From patchwork Sat Sep 3 00:22:47 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 12964854 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2FD82C54EE9 for ; Sat, 3 Sep 2022 00:23:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230173AbiICAX5 (ORCPT ); Fri, 2 Sep 2022 20:23:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53954 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231478AbiICAXd (ORCPT ); Fri, 2 Sep 2022 20:23:33 -0400 Received: from mail-pf1-x449.google.com (mail-pf1-x449.google.com [IPv6:2607:f8b0:4864:20::449]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 89C73F72D0 for ; Fri, 2 Sep 2022 17:23:27 -0700 (PDT) Received: by mail-pf1-x449.google.com with SMTP id bt5-20020a056a00438500b0053b090003b0so1704609pfb.16 for ; Fri, 02 Sep 2022 17:23:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:from:to:cc:subject:date; bh=dsW89dfckTQ7U6+iEAzjnMXnoFtieG6da3C1L59fgMo=; b=M+li2tgSgjLklpIjOA9VfDwPNm+OKNxfpflwRzPHIRwKx/FgUX/G18HXpTtFxWXJtg DsuSNy9p5JpwaF4X1yz/CMs6OOhZV5jNFdhB1X3YXGyMXj/P5rYHPc49uNaKWCqe/pc0 5dMWxYR1SeJ18Fm5c+lr/ip8+9dbYeqTxU1zN35gj10f5J0JEAJ9203X6Jrs87E1JoAK kGdPfPq9wtKlALrTfFcYoQOpiWrfz3O62XPjYSxC/RsbtS+rn4qwxdfz2VOt1H832Wgq DEJpp6qfdl89RHXUGuoq2ZuZNfwMKS174uWnm057Nk0JntqGcTTRuCb1+kuX8yaxAbM/ DCUg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; 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; bh=dsW89dfckTQ7U6+iEAzjnMXnoFtieG6da3C1L59fgMo=; b=R4VW9cd4xkSfca5p9X3lB3c7npkJC4k/j+0p0mDXaFh1Ph/f6glNSQwWhF2X8FKU2J 3ysTZ87xASKXa1ufoofnh/4MEoQR31Nhp9YgxvGNgOB5ihhhvxZ0VCGiEg6Q2oNx04Va Zwhcc/Sd0SP+IQYPSB4HT9o1Iy7B6OMPqdUHMyAgsiRzxHE0+dJZBW7ogDlgAbI48CaG AvNrUG0X46zPuzEcZNCWRIpSFXcMc15BPsVv0oL4+scGjemM1mPBWPgmFX6D6gZKwD6p DcXNeUN8jz/cIwdUVtHIFjN+oWDfAE3kn82UUkFYSwvyKjbiVI2hUn/jRAzVA//+70bc isOQ== X-Gm-Message-State: ACgBeo3AVeuelmZCX5NNCLsl/OAvlr/X+b5xravVhXX4Y7I1RMfUFnUB oYwY+YAKLR7B4MHWeA5GMqxfTSwoJrc= X-Google-Smtp-Source: AA6agR4h06+UGnMuEU1Wnc3kO/LfJikOi7PtbuVfPGKo83ROZVVtfae6ZECKmpyETJvdvT4HDAsG7+jOQzk= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a17:90a:d343:b0:1fd:b437:7ae9 with SMTP id i3-20020a17090ad34300b001fdb4377ae9mr7759560pjx.73.1662164606644; Fri, 02 Sep 2022 17:23:26 -0700 (PDT) Reply-To: Sean Christopherson Date: Sat, 3 Sep 2022 00:22:47 +0000 In-Reply-To: <20220903002254.2411750-1-seanjc@google.com> Mime-Version: 1.0 References: <20220903002254.2411750-1-seanjc@google.com> X-Mailer: git-send-email 2.37.2.789.g6183377224-goog Message-ID: <20220903002254.2411750-17-seanjc@google.com> Subject: [PATCH v2 16/23] KVM: x86: Explicitly track all possibilities for APIC map's logical modes From: Sean Christopherson To: Sean Christopherson , Paolo Bonzini Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Suravee Suthikulpanit , Maxim Levitsky , Li RongQing Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Track all possibilities for the optimized APIC map's logical modes instead of overloading the pseudo-bitmap and treating any "unknown" value as "invalid". As documented by the now-stale comment above the mode values, the values did have meaning when the optimized map was originally added. That dependent logical was removed by commit e45115b62f9a ("KVM: x86: use physical LAPIC array for logical x2APIC"), but the obfuscated behavior and its comment were left behind. Opportunistically rename "mode" to "logical_mode", partly to make it clear that the "disabled" case applies only to the logical map, but also to prove that there is no lurking code that expects "mode" to be a bitmap. Functionally, this is a glorified nop. Signed-off-by: Sean Christopherson --- arch/x86/include/asm/kvm_host.h | 21 ++++++++++-------- arch/x86/kvm/lapic.c | 38 ++++++++++++++++++++++++--------- 2 files changed, 40 insertions(+), 19 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 1fd1b66ceeb6..13dadc96d9ac 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -955,19 +955,22 @@ struct kvm_arch_memory_slot { }; /* - * We use as the mode the number of bits allocated in the LDR for the - * logical processor ID. It happens that these are all powers of two. - * This makes it is very easy to detect cases where the APICs are - * configured for multiple modes; in that case, we cannot use the map and - * hence cannot use kvm_irq_delivery_to_apic_fast either. + * Track the mode of the optimized logical map, as the rules for decoding the + * destination vary per mode. Enabling the optimized logical map requires all + * software-enabled local APIs to be in the same mode, each addressable APIC to + * be mapped to only one MDA, and each MDA to map to at most one APIC. */ -#define KVM_APIC_MODE_XAPIC_CLUSTER 4 -#define KVM_APIC_MODE_XAPIC_FLAT 8 -#define KVM_APIC_MODE_X2APIC 16 +enum kvm_apic_logical_mode { + KVM_APIC_MODE_SW_DISABLED, + KVM_APIC_MODE_XAPIC_CLUSTER, + KVM_APIC_MODE_XAPIC_FLAT, + KVM_APIC_MODE_X2APIC, + KVM_APIC_MODE_MAP_DISABLED, +}; struct kvm_apic_map { struct rcu_head rcu; - u8 mode; + enum kvm_apic_logical_mode logical_mode; u32 max_apic_id; union { struct kvm_lapic *xapic_flat_map[8]; diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index 80528d86f010..407e933eb073 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -168,7 +168,12 @@ static bool kvm_use_posted_timer_interrupt(struct kvm_vcpu *vcpu) static inline bool kvm_apic_map_get_logical_dest(struct kvm_apic_map *map, u32 dest_id, struct kvm_lapic ***cluster, u16 *mask) { - switch (map->mode) { + switch (map->logical_mode) { + case KVM_APIC_MODE_SW_DISABLED: + /* Arbitrarily use the flat map so that @cluster isn't NULL. */ + *cluster = map->xapic_flat_map; + *mask = 0; + return true; case KVM_APIC_MODE_X2APIC: { u32 offset = (dest_id >> 16) * 16; u32 max_apic_id = map->max_apic_id; @@ -193,8 +198,10 @@ static inline bool kvm_apic_map_get_logical_dest(struct kvm_apic_map *map, *cluster = map->xapic_cluster_map[(dest_id >> 4) & 0xf]; *mask = dest_id & 0xf; return true; + case KVM_APIC_MODE_MAP_DISABLED: + return false; default: - /* Not optimized. */ + WARN_ON_ONCE(1); return false; } } @@ -256,10 +263,12 @@ void kvm_recalculate_apic_map(struct kvm *kvm) goto out; new->max_apic_id = max_id; + new->logical_mode = KVM_APIC_MODE_SW_DISABLED; kvm_for_each_vcpu(i, vcpu, kvm) { struct kvm_lapic *apic = vcpu->arch.apic; struct kvm_lapic **cluster; + enum kvm_apic_logical_mode logical_mode; u32 x2apic_id, physical_id; u16 mask; u32 ldr; @@ -314,7 +323,8 @@ void kvm_recalculate_apic_map(struct kvm *kvm) new->phys_map[physical_id] = apic; } - if (!kvm_apic_sw_enabled(apic)) + if (new->logical_mode == KVM_APIC_MODE_MAP_DISABLED || + !kvm_apic_sw_enabled(apic)) continue; ldr = kvm_lapic_get_reg(apic, APIC_LDR); @@ -322,25 +332,33 @@ void kvm_recalculate_apic_map(struct kvm *kvm) continue; if (apic_x2apic_mode(apic)) { - new->mode |= KVM_APIC_MODE_X2APIC; + logical_mode = KVM_APIC_MODE_X2APIC; } else { ldr = GET_APIC_LOGICAL_ID(ldr); if (kvm_lapic_get_reg(apic, APIC_DFR) == APIC_DFR_FLAT) - new->mode |= KVM_APIC_MODE_XAPIC_FLAT; + logical_mode = KVM_APIC_MODE_XAPIC_FLAT; else - new->mode |= KVM_APIC_MODE_XAPIC_CLUSTER; + logical_mode = KVM_APIC_MODE_XAPIC_CLUSTER; } + if (new->logical_mode != KVM_APIC_MODE_SW_DISABLED && + new->logical_mode != logical_mode) { + new->logical_mode = KVM_APIC_MODE_MAP_DISABLED; + continue; + } + new->logical_mode = logical_mode; - if (!kvm_apic_map_get_logical_dest(new, ldr, &cluster, &mask)) + if (WARN_ON_ONCE(!kvm_apic_map_get_logical_dest(new, ldr, + &cluster, &mask))) { + new->logical_mode = KVM_APIC_MODE_MAP_DISABLED; continue; + } if (!mask) continue; ldr = ffs(mask) - 1; if (!is_power_of_2(mask) || cluster[ldr]) { - new->mode = KVM_APIC_MODE_XAPIC_FLAT | - KVM_APIC_MODE_XAPIC_CLUSTER; + new->logical_mode = KVM_APIC_MODE_MAP_DISABLED; continue; } cluster[ldr] = apic; @@ -993,7 +1011,7 @@ static bool kvm_apic_is_broadcast_dest(struct kvm *kvm, struct kvm_lapic **src, { if (kvm->arch.x2apic_broadcast_quirk_disabled) { if ((irq->dest_id == APIC_BROADCAST && - map->mode != KVM_APIC_MODE_X2APIC)) + map->logical_mode != KVM_APIC_MODE_X2APIC)) return true; if (irq->dest_id == X2APIC_BROADCAST) return true;