From: Ira Weiny <ira.weiny@intel.com>
To: Dave Hansen <dave.hansen@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Andy Lutomirski <luto@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Dave Hansen <dave.hansen@linux.intel.com>,
x86@kernel.org, Dan Williams <dan.j.williams@intel.com>,
Andrew Morton <akpm@linux-foundation.org>,
Fenghua Yu <fenghua.yu@intel.com>,
linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-nvdimm@lists.01.org, linux-fsdevel@vger.kernel.org,
linux-mm@kvack.org, linux-kselftest@vger.kernel.org
Subject: Re: [PATCH RFC V3 7/9] x86/entry: Preserve PKRS MSR across exceptions
Date: Wed, 14 Oct 2020 21:18:08 -0700 [thread overview]
Message-ID: <20201015041808.GS2046448@iweiny-DESK2.sc.intel.com> (raw)
In-Reply-To: <a3cb045e-3d27-eaca-c78d-d30d9a045e02@intel.com>
On Wed, Oct 14, 2020 at 09:06:44PM -0700, Dave Hansen wrote:
> On 10/14/20 8:46 PM, Ira Weiny wrote:
> > On Tue, Oct 13, 2020 at 11:52:32AM -0700, Dave Hansen wrote:
> >> On 10/9/20 12:42 PM, ira.weiny@intel.com wrote:
> >>> @@ -341,6 +341,9 @@ noinstr void irqentry_enter(struct pt_regs *regs, irqentry_state_t *state)
> >>> /* Use the combo lockdep/tracing function */
> >>> trace_hardirqs_off();
> >>> instrumentation_end();
> >>> +
> >>> +done:
> >>> + irq_save_pkrs(state);
> >>> }
> >> One nit: This saves *and* sets PKRS. It's not obvious from the call
> >> here that PKRS is altered at this site. Seems like there could be a
> >> better name.
> >>
> >> Even if we did:
> >>
> >> irq_save_set_pkrs(state, INIT_VAL);
> >>
> >> It would probably compile down to the same thing, but be *really*
> >> obvious what's going on.
> > I suppose that is true. But I think it is odd having a parameter which is the
> > same for every call site.
>
> Well, it depends on what you optimize for. I'm trying to optimize for
> the code being understood quickly the first time someone reads it. To
> me, that's more important than minimizing the number of function
> parameters (which are essentially free).
>
Agreed. Sorry I was not trying to be confrontational. There is just enough
other things which are going to take me time to get right I need to focus on
them... :-D
Sorry,
Ira
next prev parent reply other threads:[~2020-10-15 4:18 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-09 19:42 [PATCH RFC V3 0/9] PKS: Add Protection Keys Supervisor (PKS) support RFC v3 ira.weiny
2020-10-09 19:42 ` [PATCH RFC V3 1/9] x86/pkeys: Create pkeys_common.h ira.weiny
2020-10-13 17:46 ` Dave Hansen
2020-10-13 19:44 ` Ira Weiny
2020-10-09 19:42 ` [PATCH RFC V3 2/9] x86/fpu: Refactor arch_set_user_pkey_access() for PKS support ira.weiny
2020-10-13 17:50 ` Dave Hansen
2020-10-13 23:56 ` Ira Weiny
2020-10-16 10:57 ` Peter Zijlstra
2020-10-17 3:32 ` Ira Weiny
2020-10-19 9:35 ` Peter Zijlstra
2020-10-09 19:42 ` [PATCH RFC V3 3/9] x86/pks: Enable Protection Keys Supervisor (PKS) ira.weiny
2020-10-13 18:23 ` Dave Hansen
2020-10-14 2:08 ` Ira Weiny
2020-10-09 19:42 ` [PATCH RFC V3 4/9] x86/pks: Preserve the PKRS MSR on context switch ira.weiny
2020-10-13 18:31 ` Dave Hansen
2020-10-14 22:36 ` Ira Weiny
2020-10-16 11:12 ` Peter Zijlstra
2020-10-17 5:14 ` Ira Weiny
2020-10-19 9:37 ` Peter Zijlstra
2020-10-19 18:48 ` Ira Weiny
2020-10-16 11:06 ` Peter Zijlstra
2020-10-17 5:37 ` Ira Weiny
2020-10-09 19:42 ` [PATCH RFC V3 5/9] x86/pks: Add PKS kernel API ira.weiny
2020-10-13 18:43 ` Dave Hansen
2020-10-15 1:08 ` Ira Weiny
2020-10-16 11:07 ` Peter Zijlstra
2020-10-17 5:42 ` Ira Weiny
2020-10-09 19:42 ` [PATCH RFC V3 6/9] x86/entry: Pass irqentry_state_t by reference ira.weiny
2020-10-16 11:45 ` Peter Zijlstra
2020-10-16 12:55 ` Thomas Gleixner
2020-10-19 5:37 ` Ira Weiny
2020-10-19 9:32 ` Thomas Gleixner
2020-10-19 20:26 ` Ira Weiny
2020-10-19 21:12 ` Thomas Gleixner
2020-10-20 14:10 ` Ira Weiny
2020-10-09 19:42 ` [PATCH RFC V3 7/9] x86/entry: Preserve PKRS MSR across exceptions ira.weiny
2020-10-13 18:52 ` Dave Hansen
2020-10-15 3:46 ` Ira Weiny
2020-10-15 4:06 ` Dave Hansen
2020-10-15 4:18 ` Ira Weiny [this message]
2020-10-09 19:42 ` [PATCH RFC V3 8/9] x86/fault: Report the PKRS state on fault ira.weiny
2020-10-13 18:56 ` Dave Hansen
2020-10-15 4:13 ` Ira Weiny
2020-10-09 19:42 ` [PATCH RFC V3 9/9] x86/pks: Add PKS test code ira.weiny
2020-10-13 19:02 ` Dave Hansen
2020-10-15 4:46 ` Ira Weiny
2020-10-09 20:18 ` [PATCH RFC V3 0/9] PKS: Add Protection Keys Supervisor (PKS) support RFC v3 Ira Weiny
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