libvirt/SOURCES/libvirt-virhostcpu.c-fix-die_id-parsing-for-Power-hosts.patch
2021-09-10 11:58:37 +00:00

95 lines
3.3 KiB
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From b5aa3a33bc770714f8a68954c05ea362fcfd4d47 Mon Sep 17 00:00:00 2001
Message-Id: <b5aa3a33bc770714f8a68954c05ea362fcfd4d47@dist-git>
From: Daniel Henrique Barboza <danielhb413@gmail.com>
Date: Mon, 5 Oct 2020 10:25:30 -0400
Subject: [PATCH] virhostcpu.c: fix 'die_id' parsing for Power hosts
Commit 7b79ee2f78 makes assumptions about die_id parsing in
the sysfs that aren't true for Power hosts. In both Power8
and Power9, running 5.6 and 4.18 kernel respectively,
'die_id' is set to -1:
$ cat /sys/devices/system/cpu/cpu0/topology/die_id
-1
This breaks virHostCPUGetDie() parsing because it is trying to
retrieve an unsigned integer, causing problems during VM start:
virFileReadValueUint:4128 : internal error: Invalid unsigned integer
value '-1' in file '/sys/devices/system/cpu/cpu0/topology/die_id'
This isn't necessarily a PowerPC only behavior. Linux kernel commit
0e344d8c70 added in the former Documentation/cputopology.txt, now
Documentation/admin-guide/cputopology.rst, that:
To be consistent on all architectures, include/linux/topology.h
provides default definitions for any of the above macros that are
not defined by include/asm-XXX/topology.h:
1) topology_physical_package_id: -1
2) topology_die_id: -1
(...)
This means that it might be expected that an architecture that
does not implement the die_id element will mark it as -1 in
sysfs.
It is not required to change die_id implementation from uInt to
Int because of that. Instead, let's change the parsing of the
die_id in virHostCPUGetDie() to read an integer value and, in
case it's -1, default it to zero like in case of file not found.
This is enough to solve the issue Power hosts are experiencing.
Fixes: 7b79ee2f78bbf2af76df2f6466919e19ae05aeeb
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
(cherry picked from commit 0137bf0dab2738d5443e2f407239856e2aa25bb3)
https://bugzilla.redhat.com/show_bug.cgi?id=1876742
Signed-off-by: Daniel Henrique Barboza <dbarboza@redhat.com>
Message-Id: <20201005142530.3961036-1-dbarboza@redhat.com>
Reviewed-by: Jiri Denemark <jdenemar@redhat.com>
---
src/util/virhostcpu.c | 21 ++++++++++++++-------
1 file changed, 14 insertions(+), 7 deletions(-)
diff --git a/src/util/virhostcpu.c b/src/util/virhostcpu.c
index 09c959cd25..218272d7ec 100644
--- a/src/util/virhostcpu.c
+++ b/src/util/virhostcpu.c
@@ -221,16 +221,23 @@ virHostCPUGetSocket(unsigned int cpu, unsigned int *socket)
int
virHostCPUGetDie(unsigned int cpu, unsigned int *die)
{
- int ret = virFileReadValueUint(die,
- "%s/cpu/cpu%u/topology/die_id",
- SYSFS_SYSTEM_PATH, cpu);
+ int die_id;
+ int ret = virFileReadValueInt(&die_id,
+ "%s/cpu/cpu%u/topology/die_id",
+ SYSFS_SYSTEM_PATH, cpu);
- /* If the file is not there, it's 0 */
- if (ret == -2)
- *die = 0;
- else if (ret < 0)
+ if (ret == -1)
return -1;
+ /* If the file is not there, it's 0.
+ * Another alternative is die_id set to -1, meaning that
+ * the arch does not have die_id support. Set @die to
+ * 0 in this case too. */
+ if (ret == -2 || die_id < 0)
+ *die = 0;
+ else
+ *die = die_id;
+
return 0;
}
--
2.28.0