On 5/22/19 9:44 AM, Claudia wrote:
Hello,
I've read the system requirements page, the HCL, and the "advice on
finding a Qubes compatible notebook" thread, all of which seem to refer
to Intel almost exclusively. I've also done some searching around, but
there seems to be very little information about Qubes' compatibility on
AMD machines.
I already know the conventional wisdom is "buy it, try it, and return it
if it doesn't work," and that's basically what I intend to do. But
before I do, I'm hoping for some reassurance, or advice on whether I
should just skip over AMD altogether.
Is Qubes support for AMD about as good as it is for Intel? Or, is there
a reason to pay the extra money for an Intel machine? Why is there so
little information about Qubes on AMD, and so few AMD machines on the
HCL? Surely I can't be the only person wondering about this.
A few things, more specifically:
1) The system requirements page says that Intel integrated graphics are
strongly recommended over Nvidia or Radeon, for compatibility reasons.
What about AMD's integrated "Vega" graphics?
That recommendation is overly conservative because early in Qubes'
history only Intel processors had been explored and integrated graphics
was the safe bet. If I were to re-word that phrase, I'd make it sound
more like "avoid Nvidia unless you know exactly what you're doing". IOW,
AMD is not a big worry when it comes to Linux graphics.
2) It's harder to find compatibility-related information for AMD
processors. In particular, information about whether RVI ( = Intel EPT,
= SLAT) is supported by a given processor. Official specs, and even
sites like wikichip.org and cpu-monkey.com, often mention Intel EPT but
not AMD RVI. (AMD-V and IOMMU are usually mentioned, though). Is there a
specific cpu flag or something that I should be looking for in order to
know if RVI is supported? Or is it pretty much safe to assume that any
recent AMD processor with AMD-V and IOMMU will also support RVI?
I myself am just getting started with AMD on a circa 2013 laptop. Even
on this 6yr old A10 laptop, all of the virtualization features are there
– although coreboot is required for proper initialization (no surprise:
the laptop is a Lenovo Ideapad, not a Thinkpad).
FWIW, I do think you're right that any x86 processor that supports both
HVM (AMD-V) and IOMMU would also have RVI support. In the Qubes HCL, all
of the Ryzen systems were reported to have RVI(SLAT) working. One entry
also reports that IOMMU was present but not working on a "gaming"
motherboard.
These days, the main issue with these virtualization features is not
with the CPUs/chipsets themselves, but whether the BIOS/UEFI for a
specific computer model enables these features and initializes them
correctly. This is rarely an issue with business class computers from
reputable vendors.
3) Do AMD processors have integrated chipsets like Intel (4th gen and
up) processors? Or does the chipset remain on the motherboard in AMD
machines. Not a dealbreaker, but integrated chipsets definitely make
searching much easier.
Someone else with direct Ryzen experience could better answer this
question. I know that in the 15h (2013) era the chipsets were separate
(but this was also true for Intel at least up to 2012).
For what it's worth, in particular I'm looking at a few laptops with
processors such as Ryzen 5 2500U, Ryzen 7 2700U, and Ryzen 5 3500U. They
seem like great deal for the money. For example the 2500U has about the
same specs/performance as an i5-8250U, but laptops with the 2500U tend
to be around $200 cheaper than the Intel version. But, if Qubes
compatibility is most likely going to be an issue, then I'm willing to
pay the extra money for an Intel machine and avoid the hassle.
So, can I expect to have about the same luck with AMD as Intel? Or
should I just pay the extra money and play it safe with Intel? Any
advice on these particular processors, or recent AMD processors in
general, it would make me feel a lot better before I go buying and
trying at random.
You can make the process less random by focusing on sources that have a
history of delivering better quality BIOS/firmware. Systems with the
best chance of compatibility will be business-class and indicate
compatibility with Linux (or Ubuntu/Redhat) in addition to Windows,
typically from vendors Lenovo, Dell, and HP. I would have included
Purism and System76 except they don't offer AMD laptops. In general,
avoid consumer and gaming models (e.g. choose Thinkpad over Ideapad).
Do I think its worth it to try? Definitely, as long as your choice isn't
random consumer gear. AMD processors tend to be more secure in the face
of sidechannel attacks and suffer less performance degradation[1] from
resulting security patches; that's certainly a reason to go in AMD's
direction.
1.
https://www.tomshardware.com/news/intel-amd-mitigations-performance-impact,39381.html
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