[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [PATCH 3/3] mini-os: fix number of pages for PVH
Juergen Gross, le sam. 18 juin 2022 16:07:07 +0200, a ecrit: > On 18.06.22 14:13, Samuel Thibault wrote: > > Hello, > > > > Juergen Gross, le sam. 18 juin 2022 12:48:16 +0200, a ecrit: > > > @@ -124,7 +126,7 @@ void arch_mm_preinit(void *p) > > > do_exit(); > > > } > > > - last_free_pfn = e820_get_maxpfn(ret); > > > + last_free_pfn = e820_get_maxpfn(ret - e820_initial_reserved_pfns); > > > > Mmm, but the reserved pfn could be in the middle of the e820 address > > space. > > That doesn't matter. > > e820_get_maxpfn(n) will just return the pfn of the n-th RAM pfn it is > finding in the E820 map. Yes, but subtracting at this point looks a bit hacky to me. It seems to me that it'd be better to make e820_get_maxpfn count by itself the reserved pages (but never return its pfn of course), rather than having to make e820_sanitize look at the reserved pages, store it somewhere, and hope that other code will remember to subtract that before calling e820_get_maxpfn. I mean something like: unsigned long e820_get_maxpfn(unsigned long pages) { int i; unsigned long pfns = 0, start = 0; if ( !e820_entries ) e820_get_memmap(); for ( i = 0; i < e820_entries; i++ ) { pfns = e820_map[i].size >> PAGE_SHIFT; if ( e820_map[i].type == E820_RESERVED ) { /* This counts in the memory reservation, but is not usable */ pages -= pfns; continue; } if ( e820_map[i].type != E820_RAM ) continue; start = e820_map[i].addr >> PAGE_SHIFT; if ( pages <= pfns ) return start + pages; pages -= pfns; } return start + pfns; } Samuel
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