Re: [PATCH 1/3] ppc/pnv: Tune the POWER9 PCIe Host bridge model

["Michael S. Tsirkin" <mst@redhat.com>]

On Fri, Nov 26, 2021 at 06:08:30PM +0100, Cédric Le Goater wrote:
> [ Adding Alfredo the thread ]
> 
> On 11/26/21 10:09, Cédric Le Goater wrote:
> > On 11/16/21 18:01, Frederic Barrat wrote:
> > > The PHB v4 found on POWER9 doesn't request any LSI, so let's clear the
> > > Interrupt Pin register in the config space so that the model matches
> > > the hardware.
> > > 
> > > If we don't, then we inherit from the default pcie root bridge, which
> > > requests a LSI. And because we don't map it correctly in the device
> > > tree, all PHBs allocate the same bogus hw interrupt. We end up with
> > > inconsistent interrupt controller (xive) data. The problem goes away
> > > if we don't allocate the LSI in the first place.
> > > 
> > > Signed-off-by: Frederic Barrat <fbarrat@linux.ibm.com>
> > > ---
> > >   hw/pci-host/pnv_phb4.c | 5 ++++-
> > >   1 file changed, 4 insertions(+), 1 deletion(-)
> > > 
> > > diff --git a/hw/pci-host/pnv_phb4.c b/hw/pci-host/pnv_phb4.c
> > > index 5c375a9f28..1659d55b4f 100644
> > > --- a/hw/pci-host/pnv_phb4.c
> > > +++ b/hw/pci-host/pnv_phb4.c
> > > @@ -1234,10 +1234,13 @@ static void pnv_phb4_reset(DeviceState *dev)
> > >       PCIDevice *root_dev = PCI_DEVICE(&phb->root);
> > >       /*
> > > -     * Configure PCI device id at reset using a property.
> > > +     * Configure the PCI device at reset:
> > > +     *   - set the Vendor and Device ID to for the root bridge
> > > +     *   - no LSI
> > >        */
> > >       pci_config_set_vendor_id(root_dev->config, PCI_VENDOR_ID_IBM);
> > >       pci_config_set_device_id(root_dev->config, phb->device_id);
> > > +    pci_config_set_interrupt_pin(root_dev->config, 0);
> > >   }
> > >   static const char *pnv_phb4_root_bus_path(PCIHostState *host_bridge,
> > > 
> > 
> > FYI, I am seeing an issue with FreeBSD when booting from iso :
> > 
> >    https://download.freebsd.org/ftp/snapshots/powerpc/powerpc64/ISO-IMAGES/14.0/FreeBSD-14.0-CURRENT-powerpc-powerpc64-20211028-4827bf76bce-250301-disc1.iso.xz
> > 
> > Thanks,
> > 
> > C.
> > 
> > SIGTERM received, booting...
> > KDB: debugger backends: ddb
> > KDB: current backend: ddb
> > ---<<BOOT>>---
> > Copyright (c) 1992-2021 The FreeBSD Project.
> > Copyright (c) 1979, 1980, 1983, 1986, 1988, 1989, 1991, 1992, 1993, 1994
> >      The Regents of the University of California. All rights reserved.
> > FreeBSD is a registered trademark of The FreeBSD Foundation.
> > FreeBSD 14.0-CURRENT #0 main-n250301-4827bf76bce: Thu Oct 28 06:53:58 UTC 2021
> >      root@releng1.nyi.freebsd.org:/usr/obj/usr/src/powerpc.powerpc64/sys/GENERIC64 powerpc
> > FreeBSD clang version 12.0.1 (git@github.com:llvm/llvm-project.git llvmorg-12.0.1-0-gfed41342a82f)
> > WARNING: WITNESS option enabled, expect reduced performance.
> > VT: init without driver.
> > ofw_initrd: initrd loaded at 0x28000000-0x28c7928c
> > cpu0: IBM POWER9 revision 2.0, 1000.00 MHz
> > cpu0: Features dc007182<PPC32,PPC64,ALTIVEC,FPU,MMU,SMT,ISNOOP,ARCH205,ARCH206,VSX,TRUELE>
> > cpu0: Features2 bee00000<ARCH207,DSCR,ISEL,TAR,VCRYPTO,ARCH300,IEEE128,DARN>
> > real memory  = 1014484992 (967 MB)
> > avail memory = 117903360 (112 MB)
> > random: registering fast source PowerISA DARN random number generator
> > random: fast provider: "PowerISA DARN random number generator"
> > arc4random: WARNING: initial seeding bypassed the cryptographic random device because it was not yet seeded and the knob 'bypass_before_seeding' was enabled.
> > random: entropy device external interface
> > kbd0 at kbdmux0
> > ofwbus0: <Open Firmware Device Tree> on nexus0
> > opal0: <OPAL Abstraction Firmware> irq 1048560,1048561,1048562,1048563,1048564,1048565,1048566,1048567,1048568,1048569,1048570,1048571,1048572,1048573 on ofwbus0
> > opal0: registered as a time-of-day clock, resolution 0.002000s
> > simplebus0: <Flattened device tree simple bus> mem 0x6030000000000-0x60300ffffffff on ofwbus0
> > pcib0: <OPAL Host-PCI bridge> mem 0x600c3c0000000-0x600c3c0000fff,0x600c300000000-0x600c30fffffff on ofwbus0
> > pci0: <OFW PCI bus> numa-domain 0 on pcib0
> > qemu-system-ppc64: ../hw/pci/pci.c:1487: pci_irq_handler: Assertion `0 <= irq_num && irq_num < PCI_NUM_PINS' failed.
> > 


Frederic?

-- 
MST