From: Stefano Stabellini <sstabellini@kernel.org>
To: Juergen Gross <jgross@suse.com>
Cc: xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Stefano Stabellini <sstabellini@kernel.org>,
Peter Zijlstra <peterz@infradead.org>
Subject: Re: [PATCH 1/3] xen: check required Xen features
Date: Thu, 22 Apr 2021 08:26:12 -0700 (PDT) [thread overview]
Message-ID: <alpine.DEB.2.21.2104220823160.5018@sstabellini-ThinkPad-T480s> (raw)
In-Reply-To: <20210422151007.2205-2-jgross@suse.com>
On Thu, 22 Apr 2021, Juergen Gross wrote:
> Linux kernel is not supported to run on Xen versions older than 4.0.
>
> Add tests for required Xen features always being present in Xen 4.0
> and newer.
>
> Signed-off-by: Juergen Gross <jgross@suse.com>
> ---
> drivers/xen/features.c | 18 ++++++++++++++++++
> 1 file changed, 18 insertions(+)
>
> diff --git a/drivers/xen/features.c b/drivers/xen/features.c
> index 25c053b09605..60503299c9bc 100644
> --- a/drivers/xen/features.c
> +++ b/drivers/xen/features.c
> @@ -9,13 +9,26 @@
> #include <linux/types.h>
> #include <linux/cache.h>
> #include <linux/export.h>
> +#include <linux/printk.h>
>
> #include <asm/xen/hypercall.h>
>
> +#include <xen/xen.h>
> #include <xen/interface/xen.h>
> #include <xen/interface/version.h>
> #include <xen/features.h>
>
> +/*
> + * 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); \
> + }
I think this could be done as a static inline function in
include/xen/features.h. That way it would be available everywhere. Also,
static inlines are better than macro when it is possible to use them in
terms of code safety.
> 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);
> + }
> }
> --
> 2.26.2
>
next prev parent reply other threads:[~2021-04-22 15:26 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 Xen features Juergen Gross
2021-04-22 15:10 ` [PATCH 1/3] xen: check required " Juergen Gross
2021-04-22 15:26 ` Stefano Stabellini [this message]
2021-04-22 15:32 ` Juergen Gross
2021-05-10 12:11 ` Boris Ostrovsky
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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