From ac456ca0af4fe9630cf84e7efd20b7f7bf596aab Mon Sep 17 00:00:00 2001 From: "NOMURA JUNICHI(野村　淳一)" Date: Fri, 2 Feb 2024 03:51:58 +0000 Subject: x86/boot: Add a message about ignored early NMIs Commit 78a509fba9c9 ("x86/boot: Ignore NMIs during very early boot") added an empty handler in early boot stage to avoid boot failure due to spurious NMIs. Add a diagnostic message to show that early NMIs have occurred. [ bp: Touchups. ] [ Committer note: tested by stopping the guest really early and injecting NMIs through qemu's monitor. Result: early console in setup code Spurious early NMIs ignored: 13 ... ] Suggested-by: Borislav Petkov Suggested-by: H. Peter Anvin Signed-off-by: Jun'ichi Nomura Signed-off-by: Borislav Petkov (AMD) Acked-by: Kirill A. Shutemov Link: https://lore.kernel.org/lkml/20231130103339.GCZWhlA196uRklTMNF@fat_crate.local --- arch/x86/boot/compressed/ident_map_64.c | 2 +- arch/x86/boot/compressed/misc.c | 7 +++++++ arch/x86/boot/compressed/misc.h | 1 + 3 files changed, 9 insertions(+), 1 deletion(-) (limited to 'arch/x86/boot') diff --git a/arch/x86/boot/compressed/ident_map_64.c b/arch/x86/boot/compressed/ident_map_64.c index d040080d7edb..4a029baa5147 100644 --- a/arch/x86/boot/compressed/ident_map_64.c +++ b/arch/x86/boot/compressed/ident_map_64.c @@ -389,5 +389,5 @@ void do_boot_page_fault(struct pt_regs *regs, unsigned long error_code) void do_boot_nmi_trap(struct pt_regs *regs, unsigned long error_code) { - /* Empty handler to ignore NMI during early boot */ + spurious_nmi_count++; } diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c index bf2aac4f195e..bd6857a9f15a 100644 --- a/arch/x86/boot/compressed/misc.c +++ b/arch/x86/boot/compressed/misc.c @@ -52,6 +52,7 @@ struct port_io_ops pio_ops; memptr free_mem_ptr; memptr free_mem_end_ptr; +int spurious_nmi_count; static char *vidmem; static int vidport; @@ -506,6 +507,12 @@ asmlinkage __visible void *extract_kernel(void *rmode, unsigned char *output) /* Disable exception handling before booting the kernel */ cleanup_exception_handling(); + if (spurious_nmi_count) { + error_putstr("Spurious early NMIs ignored: "); + error_putdec(spurious_nmi_count); + error_putstr("\n"); + } + return output + entry_offset; } diff --git a/arch/x86/boot/compressed/misc.h b/arch/x86/boot/compressed/misc.h index 6502bc69d1b8..b353a7be380c 100644 --- a/arch/x86/boot/compressed/misc.h +++ b/arch/x86/boot/compressed/misc.h @@ -59,6 +59,7 @@ extern char _head[], _end[]; /* misc.c */ extern memptr free_mem_ptr; extern memptr free_mem_end_ptr; +extern int spurious_nmi_count; void *malloc(int size); void free(void *where); void __putstr(const char *s); -- cgit v1.2.3