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From: Oliver Upton <oliver.upton@linux.dev>
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Subject: Re: [PATCH v9 0/4] KVM: arm64: Allow the VM to select DEVICE_* and NORMAL_NC for IO memory
Date: Mon, 26 Feb 2024 23:45:30 +0000
Message-ID: <170899100569.1405597.5047894183843333522.b4-ty@linux.dev>
In-Reply-To: <20240224150546.368-1-ankita@nvidia.com>
References: <20240224150546.368-1-ankita@nvidia.com>
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On Sat, 24 Feb 2024 20:35:42 +0530, ankita@nvidia.com wrote:
> From: Ankit Agrawal <ankita@nvidia.com>
> 
> 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!

[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

--
Best,
Oliver