From: Denis Mukhin <dmukhin@xxxxxxxx>
Add a new symbol DOMID_ANY to improve the readability of the code.
Update all relevant domid_alloc() call sites and harden the domid_alloc()
input value check.
Also, fix problem with passing invalid domain IDs in
XEN_DOMCTL_createdomain: turns out libxl__domain_make() (toolstack)
uses 0xffff as domain ID.
Amends: 2d5065060710 ("xen/domain: unify domain ID allocation")
Signed-off-by: Denis Mukhin <dmukhin@xxxxxxxx>
---
Changes since v6:
- fixed libxl_domid_valid_guest() check in libxl_create.c
- Link to v6:
https://lore.kernel.org/xen-devel/20260307025451.3148078-2-dmukhin@xxxxxxxx/
- CI: https://gitlab.com/xen-project/people/dmukhin/xen/-/pipelines/2438790748
---
tools/libs/light/libxl_create.c | 4 +++-
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 | 3 +--
xen/common/domid.c | 5 ++++-
xen/include/public/xen.h | 7 +++++++
7 files changed, 23 insertions(+), 11 deletions(-)
diff --git a/tools/libs/light/libxl_create.c b/tools/libs/light/libxl_create.c
index bfc9149096a3..6fd62d140389 100644
--- a/tools/libs/light/libxl_create.c
+++ b/tools/libs/light/libxl_create.c
@@ -681,8 +681,10 @@ int libxl__domain_make(libxl__gc *gc, libxl_domain_config
*d_config,
continue;
local_domid = v;
+ } else if (libxl_domid_valid_guest(info->domid)) {
+ local_domid = info->domid;
} else {
- local_domid = info->domid; /* May not be valid */
+ local_domid = DOMID_ANY;
}
ret = xc_domain_create(ctx->xch, &local_domid, &create);
diff --git a/tools/tests/domid/harness.h b/tools/tests/domid/harness.h
index 17eb22a9a854..65da0d075a2b 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 (102)
#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 840d14419da2..3c18dae5e625 100644
--- a/xen/common/device-tree/dom0less-build.c
+++ b/xen/common/device-tree/dom0less-build.c
@@ -852,7 +852,7 @@ 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 93738931c575..b969f5ada6cc 100644
--- a/xen/common/domctl.c
+++ b/xen/common/domctl.c
@@ -409,8 +409,7 @@ 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);
if ( domid == DOMID_INVALID )
{
diff --git a/xen/common/domid.c b/xen/common/domid.c
index 2387ddb08300..b0258e477c1a 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
@@ -31,6 +31,9 @@ domid_t domid_alloc(domid_t domid)
{
static domid_t domid_last;
+ if ( domid >= DOMID_FIRST_RESERVED && domid != DOMID_ANY )
+ return DOMID_INVALID;
+
