Hi Ryan, On Thu, 12 Dec 2024 09:23:20 +0000, Ryan Roberts <ryan.roberts@xxxxxxx> wrote: > > Hi Marc, > > I believe the intent of this patch is to protect the host/KVM against a guest > that is using BBML2. The host/KVM always assumes BBML0 and therefore doesn't do > any operations that are allowed by the arch to cause a conflict abort. Therefore > the host doesn't need to handle it. But a guest could be taking advantage of > BBML2 and therefore it's architiecturally possible for a conflict abort to be > raised to EL2. I think today that would take down the host? > > So really I think this could be considered a stand-alone KVM > hardening improvement? I'm not disputing the need for a TLB Conflict abort handler. It will be a good addition once we agree on what needs to be done. > > However, it doesn't seem to me that the host is equipped to deal with > > this sort of exception for itself. Shouldn't you start with that? > > If the host isn't doing any BBML2 operations it doesn't need to handle it, I > don't think? Obviously that changes later in the series and Miko is adding the > required handling to the host. Yes, and that's what I overlooked yesterday, and I replied to that change this morning. Thanks, M. -- Without deviation from the norm, progress is not possible.
