On Thu, 22 Aug 2024 15:18:06 +0530 Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx> wrote: > On Tue, Aug 20, 2024 at 03:32:13PM -0700, Nirmal Patel wrote: > > VMD does not support INTx for devices downstream from a VMD > > endpoint. So initialize the PCI_INTERRUPT_LINE to 0 for all NVMe > > devices under VMD to ensure other applications don't try to set up > > an INTx for them. > > > > Signed-off-by: Nirmal Patel <nirmal.patel@xxxxxxxxxxxxxxx> > > I shared a diff to put it in pci_assign_irq() and you said that you > were going to test it [1]. I don't see a reply to that and now you > came up with another approach. > > What happened inbetween? Apologies, I did perform the tests and the patch worked fine. However, I was able to see lot of bridge devices had the register set to 0xFF and I didn't want to alter them. Also pci_assign_irg would still set the interrupt line register to 0 with or without VMD. Since I didn't want to introduce issues for non-VMD setup, I decide to keep the change limited only to the VMD. -Nirmal > > - Mani > > [1] > https://lore.kernel.org/linux-pci/20240801115756.0000272e@xxxxxxxxxxxxxxx > > > --- > > v2->v1: Change the execution from fixup.c to vmd.c > > --- > > drivers/pci/controller/vmd.c | 13 +++++++++++++ > > 1 file changed, 13 insertions(+) > > > > diff --git a/drivers/pci/controller/vmd.c > > b/drivers/pci/controller/vmd.c index a726de0af011..2e9b99969b81 > > 100644 --- a/drivers/pci/controller/vmd.c > > +++ b/drivers/pci/controller/vmd.c > > @@ -778,6 +778,18 @@ static int vmd_pm_enable_quirk(struct pci_dev > > *pdev, void *userdata) return 0; > > } > > > > +/* > > + * Some applications like SPDK reads PCI_INTERRUPT_LINE to decide > > + * whether INTx is enabled or not. Since VMD doesn't support INTx, > > + * write 0 to all NVMe devices under VMD. > > + */ > > +static int vmd_clr_int_line_reg(struct pci_dev *dev, void > > *userdata) +{ > > + if(dev->class == PCI_CLASS_STORAGE_EXPRESS) > > + pci_write_config_byte(dev, PCI_INTERRUPT_LINE, 0); > > + return 0; > > +} > > + > > static int vmd_enable_domain(struct vmd_dev *vmd, unsigned long > > features) { > > struct pci_sysdata *sd = &vmd->sysdata; > > @@ -932,6 +944,7 @@ static int vmd_enable_domain(struct vmd_dev > > *vmd, unsigned long features) > > pci_scan_child_bus(vmd->bus); > > vmd_domain_reset(vmd); > > + pci_walk_bus(vmd->bus, vmd_clr_int_line_reg, &features); > > > > /* When Intel VMD is enabled, the OS does not discover the > > Root Ports > > * owned by Intel VMD within the MMCFG space. > > pci_reset_bus() applies -- > > 2.39.1 > > > > >
