Messages in this thread | | | Date | Mon, 11 Jul 2016 20:59:43 +0200 | From | Radim Krčmář <> | Subject | Re: [PART2 PATCH v3 07/11] iommu/amd: Introduce amd_iommu_update_ga() |
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2016-07-11 05:11-0500, Suravee Suthikulpanit: > From: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com> > > Introduces a new IOMMU API, amd_iommu_update_ga(), which allows > KVM (SVM) to update existing posted interrupt IOMMU IRTE when > load/unload vcpu. > > Signed-off-by: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com> > --- > diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c > @@ -4481,4 +4481,67 @@ int amd_iommu_create_irq_domain(struct amd_iommu *iommu) > +int amd_iommu_update_ga(u32 vcpu_id, u32 cpu, u32 ga_tag, > + u64 base, bool is_run)
Not just in this function does the interface between svm and iommu split ga_tag into its two components (vcpu_id and ga_tag), but it seems that the combined value could always be used instead ... Is there an advantage to passing two values?
> +{ > + unsigned long flags; > + struct amd_iommu *iommu; > + > + if (!AMD_IOMMU_GUEST_IR_VAPIC(amd_iommu_guest_ir)) > + return 0; > + > + for_each_iommu(iommu) { > + struct amd_ir_data *ir_data; > + > + spin_lock_irqsave(&iommu->ga_hash_lock, flags); > + > + /* Note: Update all possible ir_data for a particular > + * vcpu in a particular vm. > + */ > + hash_for_each_possible(iommu->ga_hash, ir_data, hnode, > + AMD_IOMMU_GATAG(ga_tag, vcpu_id)) { > + struct irte_ga *irte = (struct irte_ga *) ir_data->entry;
(The ga_tag check is missing here too.)
> + if (!irte->lo.fields_vapic.guest_mode) > + continue; > + > + update_irte_ga((struct irte_ga *)ir_data->ref, > + ir_data->irq_2_irte.devid, > + base, cpu, is_run);
(The lookup leading up to here is avoidable -- svm, the caller, has the ability to map ga_tag into irte/ir_data directly with a pointer. I'm not sure if the lookup is slow enough to pardon optimization, but it might make the code simpler as well.)
> + iommu_flush_irt(iommu, ir_data->irq_2_irte.devid); > + iommu_completion_wait(iommu); > + } > + > + spin_unlock_irqrestore(&iommu->ga_hash_lock, flags);
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