Commit 6ccf6332 authored by Thomas Gleixner's avatar Thomas Gleixner Committed by Greg Kroah-Hartman

x86/kvm: Serialize L1D flush parameter setter

commit dd4bfa73 upstream

Writes to the parameter files are not serialized at the sysfs core
level, so local serialization is required.
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Tested-by: default avatarJiri Kosina <jkosina@suse.cz>
Reviewed-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: default avatarJosh Poimboeuf <jpoimboe@redhat.com>
Link: https://lkml.kernel.org/r/20180713142322.873642605@linutronix.deSigned-off-by: default avatarDavid Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent dff0982c
......@@ -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 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;
......@@ -278,7 +279,10 @@ 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)
......
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