Messages in this thread | | | Date | Wed, 30 Nov 2022 04:28:40 +0300 | From | "Kirill A. Shutemov" <> | Subject | Re: [PATCHv7 08/14] x86/mm: Reserve unaccepted memory bitmap |
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On Tue, Jul 26, 2022 at 11:07:14AM +0200, Borislav Petkov wrote: > On Tue, Jun 14, 2022 at 03:02:25PM +0300, Kirill A. Shutemov wrote: > > diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c > > index f267205f2d5a..22d1fe48dcba 100644 > > --- a/arch/x86/kernel/e820.c > > +++ b/arch/x86/kernel/e820.c > > @@ -1316,6 +1316,16 @@ void __init e820__memblock_setup(void) > > int i; > > u64 end; > > > > + /* Mark unaccepted memory bitmap reserved */ > > + if (boot_params.unaccepted_memory) { > > + unsigned long size; > > + > > + /* One bit per 2MB */ > > + size = DIV_ROUND_UP(e820__end_of_ram_pfn() * PAGE_SIZE, > > + PMD_SIZE * BITS_PER_BYTE); > > + memblock_reserve(boot_params.unaccepted_memory, size); > > + } > > + > > Hmm, I don't like how this is dropped right in the middle of a unrelated > function. > > You're adding arch/x86/mm/unaccepted_memory.c later. Why don't you put > that chunk in a function there which is called by early_reserve_memory() > which does exactly what you want - reserve memory early, before memblock > allocations?
early_reserve_memory() specifically called before e820__memory_setup() (see comment in setup_arch()), so we don't have e820_table finalized and we need it to get correct RAM size from e820__end_of_ram_pfn().
I guess we can hide the chunk in a function in unaccepted_memory.c and call it from here, but it would require #ifdeffery in a header file as the .c is only compiled for CONFIG_UNACCEPTED_MEMORY=y.
Looks like an overkill to me, no?
-- Kiryl Shutsemau / Kirill A. Shutemov
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