qemu-kvm/kvm-s390x-Rebuild-IPLB-for-SCSI-device-directly-from-DIA.patch

From 9d333e9e7614676aac3a39b0f4a5f5d67323b23d Mon Sep 17 00:00:00 2001
From: Jared Rossi <jrossi@linux.ibm.com>
Date: Sat, 19 Oct 2024 21:29:50 -0400
Subject: [PATCH 17/27] s390x: Rebuild IPLB for SCSI device directly from
 DIAG308
MIME-Version: 1.0
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RH-Author: Thomas Huth <thuth@redhat.com>
RH-MergeRequest: 277: Full boot order support for s390x [CentOS 9]
RH-Jira: RHEL-11424
RH-Acked-by: Cédric Le Goater <clg@redhat.com>
RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>
RH-Commit: [17/23] d0326ad7958cc82496bf57fd09bbc877c5b8c0ac (thuth/qemu-kvm-cs9)

Because virtio-scsi type devices use a non-architected IPLB pbt code they cannot
be set and stored normally. Instead, the IPLB must be rebuilt during re-ipl.

As s390x does not natively support multiple boot devices, the devno field is
used to store the position in the boot order for the device.

Handling the rebuild as part of DIAG308 removes the need to check the devices
for invalid IPLBs later in the IPL.

Signed-off-by: Jared Rossi <jrossi@linux.ibm.com>
Acked-by: Thomas Huth <thuth@redhat.com>
Message-ID: <20241020012953.1380075-17-jrossi@linux.ibm.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
(cherry picked from commit 455e3bc3f74ee76964efec2e0c646db15095d0d2)
---
 hw/s390x/ipl.c              | 74 ++++++-------------------------------
 hw/s390x/ipl.h              | 11 ++++--
 include/hw/s390x/ipl/qipl.h |  3 +-
 pc-bios/s390-ccw/jump2ipl.c | 11 ++++--
 target/s390x/diag.c         |  9 ++++-
 5 files changed, 38 insertions(+), 70 deletions(-)

diff --git a/hw/s390x/ipl.c b/hw/s390x/ipl.c
index f4576f8822..5fbd43c346 100644
--- a/hw/s390x/ipl.c
+++ b/hw/s390x/ipl.c
@@ -448,7 +448,6 @@ void s390_ipl_convert_loadparm(char *ascii_lp, uint8_t *ebcdic_lp)
 
 static bool s390_build_iplb(DeviceState *dev_st, IplParameterBlock *iplb)
 {
-    S390IPLState *ipl = get_ipl_device();
     CcwDevice *ccw_dev = NULL;
     SCSIDevice *sd;
     int devtype;
@@ -481,9 +480,6 @@ static bool s390_build_iplb(DeviceState *dev_st, IplParameterBlock *iplb)
             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:
             iplb->len = cpu_to_be32(S390_IPLB_MIN_CCW_LEN);
             iplb->blk0_len =
@@ -508,6 +504,16 @@ static bool s390_build_iplb(DeviceState *dev_st, IplParameterBlock *iplb)
     return false;
 }
 
+void s390_rebuild_iplb(uint16_t dev_index, IplParameterBlock *iplb)
+{
+    S390IPLState *ipl = get_ipl_device();
+    uint16_t index;
+    index = ipl->rebuilt_iplb ? ipl->iplb_index : dev_index;
+
+    ipl->rebuilt_iplb = s390_build_iplb(get_boot_device(index), iplb);
+    ipl->iplb_index = index;
+}
+
 static bool s390_init_all_iplbs(S390IPLState *ipl)
 {
     int iplb_num = 0;
@@ -564,44 +570,6 @@ static bool s390_init_all_iplbs(S390IPLState *ipl)
     return iplb_num;
 }
 
-static bool is_virtio_ccw_device_of_type(IplParameterBlock *iplb,
-                                         int virtio_id)
-{
-    uint8_t cssid;
-    uint8_t ssid;
-    uint16_t devno;
-    uint16_t schid;
-    SubchDev *sch = NULL;
-
-    if (iplb->pbt != S390_IPL_TYPE_CCW) {
-        return false;
-    }
-
-    devno = be16_to_cpu(iplb->ccw.devno);
-    ssid = iplb->ccw.ssid & 3;
-
-    for (schid = 0; schid < MAX_SCHID; schid++) {
-        for (cssid = 0; cssid < MAX_CSSID; cssid++) {
-            sch = css_find_subch(1, cssid, ssid, schid);
-
-            if (sch && sch->devno == devno) {
-                return sch->id.cu_model == virtio_id;
-            }
-        }
-    }
-    return false;
-}
-
-static bool is_virtio_net_device(IplParameterBlock *iplb)
-{
-    return is_virtio_ccw_device_of_type(iplb, VIRTIO_ID_NET);
-}
-
-static bool is_virtio_scsi_device(IplParameterBlock *iplb)
-{
-    return is_virtio_ccw_device_of_type(iplb, VIRTIO_ID_SCSI);
-}
-
 static void update_machine_ipl_properties(IplParameterBlock *iplb)
 {
     Object *machine = qdev_get_machine();
@@ -641,7 +609,7 @@ void s390_ipl_update_diag308(IplParameterBlock *iplb)
         ipl->iplb = *iplb;
         ipl->iplb_valid = true;
     }
-    ipl->netboot = is_virtio_net_device(iplb);
+
     update_machine_ipl_properties(iplb);
 }
 
@@ -668,32 +636,14 @@ IplParameterBlock *s390_ipl_get_iplb(void)
 void s390_ipl_reset_request(CPUState *cs, enum s390_reset reset_type)
 {
     S390IPLState *ipl = get_ipl_device();
-
     if (reset_type == S390_RESET_EXTERNAL || reset_type == S390_RESET_REIPL) {
         /* use CPU 0 for full resets */
         ipl->reset_cpu_index = 0;
     } else {
         ipl->reset_cpu_index = cs->cpu_index;
     }
-    ipl->reset_type = reset_type;
 
-    if (reset_type == S390_RESET_REIPL &&
-        ipl->iplb_valid &&
-        !ipl->netboot &&
-        ipl->iplb.pbt == S390_IPL_TYPE_CCW &&
-        is_virtio_scsi_device(&ipl->iplb)) {
-        CcwDevice *ccw_dev = s390_get_ccw_device(get_boot_device(0), NULL);
-
-        if (ccw_dev &&
-            cpu_to_be16(ccw_dev->sch->devno) == ipl->iplb.ccw.devno &&
-            (ccw_dev->sch->ssid & 3) == ipl->iplb.ccw.ssid) {
-            /*
-             * this is the original boot device's SCSI
-             * so restore IPL parameter info from it
-             */
-            ipl->iplb_valid = s390_build_iplb(get_boot_device(0), &ipl->iplb);
-        }
-    }
+    ipl->reset_type = reset_type;
     if (reset_type == S390_RESET_MODIFIED_CLEAR ||
         reset_type == S390_RESET_LOAD_NORMAL ||
         reset_type == S390_RESET_PV) {
diff --git a/hw/s390x/ipl.h b/hw/s390x/ipl.h
index 54eb48fd6e..d7d0b7bfd2 100644
--- a/hw/s390x/ipl.h
+++ b/hw/s390x/ipl.h
@@ -24,6 +24,7 @@
 
 void s390_ipl_convert_loadparm(char *ascii_lp, uint8_t *ebcdic_lp);
 void s390_ipl_fmt_loadparm(uint8_t *loadparm, char *str, Error **errp);
+void s390_rebuild_iplb(uint16_t index, IplParameterBlock *iplb);
 void s390_ipl_update_diag308(IplParameterBlock *iplb);
 int s390_ipl_prepare_pv_header(Error **errp);
 int s390_ipl_pv_unpack(void);
@@ -65,7 +66,8 @@ struct S390IPLState {
     bool enforce_bios;
     bool iplb_valid;
     bool iplb_valid_pv;
-    bool netboot;
+    bool rebuilt_iplb;
+    uint16_t iplb_index;
     /* reset related properties don't have to be migrated or reset */
     enum s390_reset reset_type;
     int reset_cpu_index;
@@ -172,11 +174,14 @@ static inline bool iplb_valid_pv(IplParameterBlock *iplb)
 
 static inline bool iplb_valid(IplParameterBlock *iplb)
 {
+    uint32_t len = be32_to_cpu(iplb->len);
+
     switch (iplb->pbt) {
     case S390_IPL_TYPE_FCP:
-        return be32_to_cpu(iplb->len) >= S390_IPLB_MIN_FCP_LEN;
+        return len >= S390_IPLB_MIN_FCP_LEN;
     case S390_IPL_TYPE_CCW:
-        return be32_to_cpu(iplb->len) >= S390_IPLB_MIN_CCW_LEN;
+        return len >= S390_IPLB_MIN_CCW_LEN;
+    case S390_IPL_TYPE_QEMU_SCSI:
     default:
         return false;
     }
diff --git a/include/hw/s390x/ipl/qipl.h b/include/hw/s390x/ipl/qipl.h
index 1da4f75aa8..6824391111 100644
--- a/include/hw/s390x/ipl/qipl.h
+++ b/include/hw/s390x/ipl/qipl.h
@@ -29,7 +29,8 @@
  */
 struct QemuIplParameters {
     uint8_t  qipl_flags;
-    uint8_t  reserved1[3];
+    uint8_t  index;
+    uint8_t  reserved1[2];
     uint64_t reserved2;
     uint32_t boot_menu_timeout;
     uint8_t  reserved3[2];
diff --git a/pc-bios/s390-ccw/jump2ipl.c b/pc-bios/s390-ccw/jump2ipl.c
index 8db1764ff3..99d18947d1 100644
--- a/pc-bios/s390-ccw/jump2ipl.c
+++ b/pc-bios/s390-ccw/jump2ipl.c
@@ -39,10 +39,15 @@ int jump_to_IPL_code(uint64_t address)
     write_subsystem_identification();
     write_iplb_location();
 
-    /* prevent unknown IPL types in the guest */
+    /*
+     * The IPLB for QEMU SCSI type devices must be rebuilt during re-ipl. The
+     * iplb.devno is set to the boot position of the target SCSI device.
+     */
     if (iplb.pbt == S390_IPL_TYPE_QEMU_SCSI) {
-        iplb.pbt = S390_IPL_TYPE_CCW;
-        set_iplb(&iplb);
+        iplb.devno = qipl.index;
+        if (!set_iplb(&iplb)) {
+            panic("Failed to set IPLB");
+        }
     }
 
     /*
diff --git a/target/s390x/diag.c b/target/s390x/diag.c
index 27ffd48576..a1fd54ddac 100644
--- a/target/s390x/diag.c
+++ b/target/s390x/diag.c
@@ -133,7 +133,14 @@ void handle_diag_308(CPUS390XState *env, uint64_t r1, uint64_t r3, uintptr_t ra)
 
         valid = subcode == DIAG308_PV_SET ? iplb_valid_pv(iplb) : iplb_valid(iplb);
         if (!valid) {
-            env->regs[r1 + 1] = DIAG_308_RC_INVALID;
+            if (subcode == DIAG308_SET && iplb->pbt == S390_IPL_TYPE_QEMU_SCSI) {
+                s390_rebuild_iplb(iplb->devno, iplb);
+                s390_ipl_update_diag308(iplb);
+                env->regs[r1 + 1] = DIAG_308_RC_OK;
+            } else {
+                env->regs[r1 + 1] = DIAG_308_RC_INVALID;
+            }
+
             goto out;
         }
 
-- 
2.39.3