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);
Hmm, wait, what if load_image_targphys() failed and returned a kernel_size < 0 ... won't we hit that assert() in that case? I think you might want to check for kernel_size > 0 (or even > 8) here first. > + pentry = be64_to_cpu(*iplpsw) & 0x7fffffffUL; > + } > } > if (kernel_size < 0) { > error_setg(&err, "could not load kernel '%s'", ipl->kernel); > Thomas