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>,
x86@kernel.org, Dave Hansen <dave.hansen@linux.intel.com>,
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 8/9] x86/fault: Report the PKRS state on fault
Date: Wed, 14 Oct 2020 21:13:16 -0700 [thread overview]
Message-ID: <20201015041316.GR2046448@iweiny-DESK2.sc.intel.com> (raw)
In-Reply-To: <d6546e84-2196-25fd-3d8d-5e65fe22a71c@intel.com>
On Tue, Oct 13, 2020 at 11:56:53AM -0700, Dave Hansen wrote:
> > @@ -548,6 +549,11 @@ show_fault_oops(struct pt_regs *regs, unsigned long error_code, unsigned long ad
> > (error_code & X86_PF_PK) ? "protection keys violation" :
> > "permissions violation");
> >
> > +#ifdef CONFIG_ARCH_HAS_SUPERVISOR_PKEYS
> > + if (irq_state && (error_code & X86_PF_PK))
> > + pr_alert("PKRS: 0x%x\n", irq_state->pkrs);
> > +#endif
>
> This means everyone will see 'PKRS: 0x0', even if they're on non-PKS
> hardware. I think I'd rather have this only show PKRS when we're on
> cpu_feature_enabled(PKS) hardware.
Good catch, thanks.
>
> ...
> > @@ -1148,14 +1156,15 @@ static int fault_in_kernel_space(unsigned long address)
> > */
> > static void
> > do_kern_addr_fault(struct pt_regs *regs, unsigned long hw_error_code,
> > - unsigned long address)
> > + unsigned long address, irqentry_state_t *irq_state)
> > {
> > /*
> > - * Protection keys exceptions only happen on user pages. We
> > - * have no user pages in the kernel portion of the address
> > - * space, so do not expect them here.
> > + * If protection keys are not enabled for kernel space
> > + * do not expect Pkey errors here.
> > */
>
> Let's fix the double-negative:
>
> /*
> * PF_PK is only expected on kernel addresses whenn
> * supervisor pkeys are enabled:
> */
done. thanks.
>
> > - WARN_ON_ONCE(hw_error_code & X86_PF_PK);
> > + if (!IS_ENABLED(CONFIG_ARCH_HAS_SUPERVISOR_PKEYS) ||
> > + !cpu_feature_enabled(X86_FEATURE_PKS))
> > + WARN_ON_ONCE(hw_error_code & X86_PF_PK);
>
> Yeah, please stick X86_FEATURE_PKS in disabled-features so you can use
> cpu_feature_enabled(X86_FEATURE_PKS) by itself here..
done.
thanks,
Ira
next prev parent reply other threads:[~2020-10-15 4:13 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
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 [this message]
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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