[PATCH v9 0/4] KVM: arm64: Allow the VM to select DEVICE_* and NORMAL_NC for IO memory

Ankit Agrawal ankita at nvidia.com
Tue Feb 27 00:45:38 PST 2024


>>
>> Currently, KVM for ARM64 maps at stage 2 memory that is considered device
>> with DEVICE_nGnRE memory attributes; this setting overrides (per
>> ARM architecture [1]) any device MMIO mapping present at stage 1,
>> resulting in a set-up whereby a guest operating system cannot
>> determine device MMIO mapping memory attributes on its own but
>> it is always overridden by the KVM stage 2 default.
>>
>> [...]
>
> High time to get this cooking in -next. Looks like there aren't any
> conflicts w/ VFIO, but if that changes I've pushed a topic branch to:
>
>  https://git.kernel.org/pub/scm/linux/kernel/git/oupton/linux.git/log/?h=kvm-arm64/vfio-normal-nc
>
> Applied to kvmarm/next, thanks!

Thanks Oliver for your efforts. Pardon my naivety, but what would the
sequence of steps that this series go through next before landing in an
rc branch? Also, what is the earliest branch this is supposed to land
assuming all goes well?

>
> [1/4] KVM: arm64: Introduce new flag for non-cacheable IO memory
>      https://git.kernel.org/kvmarm/kvmarm/c/c034ec84e879
> [2/4] mm: Introduce new flag to indicate wc safe
>      https://git.kernel.org/kvmarm/kvmarm/c/5c656fcdd6c6
> [3/4] KVM: arm64: Set io memory s2 pte as normalnc for vfio pci device
>      https://git.kernel.org/kvmarm/kvmarm/c/8c47ce3e1d2c
> [4/4] vfio: Convey kvm that the vfio-pci device is wc safe
>      https://git.kernel.org/kvmarm/kvmarm/c/a39d3a966a09



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