On 7/24/2023 8:54 PM, Nirmal Patel wrote:
> The hotplug functionality is broken in various combinations of guest
> OSes i.e. RHEL, SLES and hypervisors i.e. KVM and ESXI.
>
> During the VMD rootport creation, VMD honors ACPI settings and assigns
> respective values to Hotplug, AER, DPC, PM etc which works in case of
> Host OS. But these have been restored back to the power on default
> state in Guest OSes, which puts the root port hot plug enable to
> default OFF.
>
> When BIOS boots, all root ports under VMD is inaccessible by BIOS and
> they maintain their power on default states. The VMD UEFI driver loads
> and configure all devices under VMD. This is how AER, power management,
> DPC and hotplug gets enabled in UEFI, since the BIOS pci driver cannot
> access the root ports. With the absence of VMD UEFI driver in Guest,
> Hotplug stays Disabled.
>
> This change will cause the hot plug to start working again in guest,
> as the settings implemented by the UEFI VMD DXE driver will remain in
> effect in the Guest OS.
>
> Signed-off-by: Nirmal Patel <nirmal.patel@xxxxxxxxxxxxxxx>
> ---
> drivers/pci/controller/vmd.c | 2 --
> 1 file changed, 2 deletions(-)
>
> diff --git a/drivers/pci/controller/vmd.c b/drivers/pci/controller/vmd.c
> index 769eedeb8802..52c2461b4761 100644
> --- a/drivers/pci/controller/vmd.c
> +++ b/drivers/pci/controller/vmd.c
> @@ -701,8 +701,6 @@ static int vmd_alloc_irqs(struct vmd_dev *vmd)
> 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;
Gentle ping!
Thanks.
