From nobody Fri Oct 31 16:03:37 2025 Delivered-To: importer@patchew.org Received-SPF: pass (zohomail.com: domain of lists.xenproject.org designates 192.237.175.120 as permitted sender) client-ip=192.237.175.120; envelope-from=xen-devel-bounces@lists.xenproject.org; helo=lists.xenproject.org; Authentication-Results: mx.zohomail.com; dkim=fail; spf=pass (zohomail.com: domain of lists.xenproject.org designates 192.237.175.120 as permitted sender) smtp.mailfrom=xen-devel-bounces@lists.xenproject.org; dmarc=fail(p=quarantine dis=quarantine) header.from=proton.me Return-Path: Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) by mx.zohomail.com with SMTPS id 1748472673865250.99524322849777; Wed, 28 May 2025 15:51:13 -0700 (PDT) Received: from list by lists.xenproject.org with outflank-mailman.999590.1380227 (Exim 4.92) (envelope-from ) id 1uKPbp-0007ec-9k; Wed, 28 May 2025 22:50:53 +0000 Received: by outflank-mailman (output) from mailman id 999590.1380227; Wed, 28 May 2025 22:50:53 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1uKPbp-0007eV-73; Wed, 28 May 2025 22:50:53 +0000 Received: by outflank-mailman (input) for mailman id 999590; Wed, 28 May 2025 22:50:52 +0000 Received: from se1-gles-sth1-in.inumbo.com ([159.253.27.254] helo=se1-gles-sth1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1uKPbo-0007Q4-Ag for xen-devel@lists.xenproject.org; Wed, 28 May 2025 22:50:52 +0000 Received: from mail-24416.protonmail.ch (mail-24416.protonmail.ch [109.224.244.16]) by se1-gles-sth1.inumbo.com (Halon) with ESMTPS id 343bcc51-3c16-11f0-a2fe-13f23c93f187; Thu, 29 May 2025 00:50:51 +0200 (CEST) X-Outflank-Mailman: Message body and most headers restored to incoming version X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 343bcc51-3c16-11f0-a2fe-13f23c93f187 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=proton.me; s=protonmail; t=1748472650; x=1748731850; bh=OmwWZUMOFbeDlcERUII2QytwMkWMS1f8cvzQGoMCA6c=; h=Date:To:From:Cc:Subject:Message-ID:In-Reply-To:References: Feedback-ID:From:To:Cc:Date:Subject:Reply-To:Feedback-ID: Message-ID:BIMI-Selector:List-Unsubscribe:List-Unsubscribe-Post; b=dmBySYL2pYDEf0Lr7NuwQDbUYpPfJcJw87u+62oNsbw9s0QwkYEeehE+CItGOwsp0 BI56mrI6rMbquwzubxhkcB0VprWnHDDq7e8CarAnaHP5OtPFJPQz61vdzpjnTsb21D H9lqdhEEJTyotf7AcQoNHrVZneK1O2YGKhGBEqrZcU1w+Vsed2Ak+mlvwoUnXz/vmU tTxTg6T/Gx7IThwnJwAd6CP7MrvzS4086H4B+AfHYOqSI53TPWGoa5Q3RICaiWhu5X RZc+RmgAK/dOt+8FGWMWPouVQSzgZcR/FOIrdlY08HEnKOe79ny8/8Xadx6pXPiCas +8unizC47uBYA== Date: Wed, 28 May 2025 22:50:45 +0000 To: xen-devel@lists.xenproject.org From: dmkhn@proton.me Cc: andrew.cooper3@citrix.com, anthony.perard@vates.tech, jbeulich@suse.com, julien@xen.org, roger.pau@citrix.com, sstabellini@kernel.org, teddy.astie@vates.tech, dmukhin@ford.com, Denis Mukhin Subject: [PATCH v9 1/3] xen/domain: unify domain ID allocation Message-ID: <20250528225030.2652166-2-dmukhin@ford.com> In-Reply-To: <20250528225030.2652166-1-dmukhin@ford.com> References: <20250528225030.2652166-1-dmukhin@ford.com> Feedback-ID: 123220910:user:proton X-Pm-Message-ID: d78e53a68a44557a4dda5353d3ec2dfd93671e7c MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-ZohoMail-DKIM: fail (Header signature does not verify) X-ZM-MESSAGEID: 1748472675230116600 Content-Type: text/plain; charset="utf-8" From: Denis Mukhin From: Denis Mukhin Currently, hypervisor code has two different domain ID allocation implementations: (a) Sequential IDs allocation in dom0less Arm code based on max_init_domi= d; (b) Sequential IDs allocation in XEN_DOMCTL_createdomain; does not use max_init_domid (both Arm and x86). The domain ID allocation covers dom0 or late hwdom, predefined domains, post-boot domains, excluding Xen system domains (domid >=3D DOMID_FIRST_RESERVED). It makes sense to have a common helper code for such task across architectu= res (Arm and x86) and between dom0less / toolstack domU allocation. Wrap the domain ID allocation as an arch-independent function domid_alloc()= in common/domain.c based on the bitmap. Allocation algorithm: - If an explicit domain ID is provided, verify its availability and use it = if ID is not used; - If DOMID_INVALID is provided, search the range [0..DOMID_FIRST_RESERVED-1= ], starting from the last used ID and wrapping around as needed. It guarante= es that two consecutive calls will never return the same ID. ID#0 is excluded to account for late hwdom case. Also, remove is_free_domid() helper as it is not needed now. No functional change intended. Signed-off-by: Denis Mukhin --- Changes since v8: - skip ID #0 in domid_alloc() to account for late hwdom --- xen/arch/arm/domain_build.c | 17 +++++--- xen/arch/x86/setup.c | 11 +++-- xen/common/device-tree/dom0less-build.c | 10 +++-- xen/common/domain.c | 54 +++++++++++++++++++++++++ xen/common/domctl.c | 42 +++---------------- xen/include/xen/domain.h | 3 ++ 6 files changed, 87 insertions(+), 50 deletions(-) diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c index b189a7cfae..e9d563c269 100644 --- a/xen/arch/arm/domain_build.c +++ b/xen/arch/arm/domain_build.c @@ -2010,6 +2010,7 @@ void __init create_dom0(void) .grant_opts =3D XEN_DOMCTL_GRANT_version(opt_gnttab_max_version), }; unsigned int flags =3D CDF_privileged | CDF_hardware; + domid_t domid; int rc; =20 /* The vGIC for DOM0 is exactly emulating the hardware GIC */ @@ -2034,19 +2035,25 @@ void __init create_dom0(void) if ( !llc_coloring_enabled ) flags |=3D CDF_directmap; =20 - dom0 =3D domain_create(0, &dom0_cfg, flags); + domid =3D domid_alloc(0); + if ( domid =3D=3D DOMID_INVALID ) + panic("Error allocating domain ID 0\n"); + + dom0 =3D domain_create(domid, &dom0_cfg, flags); if ( IS_ERR(dom0) ) - panic("Error creating domain 0 (rc =3D %ld)\n", PTR_ERR(dom0)); + panic("Error creating domain %d (rc =3D %ld)\n", domid, PTR_ERR(do= m0)); =20 if ( llc_coloring_enabled && (rc =3D dom0_set_llc_colors(dom0)) ) - panic("Error initializing LLC coloring for domain 0 (rc =3D %d)\n"= , rc); + panic("Error initializing LLC coloring for domain %pd (rc =3D %d)\= n", + dom0, rc); =20 if ( alloc_dom0_vcpu0(dom0) =3D=3D NULL ) - panic("Error creating domain 0 vcpu0\n"); + panic("Error creating domain %pdv0\n", dom0); =20 rc =3D construct_dom0(dom0); if ( rc ) - panic("Could not set up DOM0 guest OS (rc =3D %d)\n", rc); + panic("Could not set up guest OS for domain %pd (rc =3D %d)\n", + dom0, rc); =20 set_xs_domain(dom0); } diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c index 1f5cb67bd0..b36ce4491b 100644 --- a/xen/arch/x86/setup.c +++ b/xen/arch/x86/setup.c @@ -1031,8 +1031,11 @@ static struct domain *__init create_dom0(struct boot= _info *bi) if ( iommu_enabled ) dom0_cfg.flags |=3D XEN_DOMCTL_CDF_iommu; =20 - /* Create initial domain. Not d0 for pvshim. */ - bd->domid =3D get_initial_domain_id(); + /* Allocate initial domain ID. Not d0 for pvshim. */ + bd->domid =3D domid_alloc(get_initial_domain_id()); + if ( bd->domid =3D=3D DOMID_INVALID ) + panic("Error allocating domain ID %d\n", get_initial_domain_id()); + d =3D domain_create(bd->domid, &dom0_cfg, pv_shim ? 0 : CDF_privileged | CDF_hardware); if ( IS_ERR(d) ) @@ -1064,7 +1067,7 @@ static struct domain *__init create_dom0(struct boot_= info *bi) =20 if ( (strlen(acpi_param) =3D=3D 0) && acpi_disabled ) { - printk("ACPI is disabled, notifying Domain 0 (acpi=3Doff)\n"); + printk("ACPI is disabled, notifying domain %pd (acpi=3Doff)\n"= , d); safe_strcpy(acpi_param, "off"); } =20 @@ -1079,7 +1082,7 @@ static struct domain *__init create_dom0(struct boot_= info *bi) =20 bd->d =3D d; if ( construct_dom0(bd) !=3D 0 ) - panic("Could not construct domain 0\n"); + panic("Could not construct domain %pd\n", d); =20 bd->cmdline =3D NULL; xfree(cmdline); diff --git a/xen/common/device-tree/dom0less-build.c b/xen/common/device-tr= ee/dom0less-build.c index 39cb2cd5c7..a509f8fecd 100644 --- a/xen/common/device-tree/dom0less-build.c +++ b/xen/common/device-tree/dom0less-build.c @@ -850,15 +850,13 @@ void __init create_domUs(void) struct xen_domctl_createdomain d_cfg =3D {0}; unsigned int flags =3D 0U; bool has_dtb =3D false; + domid_t domid; uint32_t val; int rc; =20 if ( !dt_device_is_compatible(node, "xen,domain") ) continue; =20 - if ( (max_init_domid + 1) >=3D DOMID_FIRST_RESERVED ) - panic("No more domain IDs available\n"); - d_cfg.max_evtchn_port =3D 1023; d_cfg.max_grant_frames =3D -1; d_cfg.max_maptrack_frames =3D -1; @@ -981,7 +979,11 @@ void __init create_domUs(void) * very important to use the pre-increment operator to call * domain_create() with a domid > 0. (domid =3D=3D 0 is reserved f= or Dom0) */ - d =3D domain_create(++max_init_domid, &d_cfg, flags); + domid =3D domid_alloc(++max_init_domid); + if ( domid =3D=3D DOMID_INVALID ) + panic("Error allocating ID for domain %s\n", dt_node_name(node= )); + + d =3D domain_create(domid, &d_cfg, flags); if ( IS_ERR(d) ) panic("Error creating domain %s (rc =3D %ld)\n", dt_node_name(node), PTR_ERR(d)); diff --git a/xen/common/domain.c b/xen/common/domain.c index abf1969e60..ae0c44fcbb 100644 --- a/xen/common/domain.c +++ b/xen/common/domain.c @@ -66,6 +66,10 @@ DEFINE_RCU_READ_LOCK(domlist_read_lock); static struct domain *domain_hash[DOMAIN_HASH_SIZE]; struct domain *domain_list; =20 +/* Non-system domain ID allocator. */ +static DEFINE_SPINLOCK(domid_lock); +static DECLARE_BITMAP(domid_bitmap, DOMID_FIRST_RESERVED); + /* * Insert a domain into the domlist/hash. This allows the domain to be lo= oked * up by domid, and therefore to be the subject of hypercalls/etc. @@ -1449,6 +1453,8 @@ void domain_destroy(struct domain *d) =20 TRACE_TIME(TRC_DOM0_DOM_REM, d->domain_id); =20 + domid_free(d->domain_id); + /* Remove from the domlist/hash. */ domlist_remove(d); =20 @@ -2405,6 +2411,54 @@ domid_t get_initial_domain_id(void) return hardware_domid; } =20 +domid_t domid_alloc(domid_t domid) +{ + spin_lock(&domid_lock); + + if ( domid < DOMID_FIRST_RESERVED ) + { + if ( __test_and_set_bit(domid, domid_bitmap) ) + domid =3D DOMID_INVALID; + } + else + { + static domid_t domid_last; + /* NB: account for late hwdom case, skip ID#0 */ + const domid_t reserved_domid =3D 0; + const bool reserved =3D __test_and_set_bit(reserved_domid, domid_b= itmap); + + domid =3D find_next_zero_bit(domid_bitmap, DOMID_FIRST_RESERVED, + domid_last); + + if ( domid =3D=3D DOMID_FIRST_RESERVED ) + domid =3D find_next_zero_bit(domid_bitmap, DOMID_FIRST_RESERVE= D, 0); + + if ( domid =3D=3D DOMID_FIRST_RESERVED ) + { + domid =3D DOMID_INVALID; + } + else + { + __set_bit(domid, domid_bitmap); + domid_last =3D domid; + } + + if ( !reserved ) + __clear_bit(reserved_domid, domid_bitmap); + } + + spin_unlock(&domid_lock); + + return domid; +} + +void domid_free(domid_t domid) +{ + spin_lock(&domid_lock); + __clear_bit(domid, domid_bitmap); + spin_unlock(&domid_lock); +} + /* * Local variables: * mode: C diff --git a/xen/common/domctl.c b/xen/common/domctl.c index bfe2e1f9f0..8ef0c147c9 100644 --- a/xen/common/domctl.c +++ b/xen/common/domctl.c @@ -49,20 +49,6 @@ static int xenctl_bitmap_to_nodemask(nodemask_t *nodemas= k, MAX_NUMNODES); } =20 -static inline int is_free_domid(domid_t dom) -{ - struct domain *d; - - if ( dom >=3D DOMID_FIRST_RESERVED ) - return 0; - - if ( (d =3D rcu_lock_domain_by_id(dom)) =3D=3D NULL ) - return 1; - - rcu_unlock_domain(d); - return 0; -} - void getdomaininfo(struct domain *d, struct xen_domctl_getdomaininfo *info) { struct vcpu *v; @@ -421,36 +407,18 @@ long do_domctl(XEN_GUEST_HANDLE_PARAM(xen_domctl_t) u= _domctl) =20 case XEN_DOMCTL_createdomain: { - domid_t dom; - static domid_t rover =3D 0; + domid_t domid =3D domid_alloc(op->domain); =20 - dom =3D op->domain; - if ( (dom > 0) && (dom < DOMID_FIRST_RESERVED) ) + if ( domid =3D=3D DOMID_INVALID ) { ret =3D -EEXIST; - if ( !is_free_domid(dom) ) - break; - } - else - { - for ( dom =3D rover + 1; dom !=3D rover; dom++ ) - { - if ( dom =3D=3D DOMID_FIRST_RESERVED ) - dom =3D 1; - if ( is_free_domid(dom) ) - break; - } - - ret =3D -ENOMEM; - if ( dom =3D=3D rover ) - break; - - rover =3D dom; + break; } =20 - d =3D domain_create(dom, &op->u.createdomain, false); + d =3D domain_create(domid, &op->u.createdomain, false); if ( IS_ERR(d) ) { + domid_free(domid); ret =3D PTR_ERR(d); d =3D NULL; break; diff --git a/xen/include/xen/domain.h b/xen/include/xen/domain.h index e10baf2615..8aab05ae93 100644 --- a/xen/include/xen/domain.h +++ b/xen/include/xen/domain.h @@ -38,6 +38,9 @@ void arch_get_domain_info(const struct domain *d, =20 domid_t get_initial_domain_id(void); =20 +domid_t domid_alloc(domid_t domid); +void domid_free(domid_t domid); + /* CDF_* constant. Internal flags for domain creation. */ /* Is this a privileged domain? */ #define CDF_privileged (1U << 0) --=20 2.34.1