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From: Michael Tokarev <mjt@tls.msk.ru>
To: Alexey Kardashevskiy <aik@ozlabs.ru>
Cc: qemu-trivial@nongnu.org, qemu-devel@nongnu.org
Subject: Re: [Qemu-trivial] [PATCH] vl: remove (max_cpus > 255) check from smp_parse
Date: Mon, 02 Dec 2013 21:06:29 +0400	[thread overview]
Message-ID: <529CBE15.8010206@msgid.tls.msk.ru> (raw)
In-Reply-To: <1385350750-21468-1-git-send-email-aik@ozlabs.ru>

25.11.2013 07:39, Alexey Kardashevskiy wrote:
> Since modern POWER7/POWER8 chips can have more that 256 CPU threads
> (>2000 actually), remove this check from smp_parse.
> 
> The CPUs number is still checked against machine->max_cpus and this check
> should be enough not to break other archs.
[]
> -    if (max_cpus > 255) {
> -        fprintf(stderr, "Unsupported number of maxcpus\n");
> -        exit(1);
> -    }

I don't know whenever this is actually safe.  Do we have any static arrays
of size 255 somewhere, which will be overflowed without this check? :)

Thanks,

/mjt


WARNING: multiple messages have this Message-ID (diff)
From: Michael Tokarev <mjt@tls.msk.ru>
To: Alexey Kardashevskiy <aik@ozlabs.ru>
Cc: qemu-trivial@nongnu.org, qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [Qemu-trivial] [PATCH] vl: remove (max_cpus > 255) check from smp_parse
Date: Mon, 02 Dec 2013 21:06:29 +0400	[thread overview]
Message-ID: <529CBE15.8010206@msgid.tls.msk.ru> (raw)
In-Reply-To: <1385350750-21468-1-git-send-email-aik@ozlabs.ru>

25.11.2013 07:39, Alexey Kardashevskiy wrote:
> Since modern POWER7/POWER8 chips can have more that 256 CPU threads
> (>2000 actually), remove this check from smp_parse.
> 
> The CPUs number is still checked against machine->max_cpus and this check
> should be enough not to break other archs.
[]
> -    if (max_cpus > 255) {
> -        fprintf(stderr, "Unsupported number of maxcpus\n");
> -        exit(1);
> -    }

I don't know whenever this is actually safe.  Do we have any static arrays
of size 255 somewhere, which will be overflowed without this check? :)

Thanks,

/mjt

  reply	other threads:[~2013-12-02 17:06 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-11-25  3:39 [Qemu-trivial] [PATCH] vl: remove (max_cpus > 255) check from smp_parse Alexey Kardashevskiy
2013-11-25  3:39 ` [Qemu-devel] " Alexey Kardashevskiy
2013-12-02 17:06 ` Michael Tokarev [this message]
2013-12-02 17:06   ` [Qemu-devel] [Qemu-trivial] " Michael Tokarev
2013-12-02 22:09   ` [Qemu-trivial] [Qemu-devel] " Andreas Färber
2013-12-02 22:09     ` [Qemu-devel] [Qemu-trivial] " Andreas Färber
2013-12-02 23:03     ` [Qemu-trivial] [Qemu-devel] " Alexey Kardashevskiy
2013-12-02 23:03       ` [Qemu-devel] [Qemu-trivial] " Alexey Kardashevskiy
2013-12-03  9:00       ` [Qemu-trivial] [Qemu-devel] " Markus Armbruster
2013-12-03  9:00         ` [Qemu-devel] [Qemu-trivial] " Markus Armbruster
2013-12-03 13:30       ` [Qemu-trivial] [Qemu-devel] " Andreas Färber
2013-12-03 13:30         ` [Qemu-devel] [Qemu-trivial] " Andreas Färber
2013-12-03 14:47         ` [Qemu-trivial] [Qemu-devel] " Eduardo Habkost
2013-12-03 14:47           ` [Qemu-devel] [Qemu-trivial] " Eduardo Habkost
2013-12-04  5:50           ` [Qemu-trivial] [Qemu-devel] " Alexey Kardashevskiy
2013-12-04  5:50             ` [Qemu-devel] [Qemu-trivial] " Alexey Kardashevskiy
2013-12-04 12:48             ` [Qemu-trivial] [Qemu-devel] " Eduardo Habkost
2013-12-04 12:48               ` [Qemu-devel] [Qemu-trivial] " Eduardo Habkost
2014-02-14  6:56               ` [Qemu-trivial] [Qemu-devel] " Alexey Kardashevskiy
2014-02-14  6:56                 ` [Qemu-devel] [Qemu-trivial] " Alexey Kardashevskiy
2014-02-14  7:34                 ` Paolo Bonzini
2014-02-14  7:34                   ` [Qemu-devel] " Paolo Bonzini
2013-12-03 10:44     ` [Qemu-trivial] [Qemu-devel] " Igor Mammedov
2013-12-03 10:44       ` [Qemu-devel] [Qemu-trivial] " Igor Mammedov
2013-12-03 14:33       ` [Qemu-trivial] [Qemu-devel] " Eduardo Habkost
2013-12-03 14:33         ` [Qemu-devel] [Qemu-trivial] " Eduardo Habkost

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