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Subject: Re: [edk2-devel] Cannot build due to recent change
To: devel@edk2.groups.io, leif@nuviainc.com, andrew.goodbody@linaro.org
Cc: Ard Biesheuvel <ard.biesheuvel@arm.com>,
 Thomas Abraham <thomas.abraham@arm.com>,
 Liming Gao <gaoliming@byosoft.com.cn>
References: <9ed015a5-f111-d661-acad-4f97dc5f5eb1@linaro.org>
 <20201001104332.GG5623@vanye>
From: "Laszlo Ersek" <lersek@redhat.com>
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on a tangent:

On 10/01/20 12:43, Leif Lindholm wrote:

> if the platform port produces EFI_RNG_PROTOCOL
> from some onboard hw, you can use the approach from edk2-platforms
> commit 1e09147a01ae ("Platforms/RaspberryPi: Fix RPi4 RngLib build error").

Emphasis on "onboard hw".

I find it incredibly attractive and good system design that

  Silicon/Broadcom/Bcm283x/Drivers/Bcm2838RngDxe

can *exist*, because the underlying *platform hardware* also exists. I
wish we had something similar for virt, i.e. randomness available from
just a handful of fixed location MMIO registers. Randomness is needed
way earlier than when various bus enumerations occur, such as PCI, or
even virtio-mmio.

See also: why virtio-serial is unusable as a real debug output device.

Yes, I know, on Intel there's RDRAND and friends; they didn't have good
press, and it's still unclear to me how much one can count on RDRAND's
presence on the various QEMU/KVM CPU models.

/end tangent

Laszlo