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Re: [PATCH v3 3/5] pc-bios: s390x: Use reset PSW if avaliable
From: |
Thomas Huth |
Subject: |
Re: [PATCH v3 3/5] pc-bios: s390x: Use reset PSW if avaliable |
Date: |
Wed, 2 Sep 2020 11:50:41 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.6.0 |
On 02/09/2020 10.46, Janosch Frank wrote:
> On 9/1/20 6:59 PM, Thomas Huth wrote:
>> On 31/08/2020 17.09, Janosch Frank wrote:
>>> If a blob provides a reset PSW then we should use it instead of
>>> branching to the PSW address and using our own mask.
>>>
>>> Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
>>> ---
>>> pc-bios/s390-ccw/bootmap.c | 3 ++-
>>> pc-bios/s390-ccw/jump2ipl.c | 22 +++++++++++++++++-----
>>> pc-bios/s390-ccw/s390-ccw.h | 1 +
>>> 3 files changed, 20 insertions(+), 6 deletions(-)
>>>
>>> diff --git a/pc-bios/s390-ccw/bootmap.c b/pc-bios/s390-ccw/bootmap.c
>>> index 8747c4ea26..5a03b1eb8b 100644
>>> --- a/pc-bios/s390-ccw/bootmap.c
>>> +++ b/pc-bios/s390-ccw/bootmap.c
>>> @@ -515,7 +515,8 @@ static void zipl_run(ScsiBlockPtr *pte)
>>> IPL_assert(entry->component_type == ZIPL_COMP_ENTRY_EXEC, "No EXEC
>>> entry");
>>>
>>> /* should not return */
>>> - jump_to_IPL_code(entry->compdat.load_psw & PSW_MASK_SHORT_ADDR);
>>> + write_reset_psw(entry->compdat.load_psw);
>>> + jump_to_IPL_code(0);
>>> }
>>>
>>> static void ipl_scsi(void)
>>> diff --git a/pc-bios/s390-ccw/jump2ipl.c b/pc-bios/s390-ccw/jump2ipl.c
>>> index b6aad32def..5b8352d257 100644
>>> --- a/pc-bios/s390-ccw/jump2ipl.c
>>> +++ b/pc-bios/s390-ccw/jump2ipl.c
>>> @@ -12,15 +12,21 @@
>>>
>>> #define KERN_IMAGE_START 0x010000UL
>>> #define RESET_PSW_MASK (PSW_MASK_SHORTPSW | PSW_MASK_64)
>>> +#define RESET_PSW ((uint64_t)&jump_to_IPL_addr | RESET_PSW_MASK)
>>>
>>> static uint64_t *reset_psw = 0, save_psw, ipl_continue;
>>>
>>> +void write_reset_psw(uint64_t psw)
>>> +{
>>> + *reset_psw = psw;
>>> +}
>>> +
>>> static void jump_to_IPL_addr(void)
>>> {
>>> __attribute__((noreturn)) void (*ipl)(void) = (void *)ipl_continue;
>>>
>>> /* Restore reset PSW */
>>> - *reset_psw = save_psw;
>>> + write_reset_psw(save_psw);
>>>
>>> ipl();
>>> /* should not return */
>>> @@ -43,9 +49,10 @@ void jump_to_IPL_code(uint64_t address)
>>> * content of non-BIOS memory after we loaded the guest, so we
>>> * save the original content and restore it in jump_to_IPL_2.
>>> */
>>> - save_psw = *reset_psw;
>>> - *reset_psw = (uint64_t) &jump_to_IPL_addr;
>>> - *reset_psw |= RESET_PSW_MASK;
>>> + if (address) {
>>> + save_psw = *reset_psw;
>>> + write_reset_psw(RESET_PSW);
>>> + }
>>> ipl_continue = address;
>>> debug_print_int("set IPL addr to", ipl_continue);
>>
>> In case you respin this series, I think I'd move the "ipl_continue =
>> address" into the if-statement, too, and change the debug_print_int line
>> to use address instead of ipl_continue.
>
> Hmm, my intention was to always have something printed.
> But I guess it would make more sense to print the reset psw addr in the
> ~address case.
I meant to only move the "ipl_continue = address" line and keep the
debug_print_int() at its current place (you just have to replace
ipl_continue there). But you're right, it would make more sense to print
the PSW at address 0 in that case instead.
Thomas