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authorThomas Gleixner2011-11-06 12:26:18 +0100
committerPaolo Bonzini2022-03-21 09:28:40 -0400
commit5e17b2ee45b941fb7bc46107810d727088be392e (patch)
tree7c1685099193fd7db854fbf5fb4eb4c31f64cf20 /arch/x86/kvm
parentf144c49e8c3950add1b051e76ebf40a258984c9d (diff)
kvm: x86: Require const tsc for RT
Non constant TSC is a nightmare on bare metal already, but with virtualization it becomes a complete disaster because the workarounds are horrible latency wise. That's also a preliminary for running RT in a guest on top of a RT host. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Message-Id: <Yh5eJSG19S2sjZfy@linutronix.de> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm')
-rw-r--r--arch/x86/kvm/x86.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 4fa4d8269e5b..c58265d9f1b2 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -8865,6 +8865,12 @@ int kvm_arch_init(void *opaque)
goto out;
}
+ if (IS_ENABLED(CONFIG_PREEMPT_RT) && !boot_cpu_has(X86_FEATURE_CONSTANT_TSC)) {
+ pr_err("RT requires X86_FEATURE_CONSTANT_TSC\n");
+ r = -EOPNOTSUPP;
+ goto out;
+ }
+
r = -ENOMEM;
x86_emulator_cache = kvm_alloc_emulator_cache();