lguest: handle trimming of our e820 map Lguest doesn't need to reserve space for the BIOS, but in commit 1b5576e69a5f Yinghai added trim_bios_range which mangles our e820 map. But e820_remove_range does not handle removing a range from the middle of a region correctly, so we end up with a bad max_pfn value. The result is we can't find our (lguest-specific) device table which we expect above the top of RAM, and fail to find the root device. Cc: Yinghai Lu Signed-off-by: Rusty Russell --- arch/x86/lguest/boot.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/arch/x86/lguest/boot.c b/arch/x86/lguest/boot.c --- a/arch/x86/lguest/boot.c +++ b/arch/x86/lguest/boot.c @@ -1135,12 +1135,15 @@ static struct notifier_block paniced = { static __init char *lguest_memory_setup(void) { /* - *The Linux bootloader header contains an "e820" memory map: the + * The Linux bootloader header contains an "e820" memory map: the * Launcher populated the first entry with our memory limit. + * + * We have to skip the traditional BIOS area here, otherwise the + * kernel messes up our map trying to "fix" it in trim_bios_range. */ - e820_add_region(boot_params.e820_map[0].addr, - boot_params.e820_map[0].size, - boot_params.e820_map[0].type); + e820_add_region(0, BIOS_BEGIN, boot_params.e820_map[0].type); + e820_add_region(BIOS_END, boot_params.e820_map[0].size - BIOS_END, + boot_params.e820_map[0].type); /* This string is for the boot messages. */ return "LGUEST";