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| author | Thomas Gleixner <tglx@linutronix.de> | 2011-11-06 12:26:18 +0100 |
|---|---|---|
| committer | Sebastian Andrzej Siewior <bigeasy@linutronix.de> | 2016-02-13 00:36:28 +0100 |
| commit | 4fb5a7b5d2c325966c525a18c135da36823794ad (patch) | |
| tree | 9096be34fb6fe217a447026880de55e6fa79d652 | |
| parent | 4f44630efebe68535b379105eb4483be7f8f9d74 (diff) | |
| download | rt-linux-4fb5a7b5d2c325966c525a18c135da36823794ad.tar.gz | |
x86: kvm 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>
| -rw-r--r-- | arch/x86/kvm/x86.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 9a2ed89045133..c11997ff0f5a5 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -5788,6 +5788,13 @@ int kvm_arch_init(void *opaque) goto out; } +#ifdef CONFIG_PREEMPT_RT_FULL + if (!boot_cpu_has(X86_FEATURE_CONSTANT_TSC)) { + printk(KERN_ERR "RT requires X86_FEATURE_CONSTANT_TSC\n"); + return -EOPNOTSUPP; + } +#endif + r = kvm_mmu_module_init(); if (r) goto out_free_percpu; |