------- Comment From <email address hidden> 2020-05-18 07:18 EDT-------
I agree, it's pretty big but this was the least impact approach we could think
of and it fixes a kernel crash that can be triggered from user space simply by invoking the s390_pci_read/write_mmio syscalls when running with MIO.
The code mostly mirrors existing PCI code with the addition of the secondary address space access and is otherwise self contained so it should be extremely unlikely to impact anything apart from these two syscalls.
With the new PCI instructions that can be used in userspace, these syscalls will not be needed in the future but we of course still need them for applications that have not been updated to use the new instructions.
------- Comment From <email address hidden> 2020-05-18 07:18 EDT------- read/write_ mmio syscalls when running with MIO.
I agree, it's pretty big but this was the least impact approach we could think
of and it fixes a kernel crash that can be triggered from user space simply by invoking the s390_pci_
The code mostly mirrors existing PCI code with the addition of the secondary address space access and is otherwise self contained so it should be extremely unlikely to impact anything apart from these two syscalls.
With the new PCI instructions that can be used in userspace, these syscalls will not be needed in the future but we of course still need them for applications that have not been updated to use the new instructions.