On Fri, Sep 02, 2022 at 04:26:57PM +0200, Ben Hutchings wrote: > On Thu, 2022-09-01 at 11:43 +0200, Greg KH wrote: > > On Mon, Aug 29, 2022 at 04:04:58PM +0200, Ben Hutchings wrote: > > > On Mon, 2022-08-29 at 10:30 +0200, gregkh@xxxxxxxxxxxxxxxxxxx wrote: > > > > The patch below does not apply to the 5.10-stable tree. > > > > If someone wants it applied there, or to any other stable or longterm > > > > tree, then please email the backport, including the original git commit > > > > id to <stable@xxxxxxxxxxxxxxx>. > > > > > > > > > > You need commit 4e3aa9238277 "x86/nospec: Unwreck the RSB stuffing" > > > before this one. I've attached the backport of that for 5.10. I > > > haven't checked the older branches. > > > > Great, thanks, this worked. But the backport did not apply to 4.19, so > > I will need that in order to take this one as well. > > I've had a look at 5.4, and it's sufficiently different from upstream > that I don't see how to move forward. > > However, I also found that the PBRSB mitigation seems broken, as commit > fc02735b14ff "KVM: VMX: Prevent guest RSB poisoning attacks with eIBRS" > was not backported (and would be hard to add). > > So, perhaps it would be best to revert the backports of: > > 2b1299322016 x86/speculation: Add RSB VM Exit protections > ba6e31af2be9 x86/speculation: Add LFENCE to RSB fill sequence > > in stable branches older than 5.10. Why? Is it because they do not work at all there, or are they causing problems? thanks, greg k-h
