On Tue, Oct 31, 2023 at 12:59:34PM -0700, Nirmal Patel wrote: > On Tue, 2023-10-31 at 10:31 -0500, Bjorn Helgaas wrote: > > On Mon, Oct 30, 2023 at 04:16:54PM -0400, Nirmal Patel wrote: > > > VMD Hotplug should be enabled or disabled based on VMD rootports' > > > Hotplug configuration in BIOS. is_hotplug_bridge is set on each > > > VMD rootport based on Hotplug capable bit in SltCap in probe.c. > > > Check is_hotplug_bridge and enable or disable native_pcie_hotplug > > > based on that value. > > > > > > Currently VMD driver copies ACPI settings or platform > > > configurations > > > for Hotplug, AER, DPC, PM, etc and enables or disables these > > > features > > > on VMD bridge which is not correct in case of Hotplug. > > > > This needs some background about why it's correct to copy the ACPI > > settings in the case of AER, DPC, PM, etc, but incorrect for hotplug. > > > > > Also during the Guest boot up, ACPI settings along with VMD UEFI > > > driver are not present in Guest BIOS which results in assigning > > > default values to Hotplug, AER, DPC, etc. As a result Hotplug is > > > disabled on VMD in the Guest OS. > > > > > > This patch will make sure that Hotplug is enabled properly in Host > > > as well as in VM. > > > > Did we come to some consensus about how or whether _OSC for the host > > bridge above the VMD device should apply to devices in the separate > > domain below the VMD? > > We are not able to come to any consensus. Someone suggested to copy > either all _OSC flags or none. But logic behind that assumption is > that the VMD is a bridge device which is not completely true. VMD is an > endpoint device and it owns its domain. Do you want to facilitate a discussion in the PCI firmware SIG about this? It seems like we may want a little text in the spec about how to handle this situation so platforms and OSes have the same expectations. Bjorn
