* Re: [Qemu-devel] [PATCH] s390x/ipl: Try to detect Linux vs non Linux for initial IPL PSW
2018-05-08 14:15 [Qemu-devel] [PATCH] s390x/ipl: Try to detect Linux vs non Linux for initial IPL PSW Christian Borntraeger
@ 2018-05-08 14:24 ` Thomas Huth
2018-05-08 16:46 ` Christian Borntraeger
2018-05-08 16:47 ` Christian Borntraeger
2 siblings, 0 replies; 4+ messages in thread
From: Thomas Huth @ 2018-05-08 14:24 UTC (permalink / raw)
To: Christian Borntraeger, Peter Maydell
Cc: qemu-devel, qemu-s390x, Cornelia Huck, David Hildenbrand,
Halil Pasic, Janosch Frank, Alexander Graf, Richard Henderson
On 08.05.2018 16:15, 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 <borntraeger@de.ibm.com>
> Acked-by: Jason J. Herne <jjherne@linux.ibm.com>
> ---
> 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 150f6c0582..c0fed26f03 100644
> --- a/hw/s390x/ipl.c
> +++ b/hw/s390x/ipl.c
> @@ -104,7 +104,9 @@ 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;
>
> @@ -156,6 +158,17 @@ 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(0x10008);
> + if (magic && !memcmp(magic, "S390EP", 6)) {
> + pentry = KERN_IMAGE_START;
> + } else {
> + /* if not Linux use the IPL PSW */
> + iplpsw = rom_ptr(0);
> + if (iplpsw) {
> + pentry = *iplpsw & 0x7fffffffUL;
> + }
else {
error_report("Failed to determine entry point");
exit(1);
}
?
Otherwise some version of GCC might complain that pentry is used
uninitialized later.
Alternatively, use "assert(iplpsw)" instead of the "if (iplpws)" ?
> + }
> }
> if (kernel_size < 0) {
> error_setg(&err, "could not load kernel '%s'", ipl->kernel);
>
Thomas
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [Qemu-devel] [PATCH] s390x/ipl: Try to detect Linux vs non Linux for initial IPL PSW
2018-05-08 14:15 [Qemu-devel] [PATCH] s390x/ipl: Try to detect Linux vs non Linux for initial IPL PSW Christian Borntraeger
2018-05-08 14:24 ` Thomas Huth
@ 2018-05-08 16:46 ` Christian Borntraeger
2018-05-08 16:47 ` Christian Borntraeger
2 siblings, 0 replies; 4+ messages in thread
From: Christian Borntraeger @ 2018-05-08 16:46 UTC (permalink / raw)
To: Peter Maydell
Cc: qemu-devel, qemu-s390x, Cornelia Huck, Thomas Huth,
David Hildenbrand, Halil Pasic, Janosch Frank, Alexander Graf,
Richard Henderson
On 05/08/2018 04:15 PM, 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 <borntraeger@de.ibm.com>
> Acked-by: Jason J. Herne <jjherne@linux.ibm.com>
> ---
> 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 150f6c0582..c0fed26f03 100644
> --- a/hw/s390x/ipl.c
> +++ b/hw/s390x/ipl.c
> @@ -104,7 +104,9 @@ 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;
>
> @@ -156,6 +158,17 @@ 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(0x10008);
> + if (magic && !memcmp(magic, "S390EP", 6)) {
> + pentry = KERN_IMAGE_START;
> + } else {
> + /* if not Linux use the IPL PSW */
> + iplpsw = rom_ptr(0);
> + if (iplpsw) {
> + pentry = *iplpsw & 0x7fffffffUL;
This needs an endianess conversion I think.
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [Qemu-devel] [PATCH] s390x/ipl: Try to detect Linux vs non Linux for initial IPL PSW
2018-05-08 14:15 [Qemu-devel] [PATCH] s390x/ipl: Try to detect Linux vs non Linux for initial IPL PSW Christian Borntraeger
2018-05-08 14:24 ` Thomas Huth
2018-05-08 16:46 ` Christian Borntraeger
@ 2018-05-08 16:47 ` Christian Borntraeger
2 siblings, 0 replies; 4+ messages in thread
From: Christian Borntraeger @ 2018-05-08 16:47 UTC (permalink / raw)
To: Peter Maydell
Cc: qemu-devel, qemu-s390x, Cornelia Huck, Thomas Huth,
David Hildenbrand, Halil Pasic, Janosch Frank, Alexander Graf,
Richard Henderson
On 05/08/2018 04:15 PM, 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 <borntraeger@de.ibm.com>
> Acked-by: Jason J. Herne <jjherne@linux.ibm.com>
> ---
> 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 150f6c0582..c0fed26f03 100644
> --- a/hw/s390x/ipl.c
> +++ b/hw/s390x/ipl.c
> @@ -104,7 +104,9 @@ 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;
>
> @@ -156,6 +158,17 @@ 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(0x10008);
> + if (magic && !memcmp(magic, "S390EP", 6)) {
> + pentry = KERN_IMAGE_START;
> + } else {
> + /* if not Linux use the IPL PSW */
> + iplpsw = rom_ptr(0);
> + if (iplpsw) {
> + pentry = *iplpsw & 0x7fffffffUL;
I forgot endianess conversion here.
> + }
> + }
> }
> if (kernel_size < 0) {
> error_setg(&err, "could not load kernel '%s'", ipl->kernel);
>
^ permalink raw reply [flat|nested] 4+ messages in thread