Series Applied and queued. see https://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux.git/log/?h=next On 31.01.2019 09:52, Michael Mueller wrote: > The Guest Information Area (GIB) and its mechanics is part of > the AIV facility. It provides hardware support to process > Adapter Interruptions (AI) for pagable storage mode guests. > > Whenever a guest cannot process an AI because none of its > vcpus is running in SIE context, a GIB alert interruption is > sent to and handled by the host program to dispatch a vcpu of > the respective guest. > > Eventually, the AI is handled by the guest. > > v6->v7: > patches 1/15 to 7/15 > prepare the existing Interruption and GISA code for > the introduction of the GIB code. (kept from v6) > patches 8/15 to 10/15 > kept from v6. > patch 11/15 > kvm_s390_gisc_register() now uses a single conditional > branch to extend IAM restore value and to set the IAM > in GISA. > patch 12/15 > kvm_s390_clear_gisa() now refactored in its own patch. > patch 13/15 > I'm keeping the 50 usec timer expiration as the statistic > data shows a single timer restart only. > gisa_get_ipm_or_restore_iam() now called when entering > kvm_s390_handle_wait(). That saves some of the timer > restarts. > Some modifications in kvm_s390_gisa_destroy() > patch 14/15 > kept from v6. > patch 15/15 > additional test on non NULL gisa origin in pending_irqs() > > v5->v6: > Futher significant change was introduced with this version > now: > > a) During the alert list processing now a hrtimer is > started to kick an idle vcpu with open I/O interrupt > mask. It then is restarted to monitor the interruption > consumption and when the IPM is clean (no relevant > ISCs pending anymore) atomically restores the IAM > and don't restarts or if new ISCs arrive kick other > idle vcpus. > > patches 1/13 to 7/13: > prepare the existing Interruption and GISA code for > the introduction of the GIB code. > patches 8/13 to 10/13: > kept from v5. > patch 11/13: > Some comments added. > patch 12/13: > Significatly changed due to the hrtimer control. > patch 13/13: > Basically kept from v5 except for a slight reordering > that shortens the patch. > > v4->v5: > Between these two versions some significant change was > introduced: > > a) During IPM look-up, the IAM gets atomically restored > if the IPM is clean. (The main strategy is: As soon no > airqs are pending anymore, get prepared for new ones > arriving). > > b) Kick a set of vcpus in WAIT state, that will be able > to handle all ISCs in IPM if possible. The main loop > that processes the GIB alert list is unchanged. > > patches 1/15 to 6/15: > prepare the existing Interruption and GISA code for > the introduction of the GIB code. > patches 7/15 to 9/15: > kept from v4. > patch 10/15: > restores the IAM in get_ipm() when clean on request > with additional parameter irq_flags > patch 12/15: > modifies kvm_s390_deliver_pending_interrupts() such > that the IAM is not restored during the deliverable_irqs() > test as we are about to enter the SIE. Restoring the > IAM would trigger the alert mechanism unnecessarily > on SIE entry. > patch 13/15: > process_gib_alert_list() now triggers a minimal set > of idle vcpus capable the handle all pending ISCs. > patch 14/15: > the wiring is logical similar to v4 but uses different > routines > patch 15/15: > kept from v4. > > v3->v4: > The central change of v4 is that the metric "vcpus_in_sie" > has been dropped. A least agressive IAM restore strategy > is being followed now. The consequence is that potentially > more GAL interruptions are to be handled by the host program. > The assuption as made that as soon the first vcpu is trying > to go into wait state, this could be the last vcpu being > open for I/O interruptions. Thus, to not loose the initiative > to deliver I/O interruptions as soon as possible, the IAM > is restored. Adding better heuristics can be done in future. > > I expect this to be the last version of the series. > > patch 01/12: Kernel msg now printed when FLIC fails > to register during arch inititialization. > patch 03/12: Commit message slightly changed with the > hint that gib initialization is called > by last patch of this serias. > patch 09/12: IAM now restored during kvm_s390_handle_wait() > patch 10/12: gib destroy case now handled upon unsuccessful > arch inititialization. > > All other patches are unchanged. > > v2->v3: > patch 01/12: Fixes a resource dealocation issue upon > unsuccessful exit from kvm_arch_init(). > It is relevant for patch 11/12 as well. > patch 08/12: The function process_gib_alert_list() has > been rewritten to reduce the number of GAL > interruptions on the host for many guest > scenarios. > patch 10/12: The IAM is now never cleared before SIE entry. > It will be cleared by millicode as soon the > first guest interruption is made pending and > not directly processed in SIE. The IAM gets > restored as soon a vm is idle, i.e. no vcpu > of that guest is in SIE context anymore. > patch 11/12: now integrates with new patch 01/12 > patch 12/12: This patch is just experimental and shall not > be part of the final series. > > The first patch of series v2: "leave AIs in IPM of GISA > during vcpu_pre_run()" has been dropped. > > All other patches are unchanged. > > v1->v2: > patch 01/12: New patch. Tt can go also standalone without the > rest of the GIB series presented here but is a > requirement > patch 03/12: kvm_s390_gib_init() now has a return code > patch 06/12: unlink_gib_alert_list() now uses cmpxchg() instead > of atomic_xchg() > patch 08/12: New patch. Foctors out __find_vcpu_for_floating_irq() > patch 09/12: process_gib_alert_list() has been simplified > the GISA clear/destroy cases have been removed > patch 11/12: kvm_s390_gisa_clear/destroy() now clear the IAM > and process the alert list directly > The IAM now gets restored in vcpu_post_run() only if > the GISA is not in alert list > patch 12/12: during kvm_arch_init() now the return code of > kvm_s390_gib_init() is honored. > > All other patches are unchanged. > > Michael Mueller (15): > KVM: s390: drop obsolete else path > KVM: s390: make bitmap declaration consistent > KVM: s390: move bitmap idle_mask into arch struct top level > KVM: s390: coding style kvm_s390_gisa_init/clear() > KVM: s390: use pending_irqs_no_gisa() where appropriate > KVM: s390: remove kvm_s390_ from gisa static inline functions > KVM: s390: introduce struct kvm_s390_gisa_interrupt > s390/cio: add function chsc_sgib() > KVM: s390: add the GIB and its related life-cyle functions > KVM: s390: add kvm reference to struct sie_page2 > KVM: s390: add functions to (un)register GISC with GISA > KVM: s390: kvm_s390_gisa_clear() now clears the IPM only > KVM: s390: add gib_alert_irq_handler() > KVM: s390: start using the GIB > KVM: s390: fix possible null pointer dereference in pending_irqs() > > arch/s390/include/asm/cio.h | 1 + > arch/s390/include/asm/irq.h | 1 + > arch/s390/include/asm/isc.h | 1 + > arch/s390/include/asm/kvm_host.h | 36 +++- > arch/s390/kernel/irq.c | 1 + > arch/s390/kvm/interrupt.c | 431 +++++++++++++++++++++++++++++++++++---- > arch/s390/kvm/kvm-s390.c | 13 +- > arch/s390/kvm/kvm-s390.h | 4 +- > drivers/s390/cio/chsc.c | 37 ++++ > drivers/s390/cio/chsc.h | 1 + > 10 files changed, 480 insertions(+), 46 deletions(-) >
