> -----Original Message----- > From: Roger Pau Monne [mailto:roger....@citrix.com] > Sent: 23 January 2019 09:48 > To: xen-devel@lists.xenproject.org > Cc: Roger Pau Monne <roger....@citrix.com>; Suravee Suthikulpanit > <suravee.suthikulpa...@amd.com>; Brian Woods <brian.wo...@amd.com>; > Juergen Gross <jgr...@suse.com>; Paul Durrant <paul.durr...@citrix.com> > Subject: [PATCH for-4.12] amd/iommu: fix present bit checking when > clearing PTE > > The current check for the present bit is wrong, since the present bit > is located in the low part of the entry. > > Fixes: e8afe1124cc1 ("iommu: elide flushing for higher order map/unmap > operations") > Signed-off-by: Roger Pau Monné <roger....@citrix.com>
No idea how I managed to get that wrong. I had a bad feeling at the time about not accessing the pte as a uint32_t[2] array. Reviewed-by: Paul Durrant <paul.durr...@citrix.com> > --- > Cc: Suravee Suthikulpanit <suravee.suthikulpa...@amd.com> > Cc: Brian Woods <brian.wo...@amd.com> > Cc: Juergen Gross <jgr...@suse.com> > Cc: Paul Durrant <paul.durr...@citrix.com> > --- > xen/drivers/passthrough/amd/iommu_map.c | 4 +--- > 1 file changed, 1 insertion(+), 3 deletions(-) > > diff --git a/xen/drivers/passthrough/amd/iommu_map.c > b/xen/drivers/passthrough/amd/iommu_map.c > index 99ac0a6862..67329b0c95 100644 > --- a/xen/drivers/passthrough/amd/iommu_map.c > +++ b/xen/drivers/passthrough/amd/iommu_map.c > @@ -39,15 +39,13 @@ static unsigned int clear_iommu_pte_present(unsigned > long l1_mfn, > unsigned long dfn) > { > uint64_t *table, *pte; > - uint32_t entry; > unsigned int flush_flags; > > table = map_domain_page(_mfn(l1_mfn)); > > pte = (table + pfn_to_pde_idx(dfn, 1)); > - entry = *pte >> 32; > > - flush_flags = get_field_from_reg_u32(entry, IOMMU_PTE_PRESENT_MASK, > + flush_flags = get_field_from_reg_u32(*pte, IOMMU_PTE_PRESENT_MASK, > IOMMU_PTE_PRESENT_SHIFT) ? > IOMMU_FLUSHF_modified : 0; > > -- > 2.20.1 _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel