From: Thomas Gleixner Date: Fri, 13 Jul 2018 14:23:21 +0000 (+0200) Subject: x86/kvm: Serialize L1D flush parameter setter X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=15e55ee33d89b9cf1745daf18260ee351058571c;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git x86/kvm: Serialize L1D flush parameter setter 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 Tested-by: Jiri Kosina Reviewed-by: Greg Kroah-Hartman Reviewed-by: Josh Poimboeuf Link: https://lkml.kernel.org/r/20180713142322.873642605@linutronix.de Signed-off-by: Greg Kroah-Hartman --- diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index ae1601fd8998..c1999911f671 100644 --- 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 char *s) 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 char *s, const struct kernel_param *kp) 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)