| Message ID | 20190603220245.22750-1-sstabellini@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v3,1/3] xen/arm: fix nr_pdxs calculation | expand |
Hi Stefano, On 6/3/19 11:02 PM, Stefano Stabellini wrote: > pfn_to_pdx expects an address, not a size, as a parameter. Specifically, > it expects the end address, then the masks calculations compensate for > any holes between start and end. Thus, we should pass the end address to > pfn_to_pdx. > > The initial pdx is stored in frametable_base_pdx, so we can subtract the > result of pfn_to_pdx(start_address) from nr_pdxs; we know that we don't > need to cover any memory in the range 0-start in the frametable. > > Remove the variable `nr_pages' because it is unused. > > Signed-off-by: Stefano Stabellini <stefanos@xilinx.com> Reviewed-by: Julien Grall <julien.grall@arm.com> Cheers,
diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c index 6ac169ce27..22ed91b5c9 100644 --- a/xen/arch/arm/mm.c +++ b/xen/arch/arm/mm.c @@ -886,8 +886,8 @@ void __init setup_xenheap_mappings(unsigned long base_mfn, /* Map a frame table to cover physical addresses ps through pe */ void __init setup_frametable_mappings(paddr_t ps, paddr_t pe) { - unsigned long nr_pages = (pe - ps) >> PAGE_SHIFT; - unsigned long nr_pdxs = pfn_to_pdx(nr_pages); + unsigned long nr_pdxs = mfn_to_pdx(mfn_add(maddr_to_mfn(pe), -1)) - + mfn_to_pdx(maddr_to_mfn(ps)) + 1; unsigned long frametable_size = nr_pdxs * sizeof(struct page_info); mfn_t base_mfn; const unsigned long mapping_size = frametable_size < MB(32) ? MB(2) : MB(32);
pfn_to_pdx expects an address, not a size, as a parameter. Specifically, it expects the end address, then the masks calculations compensate for any holes between start and end. Thus, we should pass the end address to pfn_to_pdx. The initial pdx is stored in frametable_base_pdx, so we can subtract the result of pfn_to_pdx(start_address) from nr_pdxs; we know that we don't need to cover any memory in the range 0-start in the frametable. Remove the variable `nr_pages' because it is unused. Signed-off-by: Stefano Stabellini <stefanos@xilinx.com> CC: JBeulich@suse.com --- Changes in v3: - improve commit message Changes in v2: - use mfn_to_pdx and maddr_to_mfn along with mfn_add() --- xen/arch/arm/mm.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)