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From: Jan Beulich <jbeulich@suse.com>
To: David Woodhouse <dwmw2@infradead.org>
Cc: "Stefano Stabellini" <sstabellini@kernel.org>,
	"Julien Grall" <julien@xen.org>, "Wei Liu" <wl@xen.org>,
	"Konrad Rzeszutek Wilk" <konrad.wilk@oracle.com>,
	"George Dunlap" <George.Dunlap@eu.citrix.com>,
	"Andrew Cooper" <andrew.cooper3@citrix.com>,
	"Varad Gautam" <vrd@amazon.de>,
	"Ian Jackson" <ian.jackson@eu.citrix.com>,
	"Hongyan Xia" <hongyxia@amazon.com>,
	xen-devel@lists.xenproject.org,
	"Paul Durrant" <pdurrant@amazon.co.uk>,
	"Roger Pau Monné" <roger.pau@citrix.com>
Subject: Re: [Xen-devel] [PATCH 2/8] x86/setup: Fix badpage= handling for memory above HYPERVISOR_VIRT_END
Date: Thu, 20 Feb 2020 16:38:12 +0100	[thread overview]
Message-ID: <0c84d313-6e7f-338b-723f-e76865a16798@suse.com> (raw)
In-Reply-To: <20200201003303.2363081-2-dwmw2@infradead.org>

On 01.02.2020 01:32, David Woodhouse wrote:
> --- a/xen/common/page_alloc.c
> +++ b/xen/common/page_alloc.c
> @@ -1758,6 +1758,18 @@ int query_page_offline(mfn_t mfn, uint32_t *status)
>      return 0;
>  }
>  
> +static unsigned long contig_avail_pages(struct page_info *pg, unsigned long max_pages)
> +{
> +    unsigned long i;
> +
> +    for ( i = 0 ; i < max_pages; i++)

Nit: Stray blank before first semicolon.

> +    {
> +        if ( pg[i].count_info & PGC_broken )
> +            break;
> +    }
> +    return i;

Further nits: Commonly we omit the braces in cases like this one.
We also like to have blank lines before the main return statement
of a function.

> @@ -1846,6 +1863,63 @@ static unsigned long avail_heap_pages(
>      return free_pages;
>  }
>  
> +static void mark_bad_pages(void)

__init please

> +{
> +    unsigned long bad_spfn, bad_epfn;
> +    const char *p;
> +    struct page_info *pg;
> +#ifdef CONFIG_X86
> +    const struct platform_bad_page *badpage;
> +    unsigned int i, j, array_size;
> +
> +    badpage = get_platform_badpages(&array_size);
> +    if ( badpage )
> +    {
> +        for ( i = 0; i < array_size; i++ )
> +        {
> +            for ( j = 0; j < 1UL << badpage->order; j++ )

Either you mean badpage[i].* here and below, or you're missing an
increment of badpage somewhere.

> +            {
> +                if ( mfn_valid(_mfn(badpage->mfn + j)) )
> +                {
> +                    pg = mfn_to_page(_mfn(badpage->mfn + j));
> +                    pg->count_info |= PGC_broken;
> +                    page_list_add_tail(pg, &page_broken_list);
> +                }
> +            }
> +        }
> +    }
> +#endif
> +
> +    /* Check new pages against the bad-page list. */
> +    p = opt_badpage;
> +    while ( *p != '\0' )
> +    {
> +        bad_spfn = simple_strtoul(p, &p, 0);
> +        bad_epfn = bad_spfn;
> +
> +        if ( *p == '-' )
> +        {
> +            p++;
> +            bad_epfn = simple_strtoul(p, &p, 0);
> +            if ( bad_epfn < bad_spfn )
> +                bad_epfn = bad_spfn;
> +        }
> +
> +        if ( *p == ',' )
> +            p++;
> +        else if ( *p != '\0' )
> +            break;

I think this common (with init_boot_pages()) part of parsing
would better abstracted out, such there will be just one
instance of, and hence there's no risk of things going out of
sync.

> +        while ( mfn_valid(_mfn(bad_spfn)) && bad_spfn < bad_epfn )

As per init_boot_pages() as well as per the "bad_epfn = bad_spfn;"
you have further up, the range here is inclusive at its end. I'm
also uncertain about the stopping at the first !mfn_valid() -
there may well be further valid pages later on.

Jan

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  parent reply	other threads:[~2020-02-20 15:38 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-01  0:32 [Xen-devel] [PATCH 0/8] Early cleanups and bug fixes in preparation for live update David Woodhouse
2020-02-01  0:32 ` [Xen-devel] [PATCH 1/8] x86/smp: reset x2apic_enabled in smp_send_stop() David Woodhouse
2020-02-03 16:18   ` Roger Pau Monné
2020-02-01  0:32 ` [Xen-devel] [PATCH 2/8] x86/setup: Fix badpage= handling for memory above HYPERVISOR_VIRT_END David Woodhouse
2020-02-03 10:57   ` Julien Grall
2020-02-20 15:38   ` Jan Beulich [this message]
2020-03-06 22:52   ` Julien Grall
2020-02-01  0:32 ` [Xen-devel] [PATCH 3/8] x86/setup: Don't skip 2MiB underneath relocated Xen image David Woodhouse
2020-02-01  0:32 ` [Xen-devel] [PATCH 4/8] xen/vmap: allow vm_init_type to be called during early_boot David Woodhouse
2020-02-13 10:36   ` Julien Grall
2020-02-21 16:42   ` Jan Beulich
2020-02-01  0:33 ` [Xen-devel] [PATCH 5/8] xen/vmap: allow vmap() to be called during early boot David Woodhouse
2020-02-03 14:00   ` Julien Grall
2020-02-03 16:37     ` David Woodhouse
2020-02-04 11:00       ` George Dunlap
2020-02-04 11:06         ` David Woodhouse
2020-02-04 11:18           ` David Woodhouse
2020-02-09 18:19       ` Julien Grall
2020-02-21 16:46   ` Jan Beulich
2020-02-01  0:33 ` [Xen-devel] [PATCH 6/8] x86/setup: move vm_init() before end_boot_allocator() David Woodhouse
2020-02-03 11:10   ` Xia, Hongyan
2020-02-03 14:03     ` David Woodhouse
2020-02-21 16:48   ` Jan Beulich
2020-02-01  0:33 ` [Xen-devel] [PATCH 7/8] x86/setup: simplify handling of initrdidx when no initrd present David Woodhouse
2020-02-13 10:47   ` Julien Grall
2020-02-21 16:59   ` Jan Beulich
2020-02-24 13:31     ` Julien Grall
2020-02-25 12:34       ` Jan Beulich
2020-02-26  7:13         ` Julien Grall
2020-02-26  8:37           ` Jan Beulich
2020-02-01  0:33 ` [Xen-devel] [PATCH 8/8] x86/setup: lift dom0 creation out into create_dom0() function David Woodhouse
2020-02-03 14:28   ` Julien Grall
2020-02-03 15:03     ` David Woodhouse
2020-02-21 17:06   ` Jan Beulich
2020-03-17 23:45     ` David Woodhouse

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