vfio-ccw: Add support for the schib region

The schib region can be used to obtain the latest SCHIB from the host
passthrough subchannel. Since the guest SCHIB is virtualized,
we currently only update the path related information so that the
guest is aware of any path related changes when it issues the
'stsch' instruction.

Signed-off-by: Farhan Ali <alifm@linux.ibm.com>
Signed-off-by: Eric Farman <farman@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Message-Id: <20200505125757.98209-4-farman@linux.ibm.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>

diff --git a/hw/s390x/css.c b/hw/s390x/css.c
index 5d8e08667e6f914117cd6c23a6fb99e3c18f3f52..a44faa3549b45ca9d90baa274068d2c6cb371d64 100644 (file)
--- a/hw/s390x/css.c
+++ b/hw/s390x/css.c
@@ -1335,11 +1335,20 @@ static void copy_schib_to_guest(SCHIB *dest, const SCHIB *src)
     }
 }
 
-int css_do_stsch(SubchDev *sch, SCHIB *schib)
+IOInstEnding css_do_stsch(SubchDev *sch, SCHIB *schib)
 {
+    int ret;
+
+    /*
+     * For some subchannels, we may want to update parts of
+     * the schib (e.g., update path masks from the host device
+     * for passthrough subchannels).
+     */
+    ret = s390_ccw_store(sch);
+
     /* Use current status. */
     copy_schib_to_guest(schib, &sch->curr_status);
-    return 0;
+    return ret;
 }
 
 static void copy_pmcw_from_guest(PMCW *dest, const PMCW *src)

diff --git a/hw/s390x/s390-ccw.c b/hw/s390x/s390-ccw.c
index c48510f9e5430f28f122f05b92b534e204a84a12..b497571863f692f4cf34578947f9dcca35b344da 100644 (file)
--- a/hw/s390x/s390-ccw.c
+++ b/hw/s390x/s390-ccw.c
@@ -51,6 +51,27 @@ int s390_ccw_clear(SubchDev *sch)
     return cdc->handle_clear(sch);
 }
 
+IOInstEnding s390_ccw_store(SubchDev *sch)
+{
+    S390CCWDeviceClass *cdc = NULL;
+    int ret = IOINST_CC_EXPECTED;
+
+    /*
+     * This code is called for both virtual and passthrough devices,
+     * but only applies to to the latter.  This ugly check makes that
+     * distinction for us.
+     */
+    if (object_dynamic_cast(OBJECT(sch->driver_data), TYPE_S390_CCW)) {
+        cdc = S390_CCW_DEVICE_GET_CLASS(sch->driver_data);
+    }
+
+    if (cdc && cdc->handle_store) {
+        ret = cdc->handle_store(sch);
+    }
+
+    return ret;
+}
+
 static void s390_ccw_get_dev_info(S390CCWDevice *cdev,
                                   char *sysfsdev,
                                   Error **errp)

diff --git a/hw/vfio/ccw.c b/hw/vfio/ccw.c
index ca06213d037522fa39c43c382f15e8f550ae03cd..f5a5e038aa459ed6885542d6aa2cde147019a4ef 100644 (file)
--- a/hw/vfio/ccw.c
+++ b/hw/vfio/ccw.c
@@ -41,6 +41,9 @@ struct VFIOCCWDevice {
     uint64_t async_cmd_region_size;
     uint64_t async_cmd_region_offset;
     struct ccw_cmd_region *async_cmd_region;
+    uint64_t schib_region_size;
+    uint64_t schib_region_offset;
+    struct ccw_schib_region *schib_region;
     EventNotifier io_notifier;
     bool force_orb_pfch;
     bool warned_orb_pfch;
@@ -116,6 +119,51 @@ again:
     }
 }
 
+static IOInstEnding vfio_ccw_handle_store(SubchDev *sch)
+{
+    S390CCWDevice *cdev = sch->driver_data;
+    VFIOCCWDevice *vcdev = DO_UPCAST(VFIOCCWDevice, cdev, cdev);
+    SCHIB *schib = &sch->curr_status;
+    struct ccw_schib_region *region = vcdev->schib_region;
+    SCHIB *s;
+    int ret;
+
+    /* schib region not available so nothing else to do */
+    if (!region) {
+        return IOINST_CC_EXPECTED;
+    }
+
+    memset(region, 0, sizeof(*region));
+    ret = pread(vcdev->vdev.fd, region, vcdev->schib_region_size,
+                vcdev->schib_region_offset);
+
+    if (ret == -1) {
+        /*
+         * Device is probably damaged, but store subchannel does not
+         * have a nonzero cc defined for this scenario.  Log an error,
+         * and presume things are otherwise fine.
+         */
+        error_report("vfio-ccw: store region read failed with errno=%d", errno);
+        return IOINST_CC_EXPECTED;
+    }
+
+    /*
+     * Selectively copy path-related bits of the SCHIB,
+     * rather than copying the entire struct.
+     */
+    s = (SCHIB *)region->schib_area;
+    schib->pmcw.pnom = s->pmcw.pnom;
+    schib->pmcw.lpum = s->pmcw.lpum;
+    schib->pmcw.pam = s->pmcw.pam;
+    schib->pmcw.pom = s->pmcw.pom;
+
+    if (s->scsw.flags & SCSW_FLAGS_MASK_PNO) {
+        schib->scsw.flags |= SCSW_FLAGS_MASK_PNO;
+    }
+
+    return IOINST_CC_EXPECTED;
+}
+
 static int vfio_ccw_handle_clear(SubchDev *sch)
 {
     S390CCWDevice *cdev = sch->driver_data;
@@ -382,10 +430,23 @@ static void vfio_ccw_get_region(VFIOCCWDevice *vcdev, Error **errp)
         vcdev->async_cmd_region = g_malloc0(info->size);
     }
 
+    ret = vfio_get_dev_region_info(vdev, VFIO_REGION_TYPE_CCW,
+                                   VFIO_REGION_SUBTYPE_CCW_SCHIB, &info);
+    if (!ret) {
+        vcdev->schib_region_size = info->size;
+        if (sizeof(*vcdev->schib_region) != vcdev->schib_region_size) {
+            error_setg(errp, "vfio: Unexpected size of the schib region");
+            goto out_err;
+        }
+        vcdev->schib_region_offset = info->offset;
+        vcdev->schib_region = g_malloc(info->size);
+    }
+
     g_free(info);
     return;
 
 out_err:
+    g_free(vcdev->schib_region);
     g_free(vcdev->async_cmd_region);
     g_free(vcdev->io_region);
     g_free(info);
@@ -394,6 +455,7 @@ out_err:
 
 static void vfio_ccw_put_region(VFIOCCWDevice *vcdev)
 {
+    g_free(vcdev->schib_region);
     g_free(vcdev->async_cmd_region);
     g_free(vcdev->io_region);
 }
@@ -569,6 +631,7 @@ static void vfio_ccw_class_init(ObjectClass *klass, void *data)
     cdc->handle_request = vfio_ccw_handle_request;
     cdc->handle_halt = vfio_ccw_handle_halt;
     cdc->handle_clear = vfio_ccw_handle_clear;
+    cdc->handle_store = vfio_ccw_handle_store;
 }
 
 static const TypeInfo vfio_ccw_info = {

diff --git a/include/hw/s390x/css.h b/include/hw/s390x/css.h
index f46bcafb16c3f8c80ed967e8901f211d34e17496..7e3a5e743314d4f789d96a62a1d928b21ad15f0c 100644 (file)
--- a/include/hw/s390x/css.h
+++ b/include/hw/s390x/css.h
@@ -218,6 +218,7 @@ IOInstEnding do_subchannel_work_passthrough(SubchDev *sub);
 
 int s390_ccw_halt(SubchDev *sch);
 int s390_ccw_clear(SubchDev *sch);
+IOInstEnding s390_ccw_store(SubchDev *sch);
 
 typedef enum {
     CSS_IO_ADAPTER_VIRTIO = 0,
@@ -242,7 +243,7 @@ SubchDev *css_find_subch(uint8_t m, uint8_t cssid, uint8_t ssid,
                          uint16_t schid);
 bool css_subch_visible(SubchDev *sch);
 void css_conditional_io_interrupt(SubchDev *sch);
-int css_do_stsch(SubchDev *sch, SCHIB *schib);
+IOInstEnding css_do_stsch(SubchDev *sch, SCHIB *schib);
 bool css_schid_final(int m, uint8_t cssid, uint8_t ssid, uint16_t schid);
 IOInstEnding css_do_msch(SubchDev *sch, const SCHIB *schib);
 IOInstEnding css_do_xsch(SubchDev *sch);

diff --git a/include/hw/s390x/s390-ccw.h b/include/hw/s390x/s390-ccw.h
index 7f27bc2f53144d6707036dc33eb8775956c66d0e..d8e08b5f4cd91b343a59083da5fd932e77ffdf81 100644 (file)
--- a/include/hw/s390x/s390-ccw.h
+++ b/include/hw/s390x/s390-ccw.h
@@ -37,6 +37,7 @@ typedef struct S390CCWDeviceClass {
     IOInstEnding (*handle_request) (SubchDev *sch);
     int (*handle_halt) (SubchDev *sch);
     int (*handle_clear) (SubchDev *sch);
+    IOInstEnding (*handle_store) (SubchDev *sch);
 } S390CCWDeviceClass;
 
 #endif

diff --git a/target/s390x/ioinst.c b/target/s390x/ioinst.c
index 7a14c52c123b842bba0b13f96b16b6c9843065cb..a412926d27808efe0e9245d5a8565e6491e076c7 100644 (file)
--- a/target/s390x/ioinst.c
+++ b/target/s390x/ioinst.c
@@ -292,8 +292,7 @@ void ioinst_handle_stsch(S390CPU *cpu, uint64_t reg1, uint32_t ipb,
     sch = css_find_subch(m, cssid, ssid, schid);
     if (sch) {
         if (css_subch_visible(sch)) {
-            css_do_stsch(sch, &schib);
-            cc = 0;
+            cc = css_do_stsch(sch, &schib);
         } else {
             /* Indicate no more subchannels in this css/ss */
             cc = 3;