Mailing List Archive

[xen master] xen/arm: Clarify how the domid is decided in create_domUs()
commit b3d1f523c8de3a6657b11456a56bd8f5e67e247b
Author: Luca Fancellu <luca.fancellu@arm.com>
AuthorDate: Wed Apr 14 10:14:03 2021 +0100
Commit: Julien Grall <jgrall@amazon.com>
CommitDate: Thu Apr 15 18:08:29 2021 +0100

xen/arm: Clarify how the domid is decided in create_domUs()

This patch adds a comment in create_domUs() right before
domain_create() to explain the importance of the pre-increment
operator on the variable max_init_domid, to ensure that the
domid 0 is allocated only during start_xen() function by the
create_dom0() and not on any other possible code path to the
domain_create() function.

Signed-off-by: Luca Fancellu <luca.fancellu@arm.com>
Reviewed-by: Bertrand Marquis <bertrand.marquis@arm.com>
Acked-by: Julien Grall <jgrall@amazon.com>
---
xen/arch/arm/domain_build.c | 5 +++++
1 file changed, 5 insertions(+)

diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
index 359957dc1b..b1d7b9849f 100644
--- a/xen/arch/arm/domain_build.c
+++ b/xen/arch/arm/domain_build.c
@@ -2508,6 +2508,11 @@ void __init create_domUs(void)
GUEST_VPL011_SPI - 32 + 1);
}

+ /*
+ * 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)
+ */
d = domain_create(++max_init_domid, &d_cfg, false);
if ( IS_ERR(d) )
panic("Error creating domain %s\n", dt_node_name(node));
--
generated by git-patchbot for /home/xen/git/xen.git#master