From 9f3a5f52aa63d3aa4c64a7245153549bb66bad8c Mon Sep 17 00:00:00 2001 From: Yinghai Lu Date: Mon, 29 Mar 2010 22:38:29 -0700 Subject: [PATCH] x86: Make e820_remove_range to handle all covered case Rusty found on lguest with trim_bios_range, max_pfn is not right anymore, and looks e820_remove_range does not work right. [ 0.000000] BIOS-provided physical RAM map: [ 0.000000] LGUEST: 0000000000000000 - 0000000004000000 (usable) [ 0.000000] Notice: NX (Execute Disable) protection missing in CPU or disabled in BIOS! [ 0.000000] DMI not present or invalid. [ 0.000000] last_pfn = 0x3fa0 max_arch_pfn = 0x100000 [ 0.000000] init_memory_mapping: 0000000000000000-0000000003fa0000 root cause is: the e820_remove_range doesn't handle the all covered case. e820_remove_range(BIOS_START, BIOS_END - BIOS_START, ...) produces a bogus range as a result. Make it match e820_update_range() by handling that case too. Reported-by: Rusty Russell Signed-off-by: Yinghai Lu Tested-by: Rusty Russell LKML-Reference: <4BB18E55.6090903@kernel.org> Signed-off-by: H. Peter Anvin --- arch/x86/kernel/e820.c | 24 ++++++++++++++++++++---- 1 file changed, 20 insertions(+), 4 deletions(-) diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c index 740b440fbd7..7bca3c6a02f 100644 --- a/arch/x86/kernel/e820.c +++ b/arch/x86/kernel/e820.c @@ -519,29 +519,45 @@ u64 __init e820_remove_range(u64 start, u64 size, unsigned old_type, printk(KERN_DEBUG "e820 remove range: %016Lx - %016Lx ", (unsigned long long) start, (unsigned long long) end); - e820_print_type(old_type); + if (checktype) + e820_print_type(old_type); printk(KERN_CONT "\n"); for (i = 0; i < e820.nr_map; i++) { struct e820entry *ei = &e820.map[i]; u64 final_start, final_end; + u64 ei_end; if (checktype && ei->type != old_type) continue; + + ei_end = ei->addr + ei->size; /* totally covered? */ - if (ei->addr >= start && - (ei->addr + ei->size) <= (start + size)) { + if (ei->addr >= start && ei_end <= end) { real_removed_size += ei->size; memset(ei, 0, sizeof(struct e820entry)); continue; } + + /* new range is totally covered? */ + if (ei->addr < start && ei_end > end) { + e820_add_region(end, ei_end - end, ei->type); + ei->size = start - ei->addr; + real_removed_size += size; + continue; + } + /* partially covered */ final_start = max(start, ei->addr); - final_end = min(start + size, ei->addr + ei->size); + final_end = min(end, ei_end); if (final_start >= final_end) continue; real_removed_size += final_end - final_start; + /* + * left range could be head or tail, so need to update + * size at first. + */ ei->size -= final_end - final_start; if (ei->addr < final_start) continue; -- 2.46.0