From nobody Fri May 17 04:49:28 2024 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass(p=none dis=none) header.from=gmail.com ARC-Seal: i=1; a=rsa-sha256; t=1681051391; cv=none; d=zohomail.com; s=zohoarc; b=aRgiizAiiDr4CJj9a27Ofdgjh9WMcbnZB4dg6KsuDUNXXVtJhOyvApiiBEctWZWVba7KQxkJpBTd5RDhh6bO0HR9Dyk9Zctn+ymjV3cKjCqGLI6T4i1kDvfTQ6ex9pSL4qw51hWzhxMhN/D44xQsEwsaz/stjmBHBqQkU3ZJKGE= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1681051391; h=Content-Transfer-Encoding:Cc:Date:From:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:Sender:Subject:To; bh=hZQ5EbAGhVUB35LozcJIt4zsyAn0UnxD9yILop/3N5I=; b=YSf3Y6ms0ZwYns713vFMv8UrkRd3rKLTsLP/uZQoxdwOujGRKQrmQi9BRrM8gv9fsNaub8uSw4HhYAklIeae1kGx206+GgCMgEK9BuJnBm1FAmZu/ZtSs1Bl+tyzKZkENPKvcWn0ZIWze5Qgn50ZwCpqMknaTtIwgk7UwFIDt1s= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass header.from= (p=none dis=none) Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1681051391033521.3448837166745; Sun, 9 Apr 2023 07:43:11 -0700 (PDT) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1plWFz-0005Qn-93; Sun, 09 Apr 2023 10:43:03 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1plWE1-0003eU-G7 for qemu-devel@nongnu.org; Sun, 09 Apr 2023 10:41:02 -0400 Received: from mail-pj1-x1031.google.com ([2607:f8b0:4864:20::1031]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1plWDz-0000fu-BR for qemu-devel@nongnu.org; Sun, 09 Apr 2023 10:41:00 -0400 Received: by mail-pj1-x1031.google.com with SMTP id j8so353928pjy.4 for ; Sun, 09 Apr 2023 07:40:58 -0700 (PDT) Received: from localhost.localdomain (ec2-18-162-55-96.ap-east-1.compute.amazonaws.com. [18.162.55.96]) by smtp.gmail.com with ESMTPSA id z24-20020a1709028f9800b0019aeddce6casm4371185plo.205.2023.04.09.07.40.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 09 Apr 2023 07:40:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; t=1681051257; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=hZQ5EbAGhVUB35LozcJIt4zsyAn0UnxD9yILop/3N5I=; b=B1yQSANJ70L0d2eOZgBZqFwmQUy2m97CSJmcmtymMzsS2Ge2Z9hAL3Sc+01PlKXzbd RtMhlG6HJDv2tooJHsg1Gf2fohRIikXrSuAkwDOoEC2MqCzCYE4YJwMQjkNo4mmHz4wL w5P8JlneIbwv2OI8awP4nwlFz33177Jn3YFt9BJii61tnngTgEgMlnHh1PVPh/DTKUAn o3zvQkQM0hfD9QwbFwDWriv7LVUQYUxoOQg1v6ZRp52itbU+oPgyKvxSXsJHUrzFlYYI H7yAt5Uvl9Byhfi/T2YNY+nrc6KDWJRwkEsi1bwgzfptfMbYCQ8AIhE4tWI1m5ERQ/Uf jpEQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1681051257; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=hZQ5EbAGhVUB35LozcJIt4zsyAn0UnxD9yILop/3N5I=; b=p7jRr0bARDhM9QhubWu1uIgNvdgY+3nlnrLIY2FBxaGOlN+PfbWA2uRjwcAcJxgTLQ 7dI3hFnky2oT5LnjNANP5R0w91ouaFSBeE03KfiS8p5M/G47DFKHbJkhdVjk10bwX3Z/ nbW3+nS126kqA+/oRFFBVmULLVpjzP+VRgfiNI4oSnYgqShx0DEMsTpPmIa8Epo45y/w 99yIf1LZDUqBTIHAnJHMpJZf2l6zteQD41BRW9v8rNbviufIoC6OsnZf2XOjXtuy0Noa SbNd+N3mzrTkKQNF4Elm6447vtFhNuvBdKHDg2t8SCMaZTZ88NfvxDZjuui9HVWIaL2+ uzQQ== X-Gm-Message-State: AAQBX9cdpXGDqZkcJ1vgwU5jhHClIoHGQcKontL3PXSYp6FT1VjSUEmq /1DDKwODV3Mo+p9BUcynDXc= X-Google-Smtp-Source: AKy350bSdWGYsomWLOvkF1ydjNA3B5cc22wo8klZe60C+vcJqWYg7martpVIXesGgfYFDdrsdGdHpg== X-Received: by 2002:a17:902:e292:b0:1a0:75fe:cd66 with SMTP id o18-20020a170902e29200b001a075fecd66mr8094439plc.50.1681051257374; Sun, 09 Apr 2023 07:40:57 -0700 (PDT) From: Robert Hoo To: pbonzini@redhat.com, qemu-devel@nongnu.org Cc: Robert Hoo Subject: [PATCH] accel/kvm: Don't use KVM maximum support number to alloc user memslots Date: Sun, 9 Apr 2023 22:40:15 +0800 Message-Id: <20230409144015.1610-1-robert.hoo.linux@gmail.com> X-Mailer: git-send-email 2.39.0 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=2607:f8b0:4864:20::1031; envelope-from=robert.hoo.linux@gmail.com; helo=mail-pj1-x1031.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, FREEMAIL_FROM=0.001, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-Mailman-Approved-At: Sun, 09 Apr 2023 10:43:01 -0400 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZohoMail-DKIM: pass (identity @gmail.com) X-ZM-MESSAGEID: 1681051392470100001 Content-Type: text/plain; charset="utf-8" This patch corrects QEMU to properly use what KVM_CAP_NR_MEMSLOTS means, i.e. the maximum user memslots KVM supports. 1. Rename KVMState::nr_slots --> max_slots. 2. Remember nr_slots in each KML. This also decouples each KML, e.g. x86's two KMLs don't need to have same size of slots[]. 3. Change back initial slot[] size to 32, increase it dynamically (exponentially) until the maximum number KVM supports. 32 should suites almost all normal guests. Background: Since KVM commit 4fc096a99e01d ("KVM: Raise the maximum number of user memslots"), KVM_CAP_NR_MEMSLOTS returns 32764 (SHRT_MAX - 3), which is a huge increase from previous 509 (x86). This change based on the fact that KVM alloc memslots dynamically. But QEMU allocates that huge number of user memslots statically. This is indeed unwanted by both sides. It makes: 1. Memory waste. Allocates (SHRT_MAX - 3) * sizeof(KVMSlot), while a typical VM needs far less, e.g. my VM just reached 9th as the highest mem slot ever used. x86 further, has 2 kmls. 2. Time waste. Several KML Slot functions go through the whole KML::slots[], (SHRT_MAX - 3) makes it far longer than necessary, e.g. kvm_lookup_matching_slot(), kvm_physical_memory_addr_from_host(), kvm_physical_log_clear(), kvm_log_sync_global(). Test: Temporarily set KVM_DEF_NR_SLOTS =3D 8, let it go through slot[] dynamic increase, VM launched and works well. Signed-off-by: Robert Hoo --- accel/kvm/kvm-all.c | 57 +++++++++++++++++++++++++++++----------- include/sysemu/kvm_int.h | 4 ++- 2 files changed, 45 insertions(+), 16 deletions(-) diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c index cf3a88d90e..708170139c 100644 --- a/accel/kvm/kvm-all.c +++ b/accel/kvm/kvm-all.c @@ -178,22 +178,50 @@ int kvm_get_max_memslots(void) { KVMState *s =3D KVM_STATE(current_accel()); =20 - return s->nr_slots; + return s->max_slots; } =20 -/* Called with KVMMemoryListener.slots_lock held */ +/* Called with kvm_slots_lock()'ed */ static KVMSlot *kvm_get_free_slot(KVMMemoryListener *kml) { KVMState *s =3D kvm_state; + KVMSlot *new_slots; int i; + int new_nr, old_nr; =20 - for (i =3D 0; i < s->nr_slots; i++) { + for (i =3D 0; i < kml->nr_slots; i++) { if (kml->slots[i].memory_size =3D=3D 0) { return &kml->slots[i]; } } =20 - return NULL; + /* Already reached maximum, no more can expand */ + if (kml->nr_slots >=3D s->max_slots) { + return NULL; + } + + new_nr =3D 2 * kml->nr_slots; + new_nr =3D MIN(new_nr, s->max_slots); + /* It might overflow */ + if (new_nr < 0 || new_nr <=3D kml->nr_slots) { + return NULL; + } + + new_slots =3D g_try_new0(KVMSlot, new_nr); + if (!new_slots) { + return NULL; + } + + memcpy(new_slots, kml->slots, kml->nr_slots * sizeof(KVMSlot)); + old_nr =3D kml->nr_slots; + kml->nr_slots =3D new_nr; + g_free(kml->slots); + kml->slots =3D new_slots; + for (i =3D old_nr; i < kml->nr_slots; i++) { + kml->slots[i].slot =3D i; + } + + return &kml->slots[old_nr]; } =20 bool kvm_has_free_slot(MachineState *ms) @@ -226,10 +254,9 @@ static KVMSlot *kvm_lookup_matching_slot(KVMMemoryList= ener *kml, hwaddr start_addr, hwaddr size) { - KVMState *s =3D kvm_state; int i; =20 - for (i =3D 0; i < s->nr_slots; i++) { + for (i =3D 0; i < kml->nr_slots; i++) { KVMSlot *mem =3D &kml->slots[i]; =20 if (start_addr =3D=3D mem->start_addr && size =3D=3D mem->memory_s= ize) { @@ -271,7 +298,7 @@ int kvm_physical_memory_addr_from_host(KVMState *s, voi= d *ram, int i, ret =3D 0; =20 kvm_slots_lock(); - for (i =3D 0; i < s->nr_slots; i++) { + for (i =3D 0; i < kml->nr_slots; i++) { KVMSlot *mem =3D &kml->slots[i]; =20 if (ram >=3D mem->ram && ram < mem->ram + mem->memory_size) { @@ -1002,7 +1029,7 @@ static int kvm_physical_log_clear(KVMMemoryListener *= kml, =20 kvm_slots_lock(); =20 - for (i =3D 0; i < s->nr_slots; i++) { + for (i =3D 0; i < kml->nr_slots; i++) { mem =3D &kml->slots[i]; /* Discard slots that are empty or do not overlap the section */ if (!mem->memory_size || @@ -1566,7 +1593,6 @@ static void kvm_log_sync(MemoryListener *listener, static void kvm_log_sync_global(MemoryListener *l) { KVMMemoryListener *kml =3D container_of(l, KVMMemoryListener, listener= ); - KVMState *s =3D kvm_state; KVMSlot *mem; int i; =20 @@ -1578,7 +1604,7 @@ static void kvm_log_sync_global(MemoryListener *l) * only a few used slots (small VMs). */ kvm_slots_lock(); - for (i =3D 0; i < s->nr_slots; i++) { + for (i =3D 0; i < kml->nr_slots; i++) { mem =3D &kml->slots[i]; if (mem->memory_size && mem->flags & KVM_MEM_LOG_DIRTY_PAGES) { kvm_slot_sync_dirty_pages(mem); @@ -1687,10 +1713,11 @@ void kvm_memory_listener_register(KVMState *s, KVMM= emoryListener *kml, { int i; =20 - kml->slots =3D g_new0(KVMSlot, s->nr_slots); + kml->slots =3D g_new0(KVMSlot, KVM_DEF_NR_SLOTS); + kml->nr_slots =3D KVM_DEF_NR_SLOTS; kml->as_id =3D as_id; =20 - for (i =3D 0; i < s->nr_slots; i++) { + for (i =3D 0; i < kml->nr_slots; i++) { kml->slots[i].slot =3D i; } =20 @@ -2427,11 +2454,11 @@ static int kvm_init(MachineState *ms) } =20 kvm_immediate_exit =3D kvm_check_extension(s, KVM_CAP_IMMEDIATE_EXIT); - s->nr_slots =3D kvm_check_extension(s, KVM_CAP_NR_MEMSLOTS); + s->max_slots =3D kvm_check_extension(s, KVM_CAP_NR_MEMSLOTS); =20 /* If unspecified, use the default value */ - if (!s->nr_slots) { - s->nr_slots =3D 32; + if (s->max_slots <=3D 0) { + s->max_slots =3D KVM_DEF_NR_SLOTS; } =20 s->nr_as =3D kvm_check_extension(s, KVM_CAP_MULTI_ADDRESS_SPACE); diff --git a/include/sysemu/kvm_int.h b/include/sysemu/kvm_int.h index a641c974ea..38297ae366 100644 --- a/include/sysemu/kvm_int.h +++ b/include/sysemu/kvm_int.h @@ -37,8 +37,10 @@ typedef struct KVMMemoryUpdate { MemoryRegionSection section; } KVMMemoryUpdate; =20 +#define KVM_DEF_NR_SLOTS 32 typedef struct KVMMemoryListener { MemoryListener listener; + int nr_slots; KVMSlot *slots; int as_id; QSIMPLEQ_HEAD(, KVMMemoryUpdate) transaction_add; @@ -69,7 +71,7 @@ struct KVMState { AccelState parent_obj; =20 - int nr_slots; + int max_slots; int fd; int vmfd; int coalesced_mmio; base-commit: c6f3cbca32bde9ee94d9949aa63e8a7ef2d7bc5b --=20 2.31.1