From: Catalin Marinas <catalin.marinas@arm.com>
To: Marc Zyngier <maz@kernel.org>
Cc: kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org,
Steffen Eiden <seiden@linux.ibm.com>,
Joey Gouly <joey.gouly@arm.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Oliver Upton <oupton@kernel.org>,
Zenghui Yu <yuzenghui@huawei.com>,
Fuad Tabba <fuad.tabba@linux.dev>, Will Deacon <will@kernel.org>,
Mark Rutland <mark.rutland@arm.com>
Subject: Re: [PATCH 0/2] KVM: arm64: Reenable MTE on VHE guest exit
Date: Tue, 27 Oct 2026 17:29:43 +0000 [thread overview]
Message-ID: <auDfhwB0oWFreEY2@arm.com> (raw)
In-Reply-To: <20261026082305.2515705-1-maz@kernel.org>
On Mon, Oct 26, 2026 at 08:23:03AM +0000, Marc Zyngier wrote:
> Upton taking an exception, the CPU sets PSTATE.TCO to ensure that no
> tag fault can be taken while handling the exception. It is SW's job to
> eventually clear it when it is safe to do so.
>
> It appears that when MTE is enabled and that the kernel is running
> VHE, nothing eventually clears TCO when we come back from the guest,
> so things such as KASAN_HW_TAGS will not work until the next exit to
> userspace.
>
> This series aims at fixing this. This is not a stable candidate, as
> KASAN is only a debug option.
>
> Marc Zyngier (2):
> arm64: Add return value to mte_disable_tco_entry()
> KVM: arm64: Reenable MTE tag checking on exit from guest when running
> VHE
>
> arch/arm64/include/asm/mte.h | 10 +++++++---
> arch/arm64/kvm/hyp/vhe/switch.c | 7 +++++++
> 2 files changed, 14 insertions(+), 3 deletions(-)
For both patches:
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
prev parent reply other threads:[~2026-10-27 17:29 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-26 8:23 [PATCH 0/2] KVM: arm64: Reenable MTE on VHE guest exit Marc Zyngier
2026-10-26 8:23 ` [PATCH 1/2] arm64: Add return value to mte_disable_tco_entry() Marc Zyngier
2026-10-26 8:23 ` [PATCH 2/2] KVM: arm64: Reenable MTE tag checking on exit from guest when running VHE Marc Zyngier
2026-10-26 14:06 ` [PATCH 0/2] KVM: arm64: Reenable MTE on VHE guest exit Fuad Tabba
2026-10-27 17:29 ` Catalin Marinas [this message]
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