From: Russell King - ARM Linux admin <linux@armlinux.org.uk>
To: David Brazdil <dbrazdil@google.com>
Cc: kvmarm@lists.cs.columbia.edu, Mark Rutland <mark.rutland@arm.com>,
Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Marc Zyngier <maz@kernel.org>,
Sudeep Holla <sudeep.holla@arm.com>,
linux-kernel@vger.kernel.org, James Morse <james.morse@arm.com>,
linux-arm-kernel@lists.infradead.org,
Catalin Marinas <catalin.marinas@arm.com>,
kernel-team@android.com, Will Deacon <will@kernel.org>,
Julien Thierry <julien.thierry.kdev@gmail.com>
Subject: Re: [PATCH] KVM: arm64: Allow PSCI SYSTEM_OFF/RESET to return
Date: Tue, 29 Dec 2020 17:04:12 +0000 [thread overview]
Message-ID: <20201229170412.GN1551@shell.armlinux.org.uk> (raw)
In-Reply-To: <20201229160059.64135-1-dbrazdil@google.com>
On Tue, Dec 29, 2020 at 04:00:59PM +0000, David Brazdil wrote:
> The KVM/arm64 PSCI relay assumes that SYSTEM_OFF and SYSTEM_RESET should
> not return, as dictated by the PSCI spec. However, there is firmware out
> there which breaks this assumption, leading to a hyp panic. Make KVM
> more robust to broken firmware by allowing these to return.
Are you sure you should just return?
We've had issues in the past with Linux reboot(2) that returns
to userspace, allowing on 32-bit ARM for example watchdogs to
unexpectedly continue being serviced.
--
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!
WARNING: multiple messages have this Message-ID (diff)
From: Russell King - ARM Linux admin <linux@armlinux.org.uk>
To: David Brazdil <dbrazdil@google.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>, Marc Zyngier <maz@kernel.org>,
linux-kernel@vger.kernel.org, Sudeep Holla <sudeep.holla@arm.com>,
kernel-team@android.com, kvmarm@lists.cs.columbia.edu,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] KVM: arm64: Allow PSCI SYSTEM_OFF/RESET to return
Date: Tue, 29 Dec 2020 17:04:12 +0000 [thread overview]
Message-ID: <20201229170412.GN1551@shell.armlinux.org.uk> (raw)
In-Reply-To: <20201229160059.64135-1-dbrazdil@google.com>
On Tue, Dec 29, 2020 at 04:00:59PM +0000, David Brazdil wrote:
> The KVM/arm64 PSCI relay assumes that SYSTEM_OFF and SYSTEM_RESET should
> not return, as dictated by the PSCI spec. However, there is firmware out
> there which breaks this assumption, leading to a hyp panic. Make KVM
> more robust to broken firmware by allowing these to return.
Are you sure you should just return?
We've had issues in the past with Linux reboot(2) that returns
to userspace, allowing on 32-bit ARM for example watchdogs to
unexpectedly continue being serviced.
--
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!
_______________________________________________
kvmarm mailing list
kvmarm@lists.cs.columbia.edu
https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
WARNING: multiple messages have this Message-ID (diff)
From: Russell King - ARM Linux admin <linux@armlinux.org.uk>
To: David Brazdil <dbrazdil@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>,
Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Marc Zyngier <maz@kernel.org>,
linux-kernel@vger.kernel.org, James Morse <james.morse@arm.com>,
Julien Thierry <julien.thierry.kdev@gmail.com>,
Sudeep Holla <sudeep.holla@arm.com>,
kernel-team@android.com, kvmarm@lists.cs.columbia.edu,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] KVM: arm64: Allow PSCI SYSTEM_OFF/RESET to return
Date: Tue, 29 Dec 2020 17:04:12 +0000 [thread overview]
Message-ID: <20201229170412.GN1551@shell.armlinux.org.uk> (raw)
In-Reply-To: <20201229160059.64135-1-dbrazdil@google.com>
On Tue, Dec 29, 2020 at 04:00:59PM +0000, David Brazdil wrote:
> The KVM/arm64 PSCI relay assumes that SYSTEM_OFF and SYSTEM_RESET should
> not return, as dictated by the PSCI spec. However, there is firmware out
> there which breaks this assumption, leading to a hyp panic. Make KVM
> more robust to broken firmware by allowing these to return.
Are you sure you should just return?
We've had issues in the past with Linux reboot(2) that returns
to userspace, allowing on 32-bit ARM for example watchdogs to
unexpectedly continue being serviced.
--
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2020-12-29 17:05 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-29 16:00 [PATCH] KVM: arm64: Allow PSCI SYSTEM_OFF/RESET to return David Brazdil
2020-12-29 16:00 ` David Brazdil
2020-12-29 16:00 ` David Brazdil
2020-12-29 17:04 ` Russell King - ARM Linux admin [this message]
2020-12-29 17:04 ` Russell King - ARM Linux admin
2020-12-29 17:04 ` Russell King - ARM Linux admin
2020-12-30 10:06 ` Marc Zyngier
2020-12-30 10:06 ` Marc Zyngier
2020-12-30 10:06 ` Marc Zyngier
2020-12-29 17:16 ` Marc Zyngier
2020-12-29 17:16 ` Marc Zyngier
2020-12-29 17:16 ` Marc Zyngier
2020-12-30 11:03 ` David Brazdil
2020-12-30 11:03 ` David Brazdil
2020-12-30 11:03 ` David Brazdil
2021-01-15 11:33 ` Marc Zyngier
2021-01-15 11:33 ` Marc Zyngier
2021-01-15 11:33 ` Marc Zyngier
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