[PATCH v4 06/10] KVM: x86/MMU: Factor out updating NX hugepages state for a VM

From: Ben Gardon
Date: Mon Apr 11 2022 - 17:11:05 EST


Factor out the code to update the NX hugepages state for an individual
VM. This will be expanded in future commits to allow per-VM control of
Nx hugepages.

No functional change intended.

Reviewed-by: David Matlack <dmatlack@xxxxxxxxxx>
Signed-off-by: Ben Gardon <bgardon@xxxxxxxxxx>
---
arch/x86/kvm/mmu/mmu.c | 17 +++++++++++------
1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 69a30d6d1e2b..caaa610b7878 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -6144,6 +6144,15 @@ static void __set_nx_huge_pages(bool val)
nx_huge_pages = itlb_multihit_kvm_mitigation = val;
}

+static void kvm_update_nx_huge_pages(struct kvm *kvm)
+{
+ mutex_lock(&kvm->slots_lock);
+ kvm_mmu_zap_all_fast(kvm);
+ mutex_unlock(&kvm->slots_lock);
+
+ wake_up_process(kvm->arch.nx_lpage_recovery_thread);
+}
+
static int set_nx_huge_pages(const char *val, const struct kernel_param *kp)
{
bool old_val = nx_huge_pages;
@@ -6166,13 +6175,9 @@ static int set_nx_huge_pages(const char *val, const struct kernel_param *kp)

mutex_lock(&kvm_lock);

- list_for_each_entry(kvm, &vm_list, vm_list) {
- mutex_lock(&kvm->slots_lock);
- kvm_mmu_zap_all_fast(kvm);
- mutex_unlock(&kvm->slots_lock);
+ list_for_each_entry(kvm, &vm_list, vm_list)
+ kvm_update_nx_huge_pages(kvm);

- wake_up_process(kvm->arch.nx_lpage_recovery_thread);
- }
mutex_unlock(&kvm_lock);
}

--
2.35.1.1178.g4f1659d476-goog