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spapr/irq: add KVM support to the 'dual' machine

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The interrupt mode is chosen by the CAS negotiation process and
activated after a reset to take into account the required changes in
the machine. This brings new constraints on how the associated KVM IRQ
device is initialized.

Currently, each model takes care of the initialization of the KVM
device in their realize method but this is not possible anymore as the
initialization needs to be done globaly when the interrupt mode is
known, i.e. when machine is reseted. It also means that we need a way
to delete a KVM device when another mode is chosen.

Also, to support migration, the QEMU objects holding the state to
transfer should always be available but not necessarily activated.

The overall approach of this proposal is to initialize both interrupt
mode at the QEMU level to keep the IRQ number space in sync and to
allow switching from one mode to another. For the KVM side of things,
the whole initialization of the KVM device, sources and presenters, is
grouped in a single routine. The XICS and XIVE sPAPR IRQ reset
handlers are modified accordingly to handle the init and the delete
sequences of the KVM device.

Signed-off-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Message-Id: <20190513084245.25755-15-clg@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
This commit is contained in:
Cédric Le Goater 2019-05-13 10:42:45 +02:00 • committed by David Gibson
parent 83629419a5
commit 3f777abc71
5 changed files with 97 additions and 26 deletions
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31
hw/intc/xics_kvm.c
View file

@ -33,6 +33,7 @@
#include "trace.h"
#include "sysemu/kvm.h"
#include "hw/ppc/spapr.h"
#include "hw/ppc/spapr_cpu_core.h"
#include "hw/ppc/xics.h"
#include "hw/ppc/xics_spapr.h"
#include "kvm_ppc.h"
@ -342,6 +343,16 @@ static void rtas_dummy(PowerPCCPU *cpu, SpaprMachineState *spapr,
int xics_kvm_init(SpaprMachineState *spapr, Error **errp)
{
int rc;
CPUState *cs;
Error *local_err = NULL;
/*
* The KVM XICS device already in use. This is the case when
* rebooting under the XICS-only interrupt mode.
*/
if (kernel_xics_fd != -1) {
return 0;
}
if (!kvm_enabled() || !kvm_check_extension(kvm_state, KVM_CAP_IRQ_XICS)) {
error_setg(errp,
@ -390,6 +401,26 @@ int xics_kvm_init(SpaprMachineState *spapr, Error **errp)
kvm_msi_via_irqfd_allowed = true;
kvm_gsi_direct_mapping = true;
/* Create the presenters */
CPU_FOREACH(cs) {
PowerPCCPU *cpu = POWERPC_CPU(cs);
icp_kvm_realize(DEVICE(spapr_cpu_state(cpu)->icp), &local_err);
if (local_err) {
error_propagate(errp, local_err);
goto fail;
}
}
/* Update the KVM sources */
ics_set_kvm_state(spapr->ics);
/* Connect the presenters to the initial VCPUs of the machine */
CPU_FOREACH(cs) {
PowerPCCPU *cpu = POWERPC_CPU(cs);
icp_set_kvm_state(spapr_cpu_state(cpu)->icp);
}
return 0;
fail: