From: Marc Zyngier <maz@kernel.org>
To: Mark Brown <broonie@kernel.org>
Cc: Joey Gouly <joey.gouly@arm.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Shuah Khan <shuah@kernel.org>, Oliver Upton <oupton@kernel.org>,
Ben Horgan <ben.horgan@arm.com>,
linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev,
kvm@vger.kernel.org, linux-kselftest@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v5 4/5] KVM: selftests: arm64: Skip all 32 bit IDs when set_id_regs is aarch64 only
Date: Tue, 24 Mar 2026 16:47:15 +0000 [thread overview]
Message-ID: <86pl4t41kc.wl-maz@kernel.org> (raw)
In-Reply-To: <20260317-kvm-arm64-set-id-regs-aarch64-v5-4-a60f2b956e22@kernel.org>
On Tue, 17 Mar 2026 20:10:37 +0000,
Mark Brown <broonie@kernel.org> wrote:
>
> On an aarch64 only system the 32 bit ID registers have UNDEFINED values.
> As a result set_id_regs skips tests for setting fields in these registers
> when testing an aarch64 only guest. This has the side effect of meaning
> that we don't record an expected value for these registers, meaning that
> when the subsequent tests for values being visible in guests and preserved
> over reset check the value they can spuriously fail. This can be seen by
> running on an emulated system with both NV and 32 bit enabled, NV will
> result in the guests created by the test program being 64 bit only but
> the 32 bit ID registers will have values.
I don't think papering over this problem is the right thing to do.
If the issue is that you have HW that has both NV and AArch32, then
KVM needs to be fixed to make the 32bit IDregs RAZ when NV is present
because that's not a configuration we support.
M.
--
Without deviation from the norm, progress is not possible.
next prev parent reply other threads:[~2026-03-24 16:47 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-17 20:10 [PATCH v5 0/5] KVM: selftests: arm64: Improve diagnostics from set_id_regs Mark Brown
2026-03-17 20:10 ` [PATCH v5 1/5] KVM: selftests: arm64: Report set_id_reg reads of test registers as tests Mark Brown
2026-03-17 20:10 ` [PATCH v5 2/5] KVM: selftests: arm64: Report register reset tests individually Mark Brown
2026-03-17 20:10 ` [PATCH v5 3/5] KVM: selftests: arm64: Make set_id_regs bitfield validatity checks non-fatal Mark Brown
2026-03-17 20:10 ` [PATCH v5 4/5] KVM: selftests: arm64: Skip all 32 bit IDs when set_id_regs is aarch64 only Mark Brown
2026-03-24 16:47 ` Marc Zyngier [this message]
2026-03-24 17:39 ` Mark Brown
2026-03-17 20:10 ` [PATCH v5 5/5] KVM: selftests: arm64: Use is_aarch32_id_reg() in test_vm_ftr_id_regs() Mark Brown
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