x86: Make e820_remove_range to handle all covered case (9f3a5f52) · Commits · 戴 / test

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 <rusty@rustcorp.com.au> Signed-off-by:

Yinghai Lu <yinghai@kernel.org> Tested-by:

Rusty Russell <rusty@rustcorp.com.au> LKML-Reference: <4BB18E55.6090903@kernel.org> Signed-off-by:

H. Peter Anvin <hpa@zytor.com>

arch/x86/kernel/e820.c

+20 −4

Original line number	Diff line number	Diff line
		@@ -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);
		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;

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