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Comment by josephcsible | Hacker News Reader

Isn't it reasonable for applications to assume that, now that virtually all hardware has it, even super-cheap computers like the Raspberry Pi?

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The issue for Qubes is security. GPUs can be used to subvert basically all the otherwise hardware-enforced security protections.

In a desktop, couldn't you assign a GPU to one video machine and in that scenario would there still be a security problem when there is only one VM using it?

It’s not about virtual machines. GPUs typically have direct memory access to pretty much all system RAM. There exist PCIe mitigations, but the review does not meet up to Qubes security standards.

Yes, this is what qubes would probably suggest as the solution.

The hardware may be there, but not necessarily the drivers.

The drivers are fine for GPU accelerated rendering of the app surfaces, even on the Pi. Hell, the drivers are even there >98% of the time for accelerated decode of the video format itself to boot.

Qube's unique choice in software only rendering for user applications is one born out of the isolation goals for security, not what the software/drivers/hardware could do.

> even on the Pi

Only proprietary ones, so not for everyone...

Pi 1-3 https://docs.mesa3d.org/drivers/vc4.html

Pi 4-5 https://docs.mesa3d.org/drivers/v3d.html

> Broadcom never released a public specification for the V3D 3.x or 4.x series.

So the support must be worse if you prefer free drivers?

No, as there isn't a non-free driver alternative to compare V3D to. For VC4 (Pi 1-3) there was a proprietary alternative driver... but it was a bit garbage.

It feels you may be conflating the "proprietary firmware blob on the GPU which is used to boot the Pi" story with the GPU driver itself.

Yes, you are right, "proprietary firmware blob on the GPU which is used to boot the Pi" is what I recall as a big Pi problem. So my original wording is correct that you need proprietary blobs to run Raspberry Pi, isn't it?

"Yes" in that the above statement about needing proprietary blobs to boot the Pis is certainly accurate & true (ongoing science experiments notwithstanding). "No" in that we somehow went from talking about "how apps can safely assume to rely on accelerated rasterization instead of software rasterization" to "how the Raspberry Pi family needs proprietary boot firmware to do anything with app output at all" and I've missed the connection between the two points.

> support must be worse if you prefer free drivers

Yes. Besides Qubes users, a big population of software rendering users is people who have old and/or buggy drivers that are blacklisted by Firefox.

I understand GPUs are a security nightmare. If you want to have some understanding of your security, don't use a GPU.

Yeah, if you really care about security, only use computer which use line printers as output mechanisms.

It's totally reasonable, just unfortunate for this use-case.

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