Re: SME/32-bit regression

From	Boris Ostrovsky <boris.ostrovsky@oracle.com>
Newsgroups	linux.kernel
Subject	Re: SME/32-bit regression
Date	2017-09-06 16:10 +0200
Message-ID	<umJbH-2R0-5@gated-at.bofh.it> (permalink)
References	<umzvH-3X8-9@gated-at.bofh.it> <umEOK-85j-13@gated-at.bofh.it> <umJ22-2yd-21@gated-at.bofh.it> <umJ22-2yd-19@gated-at.bofh.it>
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On 09/06/2017 09:57 AM, Thomas Gleixner wrote:
> On Wed, 6 Sep 2017, Boris Ostrovsky wrote:
>> On 09/06/2017 05:26 AM, Borislav Petkov wrote:
>>> On Tue, Sep 05, 2017 at 11:45:07PM -0400, Boris Ostrovsky wrote:
>>>> It appears there is a regression for 32-bit kernels due to SME changes.
>>>>
>>>> I bisected my particular problem
>>> It being? Doesn't boot, splats?
>> Xen guest crashes very early, before a splat can can be generated.
>>
>>>> (Xen PV guest) to
>>>> 21729f81ce8ae76a6995681d40e16f7ce8075db4 but I also saw pmd_clear_bad()
>>>> errors on baremetal. This seems to be caused by sme_me_mask being an
>>>> unsigned long as opposed to phys_addr_t (the actual problem is that
>>>> __PHYSICAL_MASK is truncated). When I declare it as u64 and drop unsigned
>>>> long cast in __sme_set()/__sme_clr() the problem goes way. (This presumably
>>>> won't work for non-PAE which I haven't tried).
>>> Right, so I think we should do this because those macros should not have
>>> any effect on !CONFIG_AMD_MEM_ENCRYPT setups.
>> This won't help though if kernel is built with SME support.
> Which is not the case for 32bit. SME depends on 64bit

Oh, OK, I didn't realize that.

-boris

Thread

SME/32-bit regression Boris Ostrovsky <boris.ostrovsky@oracle.com> - 2017-09-06 05:50 +0200
  Re: SME/32-bit regression Borislav Petkov <bp@alien8.de> - 2017-09-06 11:30 +0200
    Re: SME/32-bit regression Borislav Petkov <bp@alien8.de> - 2017-09-06 11:50 +0200
      Re: SME/32-bit regression Borislav Petkov <bp@alien8.de> - 2017-09-06 18:50 +0200
        Re: SME/32-bit regression Borislav Petkov <bp@alien8.de> - 2017-09-06 20:30 +0200
          Re: SME/32-bit regression Boris Ostrovsky <boris.ostrovsky@oracle.com> - 2017-09-06 23:10 +0200
            [PATCH] x86/mm: Make the SME mask a u64 Borislav Petkov <bp@alien8.de> - 2017-09-07 11:40 +0200
              [tip:x86/urgent] x86/mm: Make the SME mask a u64 tip-bot for Borislav Petkov <tipbot@zytor.com> - 2017-09-07 12:40 +0200
    Re: SME/32-bit regression Thomas Gleixner <tglx@linutronix.de> - 2017-09-06 16:00 +0200
      Re: SME/32-bit regression Boris Ostrovsky <boris.ostrovsky@oracle.com> - 2017-09-06 16:10 +0200
    Re: SME/32-bit regression Boris Ostrovsky <boris.ostrovsky@oracle.com> - 2017-09-06 16:00 +0200

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