From: Paolo Bonzini <pbonzini@redhat.com>
To: Mark Rutland <mark.rutland@arm.com>,
Nicolas Saenz Julienne <nsaenzju@redhat.com>
Cc: paulmck <paulmck@kernel.org>, maz <maz@kernel.org>,
frederic <frederic@kernel.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
rcu <rcu@vger.kernel.org>, Thomas Gleixner <tglx@linutronix.de>,
Will Deacon <will@kernel.org>,
kvmarm@lists.cs.columbia.edu,
linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
"kvm-riscv@lists.infradead.org" <kvm-riscv@lists.infradead.org>,
Anup Patel <Anup.Patel@wdc.com>
Subject: Re: Possible nohz-full/RCU issue in arm64 KVM
Date: Fri, 17 Dec 2021 15:51:14 +0100 [thread overview]
Message-ID: <ada9b2aa-f1e7-d566-0384-002890441a30@redhat.com> (raw)
In-Reply-To: <YbyO40zDW/kvUHEE@FVFF77S0Q05N>
On 12/17/21 14:21, Mark Rutland wrote:
> I'm not immediately sure what we*should* do here. What does x86 do for an IRQ
> taken from a guest mode? I couldn't spot any handling of that case, but I'm not
> familiar enough with the x86 exception model to know if I'm looking in the
> right place.
ARM is missing something like commit 160457140187 ("KVM: x86: Defer
vtime accounting 'til after IRQ handling", 2021-05-05).
With that change, it would be possible to move guest_exit() in the
irq-disabled region without breaking time accounting.
RISC-V has the same issue and it would be fixed in the same way, so
let's Cc Anup too.
Paolo
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next prev parent reply other threads:[~2021-12-17 14:52 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-17 11:51 Possible nohz-full/RCU issue in arm64 KVM Nicolas Saenz Julienne
2021-12-17 13:21 ` Mark Rutland
2021-12-17 14:15 ` Nicolas Saenz Julienne
2021-12-17 14:38 ` Mark Rutland
2021-12-17 15:54 ` Paolo Bonzini
2021-12-17 16:07 ` Paul E. McKenney
2021-12-17 16:20 ` Nicolas Saenz Julienne
2021-12-17 16:43 ` Paul E. McKenney
2021-12-17 16:34 ` Paolo Bonzini
2021-12-17 16:45 ` Paul E. McKenney
2021-12-17 17:02 ` Paolo Bonzini
2021-12-17 17:12 ` Paul E. McKenney
2021-12-17 17:23 ` Paolo Bonzini
2021-12-17 17:47 ` Paul E. McKenney
2022-01-04 16:39 ` Mark Rutland
2022-01-04 17:07 ` Paolo Bonzini
2022-01-11 11:32 ` Nicolas Saenz Julienne
2022-01-11 12:23 ` Mark Rutland
2021-12-17 14:51 ` Paolo Bonzini [this message]
2021-12-20 14:28 ` Marc Zyngier
2021-12-20 16:10 ` Frederic Weisbecker
2022-01-04 13:24 ` Mark Rutland
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