From: Li RongQing <lirongqing@xxxxxxxxx>
if CPU has not X86_BUG_ITLB_MULTIHIT bug, kvm-nx-lpage-re kthread
is not needed to create
Signed-off-by: Li RongQing <lirongqing@xxxxxxxxx>
---
arch/x86/kvm/mmu/mmu.c | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 8354262..be98c69 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -6667,6 +6667,11 @@ static bool get_nx_auto_mode(void)
return boot_cpu_has_bug(X86_BUG_ITLB_MULTIHIT) && !cpu_mitigations_off();
}
+static bool cpu_has_itlb_multihit(void)
+{
+ return boot_cpu_has_bug(X86_BUG_ITLB_MULTIHIT);
+}
+
static void __set_nx_huge_pages(bool val)
{
nx_huge_pages = itlb_multihit_kvm_mitigation = val;
@@ -6677,6 +6682,11 @@ static int set_nx_huge_pages(const char *val, const struct kernel_param *kp)
bool old_val = nx_huge_pages;
bool new_val;
+ if (!cpu_has_itlb_multihit()) {
+ __set_nx_huge_pages(false);
+ return 0;
+ }
+
/* In "auto" mode deploy workaround only if CPU has the bug. */
if (sysfs_streq(val, "off"))
new_val = 0;
@@ -6816,6 +6826,9 @@ static int set_nx_huge_pages_recovery_param(const char *val, const struct kernel
uint old_period, new_period;
int err;
+ if (!cpu_has_itlb_multihit())
+ return 0;
+
was_recovery_enabled = calc_nx_huge_pages_recovery_period(&old_period);
err = param_set_uint(val, kp);
@@ -6971,6 +6984,9 @@ int kvm_mmu_post_init_vm(struct kvm *kvm)
{
int err;
+ if (!cpu_has_itlb_multihit())
+ return 0;
+
err = kvm_vm_create_worker_thread(kvm, kvm_nx_huge_page_recovery_worker, 0,
"kvm-nx-lpage-recovery",
&kvm->arch.nx_huge_page_recovery_thread);
@@ -6982,6 +6998,9 @@ int kvm_mmu_post_init_vm(struct kvm *kvm)
void kvm_mmu_pre_destroy_vm(struct kvm *kvm)
{
+ if (!cpu_has_itlb_multihit())
+ return;
+
if (kvm->arch.nx_huge_page_recovery_thread)
kthread_stop(kvm->arch.nx_huge_page_recovery_thread);
}
--
2.9.4
