[+cc Rajat, LKML] On Tue, Oct 27, 2020 at 08:31:09PM +0100, Boris V. wrote: > On 25/10/2020 20:45, Boris V. wrote: > > With upgrade to kernel 5.9 my VMs stopped working, because some devices > > can't be passed through. > > This is caused by different IOMMU groups and devices being in the same > > group. > > > > For ex. with kernel 5.8 this are IOMMU groups: > > IOMMU Group 40: > > 08:01.0 PCI bridge [0604]: ASMedia Technology Inc. Device > > [1b21:118f] > > 09:00.0 Ethernet controller [0200]: Intel Corporation I211 > > Gigabit Network Connection [8086:1539] (rev 03) > > IOMMU Group 43: > > 0c:00.0 SATA controller [0106]: ASMedia Technology Inc. ASM1062 > > Serial ATA Controller [1b21:0612] (rev 02) > > IOMMU Group 44: > > 0d:00.0 USB controller [0c03]: ASMedia Technology Inc. ASM1042A > > USB 3.0 Host Controller [1b21:1142] > > > > Ethernet, SATA and USB controller in its own group. > > > > And with 5.9, everything is in one group: > > IOMMU Group 29: > > 00:1c.0 PCI bridge [0604]: Intel Corporation C610/X99 series > > chipset PCI Express Root Port #1 [8086:8d10] (rev d5) > > 00:1c.3 PCI bridge [0604]: Intel Corporation C610/X99 series > > chipset PCI Express Root Port #4 [8086:8d16] (rev d5) > > 00:1c.4 PCI bridge [0604]: Intel Corporation C610/X99 series > > chipset PCI Express Root Port #5 [8086:8d18] (rev d5) > > 00:1c.6 PCI bridge [0604]: Intel Corporation C610/X99 series > > chipset PCI Express Root Port #7 [8086:8d1c] (rev d5) > > 07:00.0 PCI bridge [0604]: ASMedia Technology Inc. Device > > [1b21:118f] > > 08:01.0 PCI bridge [0604]: ASMedia Technology Inc. Device > > [1b21:118f] > > 08:03.0 PCI bridge [0604]: ASMedia Technology Inc. Device > > [1b21:118f] > > 08:04.0 PCI bridge [0604]: ASMedia Technology Inc. Device > > [1b21:118f] > > 09:00.0 Ethernet controller [0200]: Intel Corporation I211 > > Gigabit Network Connection [8086:1539] (rev 03) > > 0c:00.0 SATA controller [0106]: ASMedia Technology Inc. ASM1062 > > Serial ATA Controller [1b21:0612] (rev 02) > > 0d:00.0 USB controller [0c03]: ASMedia Technology Inc. ASM1042A > > USB 3.0 Host Controller [1b21:1142] > > > > > > This seems to be caused by commit > > 52fbf5bdeeef415b28b8e6cdade1e48927927f60. > > commit 52fbf5bdeeef415b28b8e6cdade1e48927927f60 > > Author: Rajat Jain <rajatja@xxxxxxxxxx> > > Date: Tue Jul 7 15:46:02 2020 -0700 > > > > PCI: Cache ACS capability offset in device > > > > Currently the ACS capability is being looked up at a number of > > places. Read > > and store it once at enumeration so that it can be used by all > > later. No > > functional change intended. > > > > Link: > > https://lore.kernel.org/r/20200707224604.3737893-2-rajatja@xxxxxxxxxx > > Signed-off-by: Rajat Jain <rajatja@xxxxxxxxxx> > > Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx> > > > > drivers/pci/p2pdma.c | 2 +- > > drivers/pci/pci.c | 20 ++++++++++++++++---- > > drivers/pci/pci.h | 2 +- > > drivers/pci/probe.c | 2 +- > > drivers/pci/quirks.c | 8 ++++---- > > include/linux/pci.h | 1 + > > 6 files changed, 24 insertions(+), 11 deletions(-) > > > > > > If I revert this commit, I get back old groups. > > > > In commit log there is message 'No functional change intended'. But > > there is functional change. > > > > This is Intel Core i7-5930K CPU and X99 chipset. But I see the same > > thing on other Intel systems (didn't test on AMD). > > Some more info. > Problem seems to be that pci_dev_specific_enable_acs() is not called > anymore. > Before, pci_enable_acs() was called from pci_init_capabilities() and in > pci_enable_acs(), pci_dev_specific_enable_acs() was called. > I don't know anything about PCI and this stuff, but I'm guessing that this > function enable ACS for some Intel devices. > But after this commit, pci_acs_init() is called from pci_init_capabilities() > and if pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ACS) returns 0, > pci_enable_acs() and pci_dev_specific_enable_acs() is not called anymore. > If I apply for ex. this patch bellow, groups are right again and everything > works as before. Thanks very much for the report and the debugging. Maybe we can get this sorted and fixed for v5.10-rc2 or -rc3. > diff -ur linux-5.9.1.orig/drivers/pci/pci.c linux-5.9.1/drivers/pci/pci.c > --- linux-5.9.1.orig/drivers/pci/pci.c 2020-10-17 08:31:22.000000000 +0200 > +++ linux-5.9.1/drivers/pci/pci.c 2020-10-27 19:01:32.650010803 +0100 > @@ -3502,9 +3502,7 @@ > void pci_acs_init(struct pci_dev *dev) > { > dev->acs_cap = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ACS); > - > - if (dev->acs_cap) > - pci_enable_acs(dev); > + pci_enable_acs(dev); > } > > /** > >
