linux-kernel - Re: disabling psp in bios causes errors in dmesg

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Date:   Fri, 10 Aug 2018 09:11:56 -0500
From:   Tom Lendacky <thomas.lendacky@....com>
To:     Thomas Backlund <tmb@...eia.org>, linux-crypto@...r.kernel.org
Cc:     Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        gary.hook@....com, Brijesh Singh <brijesh.singh@....com>
Subject: Re: disabling psp in bios causes errors in dmesg

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).

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.

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
> 
>