| Message ID | 491c885f61c509d959b04cfb63676bd07e481dea.1460558667.git.robin.murphy@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wed, Apr 13, 2016 at 03:46:57PM +0100, Robin Murphy wrote: > Until we get fully plumbed into of_iommu_configure, our default > IOMMU_DOMAIN_DMA domains just bypass translation. Since we achieve that > by leaving the stream table entries set to bypass instead of pointing at > a translation context, the context bank we allocate for the domain is > completely wasted. Context banks are typically a rather limited > resource, so don't hog ones we don't need. Eric, does this resolve your remaining passthrough regressions when applied on top of my patch? Will > Reported-by: Eric Auger <eric.auger@linaro.org> > Signed-off-by: Robin Murphy <robin.murphy@arm.com> > --- > drivers/iommu/arm-smmu.c | 8 +++++++- > 1 file changed, 7 insertions(+), 1 deletion(-) > > diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c > index 5158feb..7c39ac4 100644 > --- a/drivers/iommu/arm-smmu.c > +++ b/drivers/iommu/arm-smmu.c > @@ -826,6 +826,12 @@ static int arm_smmu_init_domain_context(struct iommu_domain *domain, > if (smmu_domain->smmu) > goto out_unlock; > > + /* We're bypassing these SIDs, so don't allocate an actual context */ > + if (domain->type == IOMMU_DOMAIN_DMA) { > + smmu_domain->smmu = smmu; > + goto out_unlock; > + } > + > /* > * Mapping the requested stage onto what we support is surprisingly > * complicated, mainly because the spec allows S1+S2 SMMUs without > @@ -948,7 +954,7 @@ static void arm_smmu_destroy_domain_context(struct iommu_domain *domain) > void __iomem *cb_base; > int irq; > > - if (!smmu) > + if (!smmu || domain->type == IOMMU_DOMAIN_DMA) > return; > > /* > -- > 2.7.3.dirty >
Hi Robin, On 04/13/2016 04:46 PM, Robin Murphy wrote: > Until we get fully plumbed into of_iommu_configure, our default > IOMMU_DOMAIN_DMA domains just bypass translation. Since we achieve that > by leaving the stream table entries set to bypass instead of pointing at > a translation context, the context bank we allocate for the domain is > completely wasted. Context banks are typically a rather limited > resource, so don't hog ones we don't need. > Thanks for this fix. I recovered the ability to assign more than VFs on Overdrive HW. Tested-by: Eric Auger <eric.auger@linaro.org> Best Regards Eric > Reported-by: Eric Auger <eric.auger@linaro.org> > Signed-off-by: Robin Murphy <robin.murphy@arm.com> > --- > drivers/iommu/arm-smmu.c | 8 +++++++- > 1 file changed, 7 insertions(+), 1 deletion(-) > > diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c > index 5158feb..7c39ac4 100644 > --- a/drivers/iommu/arm-smmu.c > +++ b/drivers/iommu/arm-smmu.c > @@ -826,6 +826,12 @@ static int arm_smmu_init_domain_context(struct iommu_domain *domain, > if (smmu_domain->smmu) > goto out_unlock; > > + /* We're bypassing these SIDs, so don't allocate an actual context */ > + if (domain->type == IOMMU_DOMAIN_DMA) { > + smmu_domain->smmu = smmu; > + goto out_unlock; > + } > + > /* > * Mapping the requested stage onto what we support is surprisingly > * complicated, mainly because the spec allows S1+S2 SMMUs without > @@ -948,7 +954,7 @@ static void arm_smmu_destroy_domain_context(struct iommu_domain *domain) > void __iomem *cb_base; > int irq; > > - if (!smmu) > + if (!smmu || domain->type == IOMMU_DOMAIN_DMA) > return; > > /* >
Hi Will, On 04/15/2016 03:05 PM, Will Deacon wrote: > On Wed, Apr 13, 2016 at 03:46:57PM +0100, Robin Murphy wrote: >> Until we get fully plumbed into of_iommu_configure, our default >> IOMMU_DOMAIN_DMA domains just bypass translation. Since we achieve that >> by leaving the stream table entries set to bypass instead of pointing at >> a translation context, the context bank we allocate for the domain is >> completely wasted. Context banks are typically a rather limited >> resource, so don't hog ones we don't need. > > Eric, does this resolve your remaining passthrough regressions when applied > on top of my patch? Yes it does. Thank you for the fixes. Best Regards Eric > > Will > >> Reported-by: Eric Auger <eric.auger@linaro.org> >> Signed-off-by: Robin Murphy <robin.murphy@arm.com> >> --- >> drivers/iommu/arm-smmu.c | 8 +++++++- >> 1 file changed, 7 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c >> index 5158feb..7c39ac4 100644 >> --- a/drivers/iommu/arm-smmu.c >> +++ b/drivers/iommu/arm-smmu.c >> @@ -826,6 +826,12 @@ static int arm_smmu_init_domain_context(struct iommu_domain *domain, >> if (smmu_domain->smmu) >> goto out_unlock; >> >> + /* We're bypassing these SIDs, so don't allocate an actual context */ >> + if (domain->type == IOMMU_DOMAIN_DMA) { >> + smmu_domain->smmu = smmu; >> + goto out_unlock; >> + } >> + >> /* >> * Mapping the requested stage onto what we support is surprisingly >> * complicated, mainly because the spec allows S1+S2 SMMUs without >> @@ -948,7 +954,7 @@ static void arm_smmu_destroy_domain_context(struct iommu_domain *domain) >> void __iomem *cb_base; >> int irq; >> >> - if (!smmu) >> + if (!smmu || domain->type == IOMMU_DOMAIN_DMA) >> return; >> >> /* >> -- >> 2.7.3.dirty >>
diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c index 5158feb..7c39ac4 100644 --- a/drivers/iommu/arm-smmu.c +++ b/drivers/iommu/arm-smmu.c @@ -826,6 +826,12 @@ static int arm_smmu_init_domain_context(struct iommu_domain *domain, if (smmu_domain->smmu) goto out_unlock; + /* We're bypassing these SIDs, so don't allocate an actual context */ + if (domain->type == IOMMU_DOMAIN_DMA) { + smmu_domain->smmu = smmu; + goto out_unlock; + } + /* * Mapping the requested stage onto what we support is surprisingly * complicated, mainly because the spec allows S1+S2 SMMUs without @@ -948,7 +954,7 @@ static void arm_smmu_destroy_domain_context(struct iommu_domain *domain) void __iomem *cb_base; int irq; - if (!smmu) + if (!smmu || domain->type == IOMMU_DOMAIN_DMA) return; /*
Until we get fully plumbed into of_iommu_configure, our default IOMMU_DOMAIN_DMA domains just bypass translation. Since we achieve that by leaving the stream table entries set to bypass instead of pointing at a translation context, the context bank we allocate for the domain is completely wasted. Context banks are typically a rather limited resource, so don't hog ones we don't need. Reported-by: Eric Auger <eric.auger@linaro.org> Signed-off-by: Robin Murphy <robin.murphy@arm.com> --- drivers/iommu/arm-smmu.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)