On 28/11/2018 13:27, Michael Mueller wrote:
On 28.11.18 11:44, Cornelia Huck wrote:
On Wed, 28 Nov 2018 11:19:34 +0100
Michael Mueller <mimu@xxxxxxxxxxxxx> wrote:
The GIB (Guest Information Block) links the GISA of all guests
that have adapter interrupts pending. These interrupts cannot be
delivered because no vcpu of these guests is currently running in
SIE context. Instead, a GIB alert is issued on the host to schedule
these guests to run.
This mechanism allows to process adapter interrupts for currently
not running guests.
The GIB is created during host initialization and associated with
the Adapter Interruption Facility in case an Adapter Interruption
Virtualization Facility is available.
Signed-off-by: Michael Mueller <mimu@xxxxxxxxxxxxx>
Reviewed-by: Janosch Frank <frankja@xxxxxxxxxxxxx>
Reviewed-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
---
arch/s390/include/asm/kvm_host.h | 10 ++++++++++
arch/s390/kvm/interrupt.c | 37
+++++++++++++++++++++++++++++++++++++
arch/s390/kvm/kvm-s390.c | 1 +
arch/s390/kvm/kvm-s390.h | 2 ++
4 files changed, 50 insertions(+)
+int kvm_s390_gib_init(u8 nisc)
+{
+ if (!css_general_characteristics.aiv) {
+ KVM_EVENT(3, "%s", "gib not initialized, no AIV facility");
+ return 0;
+ }
+
+ gib = (struct kvm_s390_gib *)get_zeroed_page(GFP_KERNEL | GFP_DMA);
+ if (!gib) {
+ KVM_EVENT(3, "gib 0x%pK memory allocation failed", gib);
Just noticed this... isn't the dbf torn down again if kvm init failed,
rendering this message inaccessible? Do we need different logging for
fatal errors?
(The code is not wrong, but this logging looks a bit useless.)
That's why I added the last sentence of the commit message. But it seems
a little more tricky dependent of the module being build into the kernel
or loaded.
When build-in, there is no indication that kvm_init() failed except the
missing
/dev/kvm device. In the module load case, the s390dbf does not seem to be
able to recycle the /sys/.../kvm-trace/ directory. So the feature shall be
unregistered on kvm_init() failures.
There should be either an additional generic message from kvm_init()
displaying the rc of kvm_arch_init() or kernel messages of the failing
routines in kvm_arch_init().
Any opinions?
Using the debugfs is for my opinion something we do when the subsystem
is working.
I see no reason to use it to report initialization events.
Especially errors.
Why not use simply pr_xxx() to keep tracks in the syslog until
initialization is done?
Regards,
Pierre
+ return -ENOMEM;
+ }
+
+ gib->nisc = nisc;
+ if (chsc_sgib((u32)(u64)gib)) {
+ KVM_EVENT(3, "gib 0x%pK AIV association failed", gib);
+ free_page((unsigned long)gib);
+ gib = NULL;
+ return -EIO;
+ }
+
+ KVM_EVENT(3, "gib 0x%pK (nisc=%d) initialized", gib, gib->nisc);
+ return 0;
+}
--
Pierre Morel
Linux/KVM/QEMU in Böblingen - Germany
