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Re: [qemu-s390x] [PATCH v2 1/1] s390x/ipl: Try to detect Linux vs non Li
From: |
Thomas Huth |
Subject: |
Re: [qemu-s390x] [PATCH v2 1/1] s390x/ipl: Try to detect Linux vs non Linux for initial IPL PSW |
Date: |
Mon, 11 Jun 2018 18:11:13 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.8.0 |
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 <address@hidden>
>> ---
>> 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?
Thomas