotplugged devices, while the pci-pci bridge cannot be connected to the root complex. So both were needed.
Thanks Laszlo
OK. Is it true that dmi-pci + pci-pci under it will allow hotplug on Q35 if we just flip the bit in _OSC?