[PULL 15/23] hw/s390x: Build an IPLB for each boot device

[Thomas Huth <thuth@redhat.com>]

From: Jared Rossi <jrossi@linux.ibm.com>

Build an IPLB for any device with a bootindex (up to a maximum of 8 devices).

The IPLB chain is placed immediately before the BIOS in memory. Because this
is not a fixed address, the location of the next IPLB and number of remaining
boot devices is stored in the QIPL global variable for possible later access by
the guest during IPL.

Signed-off-by: Jared Rossi <jrossi@linux.ibm.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Message-ID: <20241020012953.1380075-16-jrossi@linux.ibm.com>
[thuth: Fix endianness problem when accessing the qipl structure]
Signed-off-by: Thomas Huth <thuth@redhat.com>
---
 hw/s390x/ipl.h              |   1 +
 include/hw/s390x/ipl/qipl.h |   4 +-
 hw/s390x/ipl.c              | 129 ++++++++++++++++++++++++++++--------
 3 files changed, 105 insertions(+), 29 deletions(-)

diff --git a/hw/s390x/ipl.h b/hw/s390x/ipl.h
index b670bad551..54eb48fd6e 100644
--- a/hw/s390x/ipl.h
+++ b/hw/s390x/ipl.h
@@ -20,6 +20,7 @@
 #include "qom/object.h"
 
 #define DIAG308_FLAGS_LP_VALID 0x80
+#define MAX_BOOT_DEVS 8 /* Max number of devices that may have a bootindex */
 
 void s390_ipl_convert_loadparm(char *ascii_lp, uint8_t *ebcdic_lp);
 void s390_ipl_fmt_loadparm(uint8_t *loadparm, char *str, Error **errp);
diff --git a/include/hw/s390x/ipl/qipl.h b/include/hw/s390x/ipl/qipl.h
index b67d2ae061..1da4f75aa8 100644
--- a/include/hw/s390x/ipl/qipl.h
+++ b/include/hw/s390x/ipl/qipl.h
@@ -32,7 +32,9 @@ struct QemuIplParameters {
     uint8_t  reserved1[3];
     uint64_t reserved2;
     uint32_t boot_menu_timeout;
-    uint8_t  reserved3[12];
+    uint8_t  reserved3[2];
+    uint16_t chain_len;
+    uint64_t next_iplb;
 } QEMU_PACKED;
 typedef struct QemuIplParameters QemuIplParameters;
 
diff --git a/hw/s390x/ipl.c b/hw/s390x/ipl.c
index 656996b500..b9d741d0b0 100644
--- a/hw/s390x/ipl.c
+++ b/hw/s390x/ipl.c
@@ -56,6 +56,13 @@ static bool iplb_extended_needed(void *opaque)
     return ipl->iplbext_migration;
 }
 
+/* Place the IPLB chain immediately before the BIOS in memory */
+static uint64_t find_iplb_chain_addr(uint64_t bios_addr, uint16_t count)
+{
+    return (bios_addr & TARGET_PAGE_MASK)
+            - (count * sizeof(IplParameterBlock));
+}
+
 static const VMStateDescription vmstate_iplb_extended = {
     .name = "ipl/iplb_extended",
     .version_id = 0,
@@ -398,6 +405,17 @@ static CcwDevice *s390_get_ccw_device(DeviceState *dev_st, int *devtype)
     return ccw_dev;
 }
 
+static uint64_t s390_ipl_map_iplb_chain(IplParameterBlock *iplb_chain)
+{
+    S390IPLState *ipl = get_ipl_device();
+    uint16_t count = be16_to_cpu(ipl->qipl.chain_len);
+    uint64_t len = sizeof(IplParameterBlock) * count;
+    uint64_t chain_addr = find_iplb_chain_addr(ipl->bios_start_addr, count);
+
+    cpu_physical_memory_write(chain_addr, iplb_chain, len);
+    return chain_addr;
+}
+
 void s390_ipl_fmt_loadparm(uint8_t *loadparm, char *str, Error **errp)
 {
     int i;
@@ -428,54 +446,51 @@ void s390_ipl_convert_loadparm(char *ascii_lp, uint8_t *ebcdic_lp)
     }
 }
 
-static bool s390_gen_initial_iplb(S390IPLState *ipl)
+static bool s390_build_iplb(DeviceState *dev_st, IplParameterBlock *iplb)
 {
-    DeviceState *dev_st;
+    S390IPLState *ipl = get_ipl_device();
     CcwDevice *ccw_dev = NULL;
     SCSIDevice *sd;
     int devtype;
     uint8_t *lp;
 
-    dev_st = get_boot_device(0);
-    if (dev_st) {
-        ccw_dev = s390_get_ccw_device(dev_st, &devtype);
-    }
-
     /*
      * Currently allow IPL only from CCW devices.
      */
+    ccw_dev = s390_get_ccw_device(dev_st, &devtype);
     if (ccw_dev) {
         lp = ccw_dev->loadparm;
 
         switch (devtype) {
         case CCW_DEVTYPE_SCSI:
             sd = SCSI_DEVICE(dev_st);
-            ipl->iplb.len = cpu_to_be32(S390_IPLB_MIN_QEMU_SCSI_LEN);
-            ipl->iplb.blk0_len =
+            iplb->len = cpu_to_be32(S390_IPLB_MIN_QEMU_SCSI_LEN);
+            iplb->blk0_len =
                 cpu_to_be32(S390_IPLB_MIN_QEMU_SCSI_LEN - S390_IPLB_HEADER_LEN);
-            ipl->iplb.pbt = S390_IPL_TYPE_QEMU_SCSI;
-            ipl->iplb.scsi.lun = cpu_to_be32(sd->lun);
-            ipl->iplb.scsi.target = cpu_to_be16(sd->id);
-            ipl->iplb.scsi.channel = cpu_to_be16(sd->channel);
-            ipl->iplb.scsi.devno = cpu_to_be16(ccw_dev->sch->devno);
-            ipl->iplb.scsi.ssid = ccw_dev->sch->ssid & 3;
+            iplb->pbt = S390_IPL_TYPE_QEMU_SCSI;
+            iplb->scsi.lun = cpu_to_be32(sd->lun);
+            iplb->scsi.target = cpu_to_be16(sd->id);
+            iplb->scsi.channel = cpu_to_be16(sd->channel);
+            iplb->scsi.devno = cpu_to_be16(ccw_dev->sch->devno);
+            iplb->scsi.ssid = ccw_dev->sch->ssid & 3;
             break;
         case CCW_DEVTYPE_VFIO:
-            ipl->iplb.len = cpu_to_be32(S390_IPLB_MIN_CCW_LEN);
-            ipl->iplb.pbt = S390_IPL_TYPE_CCW;
-            ipl->iplb.ccw.devno = cpu_to_be16(ccw_dev->sch->devno);
-            ipl->iplb.ccw.ssid = ccw_dev->sch->ssid & 3;
+            iplb->len = cpu_to_be32(S390_IPLB_MIN_CCW_LEN);
+            iplb->pbt = S390_IPL_TYPE_CCW;
+            iplb->ccw.devno = cpu_to_be16(ccw_dev->sch->devno);
+            iplb->ccw.ssid = ccw_dev->sch->ssid & 3;
             break;
         case CCW_DEVTYPE_VIRTIO_NET:
+            /* The S390IPLState netboot is true if ANY IPLB may use netboot */
             ipl->netboot = true;
             /* Fall through to CCW_DEVTYPE_VIRTIO case */
         case CCW_DEVTYPE_VIRTIO:
-            ipl->iplb.len = cpu_to_be32(S390_IPLB_MIN_CCW_LEN);
-            ipl->iplb.blk0_len =
+            iplb->len = cpu_to_be32(S390_IPLB_MIN_CCW_LEN);
+            iplb->blk0_len =
                 cpu_to_be32(S390_IPLB_MIN_CCW_LEN - S390_IPLB_HEADER_LEN);
-            ipl->iplb.pbt = S390_IPL_TYPE_CCW;
-            ipl->iplb.ccw.devno = cpu_to_be16(ccw_dev->sch->devno);
-            ipl->iplb.ccw.ssid = ccw_dev->sch->ssid & 3;
+            iplb->pbt = S390_IPL_TYPE_CCW;
+            iplb->ccw.devno = cpu_to_be16(ccw_dev->sch->devno);
+            iplb->ccw.ssid = ccw_dev->sch->ssid & 3;
             break;
         }
 
@@ -484,8 +499,8 @@ static bool s390_gen_initial_iplb(S390IPLState *ipl)
             lp = S390_CCW_MACHINE(qdev_get_machine())->loadparm;
         }
 
-        s390_ipl_convert_loadparm((char *)lp, ipl->iplb.loadparm);
-        ipl->iplb.flags |= DIAG308_FLAGS_LP_VALID;
+        s390_ipl_convert_loadparm((char *)lp, iplb->loadparm);
+        iplb->flags |= DIAG308_FLAGS_LP_VALID;
 
         return true;
     }
@@ -493,6 +508,62 @@ static bool s390_gen_initial_iplb(S390IPLState *ipl)
     return false;
 }
 
+static bool s390_init_all_iplbs(S390IPLState *ipl)
+{
+    int iplb_num = 0;
+    IplParameterBlock iplb_chain[7];
+    DeviceState *dev_st = get_boot_device(0);
+    Object *machine = qdev_get_machine();
+
+    /*
+     * Parse the boot devices.  Generate an IPLB for only the first boot device
+     * which will later be set with DIAG308.
+     */
+    if (!dev_st) {
+        ipl->qipl.chain_len = 0;
+        return false;
+    }
+
+    /* If no machine loadparm was defined fill it with spaces */
+    if (memcmp(S390_CCW_MACHINE(machine)->loadparm, NO_LOADPARM, 8) == 0) {
+        object_property_set_str(machine, "loadparm", "        ", NULL);
+    }
+
+    iplb_num = 1;
+    s390_build_iplb(dev_st, &ipl->iplb);
+
+    /*  Index any fallback boot devices */
+    while (get_boot_device(iplb_num)) {
+        iplb_num++;
+    }
+
+    if (iplb_num > MAX_BOOT_DEVS) {
+        warn_report("Excess boot devices defined! %d boot devices found, "
+                    "but only the first %d will be considered.",
+                    iplb_num, MAX_BOOT_DEVS);
+
+        iplb_num = MAX_BOOT_DEVS;
+    }
+
+    ipl->qipl.chain_len = cpu_to_be16(iplb_num - 1);
+
+    /*
+     * Build fallback IPLBs for any boot devices above index 0, up to a
+     * maximum amount as defined in ipl.h
+     */
+    if (iplb_num > 1) {
+        /* Start at 1 because the IPLB for boot index 0 is not chained */
+        for (int i = 1; i < iplb_num; i++) {
+            dev_st = get_boot_device(i);
+            s390_build_iplb(dev_st, &iplb_chain[i - 1]);
+        }
+
+        ipl->qipl.next_iplb = cpu_to_be64(s390_ipl_map_iplb_chain(iplb_chain));
+    }
+
+    return iplb_num;
+}
+
 static bool is_virtio_ccw_device_of_type(IplParameterBlock *iplb,
                                          int virtio_id)
 {
@@ -620,7 +691,7 @@ void s390_ipl_reset_request(CPUState *cs, enum s390_reset reset_type)
              * this is the original boot device's SCSI
              * so restore IPL parameter info from it
              */
-            ipl->iplb_valid = s390_gen_initial_iplb(ipl);
+            ipl->iplb_valid = s390_build_iplb(get_boot_device(0), &ipl->iplb);
         }
     }
     if (reset_type == S390_RESET_MODIFIED_CLEAR ||
@@ -714,7 +785,9 @@ void s390_ipl_prepare_cpu(S390CPU *cpu)
     if (!ipl->kernel || ipl->iplb_valid) {
         cpu->env.psw.addr = ipl->bios_start_addr;
         if (!ipl->iplb_valid) {
-            ipl->iplb_valid = s390_gen_initial_iplb(ipl);
+            ipl->iplb_valid = s390_init_all_iplbs(ipl);
+        } else {
+            ipl->qipl.chain_len = 0;
         }
     }
     s390_ipl_set_boot_menu(ipl);
-- 
2.47.0