linux-kernel - Re: [PATCH] KVM: SVM: fix NMI window after iret

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 for Android: free password hash cracker in your pocket

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

Date:	Tue, 18 Feb 2014 10:18:21 +0100
From:	Paolo Bonzini <pbonzini@...hat.com>
To:	Radim Krčmář <rkrcmar@...hat.com>,
	linux-kernel@...r.kernel.org
CC:	kvm@...r.kernel.org, joro@...tes.org, stable@...r.kernel.org
Subject: Re: [PATCH] KVM: SVM: fix NMI window after iret

Il 17/01/2014 20:52, Radim Krčmář ha scritto:
> We should open NMI window right after an iret, but SVM exits before it.
> We wanted to single step using the trap flag and then open it.
> (or we could emulate the iret instead)
> We don't do it since commit 3842d135ff2 (likely), because the iret exit
> handler does not request an event, so NMI window remains closed until
> the next exit.
>
> Fix this by making KVM_REQ_EVENT request in the iret handler.
>
> Signed-off-by: Radim Krčmář <rkrcmar@...hat.com>
> ---
>  (btw. kvm-unit-tests weren't executed on SVM since Nov 2010, at least)
>
>  arch/x86/kvm/svm.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
> index c7168a5..b5a735b 100644
> --- a/arch/x86/kvm/svm.c
> +++ b/arch/x86/kvm/svm.c
> @@ -2829,6 +2829,7 @@ static int iret_interception(struct vcpu_svm *svm)
>  	clr_intercept(svm, INTERCEPT_IRET);
>  	svm->vcpu.arch.hflags |= HF_IRET_MASK;
>  	svm->nmi_iret_rip = kvm_rip_read(&svm->vcpu);
> +	kvm_make_request(KVM_REQ_EVENT, &svm->vcpu);
>  	return 1;
>  }
>
>

Applying to kvm/queue, thanks.

Paolo
--
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/