On 11.06.2018 18:11, Thomas Huth wrote: > On 11.06.2018 15:56, David Hildenbrand wrote: >> On 11.06.2018 15:52, Christian Borntraeger wrote: >>> Right now the IPL device always starts from address 0x10000 (the usual >>> Linux entry point). To run other guests (e.g. test programs) it is >>> useful to use the IPL PSW from address 0. We can use the Linux magic >>> at 0x10008 to decide. >>> >>> Signed-off-by: Christian Borntraeger <borntrae...@de.ibm.com> >>> --- >>> v1->v2: >>> - use LINUX_MAGIC_ADDR define >>> - use assert for valid iplpsw pointer >>> - add endianess conversion >>> hw/s390x/ipl.c | 15 ++++++++++++++- >>> 1 file changed, 14 insertions(+), 1 deletion(-) >>> >>> diff --git a/hw/s390x/ipl.c b/hw/s390x/ipl.c >>> index 04245b5258..3790153fa9 100644 >>> --- a/hw/s390x/ipl.c >>> +++ b/hw/s390x/ipl.c >>> @@ -29,6 +29,7 @@ >>> #include "exec/exec-all.h" >>> >>> #define KERN_IMAGE_START 0x010000UL >>> +#define LINUX_MAGIC_ADDR 0x010008UL >>> #define KERN_PARM_AREA 0x010480UL >>> #define INITRD_START 0x800000UL >>> #define INITRD_PARM_START 0x010408UL >>> @@ -105,7 +106,9 @@ static uint64_t bios_translate_addr(void *opaque, >>> uint64_t srcaddr) >>> static void s390_ipl_realize(DeviceState *dev, Error **errp) >>> { >>> S390IPLState *ipl = S390_IPL(dev); >>> - uint64_t pentry = KERN_IMAGE_START; >>> + uint64_t *iplpsw; >>> + uint64_t pentry; >>> + char *magic; >>> int kernel_size; >>> Error *err = NULL; >>> >>> @@ -157,6 +160,16 @@ static void s390_ipl_realize(DeviceState *dev, Error >>> **errp) >>> NULL, 1, EM_S390, 0, 0); >>> if (kernel_size < 0) { >>> kernel_size = load_image_targphys(ipl->kernel, 0, ram_size); >>> + /* if this is Linux use KERN_IMAGE_START */ >>> + magic = rom_ptr(LINUX_MAGIC_ADDR); >>> + if (magic && !memcmp(magic, "S390EP", 6)) { >>> + pentry = KERN_IMAGE_START; >>> + } else { >>> + /* if not Linux use the IPL PSW */ >>> + iplpsw = rom_ptr(0); >>> + assert(iplpsw); >>> + pentry = be64_to_cpu(*iplpsw) & 0x7fffffffUL; >>> + } >>> } >>> if (kernel_size < 0) { >>> error_setg(&err, "could not load kernel '%s'", ipl->kernel); >>> >> >> Have you tried this with kvm-unit-tests? (no magic but we rely on 0x10000) > > kvm-unit-tests are elf files which should be handled by the load_elf() > some lines earlier already, so I think we should be fine there, > shouldn't we?
Indeed, this should work. > > Thomas > > -- Thanks, David / dhildenb