diff options
Diffstat (limited to 'debian/patches-rt/0090-x86-kvm-Require-const-tsc-for-RT.patch')
| -rw-r--r-- | debian/patches-rt/0090-x86-kvm-Require-const-tsc-for-RT.patch | 37 |
1 files changed, 37 insertions, 0 deletions
diff --git a/debian/patches-rt/0090-x86-kvm-Require-const-tsc-for-RT.patch b/debian/patches-rt/0090-x86-kvm-Require-const-tsc-for-RT.patch new file mode 100644 index 000000000..f748cb9d8 --- /dev/null +++ b/debian/patches-rt/0090-x86-kvm-Require-const-tsc-for-RT.patch @@ -0,0 +1,37 @@ +From 53f33d36d7741754ec7b7f2e4a0c62faa30d6902 Mon Sep 17 00:00:00 2001 +From: Thomas Gleixner <tglx@linutronix.de> +Date: Sun, 6 Nov 2011 12:26:18 +0100 +Subject: [PATCH 090/347] x86: kvm Require const tsc for RT +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.246-rt110.tar.xz + +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> +--- + arch/x86/kvm/x86.c | 7 +++++++ + 1 file changed, 7 insertions(+) + +diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c +index 417abc9ba1ad..9829e0fbdd41 100644 +--- a/arch/x86/kvm/x86.c ++++ b/arch/x86/kvm/x86.c +@@ -6875,6 +6875,13 @@ 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; +-- +2.36.1 + |