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From: Boris Ostrovsky <boris.ostrovsky@oracle.com>
To: Juergen Gross <jgross@suse.com>,
	xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org
Cc: Stefano Stabellini <sstabellini@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>
Subject: Re: [PATCH 1/3] xen: check required Xen features
Date: Mon, 10 May 2021 08:11:56 -0400	[thread overview]
Message-ID: <4282bb6f-1d19-4d00-d468-f5d4c7fb0f90@oracle.com> (raw)
In-Reply-To: <20210422151007.2205-2-jgross@suse.com>


On 4/22/21 11:10 AM, Juergen Gross wrote:
>  
> +/*
> + * Linux kernel expects at least Xen 4.0.
> + *
> + * Assume some features to be available for that reason (depending on guest
> + * mode, of course).
> + */
> +#define chk_feature(f) {						\
> +		if (!xen_feature(f))					\
> +			pr_err("Xen: feature %s not available!\n", #f);	\
> +	}


With your changes in the subsequent patches, are we still going to function properly without those features? (i.e. maybe we should just panic)


(Also, chk_required_features() perhaps?)


-boris


> +
>  u8 xen_features[XENFEAT_NR_SUBMAPS * 32] __read_mostly;
>  EXPORT_SYMBOL_GPL(xen_features);
>  
> @@ -31,4 +44,9 @@ void xen_setup_features(void)
>  		for (j = 0; j < 32; j++)
>  			xen_features[i * 32 + j] = !!(fi.submap & 1<<j);
>  	}
> +
> +	if (xen_pv_domain()) {
> +		chk_feature(XENFEAT_mmu_pt_update_preserve_ad);
> +		chk_feature(XENFEAT_gnttab_map_avail_bits);
> +	}
>  }


  parent reply	other threads:[~2021-05-10 12:12 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-22 15:10 [PATCH 0/3] xen: remove some checks for always present " Juergen Gross
2021-04-22 15:10 ` [PATCH 1/3] xen: check required " Juergen Gross
2021-04-22 15:26   ` Stefano Stabellini
2021-04-22 15:32     ` Juergen Gross
2021-05-10 12:11   ` Boris Ostrovsky [this message]
2021-05-10 13:21     ` Juergen Gross
2021-04-22 15:10 ` [PATCH 2/3] xen: assume XENFEAT_mmu_pt_update_preserve_ad being set for pv guests Juergen Gross
2021-04-22 15:10 ` [PATCH 3/3] xen: assume XENFEAT_gnttab_map_avail_bits " Juergen Gross
2021-04-22 15:16 ` [PATCH 0/3] xen: remove some checks for always present Xen features Jan Beulich
2021-04-22 15:17   ` Juergen Gross
2021-04-22 15:23     ` Jan Beulich
2021-04-22 15:28       ` Juergen Gross
2021-04-22 15:42         ` Jan Beulich
2021-04-22 15:49           ` Juergen Gross
2021-04-22 15:51           ` Andrew Cooper
2021-05-10  7:34 ` Juergen Gross
2021-05-10 11:31   ` Peter Zijlstra

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