From: Luca Fancellu <luca.fancellu@arm.com>
To: xen-devel@lists.xenproject.org
Cc: bertrand.marquis@arm.com, wei.chen@arm.com,
Stefano Stabellini <sstabellini@kernel.org>,
Julien Grall <julien@xen.org>,
Volodymyr Babchuk <Volodymyr_Babchuk@epam.com>,
Andrew Cooper <andrew.cooper3@citrix.com>,
George Dunlap <george.dunlap@citrix.com>,
Ian Jackson <iwj@xenproject.org>, Jan Beulich <jbeulich@suse.com>,
Wei Liu <wl@xen.org>
Subject: [PATCH v2 3/4] xen/arm: Reserve domid 0 for Dom0
Date: Thu, 8 Apr 2021 10:48:17 +0100 [thread overview]
Message-ID: <20210408094818.8173-4-luca.fancellu@arm.com> (raw)
In-Reply-To: <20210408094818.8173-1-luca.fancellu@arm.com>
This patch ensure that the domid 0 is allocated only during
start_xen() function by the create_dom0().
Add a comment in create_domUs() right before domain_create()
to explain the importance of the pre-increment operator
on the variable max_init_domid.
Add an additional check in do_domctl() to make sure domid 0
is never used when calling domain_create().
Signed-off-by: Luca Fancellu <luca.fancellu@arm.com>
---
xen/arch/arm/domain_build.c | 5 +++++
xen/common/domctl.c | 2 +-
2 files changed, 6 insertions(+), 1 deletion(-)
diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
index d7c9c7f4d1..3fa5c8e54c 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));
diff --git a/xen/common/domctl.c b/xen/common/domctl.c
index af044e2eda..8258f157ef 100644
--- a/xen/common/domctl.c
+++ b/xen/common/domctl.c
@@ -419,7 +419,7 @@ long do_domctl(XEN_GUEST_HANDLE_PARAM(xen_domctl_t) u_domctl)
{
if ( dom == DOMID_FIRST_RESERVED )
dom = 1;
- if ( is_free_domid(dom) )
+ if ( (dom != 0) && is_free_domid(dom) )
break;
}
--
2.17.1
next prev parent reply other threads:[~2021-04-08 9:48 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-08 9:48 [PATCH v2 0/4] xen/arm: Prevent Dom0 to be loaded when using dom0less Luca Fancellu
2021-04-08 9:48 ` [PATCH v2 1/4] xen/arm: Move dom0 creation in domain_build.c Luca Fancellu
2021-04-09 8:30 ` Julien Grall
2021-04-09 9:51 ` Luca Fancellu
2021-04-08 9:48 ` [PATCH v2 2/4] xen/arm: Handle cases when hardware_domain is NULL Luca Fancellu
2021-04-08 10:17 ` Jan Beulich
2021-04-08 13:11 ` Luca Fancellu
2021-04-08 14:36 ` Jan Beulich
2021-04-08 14:58 ` Luca Fancellu
2021-04-08 9:48 ` Luca Fancellu [this message]
2021-04-08 10:46 ` [PATCH v2 3/4] xen/arm: Reserve domid 0 for Dom0 Jan Beulich
2021-04-08 13:12 ` Luca Fancellu
2021-04-08 9:48 ` [PATCH v2 4/4] xen/arm: Prevent Dom0 to be loaded when using dom0less Luca Fancellu
2021-04-09 9:12 ` Julien Grall
2021-04-09 9:56 ` Luca Fancellu
2021-04-09 10:04 ` Julien Grall
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