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Message-Id: <20220421051244.187733-2-mlevitsk@redhat.com>
Date: Thu, 21 Apr 2022 08:12:35 +0300
From: Maxim Levitsky <mlevitsk@...hat.com>
To: kvm@...r.kernel.org
Cc: Rodrigo Vivi <rodrigo.vivi@...el.com>,
Paolo Bonzini <pbonzini@...hat.com>,
intel-gfx@...ts.freedesktop.org,
Joonas Lahtinen <joonas.lahtinen@...ux.intel.com>,
Jani Nikula <jani.nikula@...ux.intel.com>,
Thomas Gleixner <tglx@...utronix.de>,
linux-kernel@...r.kernel.org, Wanpeng Li <wanpengli@...cent.com>,
Jim Mattson <jmattson@...gle.com>,
Tvrtko Ursulin <tvrtko.ursulin@...ux.intel.com>,
"H. Peter Anvin" <hpa@...or.com>,
Vitaly Kuznetsov <vkuznets@...hat.com>,
Zhi Wang <zhi.a.wang@...el.com>,
Daniel Vetter <daniel@...ll.ch>,
intel-gvt-dev@...ts.freedesktop.org,
dri-devel@...ts.freedesktop.org, x86@...nel.org,
David Airlie <airlied@...ux.ie>,
Sean Christopherson <seanjc@...gle.com>,
Ingo Molnar <mingo@...hat.com>, Joerg Roedel <joro@...tes.org>,
Dave Hansen <dave.hansen@...ux.intel.com>,
Borislav Petkov <bp@...en8.de>,
Zhenyu Wang <zhenyuw@...ux.intel.com>,
Maxim Levitsky <mlevitsk@...hat.com>
Subject: [RFC PATCH v2 01/10] KVM: x86: mmu: allow to enable write tracking externally
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 <mlevitsk@...hat.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 2c20f715f0094..ae41d2df69fe9 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1234,7 +1234,7 @@ 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 69a30d6d1e2b9..2c4edae4b026d 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -3368,7 +3368,7 @@ 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;
@@ -3378,21 +3378,20 @@ 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++) {
@@ -3422,7 +3421,7 @@ 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);
@@ -3459,7 +3458,7 @@ 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;
@@ -5727,6 +5726,10 @@ 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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