Re: [PATCH 01/13] x86/entry: Fix AC assertion

2020-09-02 Thread Brian Gerst
On Wed, Sep 2, 2020 at 12:31 PM wrote: > > On Wed, Sep 02, 2020 at 06:24:27PM +0200, Jürgen Groß wrote: > > On 02.09.20 17:58, Brian Gerst wrote: > > > On Wed, Sep 2, 2020 at 9:38 AM Peter Zijlstra > > > wrote: > > > > > > > > From: Peter Zijlstra > > > > > > > > The WARN added in commit

Re: [PATCH 01/13] x86/entry: Fix AC assertion

2020-09-02 Thread peterz
On Wed, Sep 02, 2020 at 06:24:27PM +0200, Jürgen Groß wrote: > On 02.09.20 17:58, Brian Gerst wrote: > > On Wed, Sep 2, 2020 at 9:38 AM Peter Zijlstra wrote: > > > > > > From: Peter Zijlstra > > > > > > The WARN added in commit 3c73b81a9164 ("x86/entry, selftests: Further > > > improve user

Re: [PATCH 01/13] x86/entry: Fix AC assertion

2020-09-02 Thread Andrew Cooper
On 02/09/2020 16:58, Brian Gerst wrote: > On Wed, Sep 2, 2020 at 9:38 AM Peter Zijlstra wrote: >> From: Peter Zijlstra >> >> The WARN added in commit 3c73b81a9164 ("x86/entry, selftests: Further >> improve user entry sanity checks") unconditionally triggers on my IVB >> machine because it does

Re: [PATCH 01/13] x86/entry: Fix AC assertion

2020-09-02 Thread Jürgen Groß
On 02.09.20 17:58, Brian Gerst wrote: On Wed, Sep 2, 2020 at 9:38 AM Peter Zijlstra wrote: From: Peter Zijlstra The WARN added in commit 3c73b81a9164 ("x86/entry, selftests: Further improve user entry sanity checks") unconditionally triggers on my IVB machine because it does not support

Re: [PATCH 01/13] x86/entry: Fix AC assertion

2020-09-02 Thread Brian Gerst
On Wed, Sep 2, 2020 at 9:38 AM Peter Zijlstra wrote: > > From: Peter Zijlstra > > The WARN added in commit 3c73b81a9164 ("x86/entry, selftests: Further > improve user entry sanity checks") unconditionally triggers on my IVB > machine because it does not support SMAP. > > For !SMAP hardware we

[PATCH 01/13] x86/entry: Fix AC assertion

2020-09-02 Thread Peter Zijlstra
From: Peter Zijlstra The WARN added in commit 3c73b81a9164 ("x86/entry, selftests: Further improve user entry sanity checks") unconditionally triggers on my IVB machine because it does not support SMAP. For !SMAP hardware we patch out CLAC/STAC instructions and thus if userspace sets AC, we'll