tools/tests/domid/harness.h | 1 + tools/tests/domid/test-domid.c | 12 ++++++------ xen/common/device-tree/dom0less-build.c | 2 +- xen/common/domctl.c | 2 +- xen/common/domid.c | 2 +- xen/include/public/xen.h | 3 +++ 6 files changed, 13 insertions(+), 9 deletions(-)
From: Denis Mukhin <dmukhin@ford.com>
Add a new symbol DOMID_ANY aliasing DOMID_INVALID to improve the readability
of the code.
Update all relevant domid_alloc() call sites.
Amends: 2d5065060710 ("xen/domain: unify domain ID allocation")
Signed-off-by: Denis Mukhin <dmukhin@ford.com>
---
CI link: https://gitlab.com/xen-project/people/dmukhin/xen/-/pipelines/2043125323
---
tools/tests/domid/harness.h | 1 +
tools/tests/domid/test-domid.c | 12 ++++++------
xen/common/device-tree/dom0less-build.c | 2 +-
xen/common/domctl.c | 2 +-
xen/common/domid.c | 2 +-
xen/include/public/xen.h | 3 +++
6 files changed, 13 insertions(+), 9 deletions(-)
diff --git a/tools/tests/domid/harness.h b/tools/tests/domid/harness.h
index 17eb22a9a854..610b564d4061 100644
--- a/tools/tests/domid/harness.h
+++ b/tools/tests/domid/harness.h
@@ -41,6 +41,7 @@ extern unsigned long find_next_zero_bit(const unsigned long *addr,
#define DOMID_FIRST_RESERVED (100)
#define DOMID_INVALID (101)
+#define DOMID_ANY DOMID_INVALID
#endif /* _TEST_HARNESS_ */
diff --git a/tools/tests/domid/test-domid.c b/tools/tests/domid/test-domid.c
index 5915c4699a5c..71cc4e7fd86d 100644
--- a/tools/tests/domid/test-domid.c
+++ b/tools/tests/domid/test-domid.c
@@ -41,20 +41,20 @@ int main(int argc, char **argv)
domid_free(expected);
/*
- * Test that that two consecutive calls of domid_alloc(DOMID_INVALID)
+ * Test that that two consecutive calls of domid_alloc(DOMID_ANY)
* will never return the same ID.
* NB: ID#0 is reserved and shall not be allocated by
- * domid_alloc(DOMID_INVALID).
+ * domid_alloc(DOMID_ANY).
*/
for ( expected = 1; expected < DOMID_FIRST_RESERVED; expected++ )
{
- allocated = domid_alloc(DOMID_INVALID);
+ allocated = domid_alloc(DOMID_ANY);
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);
+ allocated = domid_alloc(DOMID_ANY);
verify(allocated == DOMID_INVALID,
"TEST 4: expected %u allocated %u\n", DOMID_INVALID, allocated);
}
@@ -64,7 +64,7 @@ int main(int argc, char **argv)
domid_free(expected);
for ( expected = 1; expected < DOMID_FIRST_RESERVED / 2; expected++ )
{
- allocated = domid_alloc(DOMID_INVALID);
+ allocated = domid_alloc(DOMID_ANY);
verify(allocated == expected,
"TEST 5: expected %u allocated %u\n", expected, allocated);
}
@@ -72,7 +72,7 @@ int main(int argc, char **argv)
/* 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);
+ allocated = domid_alloc(DOMID_ANY);
verify(allocated == expected,
"TEST 6: expected %u allocated %u\n", expected, allocated);
diff --git a/xen/common/device-tree/dom0less-build.c b/xen/common/device-tree/dom0less-build.c
index 9fd004c42af7..e2764768c983 100644
--- a/xen/common/device-tree/dom0less-build.c
+++ b/xen/common/device-tree/dom0less-build.c
@@ -848,7 +848,7 @@ void __init create_domUs(void)
if ( (max_init_domid + 1) >= DOMID_FIRST_RESERVED )
panic("No more domain IDs available\n");
- domid = domid_alloc(DOMID_INVALID);
+ domid = domid_alloc(DOMID_ANY);
if ( domid == DOMID_INVALID )
panic("Error allocating ID for domain %s\n", dt_node_name(node));
diff --git a/xen/common/domctl.c b/xen/common/domctl.c
index 954d79022645..ca91686a03d8 100644
--- a/xen/common/domctl.c
+++ b/xen/common/domctl.c
@@ -410,7 +410,7 @@ long do_domctl(XEN_GUEST_HANDLE_PARAM(xen_domctl_t) u_domctl)
case XEN_DOMCTL_createdomain:
{
/* NB: ID#0 is reserved, find the first suitable ID instead. */
- domid_t domid = domid_alloc(op->domain ?: DOMID_INVALID);
+ domid_t domid = domid_alloc(op->domain ?: DOMID_ANY);
if ( domid == DOMID_INVALID )
{
diff --git a/xen/common/domid.c b/xen/common/domid.c
index 2387ddb08300..76b7f3e7ae6e 100644
--- a/xen/common/domid.c
+++ b/xen/common/domid.c
@@ -19,7 +19,7 @@ static DECLARE_BITMAP(domid_bitmap, DOMID_FIRST_RESERVED);
* @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,
+ * - If DOMID_ANY 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
diff --git a/xen/include/public/xen.h b/xen/include/public/xen.h
index 82b9c05a76b7..b0b2651eb4f0 100644
--- a/xen/include/public/xen.h
+++ b/xen/include/public/xen.h
@@ -608,6 +608,9 @@ DEFINE_XEN_GUEST_HANDLE(mmuext_op_t);
/* DOMID_INVALID is used to identify pages with unknown owner. */
#define DOMID_INVALID xen_mk_uint(0x7FF4)
+/* Domain ID allocator: search [1..DOMID_FIRST_RESERVED-1] range. */
+#define DOMID_ANY DOMID_INVALID
+
/* Idle domain. */
#define DOMID_IDLE xen_mk_uint(0x7FFF)
--
2.51.0On 16.09.2025 19:37, dmukhin@xen.org wrote: > --- a/xen/include/public/xen.h > +++ b/xen/include/public/xen.h > @@ -608,6 +608,9 @@ DEFINE_XEN_GUEST_HANDLE(mmuext_op_t); > /* DOMID_INVALID is used to identify pages with unknown owner. */ > #define DOMID_INVALID xen_mk_uint(0x7FF4) > > +/* Domain ID allocator: search [1..DOMID_FIRST_RESERVED-1] range. */ Considering this is an implementation detail of the hypervisor, ... > +#define DOMID_ANY DOMID_INVALID ... I don't think this should go in a public header. Jan
On 16/09/2025 1:05 pm, Jan Beulich wrote: > On 16.09.2025 19:37, dmukhin@xen.org wrote: >> --- a/xen/include/public/xen.h >> +++ b/xen/include/public/xen.h >> @@ -608,6 +608,9 @@ DEFINE_XEN_GUEST_HANDLE(mmuext_op_t); >> /* DOMID_INVALID is used to identify pages with unknown owner. */ >> #define DOMID_INVALID xen_mk_uint(0x7FF4) >> >> +/* Domain ID allocator: search [1..DOMID_FIRST_RESERVED-1] range. */ > Considering this is an implementation detail of the hypervisor, ... > >> +#define DOMID_ANY DOMID_INVALID > ... I don't think this should go in a public header. Except we want it for the toolstack to use, as part of preventing 0 being a magic number to XEN_DOMCTL_createdomain. ~Andrew
On 16.09.2025 22:51, Andrew Cooper wrote: > On 16/09/2025 1:05 pm, Jan Beulich wrote: >> On 16.09.2025 19:37, dmukhin@xen.org wrote: >>> --- a/xen/include/public/xen.h >>> +++ b/xen/include/public/xen.h >>> @@ -608,6 +608,9 @@ DEFINE_XEN_GUEST_HANDLE(mmuext_op_t); >>> /* DOMID_INVALID is used to identify pages with unknown owner. */ >>> #define DOMID_INVALID xen_mk_uint(0x7FF4) >>> >>> +/* Domain ID allocator: search [1..DOMID_FIRST_RESERVED-1] range. */ >> Considering this is an implementation detail of the hypervisor, ... >> >>> +#define DOMID_ANY DOMID_INVALID >> ... I don't think this should go in a public header. > > Except we want it for the toolstack to use, as part of preventing 0 > being a magic number to XEN_DOMCTL_createdomain. Where would the toolstack want to use it? Domain creation? And why 0 (which isn't DOMID_INVALID / DOMID_ANY)? In any event, if exposure to the tool stack is wanted, then yes, this wants to stay here, but guarded by a __XEN__ || __XEN_TOOLS__ check like we do elsewhere. Jan
On 16/09/2025 10:37 am, dmukhin@xen.org wrote:
> From: Denis Mukhin <dmukhin@ford.com>
>
> Add a new symbol DOMID_ANY aliasing DOMID_INVALID to improve the readability
> of the code.
>
> Update all relevant domid_alloc() call sites.
>
> Amends: 2d5065060710 ("xen/domain: unify domain ID allocation")
> Signed-off-by: Denis Mukhin <dmukhin@ford.com>
Thankyou. This is indeed far more coherent to read at the callsites.
~Andrew
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