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Encrypted RAM is offered by the newest Intel server-grade CPUs (SGX, Skylake) and the next AMD server-grade CPUs (SME, Zen). One of the main use-cases for thes

Encrypted RAM is offered by the newest Intel server-grade CPUs (SGX, Skylake) and the next AMD server-grade CPUs (SME, Zen). One of the main use-cases for these technologies is trusted computing in a cloud environment - the customer can assert that the hardware is securing the program state from the eyes of the computer owner!. However, the cloud is actually made from cheap commodity boxes without server-grade anything! ;) Encrypting RAM pages would prevent the hypervisor from deduping pages between virtual machines, and this would be very negative for cloud providers who want to up the occupancy on each box as much as possible... In a few years, or perhaps longer, perhaps proper DDR4 and other immune memory will be mainstream in clouds. But until then, it seems we'll have a cloud fitted out with increasingly aging cheap machines with no rowhammer immunity.

makomk 10y ago
Don't think I've seen any non-server-grade processors in even the cheapest bargain-basement VPS hosts. (Low-end dedicated is different.) Cramming as many VMs into a big server as possible seems to be too important to their cost structure for that.
- willvarfar 10y ago
  We perhaps only disagree on what is "server-grade" vs what is sold for servers. Google, for example, are famous for making big data centres out of cheap commodity boxes, and I double Amazon are any different. I certainly know the rackspace blades I've played with didn't make my grade of either! :)
  - tristor 10y ago
    I can't make any claims to contrary about other providers, but I know at the very least that at one point not in too distant past the primary systems used for Rackspace Cloud hypervisors were Dell R720 rackmount servers. Maybe not the most amazing hardware, but considering how common they are you can hardly refuse to say they're "server-grade". The newer OpenCompute stuff is also clearly well-made hardware.
  - wmf 10y ago
    Everything I've read implies that cheap commodity servers like Open Compute are just as reliable as name brand Intel servers (not surprising considering that they're made from the same parts), and ~95% of the market appears to be satisfied with that level of reliability.
nickpsecurity 10y ago
I figured it would end up in security-oriented, bare-metal hosting first. Or racks people rent out for their own boxes. Didn't know something like that was on new Inte/AMD CPU's. Thanks for tip.
marcosdumay 10y ago
> However, the cloud is actually made from cheap commodity boxes without server-grade anything! ;) You know, I refuse to buy anything that does not support ECC for my home desktops (and don't even pay much for it). Only my laptop got a pass from this because there was literally no option available with it. Good to know cloud providers are not as careful... But honestly, shouldn't be a surprise.
- nickpsecurity 10y ago
  Same here. It helps to sell it if you don't say ECC = RAM + extra cash. That's the normal method. I instead say you have two options: 1. RAM that works at this price. 2. RAM that allows more crashes or corruption of your files for slightly-lower price. The Right Thing suddenly looks more obvious except to cheap skates. Now I just need one with ChipKill built-in. That's the next level of ECC. I haven't heard whether Intel or AMD got something similar.
amluto 10y ago
Encrypted RAM as AMD is implementing it (SME) protects nicely from "cold-boot attacks" but is otherwise largely a feel-good feature. It also probably doesn't help a whole lot against rowhammer-style attacks because it's merely encrypted, not authenticated. The result is that a bit flip will effectively randomize 64 bytes or whatever the block size is but will not be otherwise detected by the hardware. I bet that clever attackers will find a nice way to take over by randomizing 64 bytes. Intel's encrypted RAM is authenticated quite nicely, but it's not (yet?) designed for general purpose use -- it's for SGX only right now. Using it for everything would (if I understand correctly) add considerable space overhead and possibly considerable latency.
- willvarfar 10y ago
  But encryption will prevent dedupe meaning a vm cannot attack other occupants as described in the article.

makomk 10y ago

Don't think I've seen any non-server-grade processors in even the cheapest bargain-basement VPS hosts. (Low-end dedicated is different.) Cramming as many VMs into a big server as possible seems to be too important to their cost structure for that.

willvarfar 10y ago
We perhaps only disagree on what is "server-grade" vs what is sold for servers. Google, for example, are famous for making big data centres out of cheap commodity boxes, and I double Amazon are any different. I certainly know the rackspace blades I've played with didn't make my grade of either! :)
- tristor 10y ago
  I can't make any claims to contrary about other providers, but I know at the very least that at one point not in too distant past the primary systems used for Rackspace Cloud hypervisors were Dell R720 rackmount servers. Maybe not the most amazing hardware, but considering how common they are you can hardly refuse to say they're "server-grade". The newer OpenCompute stuff is also clearly well-made hardware.
- wmf 10y ago
  Everything I've read implies that cheap commodity servers like Open Compute are just as reliable as name brand Intel servers (not surprising considering that they're made from the same parts), and ~95% of the market appears to be satisfied with that level of reliability.

nickpsecurity 10y ago

I figured it would end up in security-oriented, bare-metal hosting first. Or racks people rent out for their own boxes. Didn't know something like that was on new Inte/AMD CPU's. Thanks for tip.

marcosdumay 10y ago

> However, the cloud is actually made from cheap commodity boxes without server-grade anything! ;) You know, I refuse to buy anything that does not support ECC for my home desktops (and don't even pay much for it). Only my laptop got a pass from this because there was literally no option available with it. Good to know cloud providers are not as careful... But honestly, shouldn't be a surprise.

nickpsecurity 10y ago
Same here. It helps to sell it if you don't say ECC = RAM + extra cash. That's the normal method. I instead say you have two options: 1. RAM that works at this price. 2. RAM that allows more crashes or corruption of your files for slightly-lower price. The Right Thing suddenly looks more obvious except to cheap skates. Now I just need one with ChipKill built-in. That's the next level of ECC. I haven't heard whether Intel or AMD got something similar.

amluto 10y ago

Encrypted RAM as AMD is implementing it (SME) protects nicely from "cold-boot attacks" but is otherwise largely a feel-good feature. It also probably doesn't help a whole lot against rowhammer-style attacks because it's merely encrypted, not authenticated. The result is that a bit flip will effectively randomize 64 bytes or whatever the block size is but will not be otherwise detected by the hardware. I bet that clever attackers will find a nice way to take over by randomizing 64 bytes. Intel's encrypted RAM is authenticated quite nicely, but it's not (yet?) designed for general purpose use -- it's for SGX only right now. Using it for everything would (if I understand correctly) add considerable space overhead and possibly considerable latency.

willvarfar 10y ago
But encryption will prevent dedupe meaning a vm cannot attack other occupants as described in the article.