4.9-stable review patch. If anyone has any objections, please let me know.
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From: Thomas Gleixner tglx@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 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/20180713142322.873642605@linutronix.de Signed-off-by: David Woodhouse dwmw@amazon.co.uk Signed-off-by: Greg Kroah-Hartman gregkh@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 @@ -194,6 +194,7 @@ 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; @@ -258,7 +259,7 @@ 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; @@ -278,7 +279,10 @@ 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)