Proposed fix to protect the kernel from Spectre (& Meltdown).pic.twitter.com/qQZr4Iw2yw
Yeah, I do @musllibc, FOSS & infosec stuff. But now is not the time for a mostly-/only-tech Twitter feed.
You can add location information to your Tweets, such as your city or precise location, from the web and via third-party applications. You always have the option to delete your Tweet location history. Learn more
Add this Tweet to your website by copying the code below. Learn more
Add this video to your website by copying the code below. Learn more
By embedding Twitter content in your website or app, you are agreeing to the Twitter Developer Agreement and Developer Policy.
| Country | Code | For customers of |
|---|---|---|
| United States | 40404 | (any) |
| Canada | 21212 | (any) |
| United Kingdom | 86444 | Vodafone, Orange, 3, O2 |
| Brazil | 40404 | Nextel, TIM |
| Haiti | 40404 | Digicel, Voila |
| Ireland | 51210 | Vodafone, O2 |
| India | 53000 | Bharti Airtel, Videocon, Reliance |
| Indonesia | 89887 | AXIS, 3, Telkomsel, Indosat, XL Axiata |
| Italy | 4880804 | Wind |
| 3424486444 | Vodafone | |
| » See SMS short codes for other countries | ||
This timeline is where you’ll spend most of your time, getting instant updates about what matters to you.
Hover over the profile pic and click the Following button to unfollow any account.
When you see a Tweet you love, tap the heart — it lets the person who wrote it know you shared the love.
The fastest way to share someone else’s Tweet with your followers is with a Retweet. Tap the icon to send it instantly.
Add your thoughts about any Tweet with a Reply. Find a topic you’re passionate about, and jump right in.
Get instant insight into what people are talking about now.
Follow more accounts to get instant updates about topics you care about.
See the latest conversations about any topic instantly.
Catch up instantly on the best stories happening as they unfold.
Proposed fix to protect the kernel from Spectre (& Meltdown).pic.twitter.com/qQZr4Iw2yw
actually I like that idea, and it should be possible with MTRRs. i like that way better than PTI.
You realize it would run at about the speed of a 386, right? With the turbo button turned off.
no, you use MTRRs to restrict which mappings are cacheable depending on user or kernel context, then do a CLFLUSH when entering/exiting kernel
MTRRs are for physical ranges, not virtual, no? But yes just flushing cache on kernel enter/return would work if you disable HT.
yes, physical, but the memory manager can handle the details. using PATs would be even more flexible
It really can't. That completely breaks logical layering and makes it hopelessly complex and therefore bug-ridden. And it probably exceeds limit on # of MTRRs.
honestly CLFLUSH would probably be "good enough" if we could CLFLUSH the sibling threads (on the same physical core) too. i wonder if there is a way to synchronize sysenter/sysexit in this way using the topology data we already have
As long as HT is there, attacker will have opportunities to observe cache effects. Exploit runs on both threads, synchronizing via shared mem spinlocks, executes syscall on one while probing cache from other.
Twitter may be over capacity or experiencing a momentary hiccup. Try again or visit Twitter Status for more information.