On Tue, Sep 29, 2020 at 11:41:29PM +0800, Baolin Wang wrote: > Hi, > > 锟斤拷 2020/9/28 23:23, Lorenzo Pieralisi 写锟斤拷: > > On Mon, Sep 28, 2020 at 10:49:57PM +0800, Baolin Wang wrote: > > > On Mon, Sep 28, 2020 at 03:00:55PM +0100, Will Deacon wrote: > > > > [+ 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. > > > > > > What I mean is, if we disable the NUMA from BIOS > > > > Please define what this means ie are you removing SRAT from ACPI static > > tables ? > > Yes. > > > > > > but we did not change the PXM for the PCI devices, > > > > If a _PXM maps to a proximity domain that is not described in the SRAT > > your firmware is buggy. > > Sorry for confusing, that's not what I mean. When the BIOS disable the NUMA > (remove the SRAT table), but the PCI devices' _PXM description is still > available, which means we can still get the pxm from acpi_evaluate_integer() > in this case.
There should not be a _PXM object if the SRAT is not available, that's a firmware bug. > So we can get below inconsistent log on ARM platform: > "No NUMA configuration found > PCI_bus 0000:00 on NUMA node 0 > ... > PCI_bus 0000:e3 on NUMA node 1" > > On X86, the pci_acpi_root_get_node() will validate the node before setting > the node id for root bus. So I think we can add this validation for ARM > platform. Or anything else I missed? We are not adding checks because x86 does it, it is certainly to paper over a firmware bug that you hopefully still have a chance to fix, let's do that instead of adding code that is not necessary. Lorenzo
