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Szmigiero" , kvm@vger.kernel.org Content-Type: text/plain; charset="us-ascii" On Sun, Dec 14, 2025, Alessandro Ratti wrote: > Hi, > > I was investigating the TODO in svm_check_intercept() about advertising > NRIPS unconditionally, and found an old patch by Sean Christopherson > (with Maciej S. Szmigiero's sign-off) that simply requires NRIPS for > nested virtualization rather than trying to emulate it. > > Link: https://lore.kernel.org/kvm/f0302382cf45d7a9527b4aebbfe694bbcfa7aff5.1651440202.git.maciej.szmigiero@oracle.com/ > > Is there a reason this approach wasn't taken? Was there pushback on > dropping support for pre-2009 CPUs, or did it just fall through the > cracks? Both Maxim[1] and Maciej lightly objected[2], and in the end dropping support for CPUs without NRIPS barely moves the needle in terms of complexity. [1] https://lore.kernel.org/kvm/2327614a18d60a5e1b0d9d3aed754cccebce3117.camel@redhat.com [2] https://lore.kernel.org/kvm/656aaf33-8c70-8b06-2cdc-fd2685a1348b@maciej.szmigiero.name > If the approach is still acceptable, I'd be happy to refresh and test > the patch. Let's just leave things as-is for now. Dealing with NRIPS=0 CPUs was annoying when fixing the soft-int reinjection issues, but it hasn't meaningfully impacted maintenance in the ~3 years since (which isn't suprising give how little code is saved by ripping it out). Thank you for the offer though!