linux-kernel - Re: [PATCH] kvm: x86: svm: remove SVM_EXIT_READ

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] [day] [month] [year] [list]

Date:	Fri, 3 Apr 2015 14:19:42 +0200
From:	Radim Krčmář <rkrcmar@...hat.com>
To:	Bandan Das <bsd@...hat.com>
Cc:	Joel Schopp <joel.schopp@....com>, Gleb Natapov <gleb@...nel.org>,
	Paolo Bonzini <pbonzini@...hat.com>, kvm@...r.kernel.org,
	Joerg Roedel <joro@...tes.org>, Borislav Petkov <bp@...en8.de>,
	linux-kernel@...r.kernel.org, David Kaplan <david.kaplan@....com>
Subject: Re: [PATCH] kvm: x86: svm: remove SVM_EXIT_READ_CR* intercepts

2015-03-12 17:17-0400, Bandan Das:
> Joel Schopp <joel.schopp@....com> writes:
> > @@ -2968,29 +2964,10 @@ static int cr_interception(struct vcpu_svm *svm)
> >  			kvm_queue_exception(&svm->vcpu, UD_VECTOR);
> >  			return 1;
> >  		}
> > -	} else { /* mov from cr */
> > -		[reads of CR 0..8]
> > +	} else { /* mov from cr, should never trap in svm */
> > +		WARN(1, "unhandled read from CR%d", cr);
> > +		kvm_queue_exception(&svm->vcpu, UD_VECTOR);
> > +		return 1;
> 
> Can we end up here if a nested hypervisor sets cr read interception ?

No.  If the nested hypervisor sets intercept bits, we're going to detect
them in 'handle_exit -> nested_svm_exit_handled -> nested_svm_intercept'
and enter L1 before the cr_interception handler.
--
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/