ISM device firmware stores unique state information that can
can cause a wholesale unmap of the associated IOMMU (e.g. when
we get a termination signal for QEMU) to trigger firmware errors
because firmware believes we are attempting to invalidate entries
that are still in-use by the guest OS (when in fact that guest is
in the process of being terminated or rebooted).
To alleviate this, register both a shutdown notifier (for unexpected
termination cases e.g. virsh destroy) as well as a reset callback
(for cases like guest OS reboot). For each of these scenarios, trigger
PCI device reset; this is enough to indicate to firmware that the IOMMU
is no longer in-use by the guest OS, making it safe to invalidate any
associated IOMMU entries.
Fixes: 15d0e7942d3b ("s390x/pci: don't fence interpreted devices without MSI-X")
Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
---
hw/s390x/s390-pci-bus.c | 28 ++++++++++++++++++++++++++++
hw/s390x/s390-pci-vfio.c | 2 ++
include/hw/s390x/s390-pci-bus.h | 5 +++++
3 files changed, 35 insertions(+)
diff --git a/hw/s390x/s390-pci-bus.c b/hw/s390x/s390-pci-bus.c
index 977e7daa15..02751f3597 100644
--- a/hw/s390x/s390-pci-bus.c
+++ b/hw/s390x/s390-pci-bus.c
@@ -24,6 +24,8 @@
#include "hw/pci/msi.h"
#include "qemu/error-report.h"
#include "qemu/module.h"
+#include "sysemu/reset.h"
+#include "sysemu/runstate.h"
#ifndef DEBUG_S390PCI_BUS
#define DEBUG_S390PCI_BUS 0
@@ -150,10 +152,30 @@ out:
psccb->header.response_code = cpu_to_be16(rc);
}
+static void s390_pci_shutdown_notifier(Notifier *n, void *opaque)
+{
+ S390PCIBusDevice *pbdev = container_of(n, S390PCIBusDevice,
+ shutdown_notifier);
+
+ pci_device_reset(pbdev->pdev);
+}
+
+static void s390_pci_reset_cb(void *opaque)
+{
+ S390PCIBusDevice *pbdev = opaque;
+
+ pci_device_reset(pbdev->pdev);
+}
+
static void s390_pci_perform_unplug(S390PCIBusDevice *pbdev)
{
HotplugHandler *hotplug_ctrl;
+ if (pbdev->pft == ZPCI_PFT_ISM) {
+ notifier_remove(&pbdev->shutdown_notifier);
+ qemu_unregister_reset(s390_pci_reset_cb, pbdev);
+ }
+
/* Unplug the PCI device */
if (pbdev->pdev) {
DeviceState *pdev = DEVICE(pbdev->pdev);
@@ -1111,6 +1133,12 @@ static void s390_pcihost_plug(HotplugHandler
*hotplug_dev, DeviceState *dev,
pbdev->fh |= FH_SHM_VFIO;
pbdev->forwarding_assist = false;
}
+ /* Register shutdown notifier and reset callback for ISM devices */
+ if (pbdev->pft == ZPCI_PFT_ISM) {
+ pbdev->shutdown_notifier.notify = s390_pci_shutdown_notifier;
+ qemu_register_shutdown_notifier(&pbdev->shutdown_notifier);
+ qemu_register_reset(s390_pci_reset_cb, pbdev);
+ }
} else {
pbdev->fh |= FH_SHM_EMUL;
/* Always intercept emulated devices */
diff --git a/hw/s390x/s390-pci-vfio.c b/hw/s390x/s390-pci-vfio.c
index 5f0adb0b4a..419763f829 100644
--- a/hw/s390x/s390-pci-vfio.c
+++ b/hw/s390x/s390-pci-vfio.c
@@ -122,6 +122,8 @@ static void s390_pci_read_base(S390PCIBusDevice *pbdev,
/* The following values remain 0 until we support other FMB formats */
pbdev->zpci_fn.fmbl = 0;
pbdev->zpci_fn.pft = 0;
+ /* Store function type separately for type-specific behavior */
+ pbdev->pft = cap->pft;
}