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Re: [PATCH 3/5] s390x: Build IPLB chain for multiple boot devices
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From: |
Thomas Huth |
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Subject: |
Re: [PATCH 3/5] s390x: Build IPLB chain for multiple boot devices |
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Date: |
Tue, 4 Jun 2024 20:26:18 +0200 |
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User-agent: |
Mozilla Thunderbird |
On 29/05/2024 17.43, jrossi@linux.ibm.com wrote:
From: Jared Rossi <jrossi@linux.ibm.com>
Write a chain of IPLBs into memory for future use.
The IPLB chain is placed immediately before the BIOS in memory at the highest
unused page boundary providing sufficient space to fit the chain. 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 later access.
At this stage the IPLB chain is not accessed by the guest during IPL.
Signed-off-by: Jared Rossi <jrossi@linux.ibm.com>
---
hw/s390x/ipl.h | 1 +
include/hw/s390x/ipl/qipl.h | 4 +-
hw/s390x/ipl.c | 129 +++++++++++++++++++++++++++---------
3 files changed, 103 insertions(+), 31 deletions(-)
diff --git a/hw/s390x/ipl.h b/hw/s390x/ipl.h
index 1dcb8984bb..4f098d3a81 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_IPLB_CHAIN 7
void s390_ipl_set_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 a6ce6ddfe3..481c459a53 100644
--- a/include/hw/s390x/ipl/qipl.h
+++ b/include/hw/s390x/ipl/qipl.h
@@ -34,7 +34,9 @@ struct QemuIplParameters {
uint8_t reserved1[3];
uint64_t netboot_start_addr;
uint32_t boot_menu_timeout;
- uint8_t reserved2[12];
+ uint8_t reserved2[2];
+ uint16_t num_iplbs;
+ uint64_t next_iplb;
} QEMU_PACKED;
typedef struct QemuIplParameters QemuIplParameters;
diff --git a/hw/s390x/ipl.c b/hw/s390x/ipl.c
index 2d4f5152b3..79429acabd 100644
--- a/hw/s390x/ipl.c
+++ b/hw/s390x/ipl.c
@@ -55,6 +55,13 @@ static bool iplb_extended_needed(void *opaque)
return ipl->iplbext_migration;
}
+/* Start IPLB chain from the boundary of the first unused page before BIOS */
I'd maybe say "upper boundary" to make it clear that this is at the end of
the page, not at the beginning?
+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,
@@ -391,6 +398,17 @@ static CcwDevice *s390_get_ccw_device(DeviceState *dev_st,
int *devtype)
return ccw_dev;
}
+static void s390_ipl_map_iplb_chain(IplParameterBlock *iplb_chain)
+{
+ S390IPLState *ipl = get_ipl_device();
+ uint16_t count = ipl->qipl.num_iplbs;
+ 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, be32_to_cpu(len));
The be32_to_cpu looks wrong here, since you just computed len in native
endianness.
+ ipl->qipl.next_iplb = chain_addr;
Just a matter of taste, but I'd prefer to set ipl->qipl.next_iplb in the
same function where you set ipl->qipl.num_iplbs ... so I'd rather return
chain_addr here and then do this on the calling site:
ipl->qipl.next_iplb = s390_ipl_map_iplb_chain(...);
+}
+
void s390_ipl_fmt_loadparm(uint8_t *loadparm, char *str, Error **errp)
{
int i;
@@ -422,54 +440,51 @@ void s390_ipl_set_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:
+ 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 ture 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;
}
@@ -478,8 +493,8 @@ static bool s390_gen_initial_iplb(S390IPLState *ipl)
lp = S390_CCW_MACHINE(qdev_get_machine())->loadparm;
}
- s390_ipl_set_loadparm((char *)lp, ipl->iplb.loadparm);
- ipl->iplb.flags |= DIAG308_FLAGS_LP_VALID;
+ s390_ipl_set_loadparm((char *)lp, iplb->loadparm);
+ iplb->flags |= DIAG308_FLAGS_LP_VALID;
return true;
}
@@ -487,6 +502,58 @@ 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);
+
+ /*
+ * Parse the boot devices. Generate an IPLB for the first boot device,
+ * which will later be set with DIAG308. Index any fallback boot devices.
+ */
+ if (!dev_st) {
+ ipl->qipl.num_iplbs = 0;
+ return false;
+ }
+
+ iplb_num = 1;
+ s390_build_iplb(dev_st, &ipl->iplb);
+ ipl->iplb.flags |= DIAG308_FLAGS_LP_VALID;
+
+ while (get_boot_device(iplb_num)) {
+ iplb_num++;
+ }
+
+ ipl->qipl.num_iplbs = iplb_num - 1;
It's somewhat confusing that ipl->qipl.num_iplbs is one less than iplb_num
... what does ipl->qipl.num_iplbs exactly define? The amount of additional
chained devices beside the first one?
A comment either here or qipl.h that describes the exact meaning of
num_iplbs would be helpful.
+
+ /*
+ * Build fallback IPLBs for any boot devices above index 0, up to a
+ * maximum amount as defined in ipl.h
+ */
+ if (iplb_num > 1) {
+ if (iplb_num > MAX_IPLB_CHAIN) {
+ warn_report("Excess boot devices defined! %d boot devices found, "
+ "but only the first %d will be considered.",
+ iplb_num, MAX_IPLB_CHAIN + 1);
+ iplb_num = MAX_IPLB_CHAIN + 1;
What's now the real maximum number of iplb_num ? If it is MAX_IPLB_CHAIN + 1
then the if-statement above looks wrong, should it be "if (iplb_num >
MAX_IPLB_CHAIN + 1)" instead?
+ }
+
+ ipl->qipl.num_iplbs = iplb_num - 1;
You could move that into the body of the above if-statement, since otherwise
the value has been set earlier in this function already.
+ /* Start at 1 because the IPLB for boot index 0 is not chained */
+ for (int i = 1; i < iplb_num; i++) {
Just to double-check: Is "i < iplb_num" right?
Or should it be "i <= iplb_num" instead?
BTW, have you successfully tested booting with 8 devices that all have a
boot index, but only the last one is bootable?
+ dev_st = get_boot_device(i);
+ s390_build_iplb(dev_st, &iplb_chain[i - 1]);
+ iplb_chain[i - 1].flags |= DIAG308_FLAGS_LP_VALID;
+ }
+
+ s390_ipl_map_iplb_chain(iplb_chain);
+ }
+
+ return iplb_num;
+}
Thomas