linux-kernel - Re: [PATCH] KVM: nVMX: Don't return error on nested bitmap memory allocation failure

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Message-ID: <554083D4.8090906@siemens.com>
Date:	Wed, 29 Apr 2015 09:10:12 +0200
From:	Jan Kiszka <jan.kiszka@...mens.com>
To:	Bandan Das <bsd@...hat.com>, kvm@...r.kernel.org
CC:	Paolo Bonzini <pbonzini@...hat.com>,
	Wincy Van <fanwenyi0529@...il.com>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] KVM: nVMX: Don't return error on nested bitmap memory
 allocation failure

Am 2015-04-28 um 21:55 schrieb Bandan Das:
> 
> If get_free_page() fails for nested bitmap area, it's evident that
> we are gonna get screwed anyway but returning failure because we failed
> allocating memory for a nested structure seems like an unnecessary big
> hammer. Also, save the call for later; after we are done with other
> non-nested allocations.

Frankly, I prefer failures over automatic degradations. And, as you
noted, the whole system will probably explode anyway if allocation of a
single page already fails. So what does this buy us?

What could makes sense is making the allocation of the vmread/write
bitmap depend on enable_shadow_vmcs, and that again depend on nested.

Jan

-- 
Siemens AG, Corporate Technology, CT RTC ITP SES-DE
Corporate Competence Center Embedded Linux
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