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| author | Thomas Gleixner <tglx@linutronix.de> | 2018-07-13 16:23:22 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2018-07-13 16:29:55 +0200 |
| commit | 895ae47f9918833c3a880fbccd41e0692b37e7d9 (patch) | |
| tree | 499a54cef162352efcf0668be9d37a7eb1360a1b /arch | |
| parent | x86/kvm: Serialize L1D flush parameter setter (diff) | |
| download | linux-895ae47f9918833c3a880fbccd41e0692b37e7d9.tar.xz linux-895ae47f9918833c3a880fbccd41e0692b37e7d9.zip | |
x86/kvm: Allow runtime control of L1D flush
All mitigation modes can be switched at run time with a static key now:
- Use sysfs_streq() instead of strcmp() to handle the trailing new line
from sysfs writes correctly.
- Make the static key management handle multiple invocations properly.
- Set the module parameter file to RW
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Jiri Kosina <jkosina@suse.cz>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lkml.kernel.org/r/20180713142322.954525119@linutronix.de
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kernel/cpu/bugs.c | 2 | ||||
| -rw-r--r-- | arch/x86/kvm/vmx.c | 13 |
2 files changed, 9 insertions, 6 deletions
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index 1b3dc586d29d..7df7df9a2753 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -660,7 +660,7 @@ void x86_spec_ctrl_setup_ap(void) #define pr_fmt(fmt) "L1TF: " fmt #if IS_ENABLED(CONFIG_KVM_INTEL) -enum vmx_l1d_flush_state l1tf_vmx_mitigation __ro_after_init = VMENTER_L1D_FLUSH_AUTO; +enum vmx_l1d_flush_state l1tf_vmx_mitigation = VMENTER_L1D_FLUSH_AUTO; EXPORT_SYMBOL_GPL(l1tf_vmx_mitigation); #endif diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 12b1a5dae767..08fcd59342ed 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -234,12 +234,15 @@ static int vmx_setup_l1d_flush(enum vmx_l1d_flush_state l1tf) l1tf_vmx_mitigation = l1tf; - if (l1tf == VMENTER_L1D_FLUSH_NEVER) - return 0; + if (l1tf != VMENTER_L1D_FLUSH_NEVER) + static_branch_enable(&vmx_l1d_should_flush); + else + static_branch_disable(&vmx_l1d_should_flush); - static_branch_enable(&vmx_l1d_should_flush); if (l1tf == VMENTER_L1D_FLUSH_ALWAYS) static_branch_enable(&vmx_l1d_flush_always); + else + static_branch_disable(&vmx_l1d_flush_always); return 0; } @@ -249,7 +252,7 @@ static int vmentry_l1d_flush_parse(const char *s) if (s) { for (i = 0; i < ARRAY_SIZE(vmentry_l1d_param); i++) { - if (!strcmp(s, vmentry_l1d_param[i].option)) + if (sysfs_streq(s, vmentry_l1d_param[i].option)) return vmentry_l1d_param[i].cmd; } } @@ -293,7 +296,7 @@ static const struct kernel_param_ops vmentry_l1d_flush_ops = { .set = vmentry_l1d_flush_set, .get = vmentry_l1d_flush_get, }; -module_param_cb(vmentry_l1d_flush, &vmentry_l1d_flush_ops, NULL, S_IRUGO); +module_param_cb(vmentry_l1d_flush, &vmentry_l1d_flush_ops, NULL, 0644); struct kvm_vmx { struct kvm kvm; |