From: Ira Weiny <ira.weiny@intel.com> To: Thomas Gleixner <tglx@linutronix.de> Cc: Dave Hansen <dave.hansen@linux.intel.com>, Dan Williams <dan.j.williams@intel.com>, Peter Zijlstra <peterz@infradead.org>, Andy Lutomirski <luto@kernel.org>, Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>, "H. Peter Anvin" <hpa@zytor.com>, Fenghua Yu <fenghua.yu@intel.com>, Rick Edgecombe <rick.p.edgecombe@intel.com>, x86@kernel.org, linux-kernel@vger.kernel.org, nvdimm@lists.linux.dev, linux-mm@kvack.org Subject: Re: [PATCH V7 08/18] x86/entry: Preserve PKRS MSR across exceptions Date: Mon, 6 Dec 2021 20:45:22 -0800 [thread overview] Message-ID: <20211207044522.GE3538886@iweiny-DESK2.sc.intel.com> (raw) In-Reply-To: <20211207015423.GA4012679@iweiny-DESK2.sc.intel.com> On Mon, Dec 06, 2021 at 05:54:23PM -0800, 'Ira Weiny' wrote: [snip] > > > > Though, if you look at the xen_pv_evtchn_do_upcall() part where you > > added this extra invocation you might figure out that adding > > pkrs_restore_irq() to irqentry_exit_cond_resched() and explicitely to > > the 'else' path in irqentry_exit() makes it magically consistent for > > both use cases. > > > > Thank you, yes good catch. However, I think I need at least 1 more call in the > !regs_irqs_disabled() && state.exit_rcu case right? > > 11:29:48 > git di > diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c > index 717091910ebc..667676ebc129 100644 > --- a/arch/x86/entry/common.c > +++ b/arch/x86/entry/common.c > @@ -363,8 +363,6 @@ __visible noinstr void xen_pv_evtchn_do_upcall(struct pt_regs *regs) > > inhcall = get_and_clear_inhcall(); > if (inhcall && !WARN_ON_ONCE(state.exit_rcu)) { > - /* Normally called by irqentry_exit, restore pkrs here */ > - pkrs_restore_irq(regs); > irqentry_exit_cond_resched(); > instrumentation_end(); > restore_inhcall(inhcall); > diff --git a/kernel/entry/common.c b/kernel/entry/common.c > index 1c0a70a17e93..60ae3d4c9cc0 100644 > --- a/kernel/entry/common.c > +++ b/kernel/entry/common.c > @@ -385,6 +385,7 @@ noinstr irqentry_state_t irqentry_enter(struct pt_regs *regs) > > void irqentry_exit_cond_resched(void) Opps... Of course regs will need to be passed in here now... Ira > { > + pkrs_restore_irq(regs); > if (!preempt_count()) { > /* Sanity check RCU and thread stack */ > rcu_irq_exit_check_preempt(); > @@ -408,8 +409,6 @@ noinstr void irqentry_exit(struct pt_regs *regs, irqentry_state_t state) > return; > } > > - pkrs_restore_irq(regs); > - > if (!regs_irqs_disabled(regs)) { > /* > * If RCU was not watching on entry this needs to be done > @@ -421,6 +420,7 @@ noinstr void irqentry_exit(struct pt_regs *regs, irqentry_state_t state) > /* Tell the tracer that IRET will enable interrupts */ > trace_hardirqs_on_prepare(); > lockdep_hardirqs_on_prepare(CALLER_ADDR0); > + pkrs_restore_irq(regs); > instrumentation_end(); > rcu_irq_exit(); > lockdep_hardirqs_on(CALLER_ADDR0); > @@ -439,6 +439,10 @@ noinstr void irqentry_exit(struct pt_regs *regs, irqentry_state_t state) > trace_hardirqs_on(); > instrumentation_end(); > } else { > + instrumentation_begin(); > + pkrs_restore_irq(regs); > + instrumentation_end(); > + > /* > * IRQ flags state is correct already. Just tell RCU if it > * was not watching on entry. > @@ -470,8 +474,8 @@ irqentry_state_t noinstr irqentry_nmi_enter(struct pt_regs *regs) > > void noinstr irqentry_nmi_exit(struct pt_regs *regs, irqentry_state_t irq_state) > { > - pkrs_restore_irq(regs); > instrumentation_begin(); > + pkrs_restore_irq(regs); > ftrace_nmi_exit(); > if (irq_state.lockdep) { > trace_hardirqs_on_prepare(); > > > Thank you again for the review, > Ira > > > [0] https://lore.kernel.org/lkml/20210804043231.2655537-5-ira.weiny@intel.com/ > [1] https://lore.kernel.org/lkml/20201217131924.GW3040@hirez.programming.kicks-ass.net/ > [2] https://lore.kernel.org/lkml/20201216013202.GY1563847@iweiny-DESK2.sc.intel.com/ > [3] https://lore.kernel.org/lkml/87y2hwqwng.fsf@nanos.tec.linutronix.de/ > > > Thanks, > > > > tglx
next prev parent reply other threads:[~2021-12-07 4:45 UTC|newest] Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-08-04 4:32 [PATCH V7 00/18] PKS/PMEM: Add Stray Write Protection ira.weiny 2021-08-04 4:32 ` [PATCH V7 01/18] x86/pkeys: Create pkeys_common.h ira.weiny 2021-08-04 4:32 ` [PATCH V7 02/18] x86/fpu: Refactor arch_set_user_pkey_access() ira.weiny 2021-11-25 14:23 ` Thomas Gleixner 2021-08-04 4:32 ` [PATCH V7 03/18] x86/pks: Add additional PKEY helper macros ira.weiny 2021-11-25 14:25 ` Thomas Gleixner 2021-11-25 16:58 ` Thomas Gleixner 2021-12-08 0:51 ` Ira Weiny 2021-12-08 15:11 ` Thomas Gleixner 2021-08-04 4:32 ` [PATCH V7 04/18] x86/pks: Add PKS defines and Kconfig options ira.weiny 2021-08-04 4:32 ` [PATCH V7 05/18] x86/pks: Add PKS setup code ira.weiny 2021-11-25 15:15 ` Thomas Gleixner 2021-11-26 3:11 ` taoyi.ty 2021-11-26 9:57 ` Thomas Gleixner 2021-11-26 11:03 ` Thomas Gleixner 2021-08-04 4:32 ` [PATCH V7 06/18] x86/fault: Adjust WARN_ON for PKey fault ira.weiny 2021-08-04 4:32 ` [PATCH V7 07/18] x86/pks: Preserve the PKRS MSR on context switch ira.weiny 2021-11-25 15:25 ` Thomas Gleixner 2021-08-04 4:32 ` [PATCH V7 08/18] x86/entry: Preserve PKRS MSR across exceptions ira.weiny 2021-11-13 0:50 ` Ira Weiny 2021-11-25 11:19 ` Thomas Gleixner 2021-12-03 1:13 ` Andy Lutomirski 2021-11-25 14:12 ` Thomas Gleixner 2021-12-07 1:54 ` Ira Weiny 2021-12-07 4:45 ` Ira Weiny [this message] 2021-12-08 0:21 ` Thomas Gleixner 2021-08-04 4:32 ` [PATCH V7 09/18] x86/pks: Add PKS kernel API ira.weiny 2021-08-04 4:32 ` [PATCH V7 10/18] x86/pks: Introduce pks_abandon_protections() ira.weiny 2021-08-04 4:32 ` [PATCH V7 11/18] x86/pks: Add PKS Test code ira.weiny 2021-08-04 4:32 ` [PATCH V7 12/18] x86/pks: Add PKS fault callbacks ira.weiny 2021-08-11 21:18 ` Edgecombe, Rick P 2021-08-17 3:21 ` Ira Weiny 2021-08-04 4:32 ` [PATCH V7 13/18] memremap_pages: Add access protection via supervisor Protection Keys (PKS) ira.weiny 2021-08-04 4:32 ` [PATCH V7 14/18] memremap_pages: Add memremap.pks_fault_mode ira.weiny 2021-08-04 4:57 ` Randy Dunlap 2021-08-07 19:32 ` Ira Weiny 2021-08-11 19:01 ` Edgecombe, Rick P 2021-08-17 3:12 ` Ira Weiny 2021-08-04 4:32 ` [PATCH V7 15/18] kmap: Add stray access protection for devmap pages ira.weiny 2021-08-04 4:32 ` [PATCH V7 16/18] dax: Stray access protection for dax_direct_access() ira.weiny 2021-08-04 4:32 ` [PATCH V7 17/18] nvdimm/pmem: Enable stray access protection ira.weiny 2021-08-04 4:32 ` [PATCH V7 18/18] devdax: " ira.weiny
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