lkml.org 
[lkml]   [2020]   [Sep]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] arm64: PCI: Validate the node before setting node id for root bus
[+ Lorenzo]

On Tue, Sep 22, 2020 at 06:33:24PM +0800, Baolin Wang wrote:
> If the BIOS disabled the NUMA configuration, but did not change the
> proximity domain description in the SRAT table, so the PCI root bus
> device may get a incorrect node id by acpi_get_node().

How "incorrect" are we talking here? What actually goes wrong? At some
point, we have to trust what the firmware is telling us.

> Thus better to add a numa node validation before setting numa node
> for the PCI root bus, like pci_acpi_root_get_node() does for X86
> architecture.
>
> Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
> ---
> arch/arm64/kernel/pci.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm64/kernel/pci.c b/arch/arm64/kernel/pci.c
> index 1006ed2..24fe2bd 100644
> --- a/arch/arm64/kernel/pci.c
> +++ b/arch/arm64/kernel/pci.c
> @@ -86,9 +86,13 @@ int pcibios_root_bridge_prepare(struct pci_host_bridge *bridge)
> struct pci_config_window *cfg = bridge->bus->sysdata;
> struct acpi_device *adev = to_acpi_device(cfg->parent);
> struct device *bus_dev = &bridge->bus->dev;
> + int node = acpi_get_node(acpi_device_handle(adev));
> +
> + if (node != NUMA_NO_NODE && !node_online(node))
> + node = NUMA_NO_NODE;

Hmm. afaict, acpi_get_node() tries quite hard to return a valid node when
it gets back NUMA_NO_NODE in acpi_map_pxm_to_node(). Seems like we're
undoing all of that here, which worries me because NUMA_NO_NODE is a bit
of a loaded gun if you interpret it as a valid node.

Anyway, I defer to Lorenzo on this.

Will

\
 
 \ /
  Last update: 2020-09-28 16:01    [W:0.055 / U:15.584 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site