4.14-stable review patch. If anyone has any objections, please let me know.
------------------ From: Thomas Gleixner <t...@linutronix.de> commit dd4bfa739a72508b75760b393d129ed7b431daab upstream Writes to the parameter files are not serialized at the sysfs core level, so local serialization is required. Signed-off-by: Thomas Gleixner <t...@linutronix.de> Tested-by: Jiri Kosina <jkos...@suse.cz> Reviewed-by: Greg Kroah-Hartman <gre...@linuxfoundation.org> Reviewed-by: Josh Poimboeuf <jpoim...@redhat.com> Link: https://lkml.kernel.org/r/20180713142322.873642...@linutronix.de Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org> --- arch/x86/kvm/vmx.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -196,6 +196,7 @@ extern const ulong vmx_return; static DEFINE_STATIC_KEY_FALSE(vmx_l1d_should_flush); static DEFINE_STATIC_KEY_FALSE(vmx_l1d_flush_always); +static DEFINE_MUTEX(vmx_l1d_flush_mutex); /* Storage for pre module init parameter parsing */ static enum vmx_l1d_flush_state __read_mostly vmentry_l1d_flush_param = VMENTER_L1D_FLUSH_AUTO; @@ -260,7 +261,7 @@ static int vmentry_l1d_flush_parse(const static int vmentry_l1d_flush_set(const char *s, const struct kernel_param *kp) { - int l1tf; + int l1tf, ret; if (!boot_cpu_has(X86_BUG_L1TF)) return 0; @@ -280,7 +281,10 @@ static int vmentry_l1d_flush_set(const c return 0; } - return vmx_setup_l1d_flush(l1tf); + mutex_lock(&vmx_l1d_flush_mutex); + ret = vmx_setup_l1d_flush(l1tf); + mutex_unlock(&vmx_l1d_flush_mutex); + return ret; } static int vmentry_l1d_flush_get(char *s, const struct kernel_param *kp)
