Re: [PATCH v18 00/23] KVM: arm64: CCA: Add basic plumbing for Realms

[Mathieu Poirier <mathieu.poirier@linaro.org>]

On Tue, Sep 22, 2026 at 02:52:56PM +0530, Aneesh Kumar K.V wrote:
> Mathieu Poirier <mathieu.poirier@linaro.org> writes:
> 
> > Hi Suzuki,
> >
> > On Tue, Sep 15, 2026 at 05:01:18PM +0100, Suzuki K Poulose wrote:
> 
>  [ ... 42 lines skipped ... ] 
> 
> >> 
> >> [0] Arm CCA KVM Support v16 : https://lore.kernel.org/all/20260803134403.80630-1-steven.price@arm.com
> >> [1] Linux firmware RMI https://lore.kernel.org/all/20260912083611.2513845-1-suzuki.poulose@arm.com
> >> [2] Linux GPF Host https://lore.kernel.org/all/20260913070459.2547407-1-suzuki.poulose@arm.com
> >> [3] https://git.gitlab.arm.com/linux-arm/linux-cca/ cca/cca-host/kvm-v18/integration
> >> [4] https://support.arm.com/documentation/den0137/2-0bet3/
> >
> > When testing on the FVP model with the above baselines, I get the following
> > error messagaes in a loop, preventing the system from reaching the command line:
> >
> > [    3.112577] Freeing unused kernel memory: 3520K
> > [    3.115398] Run /sbin/init as init process
> > [    3.142926] virtio-pci 0000:00:02.0: swiotlb buffer is full (sz: 4096 bytes),
> > total 512 (slots), used 511 (slots)
> > [    3.150111] virtio-pci 0000:00:02.0: swiotlb buffer is full (sz: 4096 bytes),
> > total 512 (slots), used 511 (slots)
> > [    3.177190] virtio-pci 0000:00:02.0: swiotlb buffer is full (sz: 4096 bytes),
> > total 512 (slots), used 511 (slots)
> > [    3.197194] virtio-pci 0000:00:02.0: swiotlb buffer is full (sz: 4096 bytes),
> > total 512 (slots), used 511 (slots)
> > [    3.217188] virtio-pci 0000:00:02.0: swiotlb buffer is full (sz: 4096 bytes),
> > total 512 (slots), used 511 (slots)
> > [    3.237194] virtio-pci 0000:00:02.0: swiotlb buffer is full (sz: 4096 bytes),
> > total 512 (slots), used 511 (slots)
> > [    3.257181] virtio-pci 0000:00:02.0: swiotlb buffer is full (sz: 4096 bytes),
> > total 512 (slots), used 511 (slots)
> > [    3.277189] virtio-pci 0000:00:02.0: swiotlb buffer is full (sz: 4096 bytes),
> > total 512 (slots), used 511 (slots)
> > [    3.297193] virtio-pci 0000:00:02.0: swiotlb buffer is full (sz: 4096 bytes),
> > total 512 (slots), used 511 (slots)
> > [    3.317188] virtio-pci 0000:00:02.0: swiotlb buffer is full (sz: 4096 bytes),
> > total 512 (slots), used 511 (slots)
> > [    8.157185] swiotlb_tbl_map_single: 241 callbacks suppressed
> >
> > I get the same result with v17.  Have you seen this before?  Perhaps a kernel
> > option that needs to be adjusted?
> >
> 
> This is due to a change in the swiotlb setup.
> 
> https://lore.kernel.org/all/yq5azeyxyfol.fsf@kernel.org
> 
> You can increase the swiotlb size using the swiotlb= kernel command-line

What size do you recommend setting it at?

> option. I also have a patch series in progress to address this issue:
> 
> https://lore.kernel.org/all/20260921063628.362078-1-aneesh.kumar@kernel.org
> 
> -aneesh
>