On Thu, Jan 13, 2022 at 02:16:35PM +0800, Jason Wang wrote: > On Thu, Jan 13, 2022 at 11:35 AM Peter Xu <pet...@redhat.com> wrote: > > > > On Wed, Jan 05, 2022 at 12:19:43PM +0800, Jason Wang wrote: > > > We use to warn on wrong rid2pasid entry. But this error could be > > > triggered by the guest and could happens during initialization. So > > > let's don't warn in this case. > > > > > > Signed-off-by: Jason Wang <jasow...@redhat.com> > > > --- > > > hw/i386/intel_iommu.c | 6 ++++-- > > > 1 file changed, 4 insertions(+), 2 deletions(-) > > > > > > diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c > > > index 4c6c016388..f2c7a23712 100644 > > > --- a/hw/i386/intel_iommu.c > > > +++ b/hw/i386/intel_iommu.c > > > @@ -1524,8 +1524,10 @@ static bool vtd_dev_pt_enabled(IntelIOMMUState *s, > > > VTDContextEntry *ce) > > > if (s->root_scalable) { > > > ret = vtd_ce_get_rid2pasid_entry(s, ce, &pe); > > > if (ret) { > > > - error_report_once("%s: vtd_ce_get_rid2pasid_entry error: > > > %"PRId32, > > > - __func__, ret); > > > + /* > > > + * This error is guest triggerable. We should assumt PT > > > + * not enabled for safety. > > > + */ > > > return false; > > > } > > > return (VTD_PE_GET_TYPE(&pe) == VTD_SM_PASID_ENTRY_PT); > > > -- > > > 2.25.1 > > > > > > > No strong opinion, but the thing is mostly all error_report_once() in this > > file > > is guest triggerable. If we remove this one then it's debatable on whether > > we > > want to remove all. > > > > IMHO we used the _once() variant just for this: it won't go into any form of > > DoS, meanwhile we'll still get some information (as hypervisor) that the > > guest > > OS may not be trustworthy. > > > > So from that pov it's still useful? Or is this error very special in some > > way? > > I want to be consistent with vtd_as_pt_enabled() where we don't even > have error_report_once().
According to the comments (which, I think, left over by myself..) in vtd_as_pt_enabled() - maybe indeed it could be triggered during guest boot. Then I assume this can indeed a special case. Acked-by: Peter Xu <pet...@redhat.com> Thanks. -- Peter Xu