[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [XEN RFC PATCH 18/40] xen/arm: Keep memory nodes in dtb for NUMA when boot from EFI
Hi Stefano, On 27/08/2021 00:24, Stefano Stabellini wrote: On Wed, 11 Aug 2021, Wei Chen wrote:EFI can get memory map from EFI system table. But EFI system table doesn't contain memory NUMA information, EFI depends on ACPI SRAT or device tree memory node to parse memory blocks' NUMA mapping. But in current code, when Xen is booting from EFI, it will delete all memory nodes in device tree. So in UEFI + DTB boot, we don't have numa-node-id for memory blocks any more. So in this patch, we will keep memory nodes in device tree for NUMA code to parse memory numa-node-id later. As a side effect, if we still parse boot memory information in early_scan_node, bootmem.info will calculate memory ranges in memory nodes twice. So we have to prvent early_scan_node to parse memory nodes in EFI boot. As EFI APIs only can be used in Arm64, so we introduced a wrapper in header file to prevent #ifdef CONFIG_ARM_64/32 in code block. Signed-off-by: Wei Chen <wei.chen@xxxxxxx> --- xen/arch/arm/bootfdt.c | 8 +++++++- xen/arch/arm/efi/efi-boot.h | 25 ------------------------- xen/include/asm-arm/setup.h | 6 ++++++ 3 files changed, 13 insertions(+), 26 deletions(-) diff --git a/xen/arch/arm/bootfdt.c b/xen/arch/arm/bootfdt.c index 476e32e0f5..7df149dbca 100644 --- a/xen/arch/arm/bootfdt.c +++ b/xen/arch/arm/bootfdt.c @@ -11,6 +11,7 @@ #include <xen/lib.h> #include <xen/kernel.h> #include <xen/init.h> +#include <xen/efi.h> #include <xen/device_tree.h> #include <xen/libfdt/libfdt.h> #include <xen/sort.h> @@ -335,7 +336,12 @@ static int __init early_scan_node(const void *fdt, { int rc = 0;- if ( device_tree_node_matches(fdt, node, "memory") )+ /* + * If system boot from EFI, bootinfo.mem has been set by EFI, + * so we don't need to parse memory node from DTB. + */ + if ( device_tree_node_matches(fdt, node, "memory") && + !arch_efi_enabled(EFI_BOOT) ) rc = process_memory_node(fdt, node, name, depth, address_cells, size_cells, &bootinfo.mem); else if ( depth == 1 && !dt_node_cmp(name, "reserved-memory") )If we are going to use the device tree info for the numa nodes (and related memory) does it make sense to still rely on the EFI tables for the memory map? Yes. AFAIK, when booting using EFI, the Device-Tree may not contain all the reserved regions. Furthermore, we are still too early to know whether we boot using ACPI and DT. I looked at Linux when I first reviewed this patch because I was wondering what happens if the DT and UEFI map disagrees.I wonder if we should just use device tree for memory and ignore EFI instead. Do you know what Linux does in this regard? Linux and Xen are the same after this patch: 1) The memory map is coming from UEFI map 2) NUMA ID is coming from the DT The commit that introduced the change in Linux is: commit 500899c2cc3e3f06140373b587a69d30650f2d9d Author: Ard Biesheuvel <ardb@xxxxxxxxxx> Date: Fri Apr 8 15:50:23 2016 -0700 efi: ARM/arm64: ignore DT memory nodes instead of removing them There are two problems with the UEFI stub DT memory node removal routine: - it deletes nodes as it traverses the tree, which happens to work but is not supported, as deletion invalidates the node iterator; - deleting memory nodes entirely may discard annotations in the form of additional properties on the nodes. Since the discovery of DT memory nodes occurs strictly before the UEFI init sequence, we can simply clear the memblock memory table before parsing the UEFI memory map. This way, it is no longer necessary to remove the nodes, so we can remove that logic from the stub as well. Reviewed-by: Matt Fleming <matt@xxxxxxxxxxxxxxxxxxx> Acked-by: Steve Capper <steve.capper@xxxxxxx> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx> Signed-off-by: David Daney <david.daney@xxxxxxxxxx> Signed-off-by: Will Deacon <will.deacon@xxxxxxx> Cheers, -- Julien Grall
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