Quoting from the comment describing the WARN functions in include/asm-generic/bug.h: * WARN(), WARN_ON(), WARN_ON_ONCE, and so on can be used to report * significant kernel issues that need prompt attention if they should ever * appear at runtime. * * Do not use these macros when checking for invalid external inputs The (buggy) firmware tables which the dmar code was calling WARN_TAINT for really are invalid external inputs. They are not under the kernel's control and the issues in them cannot be fixed by a kernel update. So logging a backtrace, which invites bug reports to be filed about this, is not helpful. BugLink: https://bugzilla.redhat.com/show_bug.cgi?id=701847 Fixes: 556ab45f9a77 ("ioat2: catch and recover from broken vtd configurations v6") Signed-off-by: Hans de Goede <hdegoede@redhat.com> --- drivers/iommu/intel-iommu.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c index 3857a5cd1a75..8fd132f8e885 100644 --- a/drivers/iommu/intel-iommu.c +++ b/drivers/iommu/intel-iommu.c @@ -4261,10 +4261,11 @@ static void quirk_ioat_snb_local_iommu(struct pci_dev *pdev) /* we know that the this iommu should be at offset 0xa000 from vtbar */ drhd = dmar_find_matched_drhd_unit(pdev); - if (WARN_TAINT_ONCE(!drhd || drhd->reg_base_addr - vtbar != 0xa000, - TAINT_FIRMWARE_WORKAROUND, - "BIOS assigned incorrect VT-d unit for Intel(R) QuickData Technology device\n")) + if (!drhd || drhd->reg_base_addr - vtbar != 0xa000) { + pr_warn_once(FW_BUG "BIOS assigned incorrect VT-d unit for Intel(R) QuickData Technology device\n"); + add_taint(TAINT_FIRMWARE_WORKAROUND, LOCKDEP_STILL_OK); pdev->dev.archdata.iommu = DUMMY_DEVICE_DOMAIN_INFO; + } } DECLARE_PCI_FIXUP_ENABLE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_IOAT_SNB, quirk_ioat_snb_local_iommu); -- 2.25.1 _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
On 2020/3/10 2:25, Hans de Goede wrote: > Quoting from the comment describing the WARN functions in > include/asm-generic/bug.h: > > * WARN(), WARN_ON(), WARN_ON_ONCE, and so on can be used to report > * significant kernel issues that need prompt attention if they should ever > * appear at runtime. > * > * Do not use these macros when checking for invalid external inputs > > The (buggy) firmware tables which the dmar code was calling WARN_TAINT > for really are invalid external inputs. They are not under the kernel's > control and the issues in them cannot be fixed by a kernel update. > So logging a backtrace, which invites bug reports to be filed about this, > is not helpful. > > BugLink: https://bugzilla.redhat.com/show_bug.cgi?id=701847 > Fixes: 556ab45f9a77 ("ioat2: catch and recover from broken vtd configurations v6") > Signed-off-by: Hans de Goede <hdegoede@redhat.com> Acked-by: Lu Baolu <baolu.lu@linux.intel.com> Best regards, baolu > --- > drivers/iommu/intel-iommu.c | 7 ++++--- > 1 file changed, 4 insertions(+), 3 deletions(-) > > diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c > index 3857a5cd1a75..8fd132f8e885 100644 > --- a/drivers/iommu/intel-iommu.c > +++ b/drivers/iommu/intel-iommu.c > @@ -4261,10 +4261,11 @@ static void quirk_ioat_snb_local_iommu(struct pci_dev *pdev) > > /* we know that the this iommu should be at offset 0xa000 from vtbar */ > drhd = dmar_find_matched_drhd_unit(pdev); > - if (WARN_TAINT_ONCE(!drhd || drhd->reg_base_addr - vtbar != 0xa000, > - TAINT_FIRMWARE_WORKAROUND, > - "BIOS assigned incorrect VT-d unit for Intel(R) QuickData Technology device\n")) > + if (!drhd || drhd->reg_base_addr - vtbar != 0xa000) { > + pr_warn_once(FW_BUG "BIOS assigned incorrect VT-d unit for Intel(R) QuickData Technology device\n"); > + add_taint(TAINT_FIRMWARE_WORKAROUND, LOCKDEP_STILL_OK); > pdev->dev.archdata.iommu = DUMMY_DEVICE_DOMAIN_INFO; > + } > } > DECLARE_PCI_FIXUP_ENABLE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_IOAT_SNB, quirk_ioat_snb_local_iommu); > > _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
On Mon, Mar 09, 2020 at 07:25:10PM +0100, Hans de Goede wrote: > Quoting from the comment describing the WARN functions in > include/asm-generic/bug.h: > > * WARN(), WARN_ON(), WARN_ON_ONCE, and so on can be used to report > * significant kernel issues that need prompt attention if they should ever > * appear at runtime. > * > * Do not use these macros when checking for invalid external inputs > > The (buggy) firmware tables which the dmar code was calling WARN_TAINT > for really are invalid external inputs. They are not under the kernel's > control and the issues in them cannot be fixed by a kernel update. > So logging a backtrace, which invites bug reports to be filed about this, > is not helpful. > > BugLink: https://bugzilla.redhat.com/show_bug.cgi?id=701847 > Fixes: 556ab45f9a77 ("ioat2: catch and recover from broken vtd configurations v6") > Signed-off-by: Hans de Goede <hdegoede@redhat.com> > --- > drivers/iommu/intel-iommu.c | 7 ++++--- > 1 file changed, 4 insertions(+), 3 deletions(-) Applied, thanks. _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu