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x86/kvm: Serialize L1D flush parameter setter 

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
This commit is contained in:
Thomas Gleixner 2018-07-13 16:23:21 +02:00
parent 4c6523ec59
commit dd4bfa739a
1 changed files with 6 additions and 2 deletions
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8
arch/x86/kvm/vmx.c
View File

@ -193,6 +193,7 @@ 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;
@ -257,7 +258,7 @@ 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;
@ -277,7 +278,10 @@ 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)