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[Qemu-devel] [PATCH 2/4] pc-bios/s390-ccw: do a subsystem reset before r
From: |
Jens Freimann |
Subject: |
[Qemu-devel] [PATCH 2/4] pc-bios/s390-ccw: do a subsystem reset before running the guest |
Date: |
Wed, 18 Jun 2014 14:16:45 +0200 |
From: Christian Borntraeger <address@hidden>
The loader BIOS has already activated several devices. Let's do a
subsystem reset before jumping into the guest. As there is no direct
way of doing so, we use diagnose 308 to bring the system in a
defined state. This is similar to what kdump on s390 uses. We have
to define a small trampoline function that restores the low bytes
to whatever the bootmap has written there.
Signed-off-by: Christian Borntraeger <address@hidden>
Signed-off-by: Jens Freimann <address@hidden>
---
pc-bios/s390-ccw/bootmap.c | 55 +++++++++++++++++++++++++++++++++++++++-------
1 file changed, 47 insertions(+), 8 deletions(-)
diff --git a/pc-bios/s390-ccw/bootmap.c b/pc-bios/s390-ccw/bootmap.c
index 53a460d..c07553b 100644
--- a/pc-bios/s390-ccw/bootmap.c
+++ b/pc-bios/s390-ccw/bootmap.c
@@ -58,6 +58,52 @@ struct mbr {
/* Scratch space */
static uint8_t sec[SECTOR_SIZE] __attribute__((__aligned__(SECTOR_SIZE)));
+typedef struct ResetInfo {
+ uint32_t ipl_mask;
+ uint32_t ipl_addr;
+ uint32_t ipl_continue;
+} ResetInfo;
+
+ResetInfo save;
+
+static void jump_to_IPL_2(void)
+{
+ ResetInfo *current = 0;
+
+ void (*ipl)(void) = (void *) (uint64_t) current->ipl_continue;
+ debug_print_addr("set IPL addr to", ipl);
+
+ /* Ensure the guest output starts fresh */
+ sclp_print("\n");
+
+ *current = save;
+ ipl(); /* should not return */
+}
+
+static void jump_to_IPL_code(uint64_t address)
+{
+ /*
+ * The IPL PSW is at address 0. We also must not overwrite the
+ * content of non-BIOS memory after we loaded the guest, so we
+ * save the original content and restore it in jump_to_IPL_2.
+ */
+ ResetInfo *current = 0;
+
+ save = *current;
+ current->ipl_addr = (uint32_t) (uint64_t) &jump_to_IPL_2;
+ current->ipl_continue = address & 0x7fffffff;
+
+ /*
+ * HACK ALERT.
+ * We use the load normal reset to keep r15 unchanged. jump_to_IPL_2
+ * can then use r15 as its stack pointer.
+ */
+ asm volatile("lghi 1,1\n\t"
+ "diag 1,1,0x308\n\t"
+ : : : "1", "memory");
+ virtio_panic("\n! IPL returns !\n");
+}
+
/* Check for ZIPL magic. Returns 0 if not matched. */
static int zipl_magic(uint8_t *ptr)
{
@@ -123,7 +169,6 @@ static int zipl_run(struct scsi_blockptr *pte)
{
struct component_header *header;
struct component_entry *entry;
- void (*ipl)(void);
uint8_t tmp_sec[SECTOR_SIZE];
virtio_read(pte->blockno, tmp_sec);
@@ -157,14 +202,8 @@ static int zipl_run(struct scsi_blockptr *pte)
goto fail;
}
- /* Ensure the guest output starts fresh */
- sclp_print("\n");
-
- /* And run the OS! */
- ipl = (void*)(entry->load_address & 0x7fffffff);
- debug_print_addr("set IPL addr to", ipl);
/* should not return */
- ipl();
+ jump_to_IPL_code(entry->load_address);
return 0;
--
1.8.5.5
- [Qemu-devel] [PATCH 0/4] s390-ccw.img: s390-ccw.img fixes, Jens Freimann, 2014/06/18
- [Qemu-devel] [PATCH 1/4] pc-bios/s390-ccw: virtio_load_direct() can't load max number of sectors, Jens Freimann, 2014/06/18
- [Qemu-devel] [PATCH 2/4] pc-bios/s390-ccw: do a subsystem reset before running the guest,
Jens Freimann <=
- [Qemu-devel] [PATCH 4/4] pc-bios/s390-ccw: update s390-ccw.img binary, Jens Freimann, 2014/06/18
- [Qemu-devel] [PATCH 3/4] pc-bios/s390-ccw: fix for fragmented SCSI bootmap, Jens Freimann, 2014/06/18
- Re: [Qemu-devel] [PATCH 0/4] s390-ccw.img: s390-ccw.img fixes, Alexander Graf, 2014/06/18
- Re: [Qemu-devel] [PATCH 0/4] s390-ccw.img: s390-ccw.img fixes, Cornelia Huck, 2014/06/23