Messages in this thread | | | Subject | Re: [PATCH] intel-iommu: Turn off translations at shutdown | From | Lu Baolu <> | Date | Fri, 8 Nov 2019 11:06:08 +0800 |
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Hi,
On 11/8/19 4:59 AM, Deepa Dinamani wrote: > The intel-iommu driver assumes that the iommu state is > cleaned up at the start of the new kernel. > But, when we try to kexec boot something other than the > Linux kernel, the cleanup cannot be relied upon. > Hence, cleanup before we go down for reboot. > > Keeping the cleanup at initialization also, in case BIOS > leaves the IOMMU enabled. > > I considered turning off iommu only during kexec reboot, > but a clean shutdown seems always a good idea. But if > someone wants to make it conditional, we can do that. > > Tested that before, the info message > 'DMAR: Translation was enabled for <iommu> but we are not in kdump mode' > would be reported for each iommu. The message will not appear when the > DMA-remapping is not enabled on entry to the kernel. > > Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com> > --- > drivers/iommu/intel-iommu.c | 22 ++++++++++++++++++++++ > 1 file changed, 22 insertions(+) > > diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c > index fe8097078669..f0636b263722 100644 > --- a/drivers/iommu/intel-iommu.c > +++ b/drivers/iommu/intel-iommu.c > @@ -4764,6 +4764,26 @@ static void intel_disable_iommus(void) > iommu_disable_translation(iommu); > } > > +static void intel_iommu_shutdown(void) > +{ > + struct dmar_drhd_unit *drhd; > + struct intel_iommu *iommu = NULL; > + > + if (no_iommu || dmar_disabled) > + return; > + > + down_write(&dmar_global_lock); > + > + /* Disable PMRs explicitly here. */ > + for_each_iommu(iommu, drhd) > + iommu_disable_protect_mem_regions(iommu); > + > + /* Make sure the IOMMUs are switched off */ > + intel_disable_iommus(); > + > + up_write(&dmar_global_lock); > +} > + > static inline struct intel_iommu *dev_to_intel_iommu(struct device *dev) > { > struct iommu_device *iommu_dev = dev_to_iommu_device(dev); > @@ -5013,6 +5033,8 @@ int __init intel_iommu_init(void) > } > up_write(&dmar_global_lock); > > + x86_platform.iommu_shutdown = intel_iommu_shutdown;
How about moving it to detect_intel_iommu() in drivers/iommu/dmar.c? And make sure that it's included with CONFIG_X86_64.
Best regards, baolu
> + > #if defined(CONFIG_X86) && defined(CONFIG_SWIOTLB) > /* > * If the system has no untrusted device or the user has decided >
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