Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Received-SPF: Pass (protection.outlook.com: domain of amd.com designates
 165.204.84.17 as permitted sender) receiver=protection.outlook.com;
 client-ip=165.204.84.17; helo=SATLEXMB04.amd.com;
From:   Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
To:     <linux-kernel@vger.kernel.org>, <kvm@vger.kernel.org>
CC:     <pbonzini@redhat.com>, <seanjc@google.com>, <joro@8bytes.org>,
        <jon.grimm@amd.com>, <wei.huang2@amd.com>, <terry.bowman@amd.com>,
        "Suravee Suthikulpanit" <suravee.suthikulpanit@amd.com>
Subject: [RFC PATCH 09/13] KVM: SVM: Introduce helper function avic_get_apic_id
Date:   Sun, 20 Feb 2022 20:19:18 -0600
Message-ID: <20220221021922.733373-10-suravee.suthikulpanit@amd.com>
In-Reply-To: <20220221021922.733373-1-suravee.suthikulpanit@amd.com>
References: <20220221021922.733373-1-suravee.suthikulpanit@amd.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Content-Type: text/plain
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 21 Feb 2022 02:22:51.2471
 (UTC)
X-MS-Exchange-CrossTenant-Network-Message-Id: ddf6afed-6185-4b9c-ba74-08d9f4e10f7d
X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d
X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=3dd8961f-e488-4e60-8e11-a82d994e183d;Ip=[165.204.84.17];Helo=[SATLEXMB04.amd.com]
X-MS-Exchange-CrossTenant-AuthSource: CO1NAM11FT037.eop-nam11.prod.protection.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Anonymous
X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem
X-MS-Exchange-Transport-CrossTenantHeadersStamped: BN9PR12MB5099
X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED,
        DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE,
        RCVD_IN_MSPIKE_H2,SPF_HELO_PASS,SPF_PASS,T_SCC_BODY_TEXT_LINE
        autolearn=ham autolearn_force=no version=3.4.6
X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on
        lindbergh.monkeyblade.net
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

This function returns the currently programmed guest physical
APIC ID of a vCPU in both xAPIC and x2APIC modes.
In case of invalid APIC ID based on the current mode,
the function returns X2APIC_BROADCAST.

Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
---
 arch/x86/kvm/svm/avic.c | 29 ++++++++++++++++++++++++++---
 1 file changed, 26 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kvm/svm/avic.c b/arch/x86/kvm/svm/avic.c
index 55b3b703b93b..3543b7a4514a 100644
--- a/arch/x86/kvm/svm/avic.c
+++ b/arch/x86/kvm/svm/avic.c
@@ -450,16 +450,35 @@ static void avic_invalidate_logical_id_entry(struct kvm_vcpu *vcpu)
 		clear_bit(AVIC_LOGICAL_ID_ENTRY_VALID_BIT, (unsigned long *)entry);
 }
 
+static inline u32 avic_get_apic_id(struct kvm_vcpu *vcpu)
+{
+	u32 apic_id = kvm_lapic_get_reg(vcpu->arch.apic, APIC_ID);
+
+	if (!apic_x2apic_mode(vcpu->arch.apic)) {
+		/*
+		 * In case of xAPIC, we do not support
+		 * APIC ID larger than 254.
+		 */
+		if (vcpu->vcpu_id >= APIC_BROADCAST)
+			return X2APIC_BROADCAST;
+		return apic_id >> 24;
+	} else
+		return apic_id;
+}
+
 static int avic_handle_ldr_update(struct kvm_vcpu *vcpu)
 {
 	int ret = 0;
 	struct vcpu_svm *svm = to_svm(vcpu);
 	u32 ldr = kvm_lapic_get_reg(vcpu->arch.apic, APIC_LDR);
-	u32 id = kvm_xapic_id(vcpu->arch.apic);
+	u32 id = avic_get_apic_id(vcpu);
 
 	if (ldr == svm->ldr_reg)
 		return 0;
 
+	if (id == X2APIC_BROADCAST)
+		return -EINVAL;
+
 	avic_invalidate_logical_id_entry(vcpu);
 
 	if (ldr)
@@ -475,7 +494,10 @@ static int avic_handle_apic_id_update(struct kvm_vcpu *vcpu)
 {
 	u64 *old, *new;
 	struct vcpu_svm *svm = to_svm(vcpu);
-	u32 id = kvm_xapic_id(vcpu->arch.apic);
+	u32 id = avic_get_apic_id(vcpu);
+
+	if (id == X2APIC_BROADCAST)
+		return 1;
 
 	if (vcpu->vcpu_id == id)
 		return 0;
@@ -497,7 +519,8 @@ static int avic_handle_apic_id_update(struct kvm_vcpu *vcpu)
 	 * APIC ID table entry if already setup the LDR.
 	 */
 	if (svm->ldr_reg)
-		avic_handle_ldr_update(vcpu);
+		if (avic_handle_ldr_update(vcpu))
+			return 1;
 
 	return 0;
 }
-- 
2.25.1