[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [xen staging] xen/arm: mm: Rework setup_xenheap_mappings()
commit 26a470875b7e6f52a2c172a26c1f9ee432ad8893 Author: Julien Grall <julien.grall@xxxxxxx> AuthorDate: Sat Jun 11 12:26:18 2022 +0100 Commit: Julien Grall <julien@xxxxxxx> CommitDate: Sat Jun 11 12:29:06 2022 +0100 xen/arm: mm: Rework setup_xenheap_mappings() The current implementation of setup_xenheap_mappings() is using 1GB mappings. This can lead to unexpected result because the mapping may alias a non-cachable region (such as device or reserved regions). For more details see B2.8 in ARM DDI 0487H.a. map_pages_to_xen() was recently reworked to allow superpage mappings, support contiguous mapping and deal with the use of page-tables before they are mapped. Most of the code in setup_xenheap_mappings() is now replaced with a single call to map_pages_to_xen(). Signed-off-by: Julien Grall <julien.grall@xxxxxxx> Signed-off-by: Julien Grall <jgrall@xxxxxxxxxx> Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx> Reviewed-by: Luca Fancellu <luca.fancellu@xxxxxxx> --- xen/arch/arm/mm.c | 87 ++++++++++++------------------------------------------- 1 file changed, 18 insertions(+), 69 deletions(-) diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c index b019e4b35b..65af44f422 100644 --- a/xen/arch/arm/mm.c +++ b/xen/arch/arm/mm.c @@ -138,17 +138,6 @@ static DEFINE_PAGE_TABLE(cpu0_pgtable); static DEFINE_PAGE_TABLES(cpu0_dommap, DOMHEAP_SECOND_PAGES); #endif -#ifdef CONFIG_ARM_64 -/* The first page of the first level mapping of the xenheap. The - * subsequent xenheap first level pages are dynamically allocated, but - * we need this one to bootstrap ourselves. */ -static DEFINE_PAGE_TABLE(xenheap_first_first); -/* The zeroeth level slot which uses xenheap_first_first. Used because - * setup_xenheap_mappings otherwise relies on mfn_to_virt which isn't - * valid for a non-xenheap mapping. */ -static __initdata int xenheap_first_first_slot = -1; -#endif - /* Common pagetable leaves */ /* Second level page tables. * @@ -831,77 +820,37 @@ void __init setup_xenheap_mappings(unsigned long base_mfn, void __init setup_xenheap_mappings(unsigned long base_mfn, unsigned long nr_mfns) { - lpae_t *first, pte; - unsigned long mfn, end_mfn; - vaddr_t vaddr; - - /* Align to previous 1GB boundary */ - mfn = base_mfn & ~((FIRST_SIZE>>PAGE_SHIFT)-1); + int rc; /* First call sets the xenheap physical and virtual offset. */ if ( mfn_eq(xenheap_mfn_start, INVALID_MFN) ) { + unsigned long mfn_gb = base_mfn & ~((FIRST_SIZE >> PAGE_SHIFT) - 1); + xenheap_mfn_start = _mfn(base_mfn); xenheap_base_pdx = mfn_to_pdx(_mfn(base_mfn)); + /* + * The base address may not be aligned to the first level + * size (e.g. 1GB when using 4KB pages). This would prevent + * superpage mappings for all the regions because the virtual + * address and machine address should both be suitably aligned. + * + * Prevent that by offsetting the start of the xenheap virtual + * address. + */ xenheap_virt_start = DIRECTMAP_VIRT_START + - (base_mfn - mfn) * PAGE_SIZE; + (base_mfn - mfn_gb) * PAGE_SIZE; } if ( base_mfn < mfn_x(xenheap_mfn_start) ) panic("cannot add xenheap mapping at %lx below heap start %lx\n", base_mfn, mfn_x(xenheap_mfn_start)); - end_mfn = base_mfn + nr_mfns; - - /* - * Virtual address aligned to previous 1GB to match physical - * address alignment done above. - */ - vaddr = (vaddr_t)__mfn_to_virt(base_mfn) & FIRST_MASK; - - while ( mfn < end_mfn ) - { - int slot = zeroeth_table_offset(vaddr); - lpae_t *p = &xen_pgtable[slot]; - - if ( p->pt.valid ) - { - /* mfn_to_virt is not valid on the 1st 1st mfn, since it - * is not within the xenheap. */ - first = slot == xenheap_first_first_slot ? - xenheap_first_first : mfn_to_virt(lpae_get_mfn(*p)); - } - else if ( xenheap_first_first_slot == -1) - { - /* Use xenheap_first_first to bootstrap the mappings */ - first = xenheap_first_first; - - pte = pte_of_xenaddr((vaddr_t)xenheap_first_first); - pte.pt.table = 1; - write_pte(p, pte); - - xenheap_first_first_slot = slot; - } - else - { - mfn_t first_mfn = alloc_boot_pages(1, 1); - - clear_page(mfn_to_virt(first_mfn)); - pte = mfn_to_xen_entry(first_mfn, MT_NORMAL); - pte.pt.table = 1; - write_pte(p, pte); - first = mfn_to_virt(first_mfn); - } - - pte = mfn_to_xen_entry(_mfn(mfn), MT_NORMAL); - /* TODO: Set pte.pt.contig when appropriate. */ - write_pte(&first[first_table_offset(vaddr)], pte); - - mfn += FIRST_SIZE>>PAGE_SHIFT; - vaddr += FIRST_SIZE; - } - - flush_xen_tlb_local(); + rc = map_pages_to_xen((vaddr_t)__mfn_to_virt(base_mfn), + _mfn(base_mfn), nr_mfns, + PAGE_HYPERVISOR_RW | _PAGE_BLOCK); + if ( rc ) + panic("Unable to setup the xenheap mappings.\n"); } #endif -- generated by git-patchbot for /home/xen/git/xen.git#staging
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