On Thu, 2015-04-02 at 14:40 +1100, Alexey Kardashevskiy wrote: > On 04/02/2015 01:50 PM, Alex Williamson wrote: > > On Thu, 2015-04-02 at 13:30 +1100, Alexey Kardashevskiy wrote: > >> On 04/02/2015 08:48 AM, Alex Williamson wrote: > >>> On Sat, 2015-03-28 at 01:54 +1100, Alexey Kardashevskiy wrote: > >>>> This makes use of the it_page_size from the iommu_table struct > >>>> as page size can differ. > >>>> > >>>> This replaces missing IOMMU_PAGE_SHIFT macro in commented debug code > >>>> as recently introduced IOMMU_PAGE_XXX macros do not include > >>>> IOMMU_PAGE_SHIFT. > >>>> > >>>> Signed-off-by: Alexey Kardashevskiy <a...@ozlabs.ru> > >>>> Reviewed-by: David Gibson <da...@gibson.dropbear.id.au> > >>>> --- > >>>> drivers/vfio/vfio_iommu_spapr_tce.c | 26 +++++++++++++------------- > >>>> 1 file changed, 13 insertions(+), 13 deletions(-) > >>>> > >>>> diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c > >>>> b/drivers/vfio/vfio_iommu_spapr_tce.c > >>>> index f835e63..8bbee22 100644 > >>>> --- a/drivers/vfio/vfio_iommu_spapr_tce.c > >>>> +++ b/drivers/vfio/vfio_iommu_spapr_tce.c > >>>> @@ -91,7 +91,7 @@ static int tce_iommu_enable(struct tce_container > >>>> *container) > >>>> * enforcing the limit based on the max that the guest can map. > >>>> */ > >>>> down_write(¤t->mm->mmap_sem); > >>>> - npages = (tbl->it_size << IOMMU_PAGE_SHIFT_4K) >> PAGE_SHIFT; > >>>> + npages = (tbl->it_size << tbl->it_page_shift) >> PAGE_SHIFT; > >>>> locked = current->mm->locked_vm + npages; > >>>> lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; > >>>> if (locked > lock_limit && !capable(CAP_IPC_LOCK)) { > >>>> @@ -120,7 +120,7 @@ static void tce_iommu_disable(struct tce_container > >>>> *container) > >>>> > >>>> down_write(¤t->mm->mmap_sem); > >>>> current->mm->locked_vm -= (container->tbl->it_size << > >>>> - IOMMU_PAGE_SHIFT_4K) >> PAGE_SHIFT; > >>>> + container->tbl->it_page_shift) >> PAGE_SHIFT; > >>>> up_write(¤t->mm->mmap_sem); > >>>> } > >>>> > >>>> @@ -222,7 +222,7 @@ static long tce_iommu_build(struct tce_container > >>>> *container, > >>>> tce, ret); > >>>> break; > >>>> } > >>>> - tce += IOMMU_PAGE_SIZE_4K; > >>>> + tce += IOMMU_PAGE_SIZE(tbl); > >>> > >>> > >>> Is PAGE_SIZE ever smaller than IOMMU_PAGE_SIZE(tbl)? IOW, can the page > >>> we got from get_user_pages_fast() ever not completely fill the tce > >>> entry? > >> > >> > >> Yes. IOMMU_PAGE_SIZE is 4K/64K/16M (16M is with huge pages enabled in QEMU > >> with -mempath), PAGE_SIZE is 4K/64K (normally 64K). > > > > Isn't that a problem then that you're filling the tce with processor > > page sizes via get_user_pages_fast(), but incrementing the tce by by > > IOMMU page size? For example, if PAGE_SIZE = 4K and IOMMU_PAGE_SIZE != > > 4K have we really pinned all of the memory backed by the tce?Where do > > you make sure the 4K page is really contiguous for the IOMMU page? > > > Aaaah. This is just not supported. Instead, after the previous patch > ("vfio: powerpc/spapr: Check that TCE page size is equal to it_page_size", > which need fixed subject), tce_page_is_contained(page4K, 64K) will return > false and the caller - tce_iommu_build() - will return -EPERM.
Ok, makes sense. Thanks _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev