From: Oliver Upton <oliver.upton@linux.dev>
To: Reiji Watanabe <reijiw@google.com>
Cc: Marc Zyngier <maz@kernel.org>,
kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org,
Andrew Jones <andrew.jones@linux.dev>,
Paolo Bonzini <pbonzini@redhat.com>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 1/9] KVM: arm64: selftests: Add helpers to extract a field of an ID register
Date: Thu, 25 Aug 2022 09:48:35 -0700 [thread overview]
Message-ID: <Ywen44OKe8gGcOcW@google.com> (raw)
In-Reply-To: <20220825050846.3418868-2-reijiw@google.com>
Hi Reiji,
On Wed, Aug 24, 2022 at 10:08:38PM -0700, Reiji Watanabe wrote:
> Introduce helpers to extract a field of an ID register.
> Subsequent patches will use those helpers.
>
> Signed-off-by: Reiji Watanabe <reijiw@google.com>
> ---
> .../selftests/kvm/include/aarch64/processor.h | 2 ++
> .../testing/selftests/kvm/lib/aarch64/processor.c | 15 +++++++++++++++
> 2 files changed, 17 insertions(+)
>
> diff --git a/tools/testing/selftests/kvm/include/aarch64/processor.h b/tools/testing/selftests/kvm/include/aarch64/processor.h
> index a8124f9dd68a..a9b4b4e0e592 100644
> --- a/tools/testing/selftests/kvm/include/aarch64/processor.h
> +++ b/tools/testing/selftests/kvm/include/aarch64/processor.h
> @@ -193,4 +193,6 @@ void smccc_hvc(uint32_t function_id, uint64_t arg0, uint64_t arg1,
>
> uint32_t guest_get_vcpuid(void);
>
> +int cpuid_get_sfield(uint64_t val, int field_shift);
> +unsigned int cpuid_get_ufield(uint64_t val, int field_shift);
> #endif /* SELFTEST_KVM_PROCESSOR_H */
> diff --git a/tools/testing/selftests/kvm/lib/aarch64/processor.c b/tools/testing/selftests/kvm/lib/aarch64/processor.c
> index 6f5551368944..0b2ad46e7ff5 100644
> --- a/tools/testing/selftests/kvm/lib/aarch64/processor.c
> +++ b/tools/testing/selftests/kvm/lib/aarch64/processor.c
> @@ -528,3 +528,18 @@ void smccc_hvc(uint32_t function_id, uint64_t arg0, uint64_t arg1,
> [arg4] "r"(arg4), [arg5] "r"(arg5), [arg6] "r"(arg6)
> : "x0", "x1", "x2", "x3", "x4", "x5", "x6", "x7");
> }
> +
> +/* Helpers to get a signed/unsigned feature field from ID register value */
> +int cpuid_get_sfield(uint64_t val, int field_shift)
> +{
> + int width = 4;
> +
> + return (int64_t)(val << (64 - width - field_shift)) >> (64 - width);
> +}
I don't believe this helper is ever used.
> +unsigned int cpuid_get_ufield(uint64_t val, int field_shift)
> +{
> + int width = 4;
> +
> + return (uint64_t)(val << (64 - width - field_shift)) >> (64 - width);
> +}
I would recommend not open-coding this and instead make use of
ARM64_FEATURE_MASK(). You could pull in linux/bitfield.h to tools, or do
something like this:
#define ARM64_FEATURE_GET(ftr, val) \
((ARM64_FEATURE_MASK(ftr) & val) >> ftr##_SHIFT)
Slight preference for FIELD_{GET,SET}() as it matches the field
extraction in the kernel as well.
--
Thanks,
Oliver
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next prev parent reply other threads:[~2022-08-25 16:50 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-25 5:08 [PATCH 0/9] KVM: arm64: selftests: Test linked {break,watch}points Reiji Watanabe
2022-08-25 5:08 ` [PATCH 1/9] KVM: arm64: selftests: Add helpers to extract a field of an ID register Reiji Watanabe
2022-08-25 16:48 ` Oliver Upton [this message]
2022-08-25 16:52 ` Ricardo Koller
2022-08-25 16:58 ` Oliver Upton
2022-08-26 0:50 ` Reiji Watanabe
2022-08-25 5:08 ` [PATCH 2/9] KVM: arm64: selftests: Add write_dbg{b,w}{c,v}r helpers in debug-exceptions Reiji Watanabe
2022-09-09 19:40 ` Ricardo Koller
2022-08-25 5:08 ` [PATCH 3/9] KVM: arm64: selftests: Remove the hard-coded {b,w}pn#0 from debug-exceptions Reiji Watanabe
2022-08-25 16:55 ` Oliver Upton
2022-08-26 0:53 ` Reiji Watanabe
2022-09-09 19:46 ` Ricardo Koller
2022-09-10 4:15 ` Reiji Watanabe
2022-08-25 5:08 ` [PATCH 4/9] KVM: arm64: selftests: Add helpers to enable debug exceptions Reiji Watanabe
2022-08-25 17:21 ` Oliver Upton
2022-08-26 0:55 ` Reiji Watanabe
2022-09-09 19:57 ` Ricardo Koller
2022-08-25 5:08 ` [PATCH 5/9] KVM: arm64: selftests: Have debug_version() use cpuid_get_ufield() helper Reiji Watanabe
2022-08-25 17:29 ` Oliver Upton
2022-08-26 0:59 ` Reiji Watanabe
2022-08-25 5:08 ` [PATCH 6/9] KVM: arm64: selftests: Change debug_version() to take ID_AA64DFR0_EL1 Reiji Watanabe
2022-08-25 5:08 ` [PATCH 7/9] KVM: arm64: selftests: Add a test case for a linked breakpoint Reiji Watanabe
2022-08-26 1:29 ` Reiji Watanabe
2022-09-09 20:18 ` Ricardo Koller
2022-09-09 20:26 ` Ricardo Koller
2022-09-10 5:22 ` Reiji Watanabe
2022-09-09 21:01 ` Ricardo Koller
2022-09-10 5:19 ` Reiji Watanabe
2022-08-25 5:08 ` [PATCH 8/9] KVM: arm64: selftests: Add a test case for a linked watchpoint Reiji Watanabe
2022-08-25 5:08 ` [PATCH 9/9] KVM: arm64: selftests: Test with every breakpoint/watchpoint Reiji Watanabe
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