linux-kernel - [PATCH v3 07/11] KVM: x86/MMU: Factor out updating NX hugepages state for a VM

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Date:   Wed, 30 Mar 2022 10:46:17 -0700
From:   Ben Gardon <bgardon@...gle.com>
To:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc:     Paolo Bonzini <pbonzini@...hat.com>, Peter Xu <peterx@...hat.com>,
        Sean Christopherson <seanjc@...gle.com>,
        David Matlack <dmatlack@...gle.com>,
        Jim Mattson <jmattson@...gle.com>,
        David Dunn <daviddunn@...gle.com>,
        Jing Zhang <jingzhangos@...gle.com>,
        Junaid Shahid <junaids@...gle.com>,
        Ben Gardon <bgardon@...gle.com>
Subject: [PATCH v3 07/11] KVM: x86/MMU: Factor out updating NX hugepages state
 for a VM

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.

Signed-off-by: Ben Gardon <bgardon@...gle.com>
---
 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 dbf46dd98618..af428cb65b3f 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -6202,6 +6202,15 @@ 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;
@@ -6224,13 +6233,9 @@ 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);
 	}
 
-- 
2.35.1.1021.g381101b075-goog