Messages in this thread | | | Subject | Re: [PATCH v2 18/24] iommu: Express DMA strictness via the domain type | From | Lu Baolu <> | Date | Thu, 29 Jul 2021 20:42:01 +0800 |
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On 2021/7/29 17:36, Robin Murphy wrote: > On 2021-07-29 08:13, Lu Baolu wrote: >> Hi Robin, >> >> On 7/28/21 11:58 PM, Robin Murphy wrote: >>> diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c >>> index 982545234cf3..eecb5657de69 100644 >>> --- a/drivers/iommu/iommu.c >>> +++ b/drivers/iommu/iommu.c >>> @@ -136,6 +136,9 @@ static int __init iommu_subsys_init(void) >>> } >>> } >>> + if (!iommu_default_passthrough() && !iommu_dma_strict) >>> + iommu_def_domain_type = IOMMU_DOMAIN_DMA_FQ; >> >> iommu_dma_strict could be changed later by the vendor iommu driver via >> iommu_set_dma_strict(). This seems not to be the right place to set >> iommu_def_domain_type. > > Ah yes, good catch once again, thanks! > > I think this *is* the right place to initially set it to honour the > command-line option, since that matches what we do for passthrough. > However also like passthrough we'll need to keep things in sync if it's > updated later, like this: > > > diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c > index 87d7b299436e..593d4555bc57 100644 > --- a/drivers/iommu/iommu.c > +++ b/drivers/iommu/iommu.c > @@ -359,6 +359,8 @@ early_param("iommu.strict", iommu_dma_setup); > void iommu_set_dma_strict(void) > { > iommu_dma_strict = true; > + if (iommu_def_domain_type == IOMMU_DOMAIN_DMA_FQ) > + iommu_def_domain_type = IOMMU_DOMAIN_DMA; > } > > static ssize_t iommu_group_attr_show(struct kobject *kobj, > > > Does that seem reasonable? I'm not sure there's any cleaner way to do it > since we don't want to inadvertently clobber the default type if the > user has given us something funky like "intel_iommu=strict > iommu.passthrough=1".
Yeah! It's reasonable as far as I can see.
Best regards, baolu
> > Cheers, > Robin. > >> >>> + >>> pr_info("Default domain type: %s %s\n", >>> iommu_domain_type_str(iommu_def_domain_type), >>> (iommu_cmd_line & IOMMU_CMD_LINE_DMA_API) ? >> >> Best regards, >> baolu
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