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From: Will Deacon <will@kernel.org>
To: linux-arm-kernel@lists.infradead.org
Cc: Marc Zyngier <maz@kernel.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>,
	kvmarm@lists.cs.columbia.edu
Subject: [PATCH 1/5] arm64: Prevent kexec and hibernation if is_protected_kvm_enabled()
Date: Thu, 23 Sep 2021 12:22:52 +0100	[thread overview]
Message-ID: <20210923112256.15767-2-will@kernel.org> (raw)
In-Reply-To: <20210923112256.15767-1-will@kernel.org>

When pKVM is enabled, the hypervisor code at EL2 and its data structures
are inaccessible to the host kernel and cannot be torn down or replaced
as this would defeat the integrity properies which pKVM aims to provide.
Furthermore, the ABI between the host and EL2 is flexible and private to
whatever the current implementation of KVM requires and so booting a new
kernel with an old EL2 component is very likely to end in disaster.

In preparation for uninstalling the hyp stub calls which are relied upon
to reset EL2, disable kexec and hibernation in the host when protected
KVM is enabled.

Cc: Marc Zyngier <maz@kernel.org>
Cc: Quentin Perret <qperret@google.com>
Signed-off-by: Will Deacon <will@kernel.org>
---
 arch/arm64/kernel/smp.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index 6f6ff072acbd..44369b99a57e 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -1128,5 +1128,6 @@ bool cpus_are_stuck_in_kernel(void)
 {
 	bool smp_spin_tables = (num_possible_cpus() > 1 && !have_cpu_die());
 
-	return !!cpus_stuck_in_kernel || smp_spin_tables;
+	return !!cpus_stuck_in_kernel || smp_spin_tables ||
+		is_protected_kvm_enabled();
 }
-- 
2.33.0.464.g1972c5931b-goog

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kvmarm@lists.cs.columbia.edu
https://lists.cs.columbia.edu/mailman/listinfo/kvmarm

WARNING: multiple messages have this Message-ID (diff)
From: Will Deacon <will@kernel.org>
To: linux-arm-kernel@lists.infradead.org
Cc: Will Deacon <will@kernel.org>, Marc Zyngier <maz@kernel.org>,
	Quentin Perret <qperret@google.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Alexandru Elisei <alexandru.elisei@arm.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	kvmarm@lists.cs.columbia.edu
Subject: [PATCH 1/5] arm64: Prevent kexec and hibernation if is_protected_kvm_enabled()
Date: Thu, 23 Sep 2021 12:22:52 +0100	[thread overview]
Message-ID: <20210923112256.15767-2-will@kernel.org> (raw)
In-Reply-To: <20210923112256.15767-1-will@kernel.org>

When pKVM is enabled, the hypervisor code at EL2 and its data structures
are inaccessible to the host kernel and cannot be torn down or replaced
as this would defeat the integrity properies which pKVM aims to provide.
Furthermore, the ABI between the host and EL2 is flexible and private to
whatever the current implementation of KVM requires and so booting a new
kernel with an old EL2 component is very likely to end in disaster.

In preparation for uninstalling the hyp stub calls which are relied upon
to reset EL2, disable kexec and hibernation in the host when protected
KVM is enabled.

Cc: Marc Zyngier <maz@kernel.org>
Cc: Quentin Perret <qperret@google.com>
Signed-off-by: Will Deacon <will@kernel.org>
---
 arch/arm64/kernel/smp.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index 6f6ff072acbd..44369b99a57e 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -1128,5 +1128,6 @@ bool cpus_are_stuck_in_kernel(void)
 {
 	bool smp_spin_tables = (num_possible_cpus() > 1 && !have_cpu_die());
 
-	return !!cpus_stuck_in_kernel || smp_spin_tables;
+	return !!cpus_stuck_in_kernel || smp_spin_tables ||
+		is_protected_kvm_enabled();
 }
-- 
2.33.0.464.g1972c5931b-goog


_______________________________________________
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linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  reply	other threads:[~2021-09-23 11:23 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-23 11:22 [PATCH 0/5] KVM: arm64: Restrict host hypercalls when pKVM is enabled Will Deacon
2021-09-23 11:22 ` Will Deacon
2021-09-23 11:22 ` Will Deacon [this message]
2021-09-23 11:22   ` [PATCH 1/5] arm64: Prevent kexec and hibernation if is_protected_kvm_enabled() Will Deacon
2021-09-23 11:45   ` Mark Rutland
2021-09-23 11:45     ` Mark Rutland
2021-09-23 12:29     ` Will Deacon
2021-09-23 12:29       ` Will Deacon
2021-09-23 11:22 ` [PATCH 2/5] KVM: arm64: Reject stub hypercalls after pKVM has been initialised Will Deacon
2021-09-23 11:22   ` Will Deacon
2021-09-29 13:37   ` Quentin Perret
2021-09-29 13:37     ` Quentin Perret
2021-09-23 11:22 ` [PATCH 3/5] KVM: arm64: Propagate errors from __pkvm_prot_finalize hypercall Will Deacon
2021-09-23 11:22   ` Will Deacon
2021-09-29 13:36   ` Quentin Perret
2021-09-29 13:36     ` Quentin Perret
2021-10-05 11:30     ` Will Deacon
2021-10-05 11:30       ` Will Deacon
2021-09-23 11:22 ` [PATCH 4/5] KVM: arm64: Prevent re-finalisation of pKVM for a given CPU Will Deacon
2021-09-23 11:22   ` Will Deacon
2021-09-29 13:41   ` Quentin Perret
2021-09-29 13:41     ` Quentin Perret
2021-09-23 11:22 ` [PATCH 5/5] KVM: arm64: Disable privileged hypercalls after pKVM finalisation Will Deacon
2021-09-23 11:22   ` Will Deacon
2021-09-23 12:56   ` Marc Zyngier
2021-09-23 12:56     ` Marc Zyngier
2021-09-23 13:02     ` Will Deacon
2021-09-23 13:02       ` Will Deacon
2021-09-23 13:11       ` Marc Zyngier
2021-09-23 13:11         ` Marc Zyngier
2021-09-23 12:58   ` Will Deacon
2021-09-23 12:58     ` Will Deacon
2021-09-23 12:21 ` [PATCH 0/5] KVM: arm64: Restrict host hypercalls when pKVM is enabled Marc Zyngier
2021-09-23 12:21   ` Marc Zyngier

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