On Fri, Dec 03, 2021 at 11:15:41AM +0800, Kai-Heng Feng wrote: > When Samsung PCIe Gen4 NVMe is connected to Intel ADL VMD, the > combination causes AER message flood and drags the system performance > down. > > The issue doesn't happen when VMD mode is disabled in BIOS, since AER > isn't enabled by acpi_pci_root_create() . When VMD mode is enabled, AER > is enabled regardless of _OSC: > [ 0.410076] acpi PNP0A08:00: _OSC: platform does not support [AER] > ... > [ 1.486704] pcieport 10000:e0:06.0: AER: enabled with IRQ 146 > > Since VMD is an aperture to regular PCIe root ports, honor ACPI _OSC to > disable PCIe features accordingly to resolve the issue. At least for some versions of this hardare, I recall ACPI is unaware of any devices in the VMD domain; the platform can not see past the VMD endpoint, so I throught the driver was supposed to always let the VMD domain use OS native support regardless of the parent's ACPI _OSC. > Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=215027 > Suggested-by: Rafael J. Wysocki <rafael@xxxxxxxxxx> > Signed-off-by: Kai-Heng Feng <kai.heng.feng@xxxxxxxxxxxxx> > --- > v3: > - Use a new helper function. > > v2: > - Use pci_find_host_bridge() instead of open coding. > > drivers/pci/controller/vmd.c | 18 ++++++++++++++++++ > 1 file changed, 18 insertions(+) > > diff --git a/drivers/pci/controller/vmd.c b/drivers/pci/controller/vmd.c > index a45e8e59d3d48..691765e6c12aa 100644 > --- a/drivers/pci/controller/vmd.c > +++ b/drivers/pci/controller/vmd.c > @@ -661,6 +661,21 @@ static int vmd_alloc_irqs(struct vmd_dev *vmd) > return 0; > } > > +/* > + * Since VMD is an aperture to regular PCIe root ports, only allow it to > + * control features that the OS is allowed to control on the physical PCI bus. > + */ > +static void vmd_copy_host_bridge_flags(struct pci_host_bridge *root_bridge, > + struct pci_host_bridge *vmd_bridge) > +{ > + vmd_bridge->native_pcie_hotplug = root_bridge->native_pcie_hotplug; > + vmd_bridge->native_shpc_hotplug = root_bridge->native_shpc_hotplug; > + vmd_bridge->native_aer = root_bridge->native_aer; > + vmd_bridge->native_pme = root_bridge->native_pme; > + vmd_bridge->native_ltr = root_bridge->native_ltr; > + vmd_bridge->native_dpc = root_bridge->native_dpc; > +} > + > static int vmd_enable_domain(struct vmd_dev *vmd, unsigned long features) > { > struct pci_sysdata *sd = &vmd->sysdata; > @@ -798,6 +813,9 @@ static int vmd_enable_domain(struct vmd_dev *vmd, unsigned long features) > return -ENODEV; > } > > + vmd_copy_host_bridge_flags(pci_find_host_bridge(vmd->dev->bus), > + to_pci_host_bridge(vmd->bus->bridge)); > + > vmd_attach_resources(vmd); > if (vmd->irq_domain) > dev_set_msi_domain(&vmd->bus->dev, vmd->irq_domain); > -- > 2.32.0 >
