On Wed, Oct 10, 2012 at 9:38 AM, Stefano Stabellini <stefano.stabell...@eu.citrix.com> wrote: >> - if (pfn >= pgt_buf_top) >> - panic("alloc_low_page: ran out of memory"); >> + if ((pgt_buf_end + 1) >= pgt_buf_top) { >> + unsigned long ret; >> + if (min_pfn_mapped >= max_pfn_mapped) >> + panic("alloc_low_page: ran out of memory"); >> + ret = memblock_find_in_range(min_pfn_mapped << PAGE_SHIFT, >> + max_pfn_mapped << PAGE_SHIFT, >> + PAGE_SIZE, PAGE_SIZE); >> + if (!ret) >> + panic("alloc_low_page: can not alloc memory"); >> + memblock_reserve(ret, PAGE_SIZE); >> + pfn = ret >> PAGE_SHIFT; > > This cannot be right: you are allocating another page to be used as > pagetable page, outside the range pgt_buf_start-pgt_buf_top. > > When that page is going to be hooked into the live pagetable, the kernel > is going to panic on Xen because the page wasn't marked RO. > > If you want to do that you need to tell the Xen subsystem of the new > page. pagetable_reserve is not the right call, we need a new one (see > past emails).
ok, will change that interface and call in from alloc_low_page. how about the pages from BRK, do we need to call xen hooks to mark it as RO? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/