Re: [libvirt] [PATCH] qemu: fix setting of VM CPU affinity with TCG
On Wed, Feb 11, 2015 at 10:00:36AM +, Daniel P. Berrange wrote: On Wed, Feb 11, 2015 at 10:18:43AM +0100, Ján Tomko wrote: On Tue, Feb 10, 2015 at 04:25:51PM +, Daniel P. Berrange wrote: If a previous commit I fixed the incorrect handling of vcpu pids for TCG mode QEMU: ... To fix this we must update qemuProcessSetVcpuAffinities so that it only reports a fatal error if the per-VCPU cpu mask is different from the VM level cpu mask. Signed-off-by: Daniel P. Berrange berra...@redhat.com --- src/qemu/qemu_process.c | 15 --- 1 file changed, 12 insertions(+), 3 deletions(-) ACK virBitmapEqual works on NULL bitmaps since commit 20448c2, so the v2 is not needed. Hmm, I got a crash of libvirtd before i added the NULL check. So I'll have to double check that again. I guess I must have had a bad build, as it doesn't crash now and the virBitmapEqual function clearly checks for NULL Regards, Daniel -- |: http://berrange.com -o-http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :| -- libvir-list mailing list libvir-list@redhat.com https://www.redhat.com/mailman/listinfo/libvir-list
Re: [libvirt] [PATCH] qemu: fix setting of VM CPU affinity with TCG
On Wed, Feb 11, 2015 at 10:18:43AM +0100, Ján Tomko wrote: On Tue, Feb 10, 2015 at 04:25:51PM +, Daniel P. Berrange wrote: If a previous commit I fixed the incorrect handling of vcpu pids for TCG mode QEMU: ... To fix this we must update qemuProcessSetVcpuAffinities so that it only reports a fatal error if the per-VCPU cpu mask is different from the VM level cpu mask. Signed-off-by: Daniel P. Berrange berra...@redhat.com --- src/qemu/qemu_process.c | 15 --- 1 file changed, 12 insertions(+), 3 deletions(-) ACK virBitmapEqual works on NULL bitmaps since commit 20448c2, so the v2 is not needed. Hmm, I got a crash of libvirtd before i added the NULL check. So I'll have to double check that again. Regards, Daniel -- |: http://berrange.com -o-http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :| -- libvir-list mailing list libvir-list@redhat.com https://www.redhat.com/mailman/listinfo/libvir-list
Re: [libvirt] [PATCH] qemu: fix setting of VM CPU affinity with TCG
On Tue, Feb 10, 2015 at 04:25:51PM +, Daniel P. Berrange wrote: If a previous commit I fixed the incorrect handling of vcpu pids for TCG mode QEMU: ... To fix this we must update qemuProcessSetVcpuAffinities so that it only reports a fatal error if the per-VCPU cpu mask is different from the VM level cpu mask. Signed-off-by: Daniel P. Berrange berra...@redhat.com --- src/qemu/qemu_process.c | 15 --- 1 file changed, 12 insertions(+), 3 deletions(-) ACK virBitmapEqual works on NULL bitmaps since commit 20448c2, so the v2 is not needed. Jan signature.asc Description: Digital signature -- libvir-list mailing list libvir-list@redhat.com https://www.redhat.com/mailman/listinfo/libvir-list
Re: [libvirt] [PATCH] qemu: fix setting of VM CPU affinity with TCG
Quoting Daniel P. Berrange (berra...@redhat.com):
If a previous commit I fixed the incorrect handling of vcpu pids
for TCG mode QEMU:
commit b07f3d821dfb11a118ee75ea275fd6ab737d9500
Author: Daniel P. Berrange berra...@redhat.com
Date: Thu Dec 18 16:34:39 2014 +
Don't setup fake CPU pids for old QEMU
The code assumes that def-vcpus == nvcpupids, so when we setup
fake CPU pids for old QEMU with nvcpupids == 1, we cause the
later code to read off the end of the array. This has fun results
like sche_setaffinity(0, ...) which changes libvirtd's own CPU
affinity, or even better sched_setaffinity($RANDOM, ...) which
changes the affinity of a random OS process.
The intent was that this would merely disable the ability to set
per-vCPU affinity. It should still have been possible to set VM
level host CPU affinity.
Unfortunately, when you set vcpu cpuset='0-1'4/vcpu, the XML
parser will internally take this initialize an entry in the
def-cputune.vcpupin array for every VCPU. IOW this is implicitly
being treated as
cputune
vcpupin cpuset='0-1' vcpu='0'/
vcpupin cpuset='0-1' vcpu='1'/
vcpupin cpuset='0-1' vcpu='2'/
vcpupin cpuset='0-1' vcpu='3'/
/cputune
Even more fun, the faked cputune elements are hidden from view when
querying the live XML, because their cpuset mask is the same as the
VM default cpumask.
The upshot was that it was impossible to set VM level CPU affinity.
To fix this we must update qemuProcessSetVcpuAffinities so that it
only reports a fatal error if the per-VCPU cpu mask is different
from the VM level cpu mask.
Signed-off-by: Daniel P. Berrange berra...@redhat.com
Thanks, confirmed this let's me place qemu in a cpuset. (Noting that
'virsh edit' always ends up squashing the cputune section when the
cpusets are identical, but that should all be reasonable)
Acked-by: Serge E. Hallyn serge.hal...@ubuntu.com
Tested-by: Serge E. Hallyn serge.hal...@ubuntu.com
---
src/qemu/qemu_process.c | 15 ---
1 file changed, 12 insertions(+), 3 deletions(-)
diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
index d5df60d..e8c532f 100644
--- a/src/qemu/qemu_process.c
+++ b/src/qemu/qemu_process.c
@@ -2497,9 +2497,18 @@ qemuProcessSetVcpuAffinities(virDomainObjPtr vm)
return 0;
if (priv-vcpupids == NULL) {
-virReportError(VIR_ERR_OPERATION_INVALID,
- %s, _(cpu affinity is not supported));
-return -1;
+/* If any CPU has custom affinity that differs from the
+ * VM default affinity, we must reject it
+ */
+for (n = 0; n def-vcpus; n++) {
+if (!virBitmapEqual(def-cpumask,
+def-cputune.vcpupin[n]-cpumask)) {
+virReportError(VIR_ERR_OPERATION_INVALID,
+ %s, _(cpu affinity is not supported));
+return -1;
+}
+}
+return 0;
}
for (n = 0; n def-vcpus; n++) {
--
2.1.0
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