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[Qemu-devel] [PATCH] spapr/irq: Add XIVE sanity checks on non-P9 machine
From: |
Cédric Le Goater |
Subject: |
[Qemu-devel] [PATCH] spapr/irq: Add XIVE sanity checks on non-P9 machines |
Date: |
Thu, 28 Mar 2019 11:00:44 +0100 |
On non-P9 machines, the XIVE interrupt mode is not advertised, see
spapr_dt_ov5_platform_support(). Add a couple of checks on the machine
configuration to filter bogus setups and prevent OS failures :
Interrupt modes
CPU/Compat XICS XIVE dual
P8/P8 OK QEMU failure (1) OK (3)
P9/P8 OK QEMU failure (2) OK (3)
P9/P9 OK OK OK
(1) CPU exception model is incompatible with XIVE and the presenters
will fail to realize.
(2) CPU exception model is compatible with XIVE, but the XIVE CAS
advertisement is dropped when in POWER8 mode. So we could ended up
booting with the XIVE DT properties but without the HCALLs. Avoid
confusing Linux with such settings and fail under QEMU.
(3) force XICS in machine init
Remove the check on XIVE-only machines in spapr_machine_init(), which
has now become redundant.
Signed-off-by: Cédric Le Goater <address@hidden>
---
hw/ppc/spapr.c | 8 +-------
hw/ppc/spapr_irq.c | 50 ++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 51 insertions(+), 7 deletions(-)
diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index adde36a01da3..33ab7b683ba2 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -2806,13 +2806,7 @@ static void spapr_machine_init(MachineState *machine)
/* advertise XIVE on POWER9 machines */
if (spapr->irq->ov5 & (SPAPR_OV5_XIVE_EXPLOIT | SPAPR_OV5_XIVE_BOTH)) {
- if (ppc_type_check_compat(machine->cpu_type, CPU_POWERPC_LOGICAL_3_00,
- 0, spapr->max_compat_pvr)) {
- spapr_ovec_set(spapr->ov5, OV5_XIVE_EXPLOIT);
- } else if (spapr->irq->ov5 & SPAPR_OV5_XIVE_EXPLOIT) {
- error_report("XIVE-only machines require a POWER9 CPU");
- exit(1);
- }
+ spapr_ovec_set(spapr->ov5, OV5_XIVE_EXPLOIT);
}
/* init CPUs */
diff --git a/hw/ppc/spapr_irq.c b/hw/ppc/spapr_irq.c
index 5809c955501c..b1f79ea9def6 100644
--- a/hw/ppc/spapr_irq.c
+++ b/hw/ppc/spapr_irq.c
@@ -16,6 +16,7 @@
#include "hw/ppc/spapr_xive.h"
#include "hw/ppc/xics.h"
#include "hw/ppc/xics_spapr.h"
+#include "cpu-models.h"
#include "sysemu/kvm.h"
#include "trace.h"
@@ -566,12 +567,55 @@ SpaprIrq spapr_irq_dual = {
.get_nodename = spapr_irq_get_nodename_dual,
};
+
+static void spapr_irq_check(SpaprMachineState *spapr, Error **errp)
+{
+ MachineState *machine = MACHINE(spapr);
+
+ /*
+ * Sanity checks on non-P9 machines. On these, XIVE is not
+ * advertised, see spapr_dt_ov5_platform_support()
+ */
+ if (!ppc_type_check_compat(machine->cpu_type, CPU_POWERPC_LOGICAL_3_00,
+ 0, spapr->max_compat_pvr)) {
+ /*
+ * If the 'dual' interrupt mode is selected, force XICS as CAS
+ * negotiation is useless.
+ */
+ if (spapr->irq == &spapr_irq_dual) {
+ spapr->irq = &spapr_irq_xics;
+ return;
+ }
+
+ /*
+ * Non-P9 machines using only XIVE is a bogus setup. We have two
+ * scenarios to take into account because of the compat mode:
+ *
+ * 1. POWER7/8 machines should fail to init later on when creating
+ * the XIVE interrupt presenters because a POWER9 exception
+ * model is required.
+
+ * 2. POWER9 machines using the POWER8 compat mode won't fail and
+ * will let the OS boot with a partial XIVE setup : DT
+ * properties but no hcalls.
+ *
+ * To cover both and not confuse the OS, add an early failure in
+ * QEMU.
+ */
+ if (spapr->irq == &spapr_irq_xive) {
+ error_setg(errp, "XIVE-only machines require a POWER9 CPU");
+ return;
+ }
+ }
+}
+
/*
* sPAPR IRQ frontend routines for devices
*/
void spapr_irq_init(SpaprMachineState *spapr, Error **errp)
{
MachineState *machine = MACHINE(spapr);
+ Error *local_err = NULL;
if (machine_kernel_irqchip_split(machine)) {
error_setg(errp, "kernel_irqchip split mode not supported on pseries");
@@ -584,6 +628,12 @@ void spapr_irq_init(SpaprMachineState *spapr, Error **errp)
return;
}
+ spapr_irq_check(spapr, &local_err);
+ if (local_err) {
+ error_propagate(errp, local_err);
+ return;
+ }
+
/* Initialize the MSI IRQ allocator. */
if (!SPAPR_MACHINE_GET_CLASS(spapr)->legacy_irq_allocation) {
spapr_irq_msi_init(spapr, spapr->irq->nr_msis);
--
2.20.1
- [Qemu-devel] [PATCH] spapr/irq: Add XIVE sanity checks on non-P9 machines,
Cédric Le Goater <=