From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:44916) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fSNIu-0005Sh-JT for qemu-devel@nongnu.org; Mon, 11 Jun 2018 09:56:17 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fSNIq-0005RS-NZ for qemu-devel@nongnu.org; Mon, 11 Jun 2018 09:56:16 -0400 References: <20180611135223.81865-1-borntraeger@de.ibm.com> From: David Hildenbrand Message-ID: Date: Mon, 11 Jun 2018 15:56:09 +0200 MIME-Version: 1.0 In-Reply-To: <20180611135223.81865-1-borntraeger@de.ibm.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v2 1/1] s390x/ipl: Try to detect Linux vs non Linux for initial IPL PSW List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Christian Borntraeger , Cornelia Huck Cc: qemu-devel , qemu-s390x , Thomas Huth , Halil Pasic , Janosch Frank , Alexander Graf , Richard Henderson 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 > --- > 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) -- Thanks, David / dhildenb