linux-kernel - Re: [PATCH] Fix e820 end address with EFI

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Date:	Sat, 28 Feb 2009 21:42:56 -0800
From:	Yinghai Lu <yinghai@...nel.org>
To:	Brian Maly <bmaly@...hat.com>, Ingo Molnar <mingo@...e.hu>,
	Huang Ying <ying.huang@...el.com>
Cc:	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] Fix e820 end address with EFI

On Sat, Feb 28, 2009 at 8:14 PM, Yinghai Lu <yinghai@...nel.org> wrote:
> On Sat, Feb 28, 2009 at 8:26 AM, Brian Maly <bmaly@...hat.com> wrote:
>>
>>   On some EFI systems (i.e. Apple) EFI runtime is mapped into higher mem
>> regions. These EFI mem regions are not always taken into consideration when
>> max_pfn is calculated in setup.c being that e820_end_of_ram_pfn() only
>> counts
>> mappings types marked as usable (E820_RAM). Currently we only count to the
>> last
>> usable e820 address range and nothing beyond. EFI can be mapped anywhere
>> within
>> e820 and is not always marked as usable e820, and so EFI runtime may be
>> missed
>> if mapped somewhere beyond last usable e820. This patch attempts to resolve
>> this problem by including all E820 mappings when EFI is enabled, so that
>> the entire e820 (and EFI runtime area) is included in computing max_pfn.
>> Tested
>> on a MacBook Pro 3.1 and resolves the issue (system now boots w/elilo+grub &
>> EFI).
>>
>
> it seems you should check and enable directly mapping when EFI runtime
> service is enabled.

it seems in efi_enter_virtual_mode already called efi_ioremap() for
the range above max_low_pfn_mapped...

so it seems you meet other problems.

YH

void __init efi_enter_virtual_mode(void)
{
        efi_memory_desc_t *md;
        efi_status_t status;
        unsigned long size;
        u64 end, systab, addr, npages;
        void *p, *va;

        efi.systab = NULL;
        for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
                md = p;
                if (!(md->attribute & EFI_MEMORY_RUNTIME))
                        continue;

                size = md->num_pages << EFI_PAGE_SHIFT;
                end = md->phys_addr + size;

                if (PFN_UP(end) <= max_low_pfn_mapped)
                        va = __va(md->phys_addr);
                else
                        va = efi_ioremap(md->phys_addr, size);

                md->virt_addr = (u64) (unsigned long) va;

                if (!va) {
                        printk(KERN_ERR PFX "ioremap of 0x%llX failed!\n",
                               (unsigned long long)md->phys_addr);
                        continue;
                }

                if (!(md->attribute & EFI_MEMORY_WB)) {
                        addr = md->virt_addr;
                        npages = md->num_pages;
                        memrange_efi_to_native(&addr, &npages);
                        set_memory_uc(addr, npages);
                }

                systab = (u64) (unsigned long) efi_phys.systab;
                if (md->phys_addr <= systab && systab < end) {
                        systab += md->virt_addr - md->phys_addr;
                        efi.systab = (efi_system_table_t *) (unsigned
long) systab;
                }
        }
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