From: Peter Zijlstra <peterz@infradead.org>
To: Fenghua Yu <fenghua.yu@intel.com>
Cc: Ravi V Shankar <ravi.v.shankar@intel.com>,
Tony Luck <tony.luck@intel.com>,
Dave Jiang <dave.jiang@intel.com>,
Ashok Raj <ashok.raj@intel.com>, x86 <x86@kernel.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
Dave Hansen <dave.hansen@intel.com>,
iommu@lists.linux-foundation.org, Ingo Molnar <mingo@redhat.com>,
Borislav Petkov <bp@alien8.de>,
Jacob Jun Pan <jacob.jun.pan@intel.com>,
Andy Lutomirski <luto@kernel.org>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH 4/8] x86/traps: Demand-populate PASID MSR via #GP
Date: Wed, 22 Sep 2021 23:11:45 +0200 [thread overview]
Message-ID: <20210922211145.GF5106@worktop.programming.kicks-ass.net> (raw)
In-Reply-To: <20210922210722.GV4323@worktop.programming.kicks-ass.net>
On Wed, Sep 22, 2021 at 11:07:22PM +0200, Peter Zijlstra wrote:
> On Mon, Sep 20, 2021 at 07:23:45PM +0000, Fenghua Yu wrote:
> > diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
> > index a58800973aed..a25d738ae839 100644
> > --- a/arch/x86/kernel/traps.c
> > +++ b/arch/x86/kernel/traps.c
> > @@ -61,6 +61,7 @@
> > #include <asm/insn.h>
> > #include <asm/insn-eval.h>
> > #include <asm/vdso.h>
> > +#include <asm/iommu.h>
> >
> > #ifdef CONFIG_X86_64
> > #include <asm/x86_init.h>
> > @@ -526,6 +527,14 @@ static enum kernel_gp_hint get_kernel_gp_address(struct pt_regs *regs,
> > return GP_CANONICAL;
> > }
> >
> > +static bool fixup_pasid_exception(void)
> > +{
> > + if (!cpu_feature_enabled(X86_FEATURE_ENQCMD))
> > + return false;
> > +
> > + return __fixup_pasid_exception();
> > +}
That is, shouldn't the above at the very least decode the instruction
causing the #GP and check it's this ENQCMD thing?
> > #define GPFSTR "general protection fault"
> >
> > DEFINE_IDTENTRY_ERRORCODE(exc_general_protection)
> > @@ -538,6 +547,9 @@ DEFINE_IDTENTRY_ERRORCODE(exc_general_protection)
> >
> > cond_local_irq_enable(regs);
> >
> > + if (user_mode(regs) && fixup_pasid_exception())
> > + goto exit;
> > +
> > if (static_cpu_has(X86_FEATURE_UMIP)) {
> > if (user_mode(regs) && fixup_umip_exception(regs))
> > goto exit;
>
> So you're eating any random #GP that might or might not be PASID
> related. And all that witout a comment... Enlighten?
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next prev parent reply other threads:[~2021-09-22 21:13 UTC|newest]
Thread overview: 77+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-20 19:23 [PATCH 0/8] Re-enable ENQCMD and PASID MSR Fenghua Yu
2021-09-20 19:23 ` [PATCH 1/8] iommu/vt-d: Clean up unused PASID updating functions Fenghua Yu
2021-09-29 7:34 ` Lu Baolu
2021-09-30 0:40 ` Fenghua Yu
2021-09-20 19:23 ` [PATCH 2/8] x86/process: Clear PASID state for a newly forked/cloned thread Fenghua Yu
2021-09-20 19:23 ` [PATCH 3/8] sched: Define and initialize a flag to identify valid PASID in the task Fenghua Yu
2021-09-20 19:23 ` [PATCH 4/8] x86/traps: Demand-populate PASID MSR via #GP Fenghua Yu
2021-09-22 21:07 ` Peter Zijlstra
2021-09-22 21:11 ` Peter Zijlstra [this message]
2021-09-22 21:26 ` Luck, Tony
2021-09-23 7:03 ` Peter Zijlstra
2021-09-22 21:33 ` Dave Hansen
2021-09-23 7:05 ` Peter Zijlstra
2021-09-22 21:36 ` Fenghua Yu
2021-09-22 23:39 ` Fenghua Yu
2021-09-23 17:14 ` Luck, Tony
2021-09-24 13:37 ` Peter Zijlstra
2021-09-24 15:39 ` Luck, Tony
2021-09-29 9:00 ` Peter Zijlstra
2021-09-23 11:31 ` Thomas Gleixner
2021-09-23 23:17 ` Andy Lutomirski
2021-09-24 2:56 ` Fenghua Yu
2021-09-24 5:12 ` Andy Lutomirski
2021-09-27 21:02 ` Luck, Tony
2021-09-27 23:51 ` Dave Hansen
2021-09-28 18:50 ` Luck, Tony
2021-09-28 19:19 ` Dave Hansen
2021-09-28 20:28 ` Luck, Tony
2021-09-28 20:55 ` Dave Hansen
2021-09-28 23:10 ` Luck, Tony
2021-09-28 23:50 ` Fenghua Yu
2021-09-29 0:08 ` Luck, Tony
2021-09-29 0:26 ` Yu, Fenghua
2021-09-29 1:06 ` Luck, Tony
2021-09-29 1:16 ` Fenghua Yu
2021-09-29 2:11 ` Luck, Tony
2021-09-29 1:56 ` Yu, Fenghua
2021-09-29 2:15 ` Luck, Tony
2021-09-29 16:58 ` Andy Lutomirski
2021-09-29 17:07 ` Luck, Tony
2021-09-29 17:48 ` Andy Lutomirski
2021-09-20 19:23 ` [PATCH 5/8] x86/mmu: Add mm-based PASID refcounting Fenghua Yu
2021-09-23 5:43 ` Lu Baolu
2021-09-30 0:44 ` Fenghua Yu
2021-09-23 14:36 ` Thomas Gleixner
2021-09-23 16:40 ` Luck, Tony
2021-09-23 17:48 ` Thomas Gleixner
2021-09-24 13:18 ` Thomas Gleixner
2021-09-24 16:12 ` Luck, Tony
2021-09-24 23:03 ` Andy Lutomirski
2021-09-24 23:11 ` Luck, Tony
2021-09-29 9:54 ` Peter Zijlstra
2021-09-29 12:28 ` Thomas Gleixner
2021-09-29 16:51 ` Luck, Tony
2021-09-29 17:07 ` Fenghua Yu
2021-09-29 16:59 ` Andy Lutomirski
2021-09-29 17:15 ` Thomas Gleixner
2021-09-29 17:41 ` Luck, Tony
2021-09-29 17:46 ` Andy Lutomirski
2021-09-29 18:07 ` Fenghua Yu
2021-09-29 18:31 ` Luck, Tony
2021-09-29 20:07 ` Thomas Gleixner
2021-09-24 16:12 ` Fenghua Yu
2021-09-25 23:13 ` Thomas Gleixner
2021-09-28 16:36 ` Fenghua Yu
2021-09-23 23:09 ` Andy Lutomirski
2021-09-23 23:22 ` Luck, Tony
2021-09-24 5:17 ` Andy Lutomirski
2021-09-20 19:23 ` [PATCH 6/8] x86/cpufeatures: Re-enable ENQCMD Fenghua Yu
2021-09-20 19:23 ` [PATCH 7/8] tools/objtool: Check for use of the ENQCMD instruction in the kernel Fenghua Yu
2021-09-22 21:03 ` Peter Zijlstra
2021-09-22 23:44 ` Fenghua Yu
2021-09-23 7:17 ` Peter Zijlstra
2021-09-23 15:26 ` Fenghua Yu
2021-09-24 0:55 ` Josh Poimboeuf
2021-09-24 0:57 ` Fenghua Yu
2021-09-20 19:23 ` [PATCH 8/8] docs: x86: Change documentation for SVA (Shared Virtual Addressing) Fenghua Yu
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