This will be used to enable write tracking from nested AVIC code
and can also be used to enable write tracking in GVT-g module
when it actually uses it as opposed to always enabling it,
when the module is compiled in the kernel.

No functional change intended.

Signed-off-by: Maxim Levitsky <mlevi...@redhat.com>
---
 arch/x86/include/asm/kvm_host.h       |  2 +-
 arch/x86/include/asm/kvm_page_track.h |  1 +
 arch/x86/kvm/mmu.h                    |  8 +++++---
 arch/x86/kvm/mmu/mmu.c                | 17 ++++++++++-------
 arch/x86/kvm/mmu/page_track.c         | 10 ++++++++--
 5 files changed, 25 insertions(+), 13 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 636df87542555..fc7df778a3d71 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1254,7 +1254,7 @@ struct kvm_arch {
         * is used as one input when determining whether certain memslot
         * related allocations are necessary.
         */
-       bool shadow_root_allocated;
+       bool mmu_page_tracking_enabled;
 
 #if IS_ENABLED(CONFIG_HYPERV)
        hpa_t   hv_root_tdp;
diff --git a/arch/x86/include/asm/kvm_page_track.h 
b/arch/x86/include/asm/kvm_page_track.h
index eb186bc57f6a9..955a5ae07b10e 100644
--- a/arch/x86/include/asm/kvm_page_track.h
+++ b/arch/x86/include/asm/kvm_page_track.h
@@ -50,6 +50,7 @@ int kvm_page_track_init(struct kvm *kvm);
 void kvm_page_track_cleanup(struct kvm *kvm);
 
 bool kvm_page_track_write_tracking_enabled(struct kvm *kvm);
+int kvm_page_track_write_tracking_enable(struct kvm *kvm);
 int kvm_page_track_write_tracking_alloc(struct kvm_memory_slot *slot);
 
 void kvm_page_track_free_memslot(struct kvm_memory_slot *slot);
diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h
index 671cfeccf04e9..44d15551f7156 100644
--- a/arch/x86/kvm/mmu.h
+++ b/arch/x86/kvm/mmu.h
@@ -269,7 +269,7 @@ int kvm_arch_write_log_dirty(struct kvm_vcpu *vcpu);
 int kvm_mmu_post_init_vm(struct kvm *kvm);
 void kvm_mmu_pre_destroy_vm(struct kvm *kvm);
 
-static inline bool kvm_shadow_root_allocated(struct kvm *kvm)
+static inline bool mmu_page_tracking_enabled(struct kvm *kvm)
 {
        /*
         * Read shadow_root_allocated before related pointers. Hence, threads
@@ -277,9 +277,11 @@ static inline bool kvm_shadow_root_allocated(struct kvm 
*kvm)
         * see the pointers. Pairs with smp_store_release in
         * mmu_first_shadow_root_alloc.
         */
-       return smp_load_acquire(&kvm->arch.shadow_root_allocated);
+       return smp_load_acquire(&kvm->arch.mmu_page_tracking_enabled);
 }
 
+int mmu_enable_write_tracking(struct kvm *kvm);
+
 #ifdef CONFIG_X86_64
 static inline bool is_tdp_mmu_enabled(struct kvm *kvm) { return 
kvm->arch.tdp_mmu_enabled; }
 #else
@@ -288,7 +290,7 @@ static inline bool is_tdp_mmu_enabled(struct kvm *kvm) { 
return false; }
 
 static inline bool kvm_memslots_have_rmaps(struct kvm *kvm)
 {
-       return !is_tdp_mmu_enabled(kvm) || kvm_shadow_root_allocated(kvm);
+       return !is_tdp_mmu_enabled(kvm) || mmu_page_tracking_enabled(kvm);
 }
 
 static inline gfn_t gfn_to_index(gfn_t gfn, gfn_t base_gfn, int level)
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 904f0faff2186..fb744616bf7df 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -3389,7 +3389,7 @@ static int mmu_alloc_direct_roots(struct kvm_vcpu *vcpu)
        return r;
 }
 
-static int mmu_first_shadow_root_alloc(struct kvm *kvm)
+int mmu_enable_write_tracking(struct kvm *kvm)
 {
        struct kvm_memslots *slots;
        struct kvm_memory_slot *slot;
@@ -3399,21 +3399,20 @@ static int mmu_first_shadow_root_alloc(struct kvm *kvm)
         * Check if this is the first shadow root being allocated before
         * taking the lock.
         */
-       if (kvm_shadow_root_allocated(kvm))
+       if (mmu_page_tracking_enabled(kvm))
                return 0;
 
        mutex_lock(&kvm->slots_arch_lock);
 
        /* Recheck, under the lock, whether this is the first shadow root. */
-       if (kvm_shadow_root_allocated(kvm))
+       if (mmu_page_tracking_enabled(kvm))
                goto out_unlock;
 
        /*
         * Check if anything actually needs to be allocated, e.g. all metadata
         * will be allocated upfront if TDP is disabled.
         */
-       if (kvm_memslots_have_rmaps(kvm) &&
-           kvm_page_track_write_tracking_enabled(kvm))
+       if (kvm_memslots_have_rmaps(kvm) && mmu_page_tracking_enabled(kvm))
                goto out_success;
 
        for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) {
@@ -3443,7 +3442,7 @@ static int mmu_first_shadow_root_alloc(struct kvm *kvm)
         * all the related pointers are set.
         */
 out_success:
-       smp_store_release(&kvm->arch.shadow_root_allocated, true);
+       smp_store_release(&kvm->arch.mmu_page_tracking_enabled, true);
 
 out_unlock:
        mutex_unlock(&kvm->slots_arch_lock);
@@ -3480,7 +3479,7 @@ static int mmu_alloc_shadow_roots(struct kvm_vcpu *vcpu)
                }
        }
 
-       r = mmu_first_shadow_root_alloc(vcpu->kvm);
+       r = mmu_enable_write_tracking(vcpu->kvm);
        if (r)
                return r;
 
@@ -5753,6 +5752,10 @@ int kvm_mmu_init_vm(struct kvm *kvm)
        node->track_write = kvm_mmu_pte_write;
        node->track_flush_slot = kvm_mmu_invalidate_zap_pages_in_memslot;
        kvm_page_track_register_notifier(kvm, node);
+
+       if (IS_ENABLED(CONFIG_KVM_EXTERNAL_WRITE_TRACKING) || !tdp_enabled)
+               mmu_enable_write_tracking(kvm);
+
        return 0;
 }
 
diff --git a/arch/x86/kvm/mmu/page_track.c b/arch/x86/kvm/mmu/page_track.c
index 2e09d1b6249f3..8857d629036d7 100644
--- a/arch/x86/kvm/mmu/page_track.c
+++ b/arch/x86/kvm/mmu/page_track.c
@@ -21,10 +21,16 @@
 
 bool kvm_page_track_write_tracking_enabled(struct kvm *kvm)
 {
-       return IS_ENABLED(CONFIG_KVM_EXTERNAL_WRITE_TRACKING) ||
-              !tdp_enabled || kvm_shadow_root_allocated(kvm);
+       return mmu_page_tracking_enabled(kvm);
 }
 
+int kvm_page_track_write_tracking_enable(struct kvm *kvm)
+{
+       return mmu_enable_write_tracking(kvm);
+}
+EXPORT_SYMBOL_GPL(kvm_page_track_write_tracking_enable);
+
+
 void kvm_page_track_free_memslot(struct kvm_memory_slot *slot)
 {
        int i;
-- 
2.26.3

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