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From: Ard Biesheuvel <ardb@kernel.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Ard Biesheuvel <ardb+git@google.com>,
	linux-efi@vger.kernel.org,  linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	 Will Deacon <will@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	 Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Subject: Re: [RFC PATCH 7/7] arm64/efi: Call EFI runtime services without disabling preemption
Date: Tue, 15 Jul 2025 10:46:43 +1000	[thread overview]
Message-ID: <CAMj1kXEw=RSnf_Af=+AKWmuxJ+0dL_4CFSX7TyKo+SSKpxc6Bw@mail.gmail.com> (raw)
In-Reply-To: <20250714105520.GS905792@noisy.programming.kicks-ass.net>

On Mon, 14 Jul 2025 at 20:55, Peter Zijlstra <peterz@infradead.org> wrote:
>
> On Mon, Jul 14, 2025 at 12:20:30PM +1000, Ard Biesheuvel wrote:
> > On Fri, 11 Jul 2025 at 23:48, Peter Zijlstra <peterz@infradead.org> wrote:
...
> > > Is the migrate_disable() strictly required, or just paranoia?
> > >
> >
> > Runtime services might be polling the secure firmware for an async
> > completion when they are interrupted, and so I don't think it is
> > generally safe to assume that an interrupted EFI runtime service can
> > be resumed on another CPU.
>
> Can we please get a comment with that migrate_disable() explaining this?
>

Sure


  reply	other threads:[~2025-07-15  0:49 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-05-14 17:43 [RFC PATCH 0/7] arm64: Make EFI calls preemptible Ard Biesheuvel
2025-05-14 17:43 ` [RFC PATCH 1/7] efi: Add missing static initializer for efi_mm::cpus_allowed_lock Ard Biesheuvel
2025-05-14 17:43 ` [RFC PATCH 2/7] efi/runtime: Return success/failure from arch_efi_call_virt_setup() Ard Biesheuvel
2025-05-14 17:43 ` [RFC PATCH 3/7] efi/runtime: Deal with arch_efi_call_virt_setup() returning failure Ard Biesheuvel
2025-05-14 17:43 ` [RFC PATCH 4/7] arm64/fpsimd: Don't warn when EFI execution context is preemptible Ard Biesheuvel
2025-05-14 17:43 ` [RFC PATCH 5/7] arm64/efi: Use a semaphore to protect the EFI stack and FP/SIMD state Ard Biesheuvel
2025-05-14 17:43 ` [RFC PATCH 6/7] arm64/efi: Move uaccess en/disable out of efi_set_pgd() Ard Biesheuvel
2025-07-11 13:41   ` Will Deacon
2025-07-14  6:38     ` Ard Biesheuvel
2025-05-14 17:43 ` [RFC PATCH 7/7] arm64/efi: Call EFI runtime services without disabling preemption Ard Biesheuvel
2025-07-11 13:48   ` Peter Zijlstra
2025-07-14  2:20     ` Ard Biesheuvel
2025-07-14 10:55       ` Peter Zijlstra
2025-07-15  0:46         ` Ard Biesheuvel [this message]
2025-07-11 13:44 ` [RFC PATCH 0/7] arm64: Make EFI calls preemptible Will Deacon

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