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From: "Jan Beulich" <JBeulich@suse.com>
To: aisaila@bitdefender.com
Cc: George Dunlap <George.Dunlap@eu.citrix.com>,
	Andrew Cooper <andrew.cooper3@citrix.com>,
	tamas@tklengyel.com, Razvan Cojocaru <rcojocaru@bitdefender.com>,
	xen-devel@lists.xen.org
Subject: Re: [PATCH v4] x86/mm: Add mem access rights to NPT
Date: Wed, 25 Jul 2018 03:14:46 -0600	[thread overview]
Message-ID: <5B583F8602000078001D78F0@prv1-mh.provo.novell.com> (raw)
In-Reply-To: <1532507399.21125.7.camel@bitdefender.com>

>>> On 25.07.18 at 10:29, <aisaila@bitdefender.com> wrote:
>> > 
>> > +static void p2m_set_access(struct p2m_domain *p2m, unsigned long
>> > gfn,
>> > +                                      p2m_access_t a)
>> > +{
>> > +    int rc;
>> > +
>> > +    if ( !p2m->mem_access_settings )
>> > +        return;
>> No error indication?
> 
> I would say ASSERT is a better choice if the code got this far and it
> could not allocate memory

For one ASSERT() is a no-op in release builds. And then it is
extremely bad practices to bring down the host when an operation
targeting just a single guest has failed. You either return an error
indicator here (and pass it up the call tree), or if that's really
unfeasible then you crash the affected domain (we do so in quite
a few other situations). But you'd need to make clear (if it's not
obvious) why passing up an error is unacceptable here.

Jan



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  reply	other threads:[~2018-07-25  9:14 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-07-23 13:48 [PATCH v4] x86/mm: Add mem access rights to NPT Alexandru Isaila
2018-07-24  8:55 ` Jan Beulich
2018-07-24  9:28   ` Razvan Cojocaru
2018-07-24  9:33     ` Jan Beulich
2018-07-24 11:26   ` George Dunlap
2018-07-24 12:02     ` Jan Beulich
2018-07-25  9:25       ` George Dunlap
2018-07-25 10:37         ` Jan Beulich
2018-08-09 12:14           ` Isaila Alexandru
2018-09-26  8:17           ` Isaila Alexandru
2018-09-26 13:13             ` George Dunlap
2018-07-25  8:29   ` Isaila Alexandru
2018-07-25  9:14     ` Jan Beulich [this message]
2018-07-25  9:28       ` Isaila Alexandru
2018-09-26 16:02 ` George Dunlap
2018-09-26 16:02   ` George Dunlap

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