Mailing List Archive

commit b5409f4e4d0722e8669123d59f15f784903d153f
Author: Jan Beulich <jbeulich@suse.com>
AuthorDate: Tue Mar 21 13:44:53 2023 +0100
Commit: Jan Beulich <jbeulich@suse.com>
CommitDate: Tue Mar 21 13:44:53 2023 +0100

core-parking: fix build with gcc12 and NR_CPUS=1

Gcc12 takes issue with core_parking_remove()'s

for ( ; i < cur_idle_nums; ++i )
core_parking_cpunum[i] = core_parking_cpunum[i + 1];

complaining that the right hand side array access is past the bounds of
1. Clearly the compiler can't know that cur_idle_nums can only ever be
zero in this case (as the sole CPU cannot be parked).

Arrange for core_parking.c's contents to not be needed altogether, and
then disable its building when NR_CPUS == 1.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
master commit: 4b0422f70feb4b1cd04598ffde805fc224f3812e
master date: 2023-03-13 15:15:42 +0100
---
xen/arch/x86/Kconfig | 2 +-
xen/arch/x86/platform_hypercall.c | 11 ++++++++---
xen/arch/x86/sysctl.c | 3 +++
xen/common/Kconfig | 1 +
4 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/xen/arch/x86/Kconfig b/xen/arch/x86/Kconfig
index 6a7825f4ba..2a5c3304e2 100644
--- a/xen/arch/x86/Kconfig
+++ b/xen/arch/x86/Kconfig
@@ -10,7 +10,7 @@ config X86
select ALTERNATIVE_CALL
select ARCH_MAP_DOMAIN_PAGE
select ARCH_SUPPORTS_INT128
- select CORE_PARKING
+ imply CORE_PARKING
select HAS_ALTERNATIVE
select HAS_COMPAT
select HAS_CPUFREQ
diff --git a/xen/arch/x86/platform_hypercall.c b/xen/arch/x86/platform_hypercall.c
index a7341dc3d7..e7deee2268 100644
--- a/xen/arch/x86/platform_hypercall.c
+++ b/xen/arch/x86/platform_hypercall.c
@@ -727,12 +727,17 @@ ret_t do_platform_op(
case XEN_CORE_PARKING_SET:
idle_nums = min_t(uint32_t,
op->u.core_parking.idle_nums, num_present_cpus() - 1);
- ret = continue_hypercall_on_cpu(
- 0, core_parking_helper, (void *)(unsigned long)idle_nums);
+ if ( CONFIG_NR_CPUS > 1 )
+ ret = continue_hypercall_on_cpu(
+ 0, core_parking_helper,
+ (void *)(unsigned long)idle_nums);
+ else if ( idle_nums )
+ ret = -EINVAL;
break;

case XEN_CORE_PARKING_GET:
- op->u.core_parking.idle_nums = get_cur_idle_nums();
+ op->u.core_parking.idle_nums = CONFIG_NR_CPUS > 1
+ ? get_cur_idle_nums() : 0;
ret = __copy_field_to_guest(u_xenpf_op, op, u.core_parking) ?
-EFAULT : 0;
break;
diff --git a/xen/arch/x86/sysctl.c b/xen/arch/x86/sysctl.c
index f82abc2488..f8f8d79755 100644
--- a/xen/arch/x86/sysctl.c
+++ b/xen/arch/x86/sysctl.c
@@ -179,6 +179,9 @@ long arch_do_sysctl(
ret = -EBUSY;
break;
}
+ if ( CONFIG_NR_CPUS <= 1 )
+ /* Mimic behavior of smt_up_down_helper(). */
+ return 0;
plug = op == XEN_SYSCTL_CPU_HOTPLUG_SMT_ENABLE;
fn = smt_up_down_helper;
hcpu = _p(plug);
diff --git a/xen/common/Kconfig b/xen/common/Kconfig
index f1ea3199c8..855c843113 100644
--- a/xen/common/Kconfig
+++ b/xen/common/Kconfig
@@ -10,6 +10,7 @@ config COMPAT

config CORE_PARKING
bool
+ depends on NR_CPUS > 1

config GRANT_TABLE
bool "Grant table support" if EXPERT
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.17