From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pf1-f201.google.com (mail-pf1-f201.google.com [209.85.210.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 51C71224231 for ; Fri, 23 May 2025 01:00:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747962032; cv=none; b=SuVrlvvllDA0Sux3bDlj94JD1okogRaWJ1qls9WRKsCjlUCXuxmT0U/G8AF4uUfIYqfGjmXkuLCBIRYP09lObzDfVG7JEIJEIHlpslCDJXve+XghfiB/OrmTUuccfegLekyvr0rWHGfNo8q4NivxV1JiigKrJ9HQGfHi3gvE+K8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747962032; c=relaxed/simple; bh=NmtIJk+NXuVQcgcHe/OX20tZuAMC4d7N9CttC/YW7ug=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=JOwcghKWoCF+xUveW1zRY167LwBPATCksub4YiWARLvWxLk9YhX30IZIT2yvzVj72c78W6VyJhRMf3CcMxLV7b8ifDW7xgkOgWC3g0q/FHR416rmq5pQTi53ElPcHM5NcI+D94CInugNdwMeHulxElqpNCBdc116cJAVQGRxcsg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=ZVrVnPQY; arc=none smtp.client-ip=209.85.210.201 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="ZVrVnPQY" Received: by mail-pf1-f201.google.com with SMTP id d2e1a72fcca58-7429fc0bfc8so324968b3a.1 for ; Thu, 22 May 2025 18:00:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1747962030; x=1748566830; darn=lists.linux.dev; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:from:to:cc:subject:date:message-id:reply-to; bh=qvU0dOld0vUayuYrP2inmYflxGewHdZ05MuEuDFSsRI=; b=ZVrVnPQYXjK4yDHfH43kUbXOdld+ahtZ6poV0u+MQtH8YTQOQgkJp1qm1lETVqZA7w HbHCw8+7zNZcf9wqEl8qTRGJOYFso+qL7GOoy+I9QPRoAR/GPQn5Wsey2EUvpsxu4hp7 4mO7oyUC6RmfA5O7QIn9BMSPpB4fzZcZ8rYXMcawCleOJ+jV/TGxw9ifZLMheM56BH0A LH9VFywbDbYDfG0sYiyU6cEqPcltWLUncolJs2qZx5BXYGVdy5mnN3bJC8qAd3yBtxbp fsUg8eMj1Sk+IcPlG6pvcYw2bX1gWuBj5ic3UEiMg678UtfvijlYEYVzrD54y7Ge+kq0 i3Pw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1747962030; x=1748566830; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=qvU0dOld0vUayuYrP2inmYflxGewHdZ05MuEuDFSsRI=; b=cvaKGeWjzGDLV7ZS7VShtpvhO/5P3Z+Wa9ki6tRyM6je8jrIHUls4QcOOuuXiav4mY HFgerqDpV/t6UVXNHDJFXoEtt7+W8PUF81BhFRC3VFf8jCXKjK29glgL9wkmaDgximJX uVwqFz6I+g+g5lMFfhqfr2lLgYNW1QC2RHHjohIEjppJ2QUkGAXPW8dtVsTp6hKVBrO2 22Xd6vH9R3NJi1rZzU81vnm6TNfTLxGlknT0vO3Wc7UbB1ZryxF6/Fz/EgptW9E/cXWG +sg9eWc7QKkWUzQgDQy7K30kxXCQsOvijvw3264Bu2StrrH32m36hfNf1EKKQTG7tY2p JIeg== X-Forwarded-Encrypted: i=1; AJvYcCVt5zRSoLu7W78GglsKn3Wn7+4lIkTBdwxKjd99IYAHiuK+YCkzld2mErtpobVdgysLV2Gjow==@lists.linux.dev X-Gm-Message-State: AOJu0YzPlbkZk2s0PMVs1dIfE+yOVPuaTWJklgIeyrxiw0K1R/3g20IN KxtMgdU1faGAkIAS+IeEDWoAqvhidTzbqEm3FROoHX2ME2OvK0bF5VzgvlzmPOMSvloEL/dAJ4I H1sT65A== X-Google-Smtp-Source: AGHT+IHUAkRGBcbeHEZC8d5MhipzP08zCSRQ2GxGmkCxhyIuuWUqgFNrdbfXKGFZCAm/KodkxoGK3IgwYXs= X-Received: from pgah21.prod.google.com ([2002:a05:6a02:4e95:b0:b26:f984:15bc]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a21:78e:b0:1f0:e6db:b382 with SMTP id adf61e73a8af0-21877a3a205mr2221344637.8.1747962029662; Thu, 22 May 2025 18:00:29 -0700 (PDT) Reply-To: Sean Christopherson Date: Thu, 22 May 2025 17:59:16 -0700 In-Reply-To: <20250523010004.3240643-1-seanjc@google.com> Precedence: bulk X-Mailing-List: iommu@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250523010004.3240643-1-seanjc@google.com> X-Mailer: git-send-email 2.49.0.1151.ga128411c76-goog Message-ID: <20250523010004.3240643-12-seanjc@google.com> Subject: [PATCH v2 11/59] KVM: SVM: Drop redundant check in AVIC code on ID during vCPU creation From: Sean Christopherson To: Sean Christopherson , Paolo Bonzini , Joerg Roedel , David Woodhouse , Lu Baolu Cc: kvm@vger.kernel.org, iommu@lists.linux.dev, linux-kernel@vger.kernel.org, Sairaj Kodilkar , Vasant Hegde , Maxim Levitsky , Joao Martins , Francesco Lavra , David Matlack Content-Type: text/plain; charset="UTF-8" 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. Opportunistically add a compile-time assertion to ensure the vcpu_id can't result in a bounds overflow, e.g. if KVM (really) messed up a maximum physical ID #define, as well as run-time assertions so that a NULL pointer dereference is morphed into a safer WARN(). No functional change intended. Tested-by: Sairaj Kodilkar Signed-off-by: Sean Christopherson --- arch/x86/kvm/svm/avic.c | 37 +++++++++++++++---------------------- 1 file changed, 15 insertions(+), 22 deletions(-) diff --git a/arch/x86/kvm/svm/avic.c b/arch/x86/kvm/svm/avic.c index f0a74b102c57..948bab48083b 100644 --- a/arch/x86/kvm/svm/avic.c +++ b/arch/x86/kvm/svm/avic.c @@ -256,26 +256,12 @@ 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; - int id = vcpu->vcpu_id; + struct kvm_svm *kvm_svm = to_kvm_svm(vcpu->kvm); struct vcpu_svm *svm = to_svm(vcpu); + u32 id = vcpu->vcpu_id; + u64 *table, new_entry; /* * Inhibit AVIC if the vCPU ID is bigger than what is supported by AVIC @@ -291,6 +277,9 @@ static int avic_init_backing_page(struct kvm_vcpu *vcpu) return 0; } + BUILD_BUG_ON((AVIC_MAX_PHYSICAL_ID + 1) * sizeof(*table) > PAGE_SIZE || + (X2AVIC_MAX_PHYSICAL_ID + 1) * sizeof(*table) > PAGE_SIZE); + if (WARN_ON_ONCE(!vcpu->arch.apic->regs)) return -EINVAL; @@ -309,9 +298,7 @@ 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); /* Note, fls64() returns the bit position, +1. */ BUILD_BUG_ON(__PHYSICAL_MASK_SHIFT > @@ -319,9 +306,9 @@ static int avic_init_backing_page(struct kvm_vcpu *vcpu) 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; } @@ -1004,6 +991,9 @@ void avic_vcpu_load(struct kvm_vcpu *vcpu, int cpu) if (WARN_ON(h_physical_id & ~AVIC_PHYSICAL_ID_ENTRY_HOST_PHYSICAL_ID_MASK)) return; + if (WARN_ON_ONCE(!svm->avic_physical_id_cache)) + return; + /* * No need to update anything if the vCPU is blocking, i.e. if the vCPU * is being scheduled in after being preempted. The CPU entries in the @@ -1044,6 +1034,9 @@ void avic_vcpu_put(struct kvm_vcpu *vcpu) lockdep_assert_preemption_disabled(); + if (WARN_ON_ONCE(!svm->avic_physical_id_cache)) + return; + /* * Note, reading the Physical ID entry outside of ir_list_lock is safe * as only the pCPU that has loaded (or is loading) the vCPU is allowed -- 2.49.0.1151.ga128411c76-goog