[PATCH v11 10/10] genirq/msi: use the MSI doorbell's IOVA when requested
From: Thomas Gleixner <hidden>
Date: 2016-07-20 09:11:48
Also in:
kvm, kvmarm, linux-iommu, lkml
On Tue, 19 Jul 2016, Eric Auger wrote: First of all - valid for all patches: Subject: sys/subsys: Sentence starts with an uppercase letter Now for this particular one: genirq/msi: use the MSI doorbell's IOVA when requested
On MSI message composition we now use the MSI doorbell's IOVA in place of the doorbell's PA in case the device is upstream to an IOMMU that requires MSI addresses to be mapped. The doorbell's allocation and mapping happened on an early stage (pci_enable_msi).
This changelog is completely useless. At least I cannot figure out what that patch actually does. And the implementation is not self explaining either.
quoted hunk ↗ jump to hunk
@@ -63,10 +63,18 @@ static int msi_compose(struct irq_data *irq_data, { int ret = 0; - if (erase) + if (erase) { memset(msg, 0, sizeof(*msg)); - else + } else { + struct device *dev; + ret = irq_chip_compose_msi_msg(irq_data, msg); + if (ret) + return ret; + + dev = msi_desc_to_dev(irq_data_get_msi_desc(irq_data)); + WARN_ON(iommu_msi_msg_pa_to_va(dev, msg));
What the heck is this call doing? And why is there only a WARN_ON and not a proper error return code handling? Thanks, tglx