Messages in this thread Patch in this message | | | From | Joerg Roedel <> | Subject | [PATCH v4 1/4] x86/realmode: Add comment for Global bit usage in trampline_pgd | Date | Thu, 2 Dec 2021 16:32:23 +0100 |
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From: Joerg Roedel <jroedel@suse.de>
Document the fact that using the trampoline_pgd will result in the creation of global TLB entries in the user range of the address space.
Signed-off-by: Joerg Roedel <jroedel@suse.de> --- arch/x86/mm/init.c | 5 +++++ 1 file changed, 5 insertions(+)
diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c index 1895986842b9..4ba024d5b63a 100644 --- a/arch/x86/mm/init.c +++ b/arch/x86/mm/init.c @@ -714,6 +714,11 @@ static void __init memory_map_bottom_up(unsigned long map_start, static void __init init_trampoline(void) { #ifdef CONFIG_X86_64 + /* + * The code below will alias kernel page-tables in the user-range of the + * address space, including the Global bit. So global TLB entries will + * be created when using the trampoline page-table. + */ if (!kaslr_memory_enabled()) trampoline_pgd_entry = init_top_pgt[pgd_index(__PAGE_OFFSET)]; else -- 2.34.0
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