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From: Rob Herring <robh@kernel.org>
To: Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>, Marc Zyngier <maz@kernel.org>
Cc: kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org
Subject: [PATCH v3 1/3] KVM: arm64: Print warning when cpu erratum can cause guests to deadlock
Date: Fri, 17 Jul 2020 14:52:31 -0600
Message-ID: <20200717205233.903344-2-robh@kernel.org> (raw)
In-Reply-To: <20200717205233.903344-1-robh@kernel.org>

If guests don't have certain CPU erratum workarounds implemented, then
there is a possibility a guest can deadlock the system. IOW, only trusted
guests should be used on systems with the erratum.

This is the case for Cortex-A57 erratum 832075.

Cc: Marc Zyngier <maz@kernel.org>
Cc: James Morse <james.morse@arm.com>
Cc: Julien Thierry <julien.thierry.kdev@gmail.com>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: kvmarm@lists.cs.columbia.edu
Signed-off-by: Rob Herring <robh@kernel.org>
---
v3:
 - s/work-arounds/workarounds/

 arch/arm64/kvm/arm.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 90cb90561446..9b070b5e212b 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -1653,6 +1653,10 @@ int kvm_arch_init(void *opaque)
 		return -ENODEV;
 	}

+	if (cpus_have_const_cap(ARM64_WORKAROUND_DEVICE_LOAD_ACQUIRE))
+		kvm_info("Guests without required CPU erratum workarounds can deadlock system!\n" \
+			 "Only trusted guests should be used on this system.\n");
+
 	for_each_online_cpu(cpu) {
 		smp_call_function_single(cpu, check_kvm_target_cpu, &ret, 1);
 		if (ret < 0) {
--
2.25.1
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Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-17 20:52 [PATCH v3 0/3] Cortex-A77 erratum 1508412 workaround Rob Herring
2020-07-17 20:52 ` Rob Herring [this message]
2020-07-17 20:52 ` [PATCH v3 2/3] arm64: Add part number for Arm Cortex-A77 Rob Herring
2020-07-17 20:52 ` [PATCH v3 3/3] arm64: Add workaround for Arm Cortex-A77 erratum 1508412 Rob Herring
2020-07-27 15:52   ` Andrew Scull
2020-07-29 16:38   ` Catalin Marinas
2020-07-30  8:22     ` Will Deacon
2020-07-31 22:55       ` Rob Herring
2020-08-03 15:03         ` Will Deacon
2020-07-31 23:21     ` Rob Herring

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