mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
synced 2026-01-19 10:03:49 -05:00
9bd8d7df19
* kvm-arm64/vfio-normal-nc: : Normal-NC support for vfio-pci @ stage-2, courtesy of Ankit Agrawal : : KVM's policy to date has been that any and all MMIO mapping at stage-2 : is treated as Device-nGnRE. This is primarily done due to concerns of : the guest triggering uncontainable failures in the system if they manage : to tickle the device / memory system the wrong way, though this is : unnecessarily restrictive for devices that can be reasoned as 'safe'. : : Unsurprisingly, the Device-* mapping can really hurt the performance of : assigned devices that can handle Gathering, and can be an outright : correctness issue if the guest driver does unaligned accesses. : : Rather than opening the floodgates to the full ecosystem of devices that : can be exposed to VMs, take the conservative approach and allow PCI : devices to be mapped as Normal-NC since it has been determined to be : 'safe'. vfio: Convey kvm that the vfio-pci device is wc safe KVM: arm64: Set io memory s2 pte as normalnc for vfio pci device mm: Introduce new flag to indicate wc safe KVM: arm64: Introduce new flag for non-cacheable IO memory Signed-off-by: Oliver Upton <oliver.upton@linux.dev>