[RFC 08/10] x86/idle: Control Indirect Branch Speculation in idle

From: Thomas Gleixner Indirect Branch Speculation (IBS) is controlled per physical core. If one thread disables it then it's disabled for the core. If a thread enters idle it makes sense to reenable IBS so the sibling thread can run with full speculation enabled in user

[RFC 08/10] x86/idle: Control Indirect Branch Speculation in idle

From: Thomas Gleixner Indirect Branch Speculation (IBS) is controlled per physical core. If one thread disables it then it's disabled for the core. If a thread enters idle it makes sense to reenable IBS so the sibling thread can run with full speculation enabled in user space. This makes only