Messages in this thread | | | Date | Fri, 13 Dec 2019 17:38:18 +0100 | From | Borislav Petkov <> | Subject | Re: [PATCH v5 4/4] x86/mm/KASLR: Adjust the padding size for the direct mapping. |
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On Fri, Dec 13, 2019 at 10:54:48PM +0800, Baoquan He wrote: > On 12/13/19 at 03:15pm, Borislav Petkov wrote: > > On Fri, Dec 13, 2019 at 09:28:50PM +0800, Baoquan He wrote: > > > In Documentation/x86/x86_64/mm.rst, the physical memory regions mapping > > > with page_offset is called as the direct mapping of physical memory. > > > > The fact that it happens to compute the *first* region's size, which > > *happens* to be the direct mapping of all physical memory is immaterial > > here. > > > > It is actually causing more confusion in an already complex piece of > > code. You can call this function just as well > > > > calc_region_size() > > > > which won't confuse readers. Because all you care about here is the > > region's size - not which region it is. > > Won't calc_region_size be too generic? We also have vmalloc and vmemmap, > and here we are specifically calculating the direct mapping of physical > memory.
It sounds like you didn't read what I wrote above so read it again pls.
> If not knowing the max address to cover all the possible hotplugged > memory, later memory hotplug will fail.
You don't have to state the obvious - I can see that in the code.
So let me ask you differently: can the parsing of the SRAT table happen shortly before kernel_randomize_memory() *without* adding all that gunk to the compressed stage, and without adding the boot_params member and done only for memory hot_add machines?
-- Regards/Gruss, Boris.
https://people.kernel.org/tglx/notes-about-netiquette
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