Re: [PATCH v2 2/5] x86/virt/tdx: Pull kexec cache flush logic into arch/x86

Dave Hansen
2026-04-01T18:30:15Z

On 4/1/26 11:12, Sean Christopherson wrote:
> Sorry, "costly" wasn't the right word. I know WBINVD super
> expensive, but unless someone cares deeply about the latency of
> offlining a CPU after its down TDX stuff, the "cost" is effectively
> zero.

I once increased the CPU online/offline latency once and got nastygrams
from folks. IIRC, I added a synchronize_rcu() which incurs way more
latency than WBINVD, but folks _do_ care about CPU online/offline
latency surprisingly.

In this case, though, I'm happy to add the WBINVD for simplicity and
wait for a possible repeat of the torches an pitchforks.