On 09/20/16 at 02:50pm, Joerg Roedel wrote: > On Thu, Sep 15, 2016 at 11:03:25PM +0800, Baoquan He wrote: > > AMD iommu creates protection domain and assign each device to it during > > iommu driver initialization stage. This happened just after system pci > > bus scanning stage, and much earlier than device driver init stage. So > > at this time if in kdump kernel the domain info, especially pte_root, > > can't be updated to dte entry. We should wait until device driver init > > stage. > > > > Signed-off-by: Baoquan He <b...@redhat.com> > > --- > > drivers/iommu/amd_iommu.c | 18 ++++++++++++++++++ > > 1 file changed, 18 insertions(+) > > > > diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c > > index fcb69ff..6c37300 100644 > > --- a/drivers/iommu/amd_iommu.c > > +++ b/drivers/iommu/amd_iommu.c > > @@ -137,6 +137,7 @@ struct iommu_dev_data { > > bool pri_tlp; /* PASID TLB required for > > PPR completions */ > > u32 errata; /* Bitmap for errata to apply */ > > + bool domain_updated; > > }; > > > > /* > > @@ -1708,6 +1709,15 @@ static void set_dte_entry(u16 devid, struct > > protection_domain *domain, bool ats) > > { > > u64 pte_root = 0; > > u64 flags = 0; > > + struct iommu_dev_data *dev_data; > > + struct amd_iommu *iommu = amd_iommu_rlookup_table[devid]; > > + > > + dev_data = find_dev_data(devid); > > + if (!dev_data) > > + return; > > + > > + if (translation_pre_enabled(iommu) && !dev_data->domain_updated) > > + return; > > > > if (domain->mode != PAGE_MODE_NONE) > > pte_root = virt_to_phys(domain->pt_root); > > @@ -1756,6 +1766,14 @@ static void set_dte_entry(u16 devid, struct > > protection_domain *domain, bool ats) > > > > static void clear_dte_entry(u16 devid) > > { > > + struct iommu_dev_data *dev_data; > > + struct amd_iommu *iommu = amd_iommu_rlookup_table[devid]; > > + > > + dev_data = find_dev_data(devid); > > + if (!dev_data) > > + return; > > + if (translation_pre_enabled(iommu) && !dev_data->domain_updated) > > + return; > > This should be moved to do_attach/do_detach. There you also already have > the dev_data you need here.
For amd-vi v1, checking in do_attach/do_detach is enough. But for v2 amd_iommu_domain_direct_map and amd_iommu_domain_enable_v2 also call it to install pte_root into dev table. So finally, I move them into these two lowest level functions to prevent any pte_root changing during iommu init stage. It involves the least code change. > > > /* remove entry from the device table seen by the hardware */ > > amd_iommu_dev_table[devid].data[0] = DTE_FLAG_V | DTE_FLAG_TV; > > amd_iommu_dev_table[devid].data[1] &= DTE_FLAG_MASK; > > -- > > 2.5.5 > > _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu