Re: [PATCH v3 00/10] Update vfio_pin/unpin_pages API

Alex Williamson
2022-07-22T22:11:39Z

On Fri, 8 Jul 2022 15:44:18 -0700
Nicolin Chen <nicolinc@nvidia.com> wrote:

> This is a preparatory series for IOMMUFD v2 patches. It prepares for
> replacing vfio_iommu_type1 implementations of vfio_pin/unpin_pages()
> with IOMMUFD version.
>
> There's a gap between these two versions: the vfio_iommu_type1 version
> inputs a non-contiguous PFN list and outputs another PFN list for the
> pinned physical page list, while the IOMMUFD version only supports a
> contiguous address input by accepting the starting IO virtual address
> of a set of pages to pin and by outputting to a physical page list.
>
> The nature of existing callers mostly aligns with the IOMMUFD version,
> except s390's vfio_ccw_cp code where some additional change is needed
> along with this series. Overall, updating to "iova" and "phys_page"
> does improve the caller side to some extent.
>
> Also fix a misuse of physical address and virtual address in the s390's
> crypto code. And update the input naming at the adjacent vfio_dma_rw().
>
> This is on github:
> https://github.com/nicolinc/iommufd/commits/vfio_pin_pages
>
> Terrence has tested this series on i915; Eric has tested on s390.
>
> Thanks!
>
> Changelog
> v3:
> * Added a patch to replace roundup with DIV_ROUND_UP in i915 gvt
> * Dropped the "driver->ops->unpin_pages" and NULL checks in PATCH-1
> * Changed to use WARN_ON and separate into lines in PATCH-1
> * Replaced "guest" words with "user" and fix typo in PATCH-5
> * Updated commit log of PATCH-1, PATCH-6, and PATCH-10
> * Added Reviewed/Acked-by from Christoph, Jason, Kirti, Kevin and Eric
> * Added Tested-by from Terrence (i915) and Eric (s390)
> v2: https://lore.kernel.org/kvm/20220706062759.24946-1-nicolinc@nvidia.com/
> * Added a patch to make vfio_unpin_pages return void
> * Added two patches to remove PFN list from two s390 callers
> * Renamed "phys_page" parameter to "pages" for vfio_pin_pages
> * Updated commit log of kmap_local_page() patch
> * Added Harald's "Reviewed-by" to pa_ind patch
> * Rebased on top of Alex's extern removal path
> v1: https://lore.kernel.org/kvm/20220616235212.15185-1-nicolinc@nvidia.com/
>
> Nicolin Chen (10):
> vfio: Make vfio_unpin_pages() return void
> drm/i915/gvt: Replace roundup with DIV_ROUND_UP
> vfio/ap: Pass in physical address of ind to ap_aqic()
> vfio/ccw: Only pass in contiguous pages
> vfio: Pass in starting IOVA to vfio_pin/unpin_pages API
> vfio/ap: Change saved_pfn to saved_iova
> vfio/ccw: Change pa_pfn list to pa_iova list
> vfio: Rename user_iova of vfio_dma_rw()
> vfio/ccw: Add kmap_local_page() for memcpy
> vfio: Replace phys_pfn with pages for vfio_pin_pages()
>
> .../driver-api/vfio-mediated-device.rst | 6 +-
> arch/s390/include/asm/ap.h | 6 +-
> drivers/gpu/drm/i915/gvt/kvmgt.c | 49 ++---
> drivers/s390/cio/vfio_ccw_cp.c | 195 +++++++++++-------
> drivers/s390/crypto/ap_queue.c | 2 +-
> drivers/s390/crypto/vfio_ap_ops.c | 54 +++--
> drivers/s390/crypto/vfio_ap_private.h | 4 +-
> drivers/vfio/vfio.c | 54 ++---
> drivers/vfio/vfio.h | 8 +-
> drivers/vfio/vfio_iommu_type1.c | 45 ++--
> include/linux/vfio.h | 9 +-
> 11 files changed, 215 insertions(+), 217 deletions(-)
>

GVT-g explodes for me with this series on my Broadwell test system,
continuously spewing the following:

[ 47.344126] ------------[ cut here ]------------
[ 47.348778] WARNING: CPU: 3 PID: 501 at drivers/vfio/vfio_iommu_type1.c:978 vfio_iommu_type1_unpin_pages+0x7b/0x100 [vfio_iommu_type1]
[ 47.360871] Modules linked in: xt_CHECKSUM xt_MASQUERADE xt_conntrack ipt_REJECT nf_reject_ipv4 nft_compat nft_chain_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 nf_tables nfnetlink tun bridge stp llc rfkill sunrpc vfat fat intel_rapl_msr intel_rapl_common x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel iTCO_wdt at24 mei_wdt mei_hdcp intel_pmc_bxt mei_pxp rapl iTCO_vendor_support intel_cstate pcspkr e1000e mei_me intel_uncore i2c_i801 mei lpc_ich i2c_smbus acpi_pad fuse zram ip_tables kvmgt mdev vfio_iommu_type1 vfio kvm irqbypass i915 crct10dif_pclmul crc32_pclmul crc32c_intel ghash_clmulni_intel pinctrl_lynxpoint i2c_algo_bit drm_buddy video drm_display_helper drm_kms_helper cec ttm drm
[ 47.423398] CPU: 3 PID: 501 Comm: gvt:rcs0 Tainted: G W 5.19.0-rc4+ #3
[ 47.431228] Hardware name: /NUC5i5MYBE, BIOS MYBDWi5v.86A.0054.2019.0520.1531 05/20/2019
[ 47.439408] RIP: 0010:vfio_iommu_type1_unpin_pages+0x7b/0x100 [vfio_iommu_type1]
[ 47.446818] Code: 10 00 00 45 31 ed 48 8b 7b 40 48 85 ff 74 12 48 8b 47 18 49 39 c6 77 23 48 8b 7f 10 48 85 ff 75 ee 48 8b 3c 24 e8 45 57 92 e4 <0f> 0b 48 83 c4 08 5b 5d 41 5c 41 5d 41 5e 41 5f c3 48 03 47 28 49
[ 47.465573] RSP: 0018:ffff9ac5806cfbe0 EFLAGS: 00010246
[ 47.470807] RAX: ffff8cb42f4c5180 RBX: ffff8cb4145c03c0 RCX: 0000000000000000
[ 47.477948] RDX: 0000000000000000 RSI: 0000163802000000 RDI: ffff8cb4145c03e0
[ 47.485088] RBP: 0000000000000001 R08: 0000000000000000 R09: ffff9ac581aed000
[ 47.492230] R10: ffff9ac5806cfc58 R11: 00000001b2202000 R12: 0000000000000001
[ 47.499370] R13: 0000000000000000 R14: 0000163802001000 R15: 0000163802000000
[ 47.506513] FS: 0000000000000000(0000) GS:ffff8cb776d80000(0000) knlGS:0000000000000000
[ 47.514608] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 47.520361] CR2: ffffdc0933f76192 CR3: 0000000118118003 CR4: 00000000003726e0
[ 47.527510] Call Trace:
[ 47.529976] <TASK>
[ 47.532091] intel_gvt_dma_unmap_guest_page+0xd5/0x110 [kvmgt]
[ 47.537948] ppgtt_invalidate_spt+0x323/0x340 [kvmgt]
[ 47.543017] ppgtt_invalidate_spt+0x173/0x340 [kvmgt]
[ 47.548088] ppgtt_invalidate_spt+0x173/0x340 [kvmgt]
[ 47.553159] ppgtt_invalidate_spt+0x173/0x340 [kvmgt]
[ 47.558228] invalidate_ppgtt_mm+0x5f/0x110 [kvmgt]
[ 47.563124] _intel_vgpu_mm_release+0xd6/0xe0 [kvmgt]
[ 47.568193] intel_vgpu_destroy_workload+0x1b7/0x1e0 [kvmgt]
[ 47.573872] workload_thread+0xa4c/0x19a0 [kvmgt]
[ 47.578613] ? _raw_spin_rq_lock_irqsave+0x20/0x20
[ 47.583422] ? dequeue_task_stop+0x70/0x70
[ 47.587530] ? _raw_spin_lock_irqsave+0x24/0x50
[ 47.592072] ? intel_vgpu_reset_submission+0x40/0x40 [kvmgt]
[ 47.597746] kthread+0xe7/0x110
[ 47.600902] ? kthread_complete_and_exit+0x20/0x20
[ 47.605702] ret_from_fork+0x22/0x30
[ 47.609293] </TASK>
[ 47.611503] ---[ end trace 0000000000000000 ]---

Line 978 is the WARN_ON(i != npage) line. For the cases where we don't
find a matching vfio_dma, I'm seeing addresses that look maybe like
we're shifting a value that's already an iova by PAGE_SHIFT somewhere.
Thanks,

Alex