From 1ed1f8fc20a4883bc0bc1f58d299b0278abc5442 Mon Sep 17 00:00:00 2001

From: Matthew Rosato <mjrosato@linux.ibm.com>

Date: Fri, 9 Dec 2022 14:57:00 -0500

Subject: [PATCH 8/9] s390x/pci: reset ISM passthrough devices on shutdown and

 system reset

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RH-Author: Cédric Le Goater <clg@redhat.com>

RH-MergeRequest: 141: s390x/pci: reset ISM passthrough devices on shutdown and system reset

RH-Bugzilla: 2163701

RH-Acked-by: Thomas Huth <thuth@redhat.com>

RH-Acked-by: Cornelia Huck <cohuck@redhat.com>

RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>

RH-Commit: [3/3] c531352b9d57f51ba938d4c46ee19a5706ade697 (clegoate/qemu-kvm-c9s)

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>

Message-Id: <20221209195700.263824-1-mjrosato@linux.ibm.com>

Reviewed-by: Eric Farman <farman@linux.ibm.com>

[thuth: Adjusted the hunk in s390-pci-vfio.c due to different context]

Signed-off-by: Thomas Huth <thuth@redhat.com>

(cherry picked from commit 03451953c79e6b31f7860ee0c35b28e181d573c1)

Signed-off-by: Cédric Le Goater <clg@redhat.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 f7bf36cec8..f51190d466 100644

--- a/hw/s390x/s390-pci-vfio.c

+++ b/hw/s390x/s390-pci-vfio.c

@@ -124,6 +124,8 @@ 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;

     /*

      * If appropriate, reduce the size of the supported DMA aperture reported

diff --git a/include/hw/s390x/s390-pci-bus.h b/include/hw/s390x/s390-pci-bus.h

index 1c46e3a269..e0a9f9385b 100644

--- a/include/hw/s390x/s390-pci-bus.h

+++ b/include/hw/s390x/s390-pci-bus.h

@@ -39,6 +39,9 @@

 #define UID_CHECKING_ENABLED 0x01

 #define ZPCI_DTSM 0x40

+/* zPCI Function Types */

+#define ZPCI_PFT_ISM 5

+

 OBJECT_DECLARE_SIMPLE_TYPE(S390pciState, S390_PCI_HOST_BRIDGE)

 OBJECT_DECLARE_SIMPLE_TYPE(S390PCIBus, S390_PCI_BUS)

 OBJECT_DECLARE_SIMPLE_TYPE(S390PCIBusDevice, S390_PCI_DEVICE)

@@ -344,6 +347,7 @@ struct S390PCIBusDevice {

     uint16_t noi;

     uint16_t maxstbl;

     uint8_t sum;

+    uint8_t pft;

     S390PCIGroup *pci_group;

     ClpRspQueryPci zpci_fn;

     S390MsixInfo msix;

@@ -352,6 +356,7 @@ struct S390PCIBusDevice {

     MemoryRegion msix_notify_mr;

     IndAddr *summary_ind;

     IndAddr *indicator;

+    Notifier shutdown_notifier;

     bool pci_unplug_request_processed;

     bool unplug_requested;

     bool interp;

-- 

2.31.1