linux-kernel - [RFC PATCH v3 03/19] KVM: x86: SVM: remove avic's broken code that updated APIC ID

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Date:   Wed, 27 Apr 2022 23:02:58 +0300
From:   Maxim Levitsky <mlevitsk@...hat.com>
To:     kvm@...r.kernel.org
Cc:     Wanpeng Li <wanpengli@...cent.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Jani Nikula <jani.nikula@...ux.intel.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Tvrtko Ursulin <tvrtko.ursulin@...ux.intel.com>,
        Rodrigo Vivi <rodrigo.vivi@...el.com>,
        Zhenyu Wang <zhenyuw@...ux.intel.com>,
        Joonas Lahtinen <joonas.lahtinen@...ux.intel.com>,
        Tom Lendacky <thomas.lendacky@....com>,
        Ingo Molnar <mingo@...hat.com>,
        David Airlie <airlied@...ux.ie>,
        Thomas Gleixner <tglx@...utronix.de>,
        Dave Hansen <dave.hansen@...ux.intel.com>, x86@...nel.org,
        intel-gfx@...ts.freedesktop.org,
        Sean Christopherson <seanjc@...gle.com>,
        Daniel Vetter <daniel@...ll.ch>,
        Borislav Petkov <bp@...en8.de>, Joerg Roedel <joro@...tes.org>,
        linux-kernel@...r.kernel.org, Jim Mattson <jmattson@...gle.com>,
        Zhi Wang <zhi.a.wang@...el.com>,
        Brijesh Singh <brijesh.singh@....com>,
        "H. Peter Anvin" <hpa@...or.com>,
        intel-gvt-dev@...ts.freedesktop.org,
        dri-devel@...ts.freedesktop.org,
        Maxim Levitsky <mlevitsk@...hat.com>
Subject: [RFC PATCH v3 03/19] KVM: x86: SVM: remove avic's broken code that updated APIC ID

AVIC is now inhibited if the guest changes apic id, thus remove
that broken code.

Signed-off-by: Maxim Levitsky <mlevitsk@...hat.com>
---
 arch/x86/kvm/svm/avic.c | 35 -----------------------------------
 1 file changed, 35 deletions(-)

diff --git a/arch/x86/kvm/svm/avic.c b/arch/x86/kvm/svm/avic.c
index 54fe03714f8a6..1102421668a11 100644
--- a/arch/x86/kvm/svm/avic.c
+++ b/arch/x86/kvm/svm/avic.c
@@ -508,35 +508,6 @@ static int avic_handle_ldr_update(struct kvm_vcpu *vcpu)
 	return ret;
 }
 
-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);
-
-	if (vcpu->vcpu_id == id)
-		return 0;
-
-	old = avic_get_physical_id_entry(vcpu, vcpu->vcpu_id);
-	new = avic_get_physical_id_entry(vcpu, id);
-	if (!new || !old)
-		return 1;
-
-	/* We need to move physical_id_entry to new offset */
-	*new = *old;
-	*old = 0ULL;
-	to_svm(vcpu)->avic_physical_id_cache = new;
-
-	/*
-	 * Also update the guest physical APIC ID in the logical
-	 * APIC ID table entry if already setup the LDR.
-	 */
-	if (svm->ldr_reg)
-		avic_handle_ldr_update(vcpu);
-
-	return 0;
-}
-
 static void avic_handle_dfr_update(struct kvm_vcpu *vcpu)
 {
 	struct vcpu_svm *svm = to_svm(vcpu);
@@ -555,10 +526,6 @@ static int avic_unaccel_trap_write(struct kvm_vcpu *vcpu)
 				AVIC_UNACCEL_ACCESS_OFFSET_MASK;
 
 	switch (offset) {
-	case APIC_ID:
-		if (avic_handle_apic_id_update(vcpu))
-			return 0;
-		break;
 	case APIC_LDR:
 		if (avic_handle_ldr_update(vcpu))
 			return 0;
@@ -650,8 +617,6 @@ int avic_init_vcpu(struct vcpu_svm *svm)
 
 void avic_apicv_post_state_restore(struct kvm_vcpu *vcpu)
 {
-	if (avic_handle_apic_id_update(vcpu) != 0)
-		return;
 	avic_handle_dfr_update(vcpu);
 	avic_handle_ldr_update(vcpu);
 }
-- 
2.26.3