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Pull vmescape mitigation fixes from Dave Hansen: "Mitigate vmscape issue with indirect branch predictor flushes. vmscape is a vulnerability that essentially takes Spectre-v2 and attacks host userspace from a guest. It particularly affects hypervisors like QEMU. Even if a hypervisor may not have any sensitive data like disk encryption keys, guest-userspace may be able to attack the guest-kernel using the hypervisor as a confused deputy. There are many ways to mitigate vmscape using the existing Spectre-v2 defenses like IBRS variants or the IBPB flushes. This series focuses solely on IBPB because it works universally across vendors and all vulnerable processors. Further work doing vendor and model-specific optimizations can build on top of this if needed / wanted. Do the normal issue mitigation dance: - Add the CPU bug boilerplate - Add a list of vulnerable CPUs - Use IBPB to flush the branch predictors after running guests" * tag 'vmscape-for-linus-20250904' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/vmscape: Add old Intel CPUs to affected list x86/vmscape: Warn when STIBP is disabled with SMT x86/bugs: Move cpu_bugs_smt_update() down x86/vmscape: Enable the mitigation x86/vmscape: Add conditional IBPB mitigation x86/vmscape: Enumerate VMSCAPE bug Documentation/hw-vuln: Add VMSCAPE documentation