| Message ID | 569C7363.80106@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Mon, 18 Jan 2016, Shannon Zhao wrote: > On 2016/1/16 1:08, Stefano Stabellini wrote: > > On Fri, 15 Jan 2016, Shannon Zhao wrote: > >> From: Shannon Zhao <shannon.zhao@linaro.org> > >> > >> Use page_to_xen_pfn in case of 64KB page. > >> > >> Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> > >> --- > >> drivers/xen/xlate_mmu.c | 2 +- > >> 1 file changed, 1 insertion(+), 1 deletion(-) > >> > >> diff --git a/drivers/xen/xlate_mmu.c b/drivers/xen/xlate_mmu.c > >> index 9692656..b9fcc2c 100644 > >> --- a/drivers/xen/xlate_mmu.c > >> +++ b/drivers/xen/xlate_mmu.c > >> @@ -227,7 +227,7 @@ int __init xen_xlate_map_ballooned_pages(xen_pfn_t **gfns, void **virt, > >> return rc; > >> } > >> for (i = 0; i < nr_grant_frames; i++) > >> - pfns[i] = page_to_pfn(pages[i]); > >> + pfns[i] = page_to_xen_pfn(pages[i]); > > > > Shannon, thanks for the patch. > > > > Keeping in mind that in the 64K case, kernel pages are 64K but xen pages > > are still 4K, I think you also need to allocate > > (nr_grant_frames/XEN_PFN_PER_PAGE) kernel pages (assuming that they are > > allocated contiguously): nr_grant_frames refers to 4K pages, while > > xen_xlate_map_ballooned_pages is allocating pages on a 64K granularity > > (sizeof(pages[0]) == 64K). > > > > Be careful that alloc_xenballooned_pages deals with 64K pages (because > > it deals with kernel pages), while xen_pfn_t is always 4K based (because > > it deals with Xen pfns). > > > > Please test it with and without CONFIG_ARM64_64K_PAGES. Thanks! > > > Stefano, thanks for your explanation. How about below patch? Good work, it looks like you covered all bases, I think it should work, but I haven't tested it myself. Just one note below. > diff --git a/drivers/xen/xlate_mmu.c b/drivers/xen/xlate_mmu.c > index 9692656..e1f7c95 100644 > --- a/drivers/xen/xlate_mmu.c > +++ b/drivers/xen/xlate_mmu.c > @@ -207,9 +207,12 @@ int __init xen_xlate_map_ballooned_pages(xen_pfn_t > **gfns, void **virt, > void *vaddr; > int rc; > unsigned int i; > + unsigned long nr_pages; > + xen_pfn_t xen_pfn = 0; > > BUG_ON(nr_grant_frames == 0); > - pages = kcalloc(nr_grant_frames, sizeof(pages[0]), GFP_KERNEL); > + nr_pages = DIV_ROUND_UP(nr_grant_frames, XEN_PFN_PER_PAGE); > + pages = kcalloc(nr_pages, sizeof(pages[0]), GFP_KERNEL); > if (!pages) > return -ENOMEM; > > @@ -218,22 +221,25 @@ int __init xen_xlate_map_ballooned_pages(xen_pfn_t > **gfns, void **virt, > kfree(pages); > return -ENOMEM; > } > - rc = alloc_xenballooned_pages(nr_grant_frames, pages); > + rc = alloc_xenballooned_pages(nr_pages, pages); > if (rc) { > - pr_warn("%s Couldn't balloon alloc %ld pfns rc:%d\n", > __func__, > - nr_grant_frames, rc); > + pr_warn("%s Couldn't balloon alloc %ld pages rc:%d\n", > __func__, > + nr_pages, rc); > kfree(pages); > kfree(pfns); > return rc; > } > - for (i = 0; i < nr_grant_frames; i++) > - pfns[i] = page_to_pfn(pages[i]); > + for (i = 0; i < nr_grant_frames; i++) { > + if ((i % XEN_PFN_PER_PAGE) == 0) > + xen_pfn = page_to_xen_pfn(pages[i / > XEN_PFN_PER_PAGE]); > + pfns[i] = xen_pfn++; > + } We might want to: pfns[i] = pfn_to_gfn(xen_pfn++); for consistency, even though for autotranslate guests pfn_to_gfn always returns pfn. > - vaddr = vmap(pages, nr_grant_frames, 0, PAGE_KERNEL); > + vaddr = vmap(pages, nr_pages, 0, PAGE_KERNEL); > if (!vaddr) { > - pr_warn("%s Couldn't map %ld pfns rc:%d\n", __func__, > - nr_grant_frames, rc); > - free_xenballooned_pages(nr_grant_frames, pages); > + pr_warn("%s Couldn't map %ld pages rc:%d\n", __func__, > + nr_pages, rc); > + free_xenballooned_pages(nr_pages, pages); > kfree(pages); > kfree(pfns); > return -ENOMEM; > > -- > Shannon >
On 2016/1/19 22:59, Stefano Stabellini wrote: > On Mon, 18 Jan 2016, Shannon Zhao wrote: >> On 2016/1/16 1:08, Stefano Stabellini wrote: >>> On Fri, 15 Jan 2016, Shannon Zhao wrote: >>>> From: Shannon Zhao <shannon.zhao@linaro.org> >>>> >>>> Use page_to_xen_pfn in case of 64KB page. >>>> >>>> Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org> >>>> --- >>>> drivers/xen/xlate_mmu.c | 2 +- >>>> 1 file changed, 1 insertion(+), 1 deletion(-) >>>> >>>> diff --git a/drivers/xen/xlate_mmu.c b/drivers/xen/xlate_mmu.c >>>> index 9692656..b9fcc2c 100644 >>>> --- a/drivers/xen/xlate_mmu.c >>>> +++ b/drivers/xen/xlate_mmu.c >>>> @@ -227,7 +227,7 @@ int __init xen_xlate_map_ballooned_pages(xen_pfn_t **gfns, void **virt, >>>> return rc; >>>> } >>>> for (i = 0; i < nr_grant_frames; i++) >>>> - pfns[i] = page_to_pfn(pages[i]); >>>> + pfns[i] = page_to_xen_pfn(pages[i]); >>> >>> Shannon, thanks for the patch. >>> >>> Keeping in mind that in the 64K case, kernel pages are 64K but xen pages >>> are still 4K, I think you also need to allocate >>> (nr_grant_frames/XEN_PFN_PER_PAGE) kernel pages (assuming that they are >>> allocated contiguously): nr_grant_frames refers to 4K pages, while >>> xen_xlate_map_ballooned_pages is allocating pages on a 64K granularity >>> (sizeof(pages[0]) == 64K). >>> >>> Be careful that alloc_xenballooned_pages deals with 64K pages (because >>> it deals with kernel pages), while xen_pfn_t is always 4K based (because >>> it deals with Xen pfns). >>> >>> Please test it with and without CONFIG_ARM64_64K_PAGES. Thanks! >>> >> Stefano, thanks for your explanation. How about below patch? > > Good work, it looks like you covered all bases, I think it should work, > but I haven't tested it myself. Just one note below. > > >> diff --git a/drivers/xen/xlate_mmu.c b/drivers/xen/xlate_mmu.c >> index 9692656..e1f7c95 100644 >> --- a/drivers/xen/xlate_mmu.c >> +++ b/drivers/xen/xlate_mmu.c >> @@ -207,9 +207,12 @@ int __init xen_xlate_map_ballooned_pages(xen_pfn_t >> **gfns, void **virt, >> void *vaddr; >> int rc; >> unsigned int i; >> + unsigned long nr_pages; >> + xen_pfn_t xen_pfn = 0; >> >> BUG_ON(nr_grant_frames == 0); >> - pages = kcalloc(nr_grant_frames, sizeof(pages[0]), GFP_KERNEL); >> + nr_pages = DIV_ROUND_UP(nr_grant_frames, XEN_PFN_PER_PAGE); >> + pages = kcalloc(nr_pages, sizeof(pages[0]), GFP_KERNEL); >> if (!pages) >> return -ENOMEM; >> >> @@ -218,22 +221,25 @@ int __init xen_xlate_map_ballooned_pages(xen_pfn_t >> **gfns, void **virt, >> kfree(pages); >> return -ENOMEM; >> } >> - rc = alloc_xenballooned_pages(nr_grant_frames, pages); >> + rc = alloc_xenballooned_pages(nr_pages, pages); >> if (rc) { >> - pr_warn("%s Couldn't balloon alloc %ld pfns rc:%d\n", >> __func__, >> - nr_grant_frames, rc); >> + pr_warn("%s Couldn't balloon alloc %ld pages rc:%d\n", >> __func__, >> + nr_pages, rc); >> kfree(pages); >> kfree(pfns); >> return rc; >> } >> - for (i = 0; i < nr_grant_frames; i++) >> - pfns[i] = page_to_pfn(pages[i]); >> + for (i = 0; i < nr_grant_frames; i++) { >> + if ((i % XEN_PFN_PER_PAGE) == 0) >> + xen_pfn = page_to_xen_pfn(pages[i / >> XEN_PFN_PER_PAGE]); >> + pfns[i] = xen_pfn++; >> + } > > We might want to: > > pfns[i] = pfn_to_gfn(xen_pfn++); > > for consistency, even though for autotranslate guests pfn_to_gfn always > returns pfn. > Ok, will add. Thanks. > >> - vaddr = vmap(pages, nr_grant_frames, 0, PAGE_KERNEL); >> + vaddr = vmap(pages, nr_pages, 0, PAGE_KERNEL); >> if (!vaddr) { >> - pr_warn("%s Couldn't map %ld pfns rc:%d\n", __func__, >> - nr_grant_frames, rc); >> - free_xenballooned_pages(nr_grant_frames, pages); >> + pr_warn("%s Couldn't map %ld pages rc:%d\n", __func__, >> + nr_pages, rc); >> + free_xenballooned_pages(nr_pages, pages); >> kfree(pages); >> kfree(pfns); >> return -ENOMEM; >> >> -- >> Shannon >>
diff --git a/drivers/xen/xlate_mmu.c b/drivers/xen/xlate_mmu.c index 9692656..e1f7c95 100644 --- a/drivers/xen/xlate_mmu.c +++ b/drivers/xen/xlate_mmu.c @@ -207,9 +207,12 @@ int __init xen_xlate_map_ballooned_pages(xen_pfn_t **gfns, void **virt, void *vaddr; int rc; unsigned int i; + unsigned long nr_pages; + xen_pfn_t xen_pfn = 0; BUG_ON(nr_grant_frames == 0); - pages = kcalloc(nr_grant_frames, sizeof(pages[0]), GFP_KERNEL); + nr_pages = DIV_ROUND_UP(nr_grant_frames, XEN_PFN_PER_PAGE); + pages = kcalloc(nr_pages, sizeof(pages[0]), GFP_KERNEL); if (!pages) return -ENOMEM;