* [PATCH v15 1/4] xen/domain: unify domain ID allocation
2025-08-09 17:07 [PATCH v15 0/4] xen/domain: domain ID allocation dmkhn
@ 2025-08-09 17:08 ` dmkhn
2025-08-11 11:00 ` Alejandro Vallejo
2025-08-11 11:14 ` Jan Beulich
2025-08-09 17:08 ` [PATCH v15 2/4] tools/include: move xc_bitops.h to xen-tools/bitops.h dmkhn
` (2 subsequent siblings)
3 siblings, 2 replies; 11+ messages in thread
From: dmkhn @ 2025-08-09 17:08 UTC (permalink / raw)
To: xen-devel
Cc: andrew.cooper3, anthony.perard, jbeulich, julien, michal.orzel,
roger.pau, sstabellini, dmukhin, Julien Grall
From: Denis Mukhin <dmukhin@ford.com>
Currently, there are two different domain ID allocation implementations:
1) Sequential IDs allocation in dom0less Arm code based on max_init_domid;
2) 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 >=
DOMID_FIRST_RESERVED).
It makes sense to have a common helper code for such task across architectures
(Arm and x86) and between dom0less / toolstack domU allocation.
Note, fixing dependency on max_init_domid is out of scope of this patch.
Wrap the domain ID allocation as an arch-independent function domid_alloc() in
new common/domid.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 [1..DOMID_FIRST_RESERVED-1],
starting from the last used ID.
Implementation guarantees that two consecutive calls will never return the
same ID. ID#0 is reserved for the first boot domain (currently, dom0) and
excluded from the allocation range.
Remove is_free_domid() helper as it is not needed now.
No functional change intended.
Signed-off-by: Denis Mukhin <dmukhin@ford.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
---
Changes since v14:
- added Julien's R-b
---
xen/arch/arm/domain_build.c | 7 +-
xen/arch/x86/setup.c | 7 +-
xen/common/Makefile | 1 +
xen/common/device-tree/dom0less-build.c | 15 ++--
xen/common/domain.c | 2 +
xen/common/domctl.c | 43 ++---------
xen/common/domid.c | 95 +++++++++++++++++++++++++
xen/include/xen/domain.h | 3 +
8 files changed, 126 insertions(+), 47 deletions(-)
create mode 100644 xen/common/domid.c
diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
index 463ae4474d30..789f2b9d3ce7 100644
--- a/xen/arch/arm/domain_build.c
+++ b/xen/arch/arm/domain_build.c
@@ -2050,6 +2050,7 @@ void __init create_dom0(void)
.grant_opts = XEN_DOMCTL_GRANT_version(opt_gnttab_max_version),
};
unsigned int flags = CDF_privileged | CDF_hardware;
+ domid_t domid;
int rc;
/* The vGIC for DOM0 is exactly emulating the hardware GIC */
@@ -2074,7 +2075,11 @@ void __init create_dom0(void)
if ( !llc_coloring_enabled )
flags |= CDF_directmap;
- dom0 = domain_create(0, &dom0_cfg, flags);
+ domid = domid_alloc(0);
+ if ( domid == DOMID_INVALID )
+ panic("Error allocating domain ID 0\n");
+
+ dom0 = domain_create(domid, &dom0_cfg, flags);
if ( IS_ERR(dom0) )
panic("Error creating domain 0 (rc = %ld)\n", PTR_ERR(dom0));
diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c
index 1543dd251cc6..398da734c0c5 100644
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -1047,8 +1047,11 @@ static struct domain *__init create_dom0(struct boot_info *bi)
if ( iommu_enabled )
dom0_cfg.flags |= XEN_DOMCTL_CDF_iommu;
- /* Create initial domain. Not d0 for pvshim. */
- bd->domid = get_initial_domain_id();
+ /* Allocate initial domain ID. Not d0 for pvshim. */
+ bd->domid = domid_alloc(get_initial_domain_id());
+ if ( bd->domid == DOMID_INVALID )
+ panic("Error allocating domain ID %u\n", get_initial_domain_id());
+
d = domain_create(bd->domid, &dom0_cfg,
pv_shim ? 0 : CDF_privileged | CDF_hardware);
if ( IS_ERR(d) )
diff --git a/xen/common/Makefile b/xen/common/Makefile
index c316957fcb36..0c7d0f5d46e1 100644
--- a/xen/common/Makefile
+++ b/xen/common/Makefile
@@ -11,6 +11,7 @@ obj-$(filter-out $(CONFIG_X86),$(CONFIG_ACPI)) += device.o
obj-$(CONFIG_DEVICE_TREE_PARSE) += device-tree/
obj-$(CONFIG_IOREQ_SERVER) += dm.o
obj-y += domain.o
+obj-y += domid.o
obj-y += event_2l.o
obj-y += event_channel.o
obj-$(CONFIG_EVTCHN_FIFO) += event_fifo.o
diff --git a/xen/common/device-tree/dom0less-build.c b/xen/common/device-tree/dom0less-build.c
index 6bb038111de9..f4b6b515d2d2 100644
--- a/xen/common/device-tree/dom0less-build.c
+++ b/xen/common/device-tree/dom0less-build.c
@@ -833,6 +833,7 @@ void __init create_domUs(void)
{
struct kernel_info ki = KERNEL_INFO_INIT;
int rc = parse_dom0less_node(node, &ki.bd);
+ domid_t domid;
if ( rc == -ENOENT )
continue;
@@ -842,13 +843,13 @@ void __init create_domUs(void)
if ( (max_init_domid + 1) >= DOMID_FIRST_RESERVED )
panic("No more domain IDs available\n");
- /*
- * The variable max_init_domid is initialized with zero, so here it's
- * very important to use the pre-increment operator to call
- * domain_create() with a domid > 0. (domid == 0 is reserved for Dom0)
- */
- ki.bd.d = domain_create(++max_init_domid,
- &ki.bd.create_cfg, ki.bd.create_flags);
+ domid = domid_alloc(DOMID_INVALID);
+ if ( domid == DOMID_INVALID )
+ panic("Error allocating ID for domain %s\n", dt_node_name(node));
+
+ max_init_domid = max(max_init_domid, domid);
+
+ ki.bd.d = domain_create(domid, &ki.bd.create_cfg, ki.bd.create_flags);
if ( IS_ERR(ki.bd.d) )
panic("Error creating domain %s (rc = %ld)\n",
dt_node_name(node), PTR_ERR(ki.bd.d));
diff --git a/xen/common/domain.c b/xen/common/domain.c
index 5241a1629eeb..a7e303253d1a 100644
--- a/xen/common/domain.c
+++ b/xen/common/domain.c
@@ -692,6 +692,8 @@ static void _domain_destroy(struct domain *d)
lock_profile_deregister_struct(LOCKPROF_TYPE_PERDOM, d);
+ domid_free(d->domain_id);
+
free_domain_struct(d);
}
diff --git a/xen/common/domctl.c b/xen/common/domctl.c
index f2a7caaf853c..71e712c1f316 100644
--- a/xen/common/domctl.c
+++ b/xen/common/domctl.c
@@ -51,20 +51,6 @@ static int xenctl_bitmap_to_nodemask(nodemask_t *nodemask,
MAX_NUMNODES);
}
-static inline int is_free_domid(domid_t dom)
-{
- struct domain *d;
-
- if ( dom >= DOMID_FIRST_RESERVED )
- return 0;
-
- if ( (d = rcu_lock_domain_by_id(dom)) == NULL )
- return 1;
-
- rcu_unlock_domain(d);
- return 0;
-}
-
void getdomaininfo(struct domain *d, struct xen_domctl_getdomaininfo *info)
{
struct vcpu *v;
@@ -423,36 +409,19 @@ long do_domctl(XEN_GUEST_HANDLE_PARAM(xen_domctl_t) u_domctl)
case XEN_DOMCTL_createdomain:
{
- domid_t dom;
- static domid_t rover = 0;
+ /* NB: ID#0 is reserved, find the first suitable ID instead. */
+ domid_t domid = domid_alloc(op->domain ?: DOMID_INVALID);
- dom = op->domain;
- if ( (dom > 0) && (dom < DOMID_FIRST_RESERVED) )
+ if ( domid == DOMID_INVALID )
{
ret = -EEXIST;
- if ( !is_free_domid(dom) )
- break;
- }
- else
- {
- for ( dom = rover + 1; dom != rover; dom++ )
- {
- if ( dom == DOMID_FIRST_RESERVED )
- dom = 1;
- if ( is_free_domid(dom) )
- break;
- }
-
- ret = -ENOMEM;
- if ( dom == rover )
- break;
-
- rover = dom;
+ break;
}
- d = domain_create(dom, &op->u.createdomain, false);
+ d = domain_create(domid, &op->u.createdomain, false);
if ( IS_ERR(d) )
{
+ domid_free(domid);
ret = PTR_ERR(d);
d = NULL;
break;
diff --git a/xen/common/domid.c b/xen/common/domid.c
new file mode 100644
index 000000000000..7839a2885810
--- /dev/null
+++ b/xen/common/domid.c
@@ -0,0 +1,95 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Domain ID allocator.
+ *
+ * Covers dom0 or late hwdom, predefined domains, post-boot domains.
+ * Excludes system domains (ID >= DOMID_FIRST_RESERVED).
+ *
+ * Copyright 2025 Ford Motor Company
+ */
+
+#include <xen/domain.h>
+
+static DEFINE_SPINLOCK(domid_lock);
+static DECLARE_BITMAP(domid_bitmap, DOMID_FIRST_RESERVED);
+
+/*
+ * Allocate domain ID.
+ *
+ * @param domid Domain ID hint:
+ * - If an explicit domain ID is provided, verify its availability and use it
+ * if ID is not used;
+ * - If DOMID_INVALID is provided, search [1..DOMID_FIRST_RESERVED-1] range,
+ * starting from the last used ID. Implementation guarantees that two
+ * consecutive calls will never return the same ID. ID#0 is reserved for
+ * the first boot domain (currently, dom0) and excluded from the allocation
+ * range.
+ * @return Valid domain ID in case of successful allocation,
+ * DOMID_INVALID - otherwise.
+ */
+domid_t domid_alloc(domid_t domid)
+{
+ static domid_t domid_last;
+
+ spin_lock(&domid_lock);
+
+ /* Exact match. */
+ if ( domid < DOMID_FIRST_RESERVED )
+ {
+ if ( __test_and_set_bit(domid, domid_bitmap) )
+ domid = DOMID_INVALID;
+ }
+ /*
+ * Exhaustive search.
+ *
+ * Domain ID#0 is reserved for the first boot domain (e.g. control domain)
+ * and excluded from allocation.
+ */
+ else
+ {
+ domid_t num = DOMID_FIRST_RESERVED;
+
+ domid = find_next_zero_bit(domid_bitmap, num, domid_last + 1);
+ if ( domid == num && domid_last != 0 )
+ {
+ num = domid_last + 1;
+ domid = find_next_zero_bit(domid_bitmap, num, 1);
+ }
+
+ ASSERT(domid <= DOMID_FIRST_RESERVED);
+ if ( domid < num )
+ {
+ __set_bit(domid, domid_bitmap);
+ domid_last = domid;
+ }
+ else
+ domid = DOMID_INVALID;
+ }
+
+ spin_unlock(&domid_lock);
+
+ return domid;
+}
+
+void domid_free(domid_t domid)
+{
+ int rc;
+
+ ASSERT(domid <= DOMID_FIRST_RESERVED);
+
+ spin_lock(&domid_lock);
+ rc = __test_and_clear_bit(domid, domid_bitmap);
+ spin_unlock(&domid_lock);
+
+ ASSERT(rc);
+}
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * tab-width: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
diff --git a/xen/include/xen/domain.h b/xen/include/xen/domain.h
index e10baf2615fd..8aab05ae93c8 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,
domid_t get_initial_domain_id(void);
+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)
--
2.34.1
^ permalink raw reply related [flat|nested] 11+ messages in thread* Re: [PATCH v15 1/4] xen/domain: unify domain ID allocation
2025-08-09 17:08 ` [PATCH v15 1/4] xen/domain: unify " dmkhn
@ 2025-08-11 11:00 ` Alejandro Vallejo
2025-08-11 23:47 ` dmkhn
2025-08-11 11:14 ` Jan Beulich
1 sibling, 1 reply; 11+ messages in thread
From: Alejandro Vallejo @ 2025-08-11 11:00 UTC (permalink / raw)
To: dmkhn, xen-devel
Cc: andrew.cooper3, anthony.perard, jbeulich, julien, michal.orzel,
roger.pau, sstabellini, dmukhin, Julien Grall, Xen-devel
On Sat Aug 9, 2025 at 7:08 PM CEST, dmkhn wrote:
> From: Denis Mukhin <dmukhin@ford.com>
>
> Currently, there are two different domain ID allocation implementations:
>
> 1) Sequential IDs allocation in dom0less Arm code based on max_init_domid;
>
> 2) 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 >=
> DOMID_FIRST_RESERVED).
>
> It makes sense to have a common helper code for such task across architectures
> (Arm and x86) and between dom0less / toolstack domU allocation.
>
> Note, fixing dependency on max_init_domid is out of scope of this patch.
>
> Wrap the domain ID allocation as an arch-independent function domid_alloc() in
> new common/domid.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 [1..DOMID_FIRST_RESERVED-1],
> starting from the last used ID.
> Implementation guarantees that two consecutive calls will never return the
> same ID. ID#0 is reserved for the first boot domain (currently, dom0) and
> excluded from the allocation range.
>
> Remove is_free_domid() helper as it is not needed now.
>
> No functional change intended.
>
> Signed-off-by: Denis Mukhin <dmukhin@ford.com>
> Reviewed-by: Julien Grall <jgrall@amazon.com>
There's a nit below about a change in v14, but with or without that:
Reviewed-by: Alejandro Vallejo <alejandro.garciavallejo@amd.com>
> ---
> Changes since v14:
> - added Julien's R-b
> ---
> xen/arch/arm/domain_build.c | 7 +-
> xen/arch/x86/setup.c | 7 +-
> xen/common/Makefile | 1 +
> xen/common/device-tree/dom0less-build.c | 15 ++--
> xen/common/domain.c | 2 +
> xen/common/domctl.c | 43 ++---------
> xen/common/domid.c | 95 +++++++++++++++++++++++++
> xen/include/xen/domain.h | 3 +
> 8 files changed, 126 insertions(+), 47 deletions(-)
> create mode 100644 xen/common/domid.c
>
> diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
> index 463ae4474d30..789f2b9d3ce7 100644
> --- a/xen/arch/arm/domain_build.c
> +++ b/xen/arch/arm/domain_build.c
> @@ -2050,6 +2050,7 @@ void __init create_dom0(void)
> .grant_opts = XEN_DOMCTL_GRANT_version(opt_gnttab_max_version),
> };
> unsigned int flags = CDF_privileged | CDF_hardware;
> + domid_t domid;
> int rc;
>
> /* The vGIC for DOM0 is exactly emulating the hardware GIC */
> @@ -2074,7 +2075,11 @@ void __init create_dom0(void)
> if ( !llc_coloring_enabled )
> flags |= CDF_directmap;
>
> - dom0 = domain_create(0, &dom0_cfg, flags);
> + domid = domid_alloc(0);
> + if ( domid == DOMID_INVALID )
> + panic("Error allocating domain ID 0\n");
> +
> + dom0 = domain_create(domid, &dom0_cfg, flags);
> if ( IS_ERR(dom0) )
> panic("Error creating domain 0 (rc = %ld)\n", PTR_ERR(dom0));
>
> diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c
> index 1543dd251cc6..398da734c0c5 100644
> --- a/xen/arch/x86/setup.c
> +++ b/xen/arch/x86/setup.c
> @@ -1047,8 +1047,11 @@ static struct domain *__init create_dom0(struct boot_info *bi)
> if ( iommu_enabled )
> dom0_cfg.flags |= XEN_DOMCTL_CDF_iommu;
>
> - /* Create initial domain. Not d0 for pvshim. */
> - bd->domid = get_initial_domain_id();
> + /* Allocate initial domain ID. Not d0 for pvshim. */
> + bd->domid = domid_alloc(get_initial_domain_id());
> + if ( bd->domid == DOMID_INVALID )
> + panic("Error allocating domain ID %u\n", get_initial_domain_id());
> +
> d = domain_create(bd->domid, &dom0_cfg,
> pv_shim ? 0 : CDF_privileged | CDF_hardware);
> if ( IS_ERR(d) )
> diff --git a/xen/common/Makefile b/xen/common/Makefile
> index c316957fcb36..0c7d0f5d46e1 100644
> --- a/xen/common/Makefile
> +++ b/xen/common/Makefile
> @@ -11,6 +11,7 @@ obj-$(filter-out $(CONFIG_X86),$(CONFIG_ACPI)) += device.o
> obj-$(CONFIG_DEVICE_TREE_PARSE) += device-tree/
> obj-$(CONFIG_IOREQ_SERVER) += dm.o
> obj-y += domain.o
> +obj-y += domid.o
> obj-y += event_2l.o
> obj-y += event_channel.o
> obj-$(CONFIG_EVTCHN_FIFO) += event_fifo.o
> diff --git a/xen/common/device-tree/dom0less-build.c b/xen/common/device-tree/dom0less-build.c
> index 6bb038111de9..f4b6b515d2d2 100644
> --- a/xen/common/device-tree/dom0less-build.c
> +++ b/xen/common/device-tree/dom0less-build.c
> @@ -833,6 +833,7 @@ void __init create_domUs(void)
> {
> struct kernel_info ki = KERNEL_INFO_INIT;
> int rc = parse_dom0less_node(node, &ki.bd);
> + domid_t domid;
>
> if ( rc == -ENOENT )
> continue;
> @@ -842,13 +843,13 @@ void __init create_domUs(void)
> if ( (max_init_domid + 1) >= DOMID_FIRST_RESERVED )
> panic("No more domain IDs available\n");
>
> - /*
> - * The variable max_init_domid is initialized with zero, so here it's
> - * very important to use the pre-increment operator to call
> - * domain_create() with a domid > 0. (domid == 0 is reserved for Dom0)
> - */
> - ki.bd.d = domain_create(++max_init_domid,
> - &ki.bd.create_cfg, ki.bd.create_flags);
> + domid = domid_alloc(DOMID_INVALID);
> + if ( domid == DOMID_INVALID )
> + panic("Error allocating ID for domain %s\n", dt_node_name(node));
> +
> + max_init_domid = max(max_init_domid, domid);
> +
> + ki.bd.d = domain_create(domid, &ki.bd.create_cfg, ki.bd.create_flags);
> if ( IS_ERR(ki.bd.d) )
> panic("Error creating domain %s (rc = %ld)\n",
> dt_node_name(node), PTR_ERR(ki.bd.d));
> diff --git a/xen/common/domain.c b/xen/common/domain.c
> index 5241a1629eeb..a7e303253d1a 100644
> --- a/xen/common/domain.c
> +++ b/xen/common/domain.c
> @@ -692,6 +692,8 @@ static void _domain_destroy(struct domain *d)
>
> lock_profile_deregister_struct(LOCKPROF_TYPE_PERDOM, d);
>
> + domid_free(d->domain_id);
> +
> free_domain_struct(d);
> }
>
> diff --git a/xen/common/domctl.c b/xen/common/domctl.c
> index f2a7caaf853c..71e712c1f316 100644
> --- a/xen/common/domctl.c
> +++ b/xen/common/domctl.c
> @@ -51,20 +51,6 @@ static int xenctl_bitmap_to_nodemask(nodemask_t *nodemask,
> MAX_NUMNODES);
> }
>
> -static inline int is_free_domid(domid_t dom)
> -{
> - struct domain *d;
> -
> - if ( dom >= DOMID_FIRST_RESERVED )
> - return 0;
> -
> - if ( (d = rcu_lock_domain_by_id(dom)) == NULL )
> - return 1;
> -
> - rcu_unlock_domain(d);
> - return 0;
> -}
> -
> void getdomaininfo(struct domain *d, struct xen_domctl_getdomaininfo *info)
> {
> struct vcpu *v;
> @@ -423,36 +409,19 @@ long do_domctl(XEN_GUEST_HANDLE_PARAM(xen_domctl_t) u_domctl)
>
> case XEN_DOMCTL_createdomain:
> {
> - domid_t dom;
> - static domid_t rover = 0;
> + /* NB: ID#0 is reserved, find the first suitable ID instead. */
> + domid_t domid = domid_alloc(op->domain ?: DOMID_INVALID);
>
> - dom = op->domain;
> - if ( (dom > 0) && (dom < DOMID_FIRST_RESERVED) )
> + if ( domid == DOMID_INVALID )
> {
> ret = -EEXIST;
> - if ( !is_free_domid(dom) )
> - break;
> - }
> - else
> - {
> - for ( dom = rover + 1; dom != rover; dom++ )
> - {
> - if ( dom == DOMID_FIRST_RESERVED )
> - dom = 1;
> - if ( is_free_domid(dom) )
> - break;
> - }
> -
> - ret = -ENOMEM;
> - if ( dom == rover )
> - break;
> -
> - rover = dom;
> + break;
> }
>
> - d = domain_create(dom, &op->u.createdomain, false);
> + d = domain_create(domid, &op->u.createdomain, false);
> if ( IS_ERR(d) )
> {
> + domid_free(domid);
> ret = PTR_ERR(d);
> d = NULL;
> break;
> diff --git a/xen/common/domid.c b/xen/common/domid.c
> new file mode 100644
> index 000000000000..7839a2885810
> --- /dev/null
> +++ b/xen/common/domid.c
> @@ -0,0 +1,95 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +/*
> + * Domain ID allocator.
> + *
> + * Covers dom0 or late hwdom, predefined domains, post-boot domains.
> + * Excludes system domains (ID >= DOMID_FIRST_RESERVED).
> + *
> + * Copyright 2025 Ford Motor Company
> + */
> +
> +#include <xen/domain.h>
> +
> +static DEFINE_SPINLOCK(domid_lock);
> +static DECLARE_BITMAP(domid_bitmap, DOMID_FIRST_RESERVED);
> +
> +/*
> + * Allocate domain ID.
> + *
> + * @param domid Domain ID hint:
> + * - If an explicit domain ID is provided, verify its availability and use it
> + * if ID is not used;
> + * - If DOMID_INVALID is provided, search [1..DOMID_FIRST_RESERVED-1] range,
> + * starting from the last used ID. Implementation guarantees that two
> + * consecutive calls will never return the same ID. ID#0 is reserved for
> + * the first boot domain (currently, dom0) and excluded from the allocation
> + * range.
> + * @return Valid domain ID in case of successful allocation,
> + * DOMID_INVALID - otherwise.
> + */
> +domid_t domid_alloc(domid_t domid)
> +{
> + static domid_t domid_last;
> +
> + spin_lock(&domid_lock);
> +
> + /* Exact match. */
> + if ( domid < DOMID_FIRST_RESERVED )
> + {
> + if ( __test_and_set_bit(domid, domid_bitmap) )
> + domid = DOMID_INVALID;
> + }
> + /*
> + * Exhaustive search.
> + *
> + * Domain ID#0 is reserved for the first boot domain (e.g. control domain)
> + * and excluded from allocation.
> + */
> + else
> + {
> + domid_t num = DOMID_FIRST_RESERVED;
nit: s/num/bound/, or something like that.
I don't care much though. If there's not going to be a v16 (and I hope not. The
series has been girdling the mailing list long enough) feel free to ignore this.
> +
> + domid = find_next_zero_bit(domid_bitmap, , domid_last + 1);
> + if ( domid == num && domid_last != 0 )
> + {
> + num = domid_last + 1;
> + domid = find_next_zero_bit(domid_bitmap, num, 1);
> + }
> +
> + ASSERT(domid <= DOMID_FIRST_RESERVED);
> + if ( domid < num )
> + {
> + __set_bit(domid, domid_bitmap);
> + domid_last = domid;
> + }
> + else
> + domid = DOMID_INVALID;
> + }
> +
> + spin_unlock(&domid_lock);
> +
> + return domid;
> +}
> +
> +void domid_free(domid_t domid)
> +{
> + int rc;
> +
> + ASSERT(domid <= DOMID_FIRST_RESERVED);
> +
> + spin_lock(&domid_lock);
> + rc = __test_and_clear_bit(domid, domid_bitmap);
> + spin_unlock(&domid_lock);
> +
> + ASSERT(rc);
> +}
> +
> +/*
> + * Local variables:
> + * mode: C
> + * c-file-style: "BSD"
> + * c-basic-offset: 4
> + * tab-width: 4
> + * indent-tabs-mode: nil
> + * End:
> + */
> diff --git a/xen/include/xen/domain.h b/xen/include/xen/domain.h
> index e10baf2615fd..8aab05ae93c8 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,
>
> domid_t get_initial_domain_id(void);
>
> +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)
^ permalink raw reply [flat|nested] 11+ messages in thread* Re: [PATCH v15 1/4] xen/domain: unify domain ID allocation
2025-08-11 11:00 ` Alejandro Vallejo
@ 2025-08-11 23:47 ` dmkhn
0 siblings, 0 replies; 11+ messages in thread
From: dmkhn @ 2025-08-11 23:47 UTC (permalink / raw)
To: Alejandro Vallejo
Cc: xen-devel, andrew.cooper3, anthony.perard, jbeulich, julien,
michal.orzel, roger.pau, sstabellini, dmukhin, Julien Grall,
Xen-devel
On Mon, Aug 11, 2025 at 01:00:00PM +0200, Alejandro Vallejo wrote:
> On Sat Aug 9, 2025 at 7:08 PM CEST, dmkhn wrote:
> > From: Denis Mukhin <dmukhin@ford.com>
> >
> > Currently, there are two different domain ID allocation implementations:
> >
> > 1) Sequential IDs allocation in dom0less Arm code based on max_init_domid;
> >
> > 2) 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 >=
> > DOMID_FIRST_RESERVED).
> >
> > It makes sense to have a common helper code for such task across architectures
> > (Arm and x86) and between dom0less / toolstack domU allocation.
> >
> > Note, fixing dependency on max_init_domid is out of scope of this patch.
> >
> > Wrap the domain ID allocation as an arch-independent function domid_alloc() in
> > new common/domid.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 [1..DOMID_FIRST_RESERVED-1],
> > starting from the last used ID.
> > Implementation guarantees that two consecutive calls will never return the
> > same ID. ID#0 is reserved for the first boot domain (currently, dom0) and
> > excluded from the allocation range.
> >
> > Remove is_free_domid() helper as it is not needed now.
> >
> > No functional change intended.
> >
> > Signed-off-by: Denis Mukhin <dmukhin@ford.com>
> > Reviewed-by: Julien Grall <jgrall@amazon.com>
>
> There's a nit below about a change in v14, but with or without that:
>
> Reviewed-by: Alejandro Vallejo <alejandro.garciavallejo@amd.com>
Thanks
>
> > ---
> > Changes since v14:
> > - added Julien's R-b
> > ---
> > xen/arch/arm/domain_build.c | 7 +-
> > xen/arch/x86/setup.c | 7 +-
> > xen/common/Makefile | 1 +
> > xen/common/device-tree/dom0less-build.c | 15 ++--
> > xen/common/domain.c | 2 +
> > xen/common/domctl.c | 43 ++---------
> > xen/common/domid.c | 95 +++++++++++++++++++++++++
> > xen/include/xen/domain.h | 3 +
> > 8 files changed, 126 insertions(+), 47 deletions(-)
> > create mode 100644 xen/common/domid.c
> >
> > diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
> > index 463ae4474d30..789f2b9d3ce7 100644
> > --- a/xen/arch/arm/domain_build.c
> > +++ b/xen/arch/arm/domain_build.c
> > @@ -2050,6 +2050,7 @@ void __init create_dom0(void)
> > .grant_opts = XEN_DOMCTL_GRANT_version(opt_gnttab_max_version),
> > };
> > unsigned int flags = CDF_privileged | CDF_hardware;
> > + domid_t domid;
> > int rc;
> >
> > /* The vGIC for DOM0 is exactly emulating the hardware GIC */
> > @@ -2074,7 +2075,11 @@ void __init create_dom0(void)
> > if ( !llc_coloring_enabled )
> > flags |= CDF_directmap;
> >
> > - dom0 = domain_create(0, &dom0_cfg, flags);
> > + domid = domid_alloc(0);
> > + if ( domid == DOMID_INVALID )
> > + panic("Error allocating domain ID 0\n");
> > +
> > + dom0 = domain_create(domid, &dom0_cfg, flags);
> > if ( IS_ERR(dom0) )
> > panic("Error creating domain 0 (rc = %ld)\n", PTR_ERR(dom0));
> >
> > diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c
> > index 1543dd251cc6..398da734c0c5 100644
> > --- a/xen/arch/x86/setup.c
> > +++ b/xen/arch/x86/setup.c
> > @@ -1047,8 +1047,11 @@ static struct domain *__init create_dom0(struct boot_info *bi)
> > if ( iommu_enabled )
> > dom0_cfg.flags |= XEN_DOMCTL_CDF_iommu;
> >
> > - /* Create initial domain. Not d0 for pvshim. */
> > - bd->domid = get_initial_domain_id();
> > + /* Allocate initial domain ID. Not d0 for pvshim. */
> > + bd->domid = domid_alloc(get_initial_domain_id());
> > + if ( bd->domid == DOMID_INVALID )
> > + panic("Error allocating domain ID %u\n", get_initial_domain_id());
> > +
> > d = domain_create(bd->domid, &dom0_cfg,
> > pv_shim ? 0 : CDF_privileged | CDF_hardware);
> > if ( IS_ERR(d) )
> > diff --git a/xen/common/Makefile b/xen/common/Makefile
> > index c316957fcb36..0c7d0f5d46e1 100644
> > --- a/xen/common/Makefile
> > +++ b/xen/common/Makefile
> > @@ -11,6 +11,7 @@ obj-$(filter-out $(CONFIG_X86),$(CONFIG_ACPI)) += device.o
> > obj-$(CONFIG_DEVICE_TREE_PARSE) += device-tree/
> > obj-$(CONFIG_IOREQ_SERVER) += dm.o
> > obj-y += domain.o
> > +obj-y += domid.o
> > obj-y += event_2l.o
> > obj-y += event_channel.o
> > obj-$(CONFIG_EVTCHN_FIFO) += event_fifo.o
> > diff --git a/xen/common/device-tree/dom0less-build.c b/xen/common/device-tree/dom0less-build.c
> > index 6bb038111de9..f4b6b515d2d2 100644
> > --- a/xen/common/device-tree/dom0less-build.c
> > +++ b/xen/common/device-tree/dom0less-build.c
> > @@ -833,6 +833,7 @@ void __init create_domUs(void)
> > {
> > struct kernel_info ki = KERNEL_INFO_INIT;
> > int rc = parse_dom0less_node(node, &ki.bd);
> > + domid_t domid;
> >
> > if ( rc == -ENOENT )
> > continue;
> > @@ -842,13 +843,13 @@ void __init create_domUs(void)
> > if ( (max_init_domid + 1) >= DOMID_FIRST_RESERVED )
> > panic("No more domain IDs available\n");
> >
> > - /*
> > - * The variable max_init_domid is initialized with zero, so here it's
> > - * very important to use the pre-increment operator to call
> > - * domain_create() with a domid > 0. (domid == 0 is reserved for Dom0)
> > - */
> > - ki.bd.d = domain_create(++max_init_domid,
> > - &ki.bd.create_cfg, ki.bd.create_flags);
> > + domid = domid_alloc(DOMID_INVALID);
> > + if ( domid == DOMID_INVALID )
> > + panic("Error allocating ID for domain %s\n", dt_node_name(node));
> > +
> > + max_init_domid = max(max_init_domid, domid);
> > +
> > + ki.bd.d = domain_create(domid, &ki.bd.create_cfg, ki.bd.create_flags);
> > if ( IS_ERR(ki.bd.d) )
> > panic("Error creating domain %s (rc = %ld)\n",
> > dt_node_name(node), PTR_ERR(ki.bd.d));
> > diff --git a/xen/common/domain.c b/xen/common/domain.c
> > index 5241a1629eeb..a7e303253d1a 100644
> > --- a/xen/common/domain.c
> > +++ b/xen/common/domain.c
> > @@ -692,6 +692,8 @@ static void _domain_destroy(struct domain *d)
> >
> > lock_profile_deregister_struct(LOCKPROF_TYPE_PERDOM, d);
> >
> > + domid_free(d->domain_id);
> > +
> > free_domain_struct(d);
> > }
> >
> > diff --git a/xen/common/domctl.c b/xen/common/domctl.c
> > index f2a7caaf853c..71e712c1f316 100644
> > --- a/xen/common/domctl.c
> > +++ b/xen/common/domctl.c
> > @@ -51,20 +51,6 @@ static int xenctl_bitmap_to_nodemask(nodemask_t *nodemask,
> > MAX_NUMNODES);
> > }
> >
> > -static inline int is_free_domid(domid_t dom)
> > -{
> > - struct domain *d;
> > -
> > - if ( dom >= DOMID_FIRST_RESERVED )
> > - return 0;
> > -
> > - if ( (d = rcu_lock_domain_by_id(dom)) == NULL )
> > - return 1;
> > -
> > - rcu_unlock_domain(d);
> > - return 0;
> > -}
> > -
> > void getdomaininfo(struct domain *d, struct xen_domctl_getdomaininfo *info)
> > {
> > struct vcpu *v;
> > @@ -423,36 +409,19 @@ long do_domctl(XEN_GUEST_HANDLE_PARAM(xen_domctl_t) u_domctl)
> >
> > case XEN_DOMCTL_createdomain:
> > {
> > - domid_t dom;
> > - static domid_t rover = 0;
> > + /* NB: ID#0 is reserved, find the first suitable ID instead. */
> > + domid_t domid = domid_alloc(op->domain ?: DOMID_INVALID);
> >
> > - dom = op->domain;
> > - if ( (dom > 0) && (dom < DOMID_FIRST_RESERVED) )
> > + if ( domid == DOMID_INVALID )
> > {
> > ret = -EEXIST;
> > - if ( !is_free_domid(dom) )
> > - break;
> > - }
> > - else
> > - {
> > - for ( dom = rover + 1; dom != rover; dom++ )
> > - {
> > - if ( dom == DOMID_FIRST_RESERVED )
> > - dom = 1;
> > - if ( is_free_domid(dom) )
> > - break;
> > - }
> > -
> > - ret = -ENOMEM;
> > - if ( dom == rover )
> > - break;
> > -
> > - rover = dom;
> > + break;
> > }
> >
> > - d = domain_create(dom, &op->u.createdomain, false);
> > + d = domain_create(domid, &op->u.createdomain, false);
> > if ( IS_ERR(d) )
> > {
> > + domid_free(domid);
> > ret = PTR_ERR(d);
> > d = NULL;
> > break;
> > diff --git a/xen/common/domid.c b/xen/common/domid.c
> > new file mode 100644
> > index 000000000000..7839a2885810
> > --- /dev/null
> > +++ b/xen/common/domid.c
> > @@ -0,0 +1,95 @@
> > +/* SPDX-License-Identifier: GPL-2.0-only */
> > +/*
> > + * Domain ID allocator.
> > + *
> > + * Covers dom0 or late hwdom, predefined domains, post-boot domains.
> > + * Excludes system domains (ID >= DOMID_FIRST_RESERVED).
> > + *
> > + * Copyright 2025 Ford Motor Company
> > + */
> > +
> > +#include <xen/domain.h>
> > +
> > +static DEFINE_SPINLOCK(domid_lock);
> > +static DECLARE_BITMAP(domid_bitmap, DOMID_FIRST_RESERVED);
> > +
> > +/*
> > + * Allocate domain ID.
> > + *
> > + * @param domid Domain ID hint:
> > + * - If an explicit domain ID is provided, verify its availability and use it
> > + * if ID is not used;
> > + * - If DOMID_INVALID is provided, search [1..DOMID_FIRST_RESERVED-1] range,
> > + * starting from the last used ID. Implementation guarantees that two
> > + * consecutive calls will never return the same ID. ID#0 is reserved for
> > + * the first boot domain (currently, dom0) and excluded from the allocation
> > + * range.
> > + * @return Valid domain ID in case of successful allocation,
> > + * DOMID_INVALID - otherwise.
> > + */
> > +domid_t domid_alloc(domid_t domid)
> > +{
> > + static domid_t domid_last;
> > +
> > + spin_lock(&domid_lock);
> > +
> > + /* Exact match. */
> > + if ( domid < DOMID_FIRST_RESERVED )
> > + {
> > + if ( __test_and_set_bit(domid, domid_bitmap) )
> > + domid = DOMID_INVALID;
> > + }
> > + /*
> > + * Exhaustive search.
> > + *
> > + * Domain ID#0 is reserved for the first boot domain (e.g. control domain)
> > + * and excluded from allocation.
> > + */
> > + else
> > + {
> > + domid_t num = DOMID_FIRST_RESERVED;
>
> nit: s/num/bound/, or something like that.
>
> I don't care much though. If there's not going to be a v16 (and I hope not. The
> series has been girdling the mailing list long enough) feel free to ignore this.
Will address.
>
> > +
> > + domid = find_next_zero_bit(domid_bitmap, , domid_last + 1);
> > + if ( domid == num && domid_last != 0 )
> > + {
> > + num = domid_last + 1;
> > + domid = find_next_zero_bit(domid_bitmap, num, 1);
> > + }
> > +
> > + ASSERT(domid <= DOMID_FIRST_RESERVED);
> > + if ( domid < num )
> > + {
> > + __set_bit(domid, domid_bitmap);
> > + domid_last = domid;
> > + }
> > + else
> > + domid = DOMID_INVALID;
> > + }
> > +
> > + spin_unlock(&domid_lock);
> > +
> > + return domid;
> > +}
> > +
> > +void domid_free(domid_t domid)
> > +{
> > + int rc;
> > +
> > + ASSERT(domid <= DOMID_FIRST_RESERVED);
> > +
> > + spin_lock(&domid_lock);
> > + rc = __test_and_clear_bit(domid, domid_bitmap);
> > + spin_unlock(&domid_lock);
> > +
> > + ASSERT(rc);
> > +}
> > +
> > +/*
> > + * Local variables:
> > + * mode: C
> > + * c-file-style: "BSD"
> > + * c-basic-offset: 4
> > + * tab-width: 4
> > + * indent-tabs-mode: nil
> > + * End:
> > + */
> > diff --git a/xen/include/xen/domain.h b/xen/include/xen/domain.h
> > index e10baf2615fd..8aab05ae93c8 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,
> >
> > domid_t get_initial_domain_id(void);
> >
> > +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)
>
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH v15 1/4] xen/domain: unify domain ID allocation
2025-08-09 17:08 ` [PATCH v15 1/4] xen/domain: unify " dmkhn
2025-08-11 11:00 ` Alejandro Vallejo
@ 2025-08-11 11:14 ` Jan Beulich
2025-08-11 23:46 ` dmkhn
1 sibling, 1 reply; 11+ messages in thread
From: Jan Beulich @ 2025-08-11 11:14 UTC (permalink / raw)
To: dmkhn
Cc: andrew.cooper3, anthony.perard, julien, michal.orzel, roger.pau,
sstabellini, dmukhin, Julien Grall, xen-devel
On 09.08.2025 19:08, dmkhn@proton.me wrote:
> --- /dev/null
> +++ b/xen/common/domid.c
> @@ -0,0 +1,95 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +/*
> + * Domain ID allocator.
> + *
> + * Covers dom0 or late hwdom, predefined domains, post-boot domains.
> + * Excludes system domains (ID >= DOMID_FIRST_RESERVED).
> + *
> + * Copyright 2025 Ford Motor Company
> + */
> +
> +#include <xen/domain.h>
> +
> +static DEFINE_SPINLOCK(domid_lock);
> +static DECLARE_BITMAP(domid_bitmap, DOMID_FIRST_RESERVED);
> +
> +/*
> + * Allocate domain ID.
> + *
> + * @param domid Domain ID hint:
> + * - If an explicit domain ID is provided, verify its availability and use it
> + * if ID is not used;
> + * - If DOMID_INVALID is provided, search [1..DOMID_FIRST_RESERVED-1] range,
> + * starting from the last used ID. Implementation guarantees that two
> + * consecutive calls will never return the same ID. ID#0 is reserved for
> + * the first boot domain (currently, dom0) and excluded from the allocation
> + * range.
> + * @return Valid domain ID in case of successful allocation,
> + * DOMID_INVALID - otherwise.
> + */
> +domid_t domid_alloc(domid_t domid)
> +{
> + static domid_t domid_last;
> +
> + spin_lock(&domid_lock);
> +
> + /* Exact match. */
> + if ( domid < DOMID_FIRST_RESERVED )
> + {
> + if ( __test_and_set_bit(domid, domid_bitmap) )
> + domid = DOMID_INVALID;
> + }
> + /*
> + * Exhaustive search.
> + *
> + * Domain ID#0 is reserved for the first boot domain (e.g. control domain)
> + * and excluded from allocation.
> + */
> + else
> + {
> + domid_t num = DOMID_FIRST_RESERVED;
> +
> + domid = find_next_zero_bit(domid_bitmap, num, domid_last + 1);
> + if ( domid == num && domid_last != 0 )
I'm pretty sure I commented on this before, yet then maybe it was in the context
of another patch: Using == here isn't sufficient; it needs to be >=. See e.g.
cpumask_next().
Jan
^ permalink raw reply [flat|nested] 11+ messages in thread* Re: [PATCH v15 1/4] xen/domain: unify domain ID allocation
2025-08-11 11:14 ` Jan Beulich
@ 2025-08-11 23:46 ` dmkhn
0 siblings, 0 replies; 11+ messages in thread
From: dmkhn @ 2025-08-11 23:46 UTC (permalink / raw)
To: Jan Beulich
Cc: andrew.cooper3, anthony.perard, julien, michal.orzel, roger.pau,
sstabellini, dmukhin, Julien Grall, xen-devel
On Mon, Aug 11, 2025 at 01:14:49PM +0200, Jan Beulich wrote:
> On 09.08.2025 19:08, dmkhn@proton.me wrote:
> > --- /dev/null
> > +++ b/xen/common/domid.c
> > @@ -0,0 +1,95 @@
> > +/* SPDX-License-Identifier: GPL-2.0-only */
> > +/*
> > + * Domain ID allocator.
> > + *
> > + * Covers dom0 or late hwdom, predefined domains, post-boot domains.
> > + * Excludes system domains (ID >= DOMID_FIRST_RESERVED).
> > + *
> > + * Copyright 2025 Ford Motor Company
> > + */
> > +
> > +#include <xen/domain.h>
> > +
> > +static DEFINE_SPINLOCK(domid_lock);
> > +static DECLARE_BITMAP(domid_bitmap, DOMID_FIRST_RESERVED);
> > +
> > +/*
> > + * Allocate domain ID.
> > + *
> > + * @param domid Domain ID hint:
> > + * - If an explicit domain ID is provided, verify its availability and use it
> > + * if ID is not used;
> > + * - If DOMID_INVALID is provided, search [1..DOMID_FIRST_RESERVED-1] range,
> > + * starting from the last used ID. Implementation guarantees that two
> > + * consecutive calls will never return the same ID. ID#0 is reserved for
> > + * the first boot domain (currently, dom0) and excluded from the allocation
> > + * range.
> > + * @return Valid domain ID in case of successful allocation,
> > + * DOMID_INVALID - otherwise.
> > + */
> > +domid_t domid_alloc(domid_t domid)
> > +{
> > + static domid_t domid_last;
> > +
> > + spin_lock(&domid_lock);
> > +
> > + /* Exact match. */
> > + if ( domid < DOMID_FIRST_RESERVED )
> > + {
> > + if ( __test_and_set_bit(domid, domid_bitmap) )
> > + domid = DOMID_INVALID;
> > + }
> > + /*
> > + * Exhaustive search.
> > + *
> > + * Domain ID#0 is reserved for the first boot domain (e.g. control domain)
> > + * and excluded from allocation.
> > + */
> > + else
> > + {
> > + domid_t num = DOMID_FIRST_RESERVED;
> > +
> > + domid = find_next_zero_bit(domid_bitmap, num, domid_last + 1);
> > + if ( domid == num && domid_last != 0 )
>
> I'm pretty sure I commented on this before, yet then maybe it was in the context
> of another patch: Using == here isn't sufficient; it needs to be >=. See e.g.
> cpumask_next().
I've missed that one. Will fix, thank you.
>
> Jan
^ permalink raw reply [flat|nested] 11+ messages in thread
* [PATCH v15 2/4] tools/include: move xc_bitops.h to xen-tools/bitops.h
2025-08-09 17:07 [PATCH v15 0/4] xen/domain: domain ID allocation dmkhn
2025-08-09 17:08 ` [PATCH v15 1/4] xen/domain: unify " dmkhn
@ 2025-08-09 17:08 ` dmkhn
2025-08-09 17:08 ` [PATCH v15 3/4] tools/tests: introduce unit tests for domain ID allocator dmkhn
2025-08-09 17:08 ` [PATCH v15 4/4] xen/domain: update create_dom0() messages dmkhn
3 siblings, 0 replies; 11+ messages in thread
From: dmkhn @ 2025-08-09 17:08 UTC (permalink / raw)
To: xen-devel
Cc: andrew.cooper3, anthony.perard, jbeulich, julien, michal.orzel,
roger.pau, sstabellini, dmukhin
From: Denis Mukhin <dmukhin@ford.com>
Move xc_bitops.h to common tools location to be shared between
the toolstack and unit test code.
Adjust the guard in xen-tools/bitops.h
Correct the #include directives and comments referring to the old
xc_bitops.h in the toolstack code.
Signed-off-by: Denis Mukhin <dmukhin@ford.com>
---
Changes since v14:
- n/a
---
.../ctrl/xc_bitops.h => include/xen-tools/bitops.h} | 6 +++---
tools/libs/ctrl/xc_misc.c | 13 +++++++------
tools/libs/guest/xg_dom_elfloader.c | 3 ++-
tools/libs/guest/xg_dom_hvmloader.c | 3 ++-
tools/libs/guest/xg_private.h | 2 +-
tools/libs/guest/xg_sr_common.h | 3 +--
6 files changed, 16 insertions(+), 14 deletions(-)
rename tools/{libs/ctrl/xc_bitops.h => include/xen-tools/bitops.h} (95%)
diff --git a/tools/libs/ctrl/xc_bitops.h b/tools/include/xen-tools/bitops.h
similarity index 95%
rename from tools/libs/ctrl/xc_bitops.h
rename to tools/include/xen-tools/bitops.h
index 4a776dc3a57f..681482f6759f 100644
--- a/tools/libs/ctrl/xc_bitops.h
+++ b/tools/include/xen-tools/bitops.h
@@ -1,5 +1,5 @@
-#ifndef XC_BITOPS_H
-#define XC_BITOPS_H 1
+#ifndef __XEN_TOOLS_BITOPS_H__
+#define __XEN_TOOLS_BITOPS_H__
/* bitmap operations for single threaded access */
@@ -81,4 +81,4 @@ static inline void bitmap_or(void *_dst, const void *_other,
dst[i] |= other[i];
}
-#endif /* XC_BITOPS_H */
+#endif /* __XEN_TOOLS_BITOPS_H__ */
diff --git a/tools/libs/ctrl/xc_misc.c b/tools/libs/ctrl/xc_misc.c
index 33e87bac2868..10ddf85667a9 100644
--- a/tools/libs/ctrl/xc_misc.c
+++ b/tools/libs/ctrl/xc_misc.c
@@ -17,8 +17,8 @@
* License along with this library; If not, see <http://www.gnu.org/licenses/>.
*/
-#include "xc_bitops.h"
#include "xc_private.h"
+#include <xen-tools/bitops.h>
#include <xen/hvm/hvm_op.h>
int xc_get_max_cpus(xc_interface *xch)
@@ -94,11 +94,12 @@ xc_cpumap_t xc_cpumap_alloc(xc_interface *xch)
}
/*
- * xc_bitops.h has macros that do this as well - however they assume that
- * the bitmask is word aligned but xc_cpumap_t is only guaranteed to be
- * byte aligned and so we need byte versions for architectures which do
- * not support misaligned accesses (which is basically everyone
- * but x86, although even on x86 it can be inefficient).
+ * <xen-tools/bitops.h> has macros that do this as well - however they
+ * assume that the bitmask is word aligned but xc_cpumap_t is only
+ * guaranteed to be byte aligned and so we need byte versions for
+ * architectures which do not support misaligned accesses (which is
+ * basically everyone but x86, although even on x86 it can be
+ * inefficient).
*
* NOTE: The xc_bitops macros now use byte alignment.
* TODO: Clean up the users of this interface.
diff --git a/tools/libs/guest/xg_dom_elfloader.c b/tools/libs/guest/xg_dom_elfloader.c
index f17930d98bf7..8531e90f8e21 100644
--- a/tools/libs/guest/xg_dom_elfloader.c
+++ b/tools/libs/guest/xg_dom_elfloader.c
@@ -25,8 +25,9 @@
#include <stdarg.h>
#include <inttypes.h>
+#include <xen-tools/bitops.h>
+
#include "xg_private.h"
-#include "xc_bitops.h"
#define XEN_VER "xen-3.0"
diff --git a/tools/libs/guest/xg_dom_hvmloader.c b/tools/libs/guest/xg_dom_hvmloader.c
index 39e1e5f579a7..0f569c20c522 100644
--- a/tools/libs/guest/xg_dom_hvmloader.c
+++ b/tools/libs/guest/xg_dom_hvmloader.c
@@ -24,8 +24,9 @@
#include <inttypes.h>
#include <assert.h>
+#include <xen-tools/bitops.h>
+
#include "xg_private.h"
-#include "xc_bitops.h"
/* ------------------------------------------------------------------------ */
/* parse elf binary */
diff --git a/tools/libs/guest/xg_private.h b/tools/libs/guest/xg_private.h
index d73947094f2e..285229cf82a3 100644
--- a/tools/libs/guest/xg_private.h
+++ b/tools/libs/guest/xg_private.h
@@ -28,9 +28,9 @@
#include <sys/stat.h>
#include "xc_private.h"
-#include "xc_bitops.h"
#include "xenguest.h"
+#include <xen-tools/bitops.h>
#include <xen/memory.h>
#include <xen/elfnote.h>
#include <xen/libelf/libelf.h>
diff --git a/tools/libs/guest/xg_sr_common.h b/tools/libs/guest/xg_sr_common.h
index 2f058ee3a6ff..2e583f2eac72 100644
--- a/tools/libs/guest/xg_sr_common.h
+++ b/tools/libs/guest/xg_sr_common.h
@@ -2,11 +2,10 @@
#define __COMMON__H
#include <stdbool.h>
+#include <xen-tools/bitops.h>
#include "xg_private.h"
#include "xg_save_restore.h"
-#include "xc_bitops.h"
-
#include "xg_sr_stream_format.h"
/* String representation of Domain Header types. */
--
2.34.1
^ permalink raw reply related [flat|nested] 11+ messages in thread* [PATCH v15 3/4] tools/tests: introduce unit tests for domain ID allocator
2025-08-09 17:07 [PATCH v15 0/4] xen/domain: domain ID allocation dmkhn
2025-08-09 17:08 ` [PATCH v15 1/4] xen/domain: unify " dmkhn
2025-08-09 17:08 ` [PATCH v15 2/4] tools/include: move xc_bitops.h to xen-tools/bitops.h dmkhn
@ 2025-08-09 17:08 ` dmkhn
2025-08-11 7:58 ` Jan Beulich
2025-08-09 17:08 ` [PATCH v15 4/4] xen/domain: update create_dom0() messages dmkhn
3 siblings, 1 reply; 11+ messages in thread
From: dmkhn @ 2025-08-09 17:08 UTC (permalink / raw)
To: xen-devel
Cc: andrew.cooper3, anthony.perard, jbeulich, julien, michal.orzel,
roger.pau, sstabellini, dmukhin, Julien Grall
From: Denis Mukhin <dmukhin@ford.com>
Introduce some basic infrastructure for doing domain ID allocation unit tests,
and add a few tests that ensure correctness of the domain ID allocator.
Use <xen-tools/bitops.h> and xen/lib/find-next-bit.c in test hardness code.
Adjust find-next-bit.c to be compiled with __XEN_TOOLS__.
Signed-off-by: Denis Mukhin <dmukhin@ford.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
---
Changes since v14:
- addressed NITs from v14's review
- extended the test for exact IDs allocation (trivial change)
- added Julien's R-b
---
tools/include/xen-tools/bitops.h | 10 +++
tools/tests/Makefile | 1 +
tools/tests/domid/.gitignore | 2 +
tools/tests/domid/Makefile | 56 ++++++++++++++++
tools/tests/domid/harness.h | 54 +++++++++++++++
tools/tests/domid/include/xen/domain.h | 1 +
tools/tests/domid/test-domid.c | 93 ++++++++++++++++++++++++++
xen/lib/find-next-bit.c | 5 ++
8 files changed, 222 insertions(+)
create mode 100644 tools/tests/domid/.gitignore
create mode 100644 tools/tests/domid/Makefile
create mode 100644 tools/tests/domid/harness.h
create mode 120000 tools/tests/domid/include/xen/domain.h
create mode 100644 tools/tests/domid/test-domid.c
diff --git a/tools/include/xen-tools/bitops.h b/tools/include/xen-tools/bitops.h
index 681482f6759f..3b98fba6d74c 100644
--- a/tools/include/xen-tools/bitops.h
+++ b/tools/include/xen-tools/bitops.h
@@ -12,6 +12,16 @@
#define BITS_PER_LONG 32
#endif
+#define ffsl(x) __builtin_ffsl(x)
+
+#define BIT_WORD(nr) ((nr) / BITS_PER_LONG)
+
+#define BITS_TO_LONGS(bits) \
+ (((bits) + BITS_PER_LONG - 1) / BITS_PER_LONG)
+
+#define DECLARE_BITMAP(name, bits) \
+ unsigned long name[BITS_TO_LONGS(bits)]
+
#define BITMAP_ENTRY(_nr,_bmap) ((_bmap))[(_nr) / 8]
#define BITMAP_SHIFT(_nr) ((_nr) % 8)
diff --git a/tools/tests/Makefile b/tools/tests/Makefile
index 36928676a666..94fa80c16880 100644
--- a/tools/tests/Makefile
+++ b/tools/tests/Makefile
@@ -2,6 +2,7 @@ XEN_ROOT = $(CURDIR)/../..
include $(XEN_ROOT)/tools/Rules.mk
SUBDIRS-y :=
+SUBDIRS-y += domid
SUBDIRS-y += resource
SUBDIRS-$(CONFIG_X86) += cpu-policy
SUBDIRS-$(CONFIG_X86) += tsx
diff --git a/tools/tests/domid/.gitignore b/tools/tests/domid/.gitignore
new file mode 100644
index 000000000000..70e306b3c074
--- /dev/null
+++ b/tools/tests/domid/.gitignore
@@ -0,0 +1,2 @@
+*.o
+test-domid
diff --git a/tools/tests/domid/Makefile b/tools/tests/domid/Makefile
new file mode 100644
index 000000000000..d96ceca6d954
--- /dev/null
+++ b/tools/tests/domid/Makefile
@@ -0,0 +1,56 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Unit tests for domain ID allocator.
+#
+# Copyright 2025 Ford Motor Company
+
+XEN_ROOT=$(CURDIR)/../../..
+include $(XEN_ROOT)/tools/Rules.mk
+
+TESTS := test-domid
+
+vpath domid.c $(XEN_ROOT)/xen/common/
+vpath find-next-bit.c $(XEN_ROOT)/xen/lib/
+
+.PHONY: all
+all: $(TESTS)
+
+.PHONY: run
+run: $(TESTS)
+ $(foreach t,$(TESTS),./$(t);)
+
+.PHONY: clean
+clean:
+ $(RM) -- *.o $(TESTS) $(DEPS_RM)
+
+.PHONY: distclean
+distclean: clean
+ $(RM) -- *~
+
+.PHONY: install
+install: all
+ $(INSTALL_DIR) $(DESTDIR)$(LIBEXEC)/tests
+ $(INSTALL_PROG) test-domid $(DESTDIR)$(LIBEXEC)/tests
+
+.PHONY: uninstall
+uninstall:
+ $(RM) -- $(DESTDIR)$(LIBEXEC)/tests/test-domid
+
+CFLAGS += -D__XEN_TOOLS__
+# find-next-bit.c
+CFLAGS += '-DEXPORT_SYMBOL(x)=' \
+ -Dfind_first_bit \
+ -Dfind_first_zero_bit \
+ -Dfind_next_bit \
+ -Dfind_next_bit_le \
+ -Dfind_next_zero_bit_le
+CFLAGS += $(APPEND_CFLAGS)
+CFLAGS += $(CFLAGS_xeninclude)
+CFLAGS += -I./include/
+
+LDFLAGS += $(APPEND_LDFLAGS)
+
+test-domid: domid.o find-next-bit.o test-domid.o
+ $(CC) $^ -o $@ $(LDFLAGS)
+
+-include $(DEPS_INCLUDE)
diff --git a/tools/tests/domid/harness.h b/tools/tests/domid/harness.h
new file mode 100644
index 000000000000..17eb22a9a854
--- /dev/null
+++ b/tools/tests/domid/harness.h
@@ -0,0 +1,54 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Unit test harness for domain ID allocator.
+ *
+ * Copyright 2025 Ford Motor Company
+ */
+
+#ifndef _TEST_HARNESS_
+#define _TEST_HARNESS_
+
+#include <assert.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+
+#include <xen-tools/common-macros.h>
+#include <xen-tools/bitops.h>
+
+typedef bool spinlock_t;
+typedef uint16_t domid_t;
+
+extern domid_t domid_alloc(domid_t domid);
+extern void domid_free(domid_t domid);
+
+extern unsigned long find_next_zero_bit(const unsigned long *addr,
+ unsigned long size,
+ unsigned long offset);
+
+#define __test_and_set_bit(nr, addr) test_and_set_bit(nr, addr)
+#define __test_and_clear_bit(nr, addr) test_and_clear_bit(nr, addr)
+#define __set_bit(nr, addr) set_bit(nr, addr)
+
+#define BUG_ON(x) assert(!(x))
+#define ASSERT(x) assert(x)
+
+#define DEFINE_SPINLOCK(l) spinlock_t l
+#define spin_lock(l) (assert(!*(l)), *(l) = true)
+#define spin_unlock(l) (assert(*(l)), *(l) = false)
+
+#define printk printf
+
+#define DOMID_FIRST_RESERVED (100)
+#define DOMID_INVALID (101)
+
+#endif /* _TEST_HARNESS_ */
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
diff --git a/tools/tests/domid/include/xen/domain.h b/tools/tests/domid/include/xen/domain.h
new file mode 120000
index 000000000000..2eda9aed088e
--- /dev/null
+++ b/tools/tests/domid/include/xen/domain.h
@@ -0,0 +1 @@
+../../harness.h
\ No newline at end of file
diff --git a/tools/tests/domid/test-domid.c b/tools/tests/domid/test-domid.c
new file mode 100644
index 000000000000..51a88a6a9550
--- /dev/null
+++ b/tools/tests/domid/test-domid.c
@@ -0,0 +1,93 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Unit tests for domain ID allocator.
+ *
+ * Copyright 2025 Ford Motor Company
+ */
+
+#include "harness.h"
+
+#define verify(exp, fmt, args...) do { \
+ if ( !(exp) ) \
+ printf(fmt, ## args); \
+ assert(exp); \
+} while (0);
+
+/*
+ * Fail on the first error, since tests are dependent on each other.
+ */
+int main(int argc, char **argv)
+{
+ domid_t expected, allocated;
+
+ /* Test ID cannot be allocated twice. */
+ for ( expected = 0; expected < DOMID_FIRST_RESERVED; expected++ )
+ {
+ allocated = domid_alloc(expected);
+ verify(allocated == expected,
+ "TEST 1: expected %u allocated %u\n", expected, allocated);
+ }
+ for ( expected = 0; expected < DOMID_FIRST_RESERVED; expected++ )
+ {
+ allocated = domid_alloc(expected);
+ verify(allocated == DOMID_INVALID,
+ "TEST 2: expected %u allocated %u\n", DOMID_INVALID, allocated);
+ }
+
+ /* Ensure all IDs, including ID#0 are not allocated. */
+ for ( expected = 0; expected < DOMID_FIRST_RESERVED; expected++ )
+ domid_free(expected);
+
+ /*
+ * Test that that two consecutive calls of domid_alloc(DOMID_INVALID)
+ * will never return the same ID.
+ * NB: ID#0 is reserved and shall not be allocated by
+ * domid_alloc(DOMID_INVALID).
+ */
+ for ( expected = 1; expected < DOMID_FIRST_RESERVED; expected++ )
+ {
+ allocated = domid_alloc(DOMID_INVALID);
+ verify(allocated == expected,
+ "TEST 3: expected %u allocated %u\n", expected, allocated);
+ }
+ for ( expected = 1; expected < DOMID_FIRST_RESERVED; expected++ )
+ {
+ allocated = domid_alloc(DOMID_INVALID);
+ verify(allocated == DOMID_INVALID,
+ "TEST 4: expected %u allocated %u\n", DOMID_INVALID, allocated);
+ }
+
+ /* Re-allocate first ID from [1..DOMID_FIRST_RESERVED/2]. */
+ for ( expected = 1; expected < DOMID_FIRST_RESERVED / 2; expected++ )
+ domid_free(expected);
+ for ( expected = 1; expected < DOMID_FIRST_RESERVED / 2; expected++ )
+ {
+ allocated = domid_alloc(DOMID_INVALID);
+ verify(allocated == expected,
+ "TEST 5: expected %u allocated %u\n", expected, allocated);
+ }
+
+ /* Re-allocate last ID from [1..DOMID_FIRST_RESERVED - 1]. */
+ expected = DOMID_FIRST_RESERVED - 1;
+ domid_free(DOMID_FIRST_RESERVED - 1);
+ allocated = domid_alloc(DOMID_INVALID);
+ verify(allocated == expected,
+ "TEST 6: expected %u allocated %u\n", expected, allocated);
+
+ /* Allocate an invalid ID. */
+ expected = DOMID_INVALID;
+ allocated = domid_alloc(DOMID_FIRST_RESERVED);
+ verify(allocated == expected,
+ "TEST 7: expected %u allocated %u\n", expected, allocated);
+
+ return 0;
+}
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
diff --git a/xen/lib/find-next-bit.c b/xen/lib/find-next-bit.c
index 9b8d7814f20c..539c7f2022b0 100644
--- a/xen/lib/find-next-bit.c
+++ b/xen/lib/find-next-bit.c
@@ -8,8 +8,13 @@
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
+
+#ifdef __XEN_TOOLS__
+#include <xen-tools/bitops.h>
+#else
#include <xen/bitops.h>
#include <xen/byteorder.h>
+#endif
#define __ffs(x) (ffsl(x) - 1)
#define ffz(x) __ffs(~(x))
--
2.34.1
^ permalink raw reply related [flat|nested] 11+ messages in thread* Re: [PATCH v15 3/4] tools/tests: introduce unit tests for domain ID allocator
2025-08-09 17:08 ` [PATCH v15 3/4] tools/tests: introduce unit tests for domain ID allocator dmkhn
@ 2025-08-11 7:58 ` Jan Beulich
2025-08-11 23:53 ` dmkhn
0 siblings, 1 reply; 11+ messages in thread
From: Jan Beulich @ 2025-08-11 7:58 UTC (permalink / raw)
To: dmkhn
Cc: andrew.cooper3, anthony.perard, julien, michal.orzel, roger.pau,
sstabellini, dmukhin, Julien Grall, xen-devel
On 09.08.2025 19:08, dmkhn@proton.me wrote:
> diff --git a/tools/tests/domid/include/xen/domain.h b/tools/tests/domid/include/xen/domain.h
> new file mode 120000
> index 000000000000..2eda9aed088e
> --- /dev/null
> +++ b/tools/tests/domid/include/xen/domain.h
> @@ -0,0 +1 @@
> +../../harness.h
> \ No newline at end of file
In the tests we generally generate symlinks as necessary, rather than having them be
present in git. Furthermore it's not quite clear why a file of this name is needed
in a test harness anyway. Elsewhere we adjust hypervisor sources to make respective
#include-s conditional.
Jan
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH v15 3/4] tools/tests: introduce unit tests for domain ID allocator
2025-08-11 7:58 ` Jan Beulich
@ 2025-08-11 23:53 ` dmkhn
0 siblings, 0 replies; 11+ messages in thread
From: dmkhn @ 2025-08-11 23:53 UTC (permalink / raw)
To: Jan Beulich
Cc: andrew.cooper3, anthony.perard, julien, michal.orzel, roger.pau,
sstabellini, dmukhin, Julien Grall, xen-devel
On Mon, Aug 11, 2025 at 09:58:24AM +0200, Jan Beulich wrote:
> On 09.08.2025 19:08, dmkhn@proton.me wrote:
> > diff --git a/tools/tests/domid/include/xen/domain.h b/tools/tests/domid/include/xen/domain.h
> > new file mode 120000
> > index 000000000000..2eda9aed088e
> > --- /dev/null
> > +++ b/tools/tests/domid/include/xen/domain.h
> > @@ -0,0 +1 @@
> > +../../harness.h
> > \ No newline at end of file
>
> In the tests we generally generate symlinks as necessary, rather than having them be
> present in git. Furthermore it's not quite clear why a file of this name is needed
> in a test harness anyway. Elsewhere we adjust hypervisor sources to make respective
> #include-s conditional.
I'll fix the makefile for the test so dependencies are resolved on the fly
and no need for code adjustment.
>
> Jan
^ permalink raw reply [flat|nested] 11+ messages in thread
* [PATCH v15 4/4] xen/domain: update create_dom0() messages
2025-08-09 17:07 [PATCH v15 0/4] xen/domain: domain ID allocation dmkhn
` (2 preceding siblings ...)
2025-08-09 17:08 ` [PATCH v15 3/4] tools/tests: introduce unit tests for domain ID allocator dmkhn
@ 2025-08-09 17:08 ` dmkhn
3 siblings, 0 replies; 11+ messages in thread
From: dmkhn @ 2025-08-09 17:08 UTC (permalink / raw)
To: xen-devel
Cc: andrew.cooper3, anthony.perard, jbeulich, julien, michal.orzel,
roger.pau, sstabellini, dmukhin, Alejandro Vallejo, Julien Grall
From: Denis Mukhin <dmukhin@ford.com>
Use %pd for domain identification in error/panic messages in create_dom0().
No functional change.
Signed-off-by: Denis Mukhin <dmukhin@ford.com>
Reviewed-by: Alejandro Vallejo <alejandro.garciavallejo@amd.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Julien Grall <jgrall@amazon.com>
---
Changes since v14:
- added Julien's A-b
---
xen/arch/arm/domain_build.c | 6 +++---
xen/arch/x86/setup.c | 4 ++--
2 files changed, 5 insertions(+), 5 deletions(-)
diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
index 789f2b9d3ce7..02a15d160962 100644
--- a/xen/arch/arm/domain_build.c
+++ b/xen/arch/arm/domain_build.c
@@ -2084,14 +2084,14 @@ void __init create_dom0(void)
panic("Error creating domain 0 (rc = %ld)\n", PTR_ERR(dom0));
if ( llc_coloring_enabled && (rc = dom0_set_llc_colors(dom0)) )
- panic("Error initializing LLC coloring for domain 0 (rc = %d)\n", rc);
+ panic("Error initializing LLC coloring for %pd (rc = %d)\n", dom0, rc);
if ( vcpu_create(dom0, 0) == NULL )
- panic("Error creating domain 0 vcpu0\n");
+ panic("Error creating %pdv0\n", dom0);
rc = construct_dom0(dom0);
if ( rc )
- panic("Could not set up DOM0 guest OS (rc = %d)\n", rc);
+ panic("Could not set up %pd guest OS (rc = %d)\n", dom0, rc);
set_xs_domain(dom0);
}
diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c
index 398da734c0c5..bf21c55f7193 100644
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -1084,7 +1084,7 @@ static struct domain *__init create_dom0(struct boot_info *bi)
if ( (strlen(acpi_param) == 0) && acpi_disabled )
{
- printk("ACPI is disabled, notifying Domain 0 (acpi=off)\n");
+ printk("ACPI is disabled, notifying %pd (acpi=off)\n", d);
safe_strcpy(acpi_param, "off");
}
@@ -1099,7 +1099,7 @@ static struct domain *__init create_dom0(struct boot_info *bi)
bd->d = d;
if ( construct_dom0(bd) != 0 )
- panic("Could not construct domain 0\n");
+ panic("Could not construct %pd\n", d);
bd->cmdline = NULL;
xfree(cmdline);
--
2.34.1
^ permalink raw reply related [flat|nested] 11+ messages in thread