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17cde5e601
This will replace irq_domain_check_msi_remap() in following patches. The new API makes it more clear what "msi_remap" actually means from a functional perspective instead of identifying an implementation specific HW feature. Isolated MSI means that HW modeled by an irq_domain on the path from the initiating device to the CPU will validate that the MSI message specifies an interrupt number that the device is authorized to trigger. This must block devices from triggering interrupts they are not authorized to trigger. Currently authorization means the MSI vector is one assigned to the device. This is interesting for securing VFIO use cases where a rouge MSI (eg created by abusing a normal PCI MemWr DMA) must not allow the VFIO userspace to impact outside its security domain, eg userspace triggering interrupts on kernel drivers, a VM triggering interrupts on the hypervisor, or a VM triggering interrupts on another VM. As this is actually modeled as a per-irq_domain property, not a global platform property, correct the interface to accept the device parameter and scan through only the part of the irq_domains hierarchy originating from the source device. Locate the new code in msi.c as it naturally only works with CONFIG_GENERIC_MSI_IRQ, which also requires CONFIG_IRQ_DOMAIN and IRQ_DOMAIN_HIERARCHY. Link: https://lore.kernel.org/r/1-v3-3313bb5dd3a3+10f11-secure_msi_jgg@nvidia.com Tested-by: Matthew Rosato <mjrosato@linux.ibm.com> Reviewed-by: Kevin Tian <kevin.tian@intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.