Re: disabling psp in bios causes errors in dmesg

[Tom Lendacky]

On 8/10/2018 9:11 AM, Tom Lendacky wrote:
> On 8/10/2018 2:03 AM, Thomas Backlund wrote:
>> Hi,
>>
>> this is tested on kernel 4.17.14
>>
>> hw:
>>
>> MSI X399 GAMING PRO CARBON AC (MS-7B09) bios 1.A0
>>
>> AMD Ryzen Threadripper 1950X
>>
>>
>> Disabling psp in bios gets this in the logs:
> 
> Hmm, I'm not familiar with that BIOS option so I'm not exactly sure what
> it is doing under the covers.  Having said that, it would seem that a
> register read is indicating that SEV is supported when it is not on this
> platform.  Maybe the register read is returning all 1s, (i.e. 0xffffffff).

The register read was returning all 1s.  The issue was reported to the
BIOS team and a fix is in process, but that may take some time to move
through all the vendors.  So in the meantime, see the next comment below.

> 
> You can work around this by blacklisting the ccp driver module for now.
> In the mean time, we'll try to understand what is occurring here and
> provide a fix if we can.

A patch has been submitted which adds a command timeout and should also
resolve this issue.  Please see:
  https://marc.info/?l=linux-crypto-vger&m=153436754612783&w=2

This patch is not yet accepted and needs adjusting when being applied to
an older kernel (4.16 - 4.18).  Once accepted, versions of the patch will
be submitted to stable.

Thanks,
Tom

> 
> Thanks,
> Tom
> 
>>
>>
>> [  246.748978] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables
>> this message.
>> [  246.748978] systemd-udevd   D    0   724    716 0x80000124
>> [  246.748980] Call Trace:
>> [  246.748986]  ? __schedule+0x234/0x840
>> [  246.748988]  schedule+0x28/0x80
>> [  246.748993]  __sev_do_cmd_locked+0x1f0/0x270 [ccp]
>> [  246.748996]  ? wait_woken+0x80/0x80
>> [  246.748997]  ? 0xffffffffc0683000
>> [  246.749001]  __sev_platform_init_locked+0x2f/0x80 [ccp]
>> [  246.749001]  ? mutex_lock+0xe/0x30
>> [  246.749004]  sev_platform_init+0x1d/0x30 [ccp]
>> [  246.749007]  psp_pci_init+0x40/0xe0 [ccp]
>> [  246.749008]  ? 0xffffffffc0683000
>> [  246.749011]  sp_mod_init+0x16/0x1000 [ccp]
>> [  246.749012]  do_one_initcall+0x46/0x1c3
>> [  246.749014]  ? _cond_resched+0x15/0x30
>> [  246.749017]  ? kmem_cache_alloc_trace+0x3a/0x170
>> [  246.749019]  do_init_module+0x5a/0x210
>> [  246.749020]  load_module+0x215b/0x2530
>> [  246.749021]  ? kmem_cache_alloc_node_trace+0x45/0x190
>> [  246.749024]  ? vmap_page_range_noflush+0x24d/0x320
>> [  246.749026]  ? __do_sys_init_module+0x136/0x180
>> [  246.749026]  ? _cond_resched+0x15/0x30
>> [  246.749027]  __do_sys_init_module+0x136/0x180
>> [  246.749029]  do_syscall_64+0x55/0x100
>> [  246.749031]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
>> [  246.749032] RIP: 0033:0x7ffb1a09018a
>> [  246.749033] RSP: 002b:00007ffe196680c8 EFLAGS: 00000246 ORIG_RAX:
>> 00000000000000af
>> [  246.749034] RAX: ffffffffffffffda RBX: 00005562bb20d080 RCX:
>> 00007ffb1a09018a
>> [  246.749034] RDX: 00007ffb1994e6f8 RSI: 0000000000029e50 RDI:
>> 00005562bba5e710
>> [  246.749035] RBP: 00007ffb1994e6f8 R08: 0000000000000004 R09:
>> 0000000000000000
>> [  246.749035] R10: 0000000000000005 R11: 0000000000000246 R12:
>> 00005562bba5e710
>> [  246.749036] R13: 0000000000020000 R14: 00005562bb1fde70 R15:
>> 00005562bb20d080
>>
>>
>> Should it not detect that its disabled and bail out ?
>>
>> -- 
>>
>> Thomas
>>
>>