linux-kernel - [PATCH 09/10] KVM: SVM: Drop redundant check in AVIC code on ID during vCPU creation

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Message-ID: <20230815213533.548732-10-seanjc@google.com>
Date:   Tue, 15 Aug 2023 14:35:32 -0700
From:   Sean Christopherson <seanjc@...gle.com>
To:     Sean Christopherson <seanjc@...gle.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Joerg Roedel <joro@...tes.org>
Cc:     kvm@...r.kernel.org, iommu@...ts.linux.dev,
        linux-kernel@...r.kernel.org, Maxim Levitsky <mlevitsk@...hat.com>
Subject: [PATCH 09/10] KVM: SVM: Drop redundant check in AVIC code on ID
 during vCPU creation

Drop avic_get_physical_id_entry()'s compatibility check on the incoming
ID, as its sole caller, avic_init_backing_page(), performs the exact same
check.  Drop avic_get_physical_id_entry() entirely as the only remaining
functionality is getting the address of the Physical ID table, and
accessing the array without an immediate bounds check is kludgy.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 arch/x86/kvm/svm/avic.c | 28 ++++++----------------------
 1 file changed, 6 insertions(+), 22 deletions(-)

diff --git a/arch/x86/kvm/svm/avic.c b/arch/x86/kvm/svm/avic.c
index 3b2d00d9ca9b..6803e2d7bc22 100644
--- a/arch/x86/kvm/svm/avic.c
+++ b/arch/x86/kvm/svm/avic.c
@@ -263,26 +263,12 @@ void avic_init_vmcb(struct vcpu_svm *svm, struct vmcb *vmcb)
 		avic_deactivate_vmcb(svm);
 }
 
-static u64 *avic_get_physical_id_entry(struct kvm_vcpu *vcpu,
-				       unsigned int index)
-{
-	u64 *avic_physical_id_table;
-	struct kvm_svm *kvm_svm = to_kvm_svm(vcpu->kvm);
-
-	if ((!x2avic_enabled && index > AVIC_MAX_PHYSICAL_ID) ||
-	    (index > X2AVIC_MAX_PHYSICAL_ID))
-		return NULL;
-
-	avic_physical_id_table = page_address(kvm_svm->avic_physical_id_table_page);
-
-	return &avic_physical_id_table[index];
-}
-
 static int avic_init_backing_page(struct kvm_vcpu *vcpu)
 {
-	u64 *entry, new_entry;
+	struct kvm_svm *kvm_svm = to_kvm_svm(vcpu->kvm);
+	struct vcpu_svm *svm = to_svm(vcpu);
+	u64 *table, new_entry;
 	int id = vcpu->vcpu_id;
-	struct vcpu_svm *svm = to_svm(vcpu);
 
 	/*
 	 * Inhibit AVIC if the vCPU ID is bigger than what is supported by AVIC
@@ -318,15 +304,13 @@ static int avic_init_backing_page(struct kvm_vcpu *vcpu)
 	}
 
 	/* Setting AVIC backing page address in the phy APIC ID table */
-	entry = avic_get_physical_id_entry(vcpu, id);
-	if (!entry)
-		return -EINVAL;
+	table = page_address(kvm_svm->avic_physical_id_table_page);
 
 	new_entry = avic_get_backing_page_address(svm) |
 		    AVIC_PHYSICAL_ID_ENTRY_VALID_MASK;
-	WRITE_ONCE(*entry, new_entry);
+	WRITE_ONCE(table[id], new_entry);
 
-	svm->avic_physical_id_cache = entry;
+	svm->avic_physical_id_cache = &table[id];
 
 	return 0;
 }
-- 
2.41.0.694.ge786442a9b-goog