From: Julien Grall <julien@xen.org>
To: Vladimir Murzin <vladimir.murzin@arm.com>,
xen-devel@lists.xenproject.org
Cc: sstabellini@kernel.org, Volodymyr_Babchuk@epam.com,
Ian Jackson <iwj@xenproject.org>
Subject: Re: [XEN PATCH] xen/arm: Relax GIC version check
Date: Wed, 20 Jan 2021 15:12:31 +0000 [thread overview]
Message-ID: <5df5270d-216b-3f14-5416-bd3a12da3650@xen.org> (raw)
In-Reply-To: <20210120112644.8882-1-vladimir.murzin@arm.com>
(+ Ian)
Hi Vladimir,
On 20/01/2021 11:26, Vladimir Murzin wrote:
> Supported values are
>
> 0b0000 GIC CPU interface system registers not implemented.
>
> 0b0001 System register interface to versions 3.0 and 4.0 of the GIC
> CPU interface is supported.
>
> 0b0011 System register interface to version 4.1 of the GIC CPU
> interface is supported.
>
> 4.1 is still backward compatible with 4.0/3.0, moreover ARM ARM
> guarantees that future versions of the GIC CPU interface retain
> backwards compatible.
>
> Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
Acked-by: Julien Grall <jgrall@amazon.com>
@Ian: I would like your put as the RM for 4.15.
Technically, it could be consider as a new "feature" because Xen would
fail to boot on such HW.
However, I think the change is small enough and doesn't introduce risk
on existing supported HW.
Therefore, I would like to merge it for 4.15. @Ian does it sounds good
to you?
> ---
> xen/include/asm-arm/cpufeature.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/xen/include/asm-arm/cpufeature.h b/xen/include/asm-arm/cpufeature.h
> index 13a2739a6..c6e5711b2 100644
> --- a/xen/include/asm-arm/cpufeature.h
> +++ b/xen/include/asm-arm/cpufeature.h
> @@ -17,7 +17,7 @@
> #define cpu_has_el3_64 (boot_cpu_feature64(el3) >= 1)
> #define cpu_has_fp (boot_cpu_feature64(fp) < 8)
> #define cpu_has_simd (boot_cpu_feature64(simd) < 8)
> -#define cpu_has_gicv3 (boot_cpu_feature64(gic) == 1)
> +#define cpu_has_gicv3 (boot_cpu_feature64(gic) >= 1)
> #endif
>
> #define cpu_feature32(c, feat) ((c)->pfr32.feat)
>
--
Julien Grall
next prev parent reply other threads:[~2021-01-20 15:12 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-20 11:26 [XEN PATCH] xen/arm: Relax GIC version check Vladimir Murzin
2021-01-20 13:49 ` Bertrand Marquis
2021-01-20 15:12 ` Julien Grall [this message]
2021-01-20 15:34 ` Ian Jackson
2021-01-20 17:44 ` Julien Grall
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