linux-kernel - Re: [kvm-devel] [PATCH] KVM: Avoid using vmx instruction directly

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Thu, 9 Nov 2006 15:42:30 +0100
From:	Arnd Bergmann <arnd@...db.de>
To:	Avi Kivity <avi@...ranet.com>
Cc:	kvm-devel@...ts.sourceforge.net, akpm@...l.org,
	linux-kernel@...r.kernel.org
Subject: Re: [kvm-devel] [PATCH] KVM: Avoid using vmx instruction directly

On Thursday 09 November 2006 14:36, Avi Kivity wrote:
> 
> >
> > I'm not an expert on inline assembly, but don't you need an extra
> > '"m" (phys_addr)' to make sure that gcc actually puts the variable
> > on the stack instead of passing a NULL pointer as '"a"(&phys_addr)'?
> 
> Taking a variable's address should force its contents into memory (like 
> calling an uninlined function with &var).

No it doesn't. You're not telling gcc that the inline assembly cares
about the contents of the variable, so it could be a reference to
a stack slot while the contents are still in a register. Or gcc
might move the assignment of phys_addr to after the inline assembly.

	Arnd <><
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/