On Tue, 28 Jul, at 01:18:37PM, Dmitry Skorodumov wrote:
> Matt Fleming <matt@...> writes:
>
> > On Wed, 22 Jul, at 07:31:08PM, Dmitry Skorodumov wrote:
> > > The efi_info structure stores low 32 bits of memory map
> > > in efi_memmap and high 32 bits in efi_memmap_hi.
> > >
> > > While constructing pointer in the setup_e820(), need
> > > to take into account all 64 bits of the pointer.
>
> > > tested in Parallels virtual machine with more then 3GB of memory
>
> > When you say "tested", you mean that it doesn't boot correctly without
> > your patch but does boot correctly with it applied? What I'm really
> > asking is: are we sure that your setup triggered this new code?
>
> Yes, while debugging I added a lot of logging to trace the problem.
> Parallels VM doesn't boot correctly without the patch.
OK cool, I would definitely include this in the patch commit message.
> I believe that any EDK2-based efi-bios will not work also,
> though I heard that OVMF uses own linux boot loader..
> It is because the memory for memmap was allocated from EFI_LOADER_DATA pool -
> efi_call_early(allocate_pool, EFI_LOADER_DATA, map_size... );
>
> It is possible to kludge the problem by patching EFI-bios of the machine
> to allocate EFI_LOADER_DATA-memory below the 4GB space,
> but I think that fixing setup_e820() is the right thing.
Yes your fix looks correct to me, I just wanted to know whether you hit
the bug with a real workload or via code inspection.
> > > + m = efi->efi_memmap;
> > > +#ifdef CONFIG_X86_64
> > > + m |= (u64)efi->efi_memmap_hi << 32;
> > > +#endif
> ..
> > > for (i = 0; i < nr_desc; i++) {
> > > - unsigned long m = efi->efi_memmap;
> > > d = (efi_memory_desc_t *)(m + (i * efi->efi_memdesc_size));
>
> > Is there a reason that adding efi->efi_memmap_hi can't be done inside
> > this for loop? Gcc should be smart enough to hoist this calculation out
> > of the loop.
>
> Smart from its side.. I'll correct this and resend the patch.
Great, thanks.
--
Matt Fleming, Intel Open Source Technology Center
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