From: Alex Williamson <alex.williamson@redhat.com>
To: Alexey Kardashevskiy <aik@ozlabs.ru>
Cc: linuxppc-dev@lists.ozlabs.org,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH kernel v7 04/31] vfio: powerpc/spapr: Use it_page_size
Date: Wed, 01 Apr 2015 20:50:33 -0600 [thread overview]
Message-ID: <1427943033.5567.329.camel@redhat.com> (raw)
In-Reply-To: <551CA9D7.2060804@ozlabs.ru>
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 <aik@ozlabs.ru>
> >> Reviewed-by: David Gibson <david@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?
next prev parent reply other threads:[~2015-04-02 2:51 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-27 14:54 [PATCH kernel v7 00/31] powerpc/iommu/vfio: Enable Dynamic DMA windows Alexey Kardashevskiy
2015-03-27 14:54 ` [PATCH kernel v7 01/31] vfio: powerpc/spapr: Move page pinning from arch code to VFIO IOMMU driver Alexey Kardashevskiy
2015-03-27 14:54 ` [PATCH kernel v7 02/31] vfio: powerpc/spapr: Do cleanup when releasing the group Alexey Kardashevskiy
2015-03-27 14:54 ` [PATCH kernel v7 03/31] vfio: powerpc/spapr: Check that TCE page size is equal to it_page_size Alexey Kardashevskiy
2015-03-27 14:54 ` [PATCH kernel v7 04/31] vfio: powerpc/spapr: Use it_page_size Alexey Kardashevskiy
2015-04-01 21:48 ` Alex Williamson
2015-04-02 2:30 ` Alexey Kardashevskiy
2015-04-02 2:50 ` Alex Williamson [this message]
2015-04-02 3:40 ` Alexey Kardashevskiy
2015-04-02 3:46 ` Alex Williamson
2015-03-27 14:54 ` [PATCH kernel v7 05/31] vfio: powerpc/spapr: Move locked_vm accounting to helpers Alexey Kardashevskiy
2015-03-27 14:54 ` [PATCH kernel v7 06/31] vfio: powerpc/spapr: Disable DMA mappings on disabled container Alexey Kardashevskiy
2015-03-27 14:54 ` [PATCH kernel v7 07/31] vfio: powerpc/spapr: Moving pinning/unpinning to helpers Alexey Kardashevskiy
2015-03-27 14:54 ` [PATCH kernel v7 08/31] vfio: powerpc/spapr: Rework groups attaching Alexey Kardashevskiy
2015-03-27 14:54 ` [PATCH kernel v7 09/31] powerpc/powernv: Do not set "read" flag if direction==DMA_NONE Alexey Kardashevskiy
2015-03-27 14:54 ` [PATCH kernel v7 10/31] powerpc/iommu: Move tce_xxx callbacks from ppc_md to iommu_table Alexey Kardashevskiy
2015-03-27 14:54 ` [PATCH kernel v7 11/31] powerpc/iommu: Introduce iommu_table_alloc() helper Alexey Kardashevskiy
2015-03-27 14:54 ` [PATCH kernel v7 12/31] powerpc/spapr: vfio: Switch from iommu_table to new iommu_table_group Alexey Kardashevskiy
2015-03-31 21:34 ` Alex Williamson
2015-04-01 21:48 ` Alex Williamson
2015-04-02 2:33 ` Alexey Kardashevskiy
2015-04-02 2:51 ` Alex Williamson
2015-03-27 14:54 ` [PATCH kernel v7 13/31] vfio: powerpc/spapr: powerpc/iommu: Rework IOMMU ownership control Alexey Kardashevskiy
2015-03-27 14:54 ` [PATCH kernel v7 14/31] vfio: powerpc/spapr: powerpc/powernv/ioda2: " Alexey Kardashevskiy
2015-03-27 14:54 ` [PATCH kernel v7 15/31] powerpc/iommu: Fix IOMMU ownership control functions Alexey Kardashevskiy
2015-03-27 14:55 ` [PATCH kernel v7 16/31] powerpc/powernv/ioda/ioda2: Rework tce_build()/tce_free() Alexey Kardashevskiy
2015-03-27 14:55 ` [PATCH kernel v7 17/31] powerpc/iommu/powernv: Release replaced TCE Alexey Kardashevskiy
2015-03-27 14:55 ` [PATCH kernel v7 18/31] powerpc/powernv/ioda2: Rework iommu_table creation Alexey Kardashevskiy
2015-03-27 14:55 ` [PATCH kernel v7 19/31] powerpc/powernv/ioda2: Introduce pnv_pci_ioda2_create_table/pnc_pci_free_table Alexey Kardashevskiy
2015-03-27 14:55 ` [PATCH kernel v7 20/31] powerpc/powernv/ioda2: Introduce pnv_pci_ioda2_set_window Alexey Kardashevskiy
2015-03-27 14:55 ` [PATCH kernel v7 21/31] powerpc/iommu: Split iommu_free_table into 2 helpers Alexey Kardashevskiy
2015-03-27 14:55 ` [PATCH kernel v7 22/31] powerpc/powernv: Implement multilevel TCE tables Alexey Kardashevskiy
2015-03-27 14:55 ` [PATCH kernel v7 23/31] powerpc/powernv: Change prototypes to receive iommu Alexey Kardashevskiy
2015-03-27 14:55 ` [PATCH kernel v7 24/31] powerpc/powernv/ioda: Define and implement DMA table/window management callbacks Alexey Kardashevskiy
2015-03-27 14:55 ` [PATCH kernel v7 25/31] vfio: powerpc/spapr: powerpc/powernv/ioda2: Rework ownership Alexey Kardashevskiy
2015-03-27 14:55 ` [PATCH kernel v7 26/31] powerpc/iommu: Add userspace view of TCE table Alexey Kardashevskiy
2015-04-02 20:50 ` Alex Williamson
2015-04-08 3:22 ` Alexey Kardashevskiy
2015-04-08 15:43 ` Alex Williamson
2015-04-09 3:21 ` Alexey Kardashevskiy
2015-04-09 3:46 ` Alex Williamson
2015-03-27 14:55 ` [PATCH kernel v7 27/31] powerpc/iommu/ioda2: Add get_table_size() to calculate the size of fiture table Alexey Kardashevskiy
2015-03-27 14:55 ` [PATCH kernel v7 28/31] powerpc/mmu: Add userspace-to-physical addresses translation cache Alexey Kardashevskiy
2015-04-01 21:48 ` Alex Williamson
2015-04-02 2:35 ` Alexey Kardashevskiy
2015-03-27 14:55 ` [PATCH kernel v7 29/31] vfio: powerpc/spapr: Register memory and define IOMMU v2 Alexey Kardashevskiy
2015-03-27 14:55 ` [PATCH kernel v7 30/31] vfio: powerpc/spapr: Support multiple groups in one container if possible Alexey Kardashevskiy
2015-03-27 14:55 ` [PATCH kernel v7 31/31] vfio: powerpc/spapr: Support Dynamic DMA windows Alexey Kardashevskiy
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