On Fri, Apr 08, 2016 at 04:36:44PM +1000, Alexey Kardashevskiy wrote:
> When SRIOV is disabled, the existing code presumes there is no
> virtual function (VF) in use and destroys all associated PEs.
> However it is possible to get into the situation when the user
> activated SRIOV disabling while a VF is still in use via VFIO.
> For example, unbinding a physical function (PF) while there is a guest
> running with a VF passed throuhgh via VFIO will trigger the bug.
>
> This defines an IODA2-specific IOMMU group release() callback.
> This moves all the disposal code from pnv_ioda_release_vf_PE() to this
> new callback so the cleanup happens when the last user of an IOMMU
> group released the reference.
>
> As pnv_pci_ioda2_release_dma_pe() was reduced to just calling
> iommu_group_put(), this merges pnv_pci_ioda2_release_dma_pe()
> into pnv_ioda_release_vf_PE().
>
> Signed-off-by: Alexey Kardashevskiy <a...@ozlabs.ru>
> ---
> arch/powerpc/platforms/powernv/pci-ioda.c | 33
> +++++++++++++------------------
> 1 file changed, 14 insertions(+), 19 deletions(-)
>
> diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c
> b/arch/powerpc/platforms/powernv/pci-ioda.c
> index ce9f2bf..8108c54 100644
> --- a/arch/powerpc/platforms/powernv/pci-ioda.c
> +++ b/arch/powerpc/platforms/powernv/pci-ioda.c
> @@ -1333,27 +1333,25 @@ static void pnv_pci_ioda2_set_bypass(struct
> pnv_ioda_pe *pe, bool enable);
> static void pnv_pci_ioda2_group_release(void *iommu_data)
> {
> struct iommu_table_group *table_group = iommu_data;
> + struct pnv_ioda_pe *pe = container_of(table_group,
> + struct pnv_ioda_pe, table_group);
> + struct pci_controller *hose = pci_bus_to_host(pe->parent_dev->bus);
> + struct pnv_phb *phb = hose->private_data;
> + struct iommu_table *tbl = pe->table_group.tables[0];
> + int64_t rc;
>
> - table_group->group = NULL;
> -}
> -
> -static void pnv_pci_ioda2_release_dma_pe(struct pci_dev *dev, struct
> pnv_ioda_pe *pe)
> -{
> - struct iommu_table *tbl;
> - int64_t rc;
> -
> - tbl = pe->table_group.tables[0];
> rc = pnv_pci_ioda2_unset_window(&pe->table_group, 0);
Is it safe to go manipulating the PE windows, etc. after SR-IOV is
disabled?
When SR-IOV is disabled, you need to immediately disable the VF (I'm
guessing that happens somewhere) and stop all access to the VF
"hardware". Only the iommu group structure *has* to stick around
until the reference count drops to zero. I think other structures and
hardware reconfiguration can be deferred or done immediately,
whichever is more convenient.
> if (rc)
> pe_warn(pe, "OPAL error %ld release DMA window\n", rc);
>
> pnv_pci_ioda2_set_bypass(pe, false);
> - if (pe->table_group.group) {
> - iommu_group_put(pe->table_group.group);
> - BUG_ON(pe->table_group.group);
> - }
> +
> + BUG_ON(!tbl);
> pnv_pci_ioda2_table_free_pages(tbl);
> - iommu_free_table(tbl, of_node_full_name(dev->dev.of_node));
> + iommu_free_table(tbl, of_node_full_name(pe->parent_dev->dev.of_node));
> +
> + pnv_ioda_deconfigure_pe(phb, pe);
> + pnv_ioda_free_pe(phb, pe->pe_number);
> }
>
> static void pnv_ioda_release_vf_PE(struct pci_dev *pdev)
> @@ -1376,16 +1374,13 @@ static void pnv_ioda_release_vf_PE(struct pci_dev
> *pdev)
> if (pe->parent_dev != pdev)
> continue;
>
> - pnv_pci_ioda2_release_dma_pe(pdev, pe);
> -
> /* Remove from list */
> mutex_lock(&phb->ioda.pe_list_mutex);
> list_del(&pe->list);
> mutex_unlock(&phb->ioda.pe_list_mutex);
>
> - pnv_ioda_deconfigure_pe(phb, pe);
> -
> - pnv_ioda_free_pe(phb, pe->pe_number);
> + if (pe->table_group.group)
> + iommu_group_put(pe->table_group.group);
> }
> }
>
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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