From patchwork Sat Oct 21 13:40:15 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Daan De Meyer X-Patchwork-Id: 1852999 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256 header.s=20230601 header.b=CMe0QBtJ; dkim-atps=neutral Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=patchwork.ozlabs.org) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-ECDSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4SCN9q0d0Lz202k for ; Sun, 22 Oct 2023 00:49:50 +1100 (AEDT) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1quCLo-0003gm-SL; Sat, 21 Oct 2023 09:49:18 -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 1quCDP-0000k0-Rh for qemu-devel@nongnu.org; Sat, 21 Oct 2023 09:40:31 -0400 Received: from mail-wm1-x32c.google.com ([2a00:1450:4864:20::32c]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1quCDO-0006M1-7q for qemu-devel@nongnu.org; Sat, 21 Oct 2023 09:40:31 -0400 Received: by mail-wm1-x32c.google.com with SMTP id 5b1f17b1804b1-40837ebba42so13236575e9.0 for ; Sat, 21 Oct 2023 06:40:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1697895628; x=1698500428; darn=nongnu.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=At1jsVLlupIiRvoiq5by/aHnfQWBZjYV5W5vgE3NJa4=; b=CMe0QBtJmS2VSIWcpiMjYq+J0jqR9gIeBJVejyDZdaW5/Vr38ObIsKgo0GH022TDm2 dVwjCqtPsNKk4Y70veF4sOU9gPj4CgFHHMmsdmi31HbD3NeXBnPTN6cGvYHyBEYRcfMU b8jFqxk43wHdgOFNiEQ9hxh6YvNlFAthNwnNqGfPiFTPUeUPDscnumHqdaTHh+3VuBkO YcQQ1n1l7FohcISv7bv3+lunRKVDNO0WFdOI14nk+cPJVf+okE1fUJEk5/oum5fIHMgs ELyQqqQZ94206sLXfgPofgJ+kFfJOrJMBFDwkhBClYxbFO1YieSAIF4/rK3i2rZenMEb Poyw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1697895628; x=1698500428; 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=At1jsVLlupIiRvoiq5by/aHnfQWBZjYV5W5vgE3NJa4=; b=K/hWi8kSphUVZZ/mBXO6Iru8vu2JZhkbtwyc/1jQI94oVmEaPRUWBs9XRNGRMCramP J475IeohrGnf8D+yWucelguqS95zbpmt7DUAlKbYK4FO7bTJLWd75rVkG/pBOnLGLiQC 3KdLXZmoKGg6DCUlkk66KBBcw90QzBAtKs8NQ9wWgZzLKUHZV4fhZJOxBz8CvZ84zYeq 7xGmdkDJ0EjQYD1MjQbJZYEXLy1c1fXR/0SStvQd7Nsw8s12y6WcKn3eo/g4gCUS5dFH Eop7z2AUBQpKeVRunQi9YlWtoJAOStRy7T4L9YU/0LXS+ZlTLtYsYuMlaIhXOMICwhsO h5Vw== X-Gm-Message-State: AOJu0YzulPGC1iOzvXPiPLOhwwlranFyrETLALMXTIjAqikPxpxf++L7 7fIbdG0CMyeaG4Ka3dKqclTWf5gY4do= X-Google-Smtp-Source: AGHT+IEnZ/0NJLa2Gx/dyL23Jh+pUGPX2QqVxWhvvc8m5QJWNV2Sl/aI/LuNDM2hajRdioanaI2evA== X-Received: by 2002:a05:600c:4f45:b0:407:7e7a:6017 with SMTP id m5-20020a05600c4f4500b004077e7a6017mr3625970wmq.11.1697895627615; Sat, 21 Oct 2023 06:40:27 -0700 (PDT) Received: from localhost.localdomain ([2a02:a03f:864b:8201:e534:34f4:1c34:8de7]) by smtp.googlemail.com with ESMTPSA id e7-20020a05600c218700b00407efbc4361sm9302948wme.9.2023.10.21.06.40.26 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 21 Oct 2023 06:40:26 -0700 (PDT) From: Daan De Meyer To: qemu-devel@nongnu.org Cc: kvm@vger.kernel.org, Paolo Bonzini , Daan De Meyer Subject: [PATCH] Add class property to configure KVM device node to use Date: Sat, 21 Oct 2023 15:40:15 +0200 Message-ID: <20231021134015.1119597-1-daan.j.demeyer@gmail.com> X-Mailer: git-send-email 2.41.0 MIME-Version: 1.0 Received-SPF: pass client-ip=2a00:1450:4864:20::32c; envelope-from=daan.j.demeyer@gmail.com; helo=mail-wm1-x32c.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: Sat, 21 Oct 2023 09:48:48 -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+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org This allows passing the KVM device node to use as a file descriptor via /dev/fdset/XX. Passing the device node to use as a file descriptor allows running qemu unprivileged even when the user running qemu is not in the kvm group on distributions where access to /dev/kvm is gated behind membership of the kvm group (as long as the process invoking qemu is able to open /dev/kvm and passes the file descriptor to qemu). Signed-off-by: Daan De Meyer Reviewed-by: Daniel P. Berrangé --- accel/kvm/kvm-all.c | 25 ++++++++++++++++++++++++- include/sysemu/kvm_int.h | 1 + qemu-options.hx | 8 +++++++- 3 files changed, 32 insertions(+), 2 deletions(-) diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c index 72e1d1141c..3e0b2d00e9 100644 --- a/accel/kvm/kvm-all.c +++ b/accel/kvm/kvm-all.c @@ -2478,7 +2478,7 @@ static int kvm_init(MachineState *ms) QTAILQ_INIT(&s->kvm_sw_breakpoints); #endif QLIST_INIT(&s->kvm_parked_vcpus); - s->fd = qemu_open_old("/dev/kvm", O_RDWR); + s->fd = qemu_open_old(s->device ?: "/dev/kvm", O_RDWR); if (s->fd == -1) { fprintf(stderr, "Could not access KVM kernel module: %m\n"); ret = -errno; @@ -3775,6 +3775,24 @@ static void kvm_set_dirty_ring_size(Object *obj, Visitor *v, s->kvm_dirty_ring_size = value; } +static char *kvm_get_device(Object *obj, + Error **errp G_GNUC_UNUSED) +{ + KVMState *s = KVM_STATE(obj); + + return g_strdup(s->device); +} + +static void kvm_set_device(Object *obj, + const char *value, + Error **errp G_GNUC_UNUSED) +{ + KVMState *s = KVM_STATE(obj); + + g_free(s->device); + s->device = g_strdup(value); +} + static void kvm_accel_instance_init(Object *obj) { KVMState *s = KVM_STATE(obj); @@ -3793,6 +3811,7 @@ static void kvm_accel_instance_init(Object *obj) s->xen_version = 0; s->xen_gnttab_max_frames = 64; s->xen_evtchn_max_pirq = 256; + s->device = NULL; } /** @@ -3833,6 +3852,10 @@ static void kvm_accel_class_init(ObjectClass *oc, void *data) object_class_property_set_description(oc, "dirty-ring-size", "Size of KVM dirty page ring buffer (default: 0, i.e. use bitmap)"); + object_class_property_add_str(oc, "device", kvm_get_device, kvm_set_device); + object_class_property_set_description(oc, "device", + "Path to the device node to use (default: /dev/kvm)"); + kvm_arch_accel_class_init(oc); } diff --git a/include/sysemu/kvm_int.h b/include/sysemu/kvm_int.h index a5b9122cb8..19a5364a4b 100644 --- a/include/sysemu/kvm_int.h +++ b/include/sysemu/kvm_int.h @@ -124,6 +124,7 @@ struct KVMState uint32_t xen_caps; uint16_t xen_gnttab_max_frames; uint16_t xen_evtchn_max_pirq; + char *device; }; void kvm_memory_listener_register(KVMState *s, KVMMemoryListener *kml, diff --git a/qemu-options.hx b/qemu-options.hx index 54a7e94970..40ad15a9da 100644 --- a/qemu-options.hx +++ b/qemu-options.hx @@ -188,7 +188,8 @@ DEF("accel", HAS_ARG, QEMU_OPTION_accel, " dirty-ring-size=n (KVM dirty ring GFN count, default 0)\n" " eager-split-size=n (KVM Eager Page Split chunk size, default 0, disabled. ARM only)\n" " notify-vmexit=run|internal-error|disable,notify-window=n (enable notify VM exit and set notify window, x86 only)\n" - " thread=single|multi (enable multi-threaded TCG)\n", QEMU_ARCH_ALL) + " thread=single|multi (enable multi-threaded TCG)\n" + " device=path (KVM device path, default /dev/kvm)\n", QEMU_ARCH_ALL) SRST ``-accel name[,prop=value[,...]]`` This is used to enable an accelerator. Depending on the target @@ -269,6 +270,11 @@ SRST open up for a specified of time (i.e. notify-window). Default: notify-vmexit=run,notify-window=0. + ``device=path`` + Sets the path to the KVM device node. Defaults to ``/dev/kvm``. This + option can be used to pass the KVM device to use via a file descriptor + by setting the value to ``/dev/fdset/NN``. + ERST DEF("smp", HAS_ARG, QEMU_OPTION_smp,