KVM: x86: Use sysfs_emit() instead of sprintf()

Use sysfs_emit() instead of the sprintf() for sysfs entries. sysfs_emit()
knows the maximum of the temporary buffer used for outputting sysfs
content and avoids overrunning the buffer length.

Signed-off-by: Like Xu <likexu@tencent.com>
Link: https://lore.kernel.org/r/20230625073438.57427-1-likexu@tencent.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

Author: Like Xu

arch/x86/kvm/mmu/mmu.c

@@ -6862,7 +6862,7 @@ static void mmu_destroy_caches(void)
 static int get_nx_huge_pages(char *buffer, const struct kernel_param *kp)
 {
 	if (nx_hugepage_mitigation_hard_disabled)
-		return sprintf(buffer, "never\n");
+		return sysfs_emit(buffer, "never\n");
 
 	return param_get_bool(buffer, kp);
 }

arch/x86/kvm/vmx/vmx.c

@@ -366,9 +366,9 @@ static int vmentry_l1d_flush_set(const char *s, const struct kernel_param *kp)
 static int vmentry_l1d_flush_get(char *s, const struct kernel_param *kp)
 {
 	if (WARN_ON_ONCE(l1tf_vmx_mitigation >= ARRAY_SIZE(vmentry_l1d_param)))
-		return sprintf(s, "???\n");
+		return sysfs_emit(s, "???\n");
 
-	return sprintf(s, "%s\n", vmentry_l1d_param[l1tf_vmx_mitigation].option);
+	return sysfs_emit(s, "%s\n", vmentry_l1d_param[l1tf_vmx_mitigation].option);
 }
 
 static void vmx_setup_fb_clear_ctrl(void)