From: Marc Zyngier <maz@kernel.org>
To: linux-arm-kernel@lists.infradead.org,
kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org
Cc: Will Deacon <will@kernel.org>, James Morse <james.morse@arm.com>,
Julien Thierry <julien.thierry.kdev@gmail.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
David Brazdil <dbarzdil@google.com>,
kernel-team@android.com
Subject: [PATCH v2 0/2] KVM: arm64: Expose CSV3 to guests on running on Meltdown-safe HW
Date: Fri, 4 Dec 2020 18:37:07 +0000 [thread overview]
Message-ID: <20201204183709.784533-1-maz@kernel.org> (raw)
Will recently pointed out that when running on big-little systems that
are known not to be vulnerable to Metldown, guests are not presented
with the CSV3 property if the physical HW include a core that doesn't
have CSV3, despite being known to be safe (it is on the kpti_safe_list).
Since this is valuable information that can be cheaply given to the
guest, let's just do that. The scheme is the same as what we do for
CSV2, allowing userspace to change the default setting if this doesn't
advertise a safer setting than what the kernel thinks it is.
* From v1:
- Fix the clearing of ID_AA64PFR0_EL1.CSV3 on update from userspace
- Actually store the userspace value
Marc Zyngier (2):
arm64: Make the Meltdown mitigation state available
KVM: arm64: Advertise ID_AA64PFR0_EL1.CSV3=1 if the CPUs are
Meltdown-safe
arch/arm64/include/asm/kvm_host.h | 1 +
arch/arm64/include/asm/spectre.h | 2 ++
arch/arm64/kernel/cpufeature.c | 20 +++++++++++++++++---
arch/arm64/kvm/arm.c | 6 ++++--
arch/arm64/kvm/sys_regs.c | 16 +++++++++++++---
5 files changed, 37 insertions(+), 8 deletions(-)
--
2.28.0
WARNING: multiple messages have this Message-ID (diff)
From: Marc Zyngier <maz@kernel.org>
To: linux-arm-kernel@lists.infradead.org,
kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org
Cc: Will Deacon <will@kernel.org>,
David Brazdil <dbarzdil@google.com>,
kernel-team@android.com
Subject: [PATCH v2 0/2] KVM: arm64: Expose CSV3 to guests on running on Meltdown-safe HW
Date: Fri, 4 Dec 2020 18:37:07 +0000 [thread overview]
Message-ID: <20201204183709.784533-1-maz@kernel.org> (raw)
Will recently pointed out that when running on big-little systems that
are known not to be vulnerable to Metldown, guests are not presented
with the CSV3 property if the physical HW include a core that doesn't
have CSV3, despite being known to be safe (it is on the kpti_safe_list).
Since this is valuable information that can be cheaply given to the
guest, let's just do that. The scheme is the same as what we do for
CSV2, allowing userspace to change the default setting if this doesn't
advertise a safer setting than what the kernel thinks it is.
* From v1:
- Fix the clearing of ID_AA64PFR0_EL1.CSV3 on update from userspace
- Actually store the userspace value
Marc Zyngier (2):
arm64: Make the Meltdown mitigation state available
KVM: arm64: Advertise ID_AA64PFR0_EL1.CSV3=1 if the CPUs are
Meltdown-safe
arch/arm64/include/asm/kvm_host.h | 1 +
arch/arm64/include/asm/spectre.h | 2 ++
arch/arm64/kernel/cpufeature.c | 20 +++++++++++++++++---
arch/arm64/kvm/arm.c | 6 ++++--
arch/arm64/kvm/sys_regs.c | 16 +++++++++++++---
5 files changed, 37 insertions(+), 8 deletions(-)
--
2.28.0
_______________________________________________
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: Marc Zyngier <maz@kernel.org>
To: linux-arm-kernel@lists.infradead.org,
kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>,
Will Deacon <will@kernel.org>,
David Brazdil <dbarzdil@google.com>,
James Morse <james.morse@arm.com>,
kernel-team@android.com,
Julien Thierry <julien.thierry.kdev@gmail.com>
Subject: [PATCH v2 0/2] KVM: arm64: Expose CSV3 to guests on running on Meltdown-safe HW
Date: Fri, 4 Dec 2020 18:37:07 +0000 [thread overview]
Message-ID: <20201204183709.784533-1-maz@kernel.org> (raw)
Will recently pointed out that when running on big-little systems that
are known not to be vulnerable to Metldown, guests are not presented
with the CSV3 property if the physical HW include a core that doesn't
have CSV3, despite being known to be safe (it is on the kpti_safe_list).
Since this is valuable information that can be cheaply given to the
guest, let's just do that. The scheme is the same as what we do for
CSV2, allowing userspace to change the default setting if this doesn't
advertise a safer setting than what the kernel thinks it is.
* From v1:
- Fix the clearing of ID_AA64PFR0_EL1.CSV3 on update from userspace
- Actually store the userspace value
Marc Zyngier (2):
arm64: Make the Meltdown mitigation state available
KVM: arm64: Advertise ID_AA64PFR0_EL1.CSV3=1 if the CPUs are
Meltdown-safe
arch/arm64/include/asm/kvm_host.h | 1 +
arch/arm64/include/asm/spectre.h | 2 ++
arch/arm64/kernel/cpufeature.c | 20 +++++++++++++++++---
arch/arm64/kvm/arm.c | 6 ++++--
arch/arm64/kvm/sys_regs.c | 16 +++++++++++++---
5 files changed, 37 insertions(+), 8 deletions(-)
--
2.28.0
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next reply other threads:[~2020-12-04 18:38 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-04 18:37 Marc Zyngier [this message]
2020-12-04 18:37 ` [PATCH v2 0/2] KVM: arm64: Expose CSV3 to guests on running on Meltdown-safe HW Marc Zyngier
2020-12-04 18:37 ` Marc Zyngier
2020-12-04 18:37 ` [PATCH v2 1/2] arm64: Make the Meltdown mitigation state available Marc Zyngier
2020-12-04 18:37 ` Marc Zyngier
2020-12-04 18:37 ` Marc Zyngier
2020-12-04 18:37 ` [PATCH v2 2/2] KVM: arm64: Advertise ID_AA64PFR0_EL1.CSV3=1 if the CPUs are Meltdown-safe Marc Zyngier
2020-12-04 18:37 ` Marc Zyngier
2020-12-04 18:37 ` Marc Zyngier
2020-12-10 13:53 ` [PATCH v2 0/2] KVM: arm64: Expose CSV3 to guests on running on Meltdown-safe HW Will Deacon
2020-12-10 13:53 ` Will Deacon
2020-12-10 13:53 ` Will Deacon
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