From f1e525009493cbd569e7c8dd7d58157855f8658d Mon Sep 17 00:00:00 2001 From: Juergen Gross Date: Wed, 23 Nov 2022 12:45:23 +0100 Subject: x86/boot: Skip realmode init code when running as Xen PV guest When running as a Xen PV guest there is no need for setting up the realmode trampoline, as realmode isn't supported in this environment. Trying to setup the trampoline has been proven to be problematic in some cases, especially when trying to debug early boot problems with Xen requiring to keep the EFI boot-services memory mapped (some firmware variants seem to claim basically all memory below 1Mb for boot services). Introduce new x86_platform_ops operations for that purpose, which can be set to a NOP by the Xen PV specific kernel boot code. [ bp: s/call_init_real_mode/do_init_real_mode/ ] Fixes: 084ee1c641a0 ("x86, realmode: Relocator for realmode code") Suggested-by: H. Peter Anvin Signed-off-by: Juergen Gross Signed-off-by: Borislav Petkov Link: https://lore.kernel.org/r/20221123114523.3467-1-jgross@suse.com --- arch/x86/kernel/setup.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/x86/kernel/setup.c') diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c index 216fee7144ee..892609cde4a2 100644 --- a/arch/x86/kernel/setup.c +++ b/arch/x86/kernel/setup.c @@ -1175,7 +1175,7 @@ void __init setup_arch(char **cmdline_p) * Moreover, on machines with SandyBridge graphics or in setups that use * crashkernel the entire 1M is reserved anyway. */ - reserve_real_mode(); + x86_platform.realmode_reserve(); init_mem_mapping(); -- cgit