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From:   "Suthikulpanit, Suravee" <Suravee.Suthikulpanit@amd.com>
To:     "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "kvm@vger.kernel.org" <kvm@vger.kernel.org>
CC:     "pbonzini@redhat.com" <pbonzini@redhat.com>,
        "rkrcmar@redhat.com" <rkrcmar@redhat.com>,
        "joro@8bytes.org" <joro@8bytes.org>,
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        "jschoenh@amazon.de" <jschoenh@amazon.de>,
        "karahmed@amazon.de" <karahmed@amazon.de>,
        "rimasluk@amazon.com" <rimasluk@amazon.com>,
        "Grimm, Jon" <Jon.Grimm@amd.com>,
        "Suthikulpanit, Suravee" <Suravee.Suthikulpanit@amd.com>
Subject: [PATCH v2 08/15] svm: Add support for setup/destroy virutal APIC
 backing page for AVIC
Thread-Topic: [PATCH v2 08/15] svm: Add support for setup/destroy virutal APIC
 backing page for AVIC
Thread-Index: AQHVU4YDWF82b235sEatrd+nfFcRLg==
Date:   Thu, 15 Aug 2019 16:25:12 +0000
Message-ID: <1565886293-115836-9-git-send-email-suravee.suthikulpanit@amd.com>
References: <1565886293-115836-1-git-send-email-suravee.suthikulpanit@amd.com>
In-Reply-To: <1565886293-115836-1-git-send-email-suravee.suthikulpanit@amd.com>
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Activate/deactivate AVIC requires setting/unsetting the memory region used
for virtual APIC backing page (APIC_ACCESS_PAGE_PRIVATE_MEMSLOT).
So, re-factor avic_init_access_page() to avic_setup_access_page()
and add srcu_read_lock/unlock, which are needed to allow this function
to be called during run-time.

Also, introduce avic_destroy_access_page() to unset the page when
deactivate AVIC.

Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
---
 arch/x86/kvm/svm.c | 48 +++++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 43 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index b674cd0..47f2439 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -1468,7 +1468,9 @@ static u64 svm_write_l1_tsc_offset(struct kvm_vcpu *v=
cpu, u64 offset)
 static void avic_init_vmcb(struct vcpu_svm *svm)
 {
 	struct vmcb *vmcb =3D svm->vmcb;
-	struct kvm_svm *kvm_svm =3D to_kvm_svm(svm->vcpu.kvm);
+	struct kvm *kvm =3D svm->vcpu.kvm;
+	struct kvm_svm *kvm_svm =3D to_kvm_svm(kvm);
+
 	phys_addr_t bpa =3D __sme_set(page_to_phys(svm->avic_backing_page));
 	phys_addr_t lpa =3D __sme_set(page_to_phys(kvm_svm->avic_logical_id_table=
_page));
 	phys_addr_t ppa =3D __sme_set(page_to_phys(kvm_svm->avic_physical_id_tabl=
e_page));
@@ -1477,7 +1479,13 @@ static void avic_init_vmcb(struct vcpu_svm *svm)
 	vmcb->control.avic_logical_id =3D lpa & AVIC_HPA_MASK;
 	vmcb->control.avic_physical_id =3D ppa & AVIC_HPA_MASK;
 	vmcb->control.avic_physical_id |=3D AVIC_MAX_PHYSICAL_ID_COUNT;
-	vmcb->control.int_ctl |=3D AVIC_ENABLE_MASK;
+
+	mutex_lock(&kvm->arch.apicv_lock);
+	if (kvm->arch.apicv_state =3D=3D APICV_ACTIVATED)
+		vmcb->control.int_ctl |=3D AVIC_ENABLE_MASK;
+	else
+		vmcb->control.int_ctl &=3D ~AVIC_ENABLE_MASK;
+	mutex_unlock(&kvm->arch.apicv_lock);
 }
=20
 static void init_vmcb(struct vcpu_svm *svm)
@@ -1660,19 +1668,24 @@ static u64 *avic_get_physical_id_entry(struct kvm_v=
cpu *vcpu,
  * field of the VMCB. Therefore, we set up the
  * APIC_ACCESS_PAGE_PRIVATE_MEMSLOT (4KB) here.
  */
-static int avic_init_access_page(struct kvm_vcpu *vcpu)
+static int avic_setup_access_page(struct kvm_vcpu *vcpu, bool init)
 {
 	struct kvm *kvm =3D vcpu->kvm;
 	int ret =3D 0;
=20
 	mutex_lock(&kvm->slots_lock);
+
 	if (kvm->arch.apic_access_page_done)
 		goto out;
=20
+	if (!init)
+		srcu_read_unlock(&kvm->srcu, vcpu->srcu_idx);
 	ret =3D __x86_set_memory_region(kvm,
 				      APIC_ACCESS_PAGE_PRIVATE_MEMSLOT,
 				      APIC_DEFAULT_PHYS_BASE,
 				      PAGE_SIZE);
+	if (!init)
+		vcpu->srcu_idx =3D srcu_read_lock(&kvm->srcu);
 	if (ret)
 		goto out;
=20
@@ -1682,14 +1695,39 @@ static int avic_init_access_page(struct kvm_vcpu *v=
cpu)
 	return ret;
 }
=20
+static void avic_destroy_access_page(struct kvm_vcpu *vcpu)
+{
+	struct kvm *kvm =3D vcpu->kvm;
+
+	mutex_lock(&kvm->slots_lock);
+
+	if (!kvm->arch.apic_access_page_done)
+		goto out;
+
+	srcu_read_unlock(&kvm->srcu, vcpu->srcu_idx);
+	__x86_set_memory_region(kvm,
+				APIC_ACCESS_PAGE_PRIVATE_MEMSLOT,
+				APIC_DEFAULT_PHYS_BASE,
+				0);
+	vcpu->srcu_idx =3D srcu_read_lock(&kvm->srcu);
+	kvm->arch.apic_access_page_done =3D false;
+out:
+	mutex_unlock(&kvm->slots_lock);
+}
+
 static int avic_init_backing_page(struct kvm_vcpu *vcpu)
 {
-	int ret;
+	int ret =3D 0;
 	u64 *entry, new_entry;
 	int id =3D vcpu->vcpu_id;
+	struct kvm *kvm =3D vcpu->kvm;
 	struct vcpu_svm *svm =3D to_svm(vcpu);
=20
-	ret =3D avic_init_access_page(vcpu);
+	mutex_lock(&kvm->arch.apicv_lock);
+	if (kvm->arch.apicv_state =3D=3D APICV_ACTIVATED)
+		ret =3D avic_setup_access_page(vcpu, true);
+	mutex_unlock(&kvm->arch.apicv_lock);
+
 	if (ret)
 		return ret;
=20
--=20
1.8.3.1