linux-kernel - [PATCH 09/12] KVM: SVM: Introduce helper functions to (de)activate AVIC and x2AVIC

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Message-ID: <20220405230855.15376-10-suravee.suthikulpanit@amd.com>
Date:   Tue, 5 Apr 2022 18:08:52 -0500
From:   Suravee Suthikulpanit <suravee.suthikulpanit@....com>
To:     <linux-kernel@...r.kernel.org>, <kvm@...r.kernel.org>,
        <x86@...nel.org>
CC:     <mlevitsk@...hat.com>, <seanjc@...gle.com>, <pbonzini@...hat.com>,
        <joro@...tes.org>, <tglx@...utronix.de>, <mingo@...hat.com>,
        <bp@...en8.de>, <peterz@...radead.org>, <hpa@...or.com>,
        <jon.grimm@....com>, <wei.huang2@....com>, <terry.bowman@....com>,
        Suravee Suthikulpanit <suravee.suthikulpanit@....com>,
        kernel test robot <lkp@...el.com>
Subject: [PATCH 09/12] KVM: SVM: Introduce helper functions to (de)activate AVIC and x2AVIC

Refactor the current logic for (de)activate AVIC into helper functions,
and also add logic for (de)activate x2AVIC. The helper function are used
when initializing AVIC and switching from AVIC to x2AVIC mode
(handled by svm_refresh_spicv_exec_ctrl()).

When an AVIC-enabled guest switches from APIC to x2APIC mode during
runtime, the SVM driver needs to perform the following steps:

1. Set the x2APIC mode bit for AVIC in VMCB along with the maximum
APIC ID support for each mode accodingly.

2. Disable x2APIC MSRs interception in order to allow the hardware
to virtualize x2APIC MSRs accesses.

Reported-by: kernel test robot <lkp@...el.com>
Reviewed-by: Maxim Levitsky <mlevitsk@...hat.com>
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@....com>
---
 arch/x86/include/asm/svm.h |  1 +
 arch/x86/kvm/svm/avic.c    | 48 ++++++++++++++++++++++++++++++++++----
 2 files changed, 44 insertions(+), 5 deletions(-)

diff --git a/arch/x86/include/asm/svm.h b/arch/x86/include/asm/svm.h
index 1ccf301648a0..2519209c5f4a 100644
--- a/arch/x86/include/asm/svm.h
+++ b/arch/x86/include/asm/svm.h
@@ -248,6 +248,7 @@ enum avic_ipi_failure_cause {
 	AVIC_IPI_FAILURE_INVALID_BACKING_PAGE,
 };
 
+#define AVIC_PHYSICAL_MAX_INDEX_MASK	GENMASK_ULL(9, 0)
 
 /*
  * For AVIC, the max index allowed for physical APIC ID
diff --git a/arch/x86/kvm/svm/avic.c b/arch/x86/kvm/svm/avic.c
index 58b58a327826..4f9990526485 100644
--- a/arch/x86/kvm/svm/avic.c
+++ b/arch/x86/kvm/svm/avic.c
@@ -66,6 +66,45 @@ struct amd_svm_iommu_ir {
 	void *data;		/* Storing pointer to struct amd_ir_data */
 };
 
+static inline void avic_set_x2apic_msr_interception(struct vcpu_svm *svm, bool disable)
+{
+	int i;
+
+	for (i = 0x800; i <= 0x8ff; i++)
+		set_msr_interception(&svm->vcpu, svm->msrpm, i,
+				     !disable, !disable);
+}
+
+static void avic_activate_vmcb(struct vcpu_svm *svm)
+{
+	struct vmcb *vmcb = svm->vmcb01.ptr;
+
+	vmcb->control.int_ctl &= ~(AVIC_ENABLE_MASK | X2APIC_MODE_MASK);
+	vmcb->control.avic_physical_id &= ~AVIC_PHYSICAL_MAX_INDEX_MASK;
+
+	vmcb->control.int_ctl |= AVIC_ENABLE_MASK;
+	if (apic_x2apic_mode(svm->vcpu.arch.apic)) {
+		vmcb->control.int_ctl |= X2APIC_MODE_MASK;
+		vmcb->control.avic_physical_id |= X2AVIC_MAX_PHYSICAL_ID;
+		/* Disabling MSR intercept for x2APIC registers */
+		avic_set_x2apic_msr_interception(svm, false);
+	} else {
+		vmcb->control.avic_physical_id |= AVIC_MAX_PHYSICAL_ID;
+		/* Enabling MSR intercept for x2APIC registers */
+		avic_set_x2apic_msr_interception(svm, true);
+	}
+}
+
+static void avic_deactivate_vmcb(struct vcpu_svm *svm)
+{
+	struct vmcb *vmcb = svm->vmcb01.ptr;
+
+	vmcb->control.int_ctl &= ~(AVIC_ENABLE_MASK | X2APIC_MODE_MASK);
+	vmcb->control.avic_physical_id &= ~AVIC_PHYSICAL_MAX_INDEX_MASK;
+
+	/* Enabling MSR intercept for x2APIC registers */
+	avic_set_x2apic_msr_interception(svm, true);
+}
 
 /* Note:
  * This function is called from IOMMU driver to notify
@@ -183,13 +222,12 @@ void avic_init_vmcb(struct vcpu_svm *svm)
 	vmcb->control.avic_backing_page = bpa & AVIC_HPA_MASK;
 	vmcb->control.avic_logical_id = lpa & AVIC_HPA_MASK;
 	vmcb->control.avic_physical_id = ppa & AVIC_HPA_MASK;
-	vmcb->control.avic_physical_id |= AVIC_MAX_PHYSICAL_ID;
 	vmcb->control.avic_vapic_bar = APIC_DEFAULT_PHYS_BASE & VMCB_AVIC_APIC_BAR_MASK;
 
 	if (kvm_apicv_activated(svm->vcpu.kvm))
-		vmcb->control.int_ctl |= AVIC_ENABLE_MASK;
+		avic_activate_vmcb(svm);
 	else
-		vmcb->control.int_ctl &= ~AVIC_ENABLE_MASK;
+		avic_deactivate_vmcb(svm);
 }
 
 static u64 *avic_get_physical_id_entry(struct kvm_vcpu *vcpu,
@@ -691,9 +729,9 @@ void svm_refresh_apicv_exec_ctrl(struct kvm_vcpu *vcpu)
 		 * accordingly before re-activating.
 		 */
 		avic_post_state_restore(vcpu);
-		vmcb->control.int_ctl |= AVIC_ENABLE_MASK;
+		avic_activate_vmcb(svm);
 	} else {
-		vmcb->control.int_ctl &= ~AVIC_ENABLE_MASK;
+		avic_deactivate_vmcb(svm);
 	}
 	vmcb_mark_dirty(vmcb, VMCB_AVIC);
 
-- 
2.25.1