From: Alexey Kardashevskiy <aik@xxxxxxxxx> he current VFIO-on-POWER implementation supports only user mode driven mapping, i.e. QEMU is sending requests to map/unmap pages. However this approach is really slow in really fast hardware so it is better to be moved to the real mode. The patch adds an API to increment/decrement page counter as get_user_pages API used for user mode mapping does not work in the real mode. CONFIG_SPARSEMEM_VMEMMAP and CONFIG_FLATMEN are supported. Signed-off-by: Alexey Kardashevskiy <aik@xxxxxxxxx> Cc: David Gibson <david@xxxxxxxxxxxxxxxxxxxxx> --- arch/powerpc/include/asm/pgtable-ppc64.h | 3 ++ arch/powerpc/mm/init_64.c | 56 +++++++++++++++++++++++++++++- 2 files changed, 58 insertions(+), 1 deletion(-) diff --git a/arch/powerpc/include/asm/pgtable-ppc64.h b/arch/powerpc/include/asm/pgtable-ppc64.h index ddcc898..b7a1fb2 100644 --- a/arch/powerpc/include/asm/pgtable-ppc64.h +++ b/arch/powerpc/include/asm/pgtable-ppc64.h @@ -377,6 +377,9 @@ static inline pte_t *find_linux_pte_or_hugepte(pgd_t *pgdir, unsigned long ea, } #endif /* !CONFIG_HUGETLB_PAGE */ +struct page *vmemmap_pfn_to_page(unsigned long pfn); +long vmemmap_get_page(struct page *page); +long vmemmap_put_page(struct page *page); pte_t lookup_linux_pte(pgd_t *pgdir, unsigned long hva, int writing, unsigned long *pte_sizep); diff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c index 95a4529..068e9e9 100644 --- a/arch/powerpc/mm/init_64.c +++ b/arch/powerpc/mm/init_64.c @@ -297,5 +297,59 @@ int __meminit vmemmap_populate(struct page *start_page, return 0; } -#endif /* CONFIG_SPARSEMEM_VMEMMAP */ +struct page *vmemmap_pfn_to_page(unsigned long pfn) +{ + struct vmemmap_backing *vmem_back; + struct page *page; + unsigned long page_size = 1 << mmu_psize_defs[mmu_vmemmap_psize].shift; + unsigned long pg_va = (unsigned long) pfn_to_page(pfn); + + for (vmem_back = vmemmap_list; vmem_back; vmem_back = vmem_back->list) { + if (pg_va < vmem_back->virt_addr) + continue; + + /* Check that page struct is not split between real pages */ + if ((pg_va + sizeof(struct page)) > + (vmem_back->virt_addr + page_size)) + return NULL; + + page = (struct page *) (vmem_back->phys + pg_va - + vmem_back->virt_addr); + return page; + } + + return NULL; +} + +#elif defined(CONFIG_FLATMEM) + +struct page *vmemmap_pfn_to_page(unsigned long pfn) +{ + struct page *page = pfn_to_page(pfn); + return page; +} + +#endif /* CONFIG_SPARSEMEM_VMEMMAP/CONFIG_FLATMEM */ + +#if defined(CONFIG_SPARSEMEM_VMEMMAP) || defined(CONFIG_FLATMEM) +long vmemmap_get_page(struct page *page) +{ + if (PageTail(page)) + return -EAGAIN; + + get_page(page); + + return 0; +} + +long vmemmap_put_page(struct page *page) +{ + if (PageCompound(page)) + return -EAGAIN; + + put_page(page); + + return 0; +} +#endif -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html