From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Kiszka Subject: Re: [PATCH] KVM: nVMX: Fix direct injection of interrupts from L0 to L2 Date: Sun, 17 Feb 2013 18:39:51 +0100 Message-ID: <512115E7.9070405@web.de> References: <511FBD76.8010307@web.de> <20130217150721.GU9817@redhat.com> <5120F7CE.6050905@web.de> <20130217162617.GW9817@redhat.com> <51210CD1.3010208@web.de> <20130217173534.GB15961@redhat.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="----enig2MUVTQMHPDADQSSWCXWEI" Cc: Marcelo Tosatti , kvm , Nadav Har'El , "Nakajima, Jun" To: Gleb Natapov Return-path: Received: from mout.web.de ([212.227.17.12]:53629 "EHLO mout.web.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751357Ab3BQRj6 (ORCPT ); Sun, 17 Feb 2013 12:39:58 -0500 In-Reply-To: <20130217173534.GB15961@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: This is an OpenPGP/MIME signed message (RFC 4880 and 3156) ------enig2MUVTQMHPDADQSSWCXWEI Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable On 2013-02-17 18:35, Gleb Natapov wrote: > On Sun, Feb 17, 2013 at 06:01:05PM +0100, Jan Kiszka wrote: >> On 2013-02-17 17:26, Gleb Natapov wrote: >>> On Sun, Feb 17, 2013 at 04:31:26PM +0100, Jan Kiszka wrote: >>>> On 2013-02-17 16:07, Gleb Natapov wrote: >>>>> On Sat, Feb 16, 2013 at 06:10:14PM +0100, Jan Kiszka wrote: >>>>>> From: Jan Kiszka >>>>>> >>>>>> If L1 does not set PIN_BASED_EXT_INTR_MASK, we incorrectly skipped= >>>>>> vmx_complete_interrupts on L2 exits. This is required because, wit= h >>>>>> direct interrupt injection from L0 to L2, L0 has to update its pen= ding >>>>>> events. >>>>>> >>>>>> Also, we need to allow vmx_cancel_injection when entering L2 in we= left >>>>>> to L0. This condition is indirectly derived from the absence of va= lid >>>>>> vectoring info in vmcs12. We no explicitly clear it if we find out= that >>>>>> the L2 exit is not targeting L1 but L0. >>>>>> >>>>> We really need to overhaul how interrupt injection is emulated in n= ested >>>>> VMX. Why not put pending events into event queue instead of >>>>> get_vmcs12(vcpu)->idt_vectoring_info_field and inject them in usual= way. >>>> >>>> I was thinking about the same step but felt unsure so far if >>>> vmx_complete_interrupts & Co. do not include any assumptions about t= he >>>> vmcs configuration that won't match what L1 does. So I went for a >>>> different path first, specifically to avoid impact on these hairy bi= ts >>>> for non-nested mode. >>>> >>> Assumption made by those functions should be still correct since gues= t >>> VMCS configuration is not applied directly to real HW, but we should = be >>> careful of course. For instance interrupt queues should be cleared >>> during nested vmexit and event transfered back to idt_vectoring_info_= field. >>> IIRC this is how nested SVM works BTW. >> >> Checking __vmx_complete_interrupts, the first issue I find is that typ= e >> 5 (privileged software exception) is not decoded, thus will be lost if= >> L2 leaves this way. That's a reason why it might be better to re-injec= t >> the content of vmcs12 if it is valid. VMX is a bit more hairy than SVM= , >> I guess. >> > I do not see type 5 in SDM Table 24-15. We handle every type specified > there. Why shouldn't we? SVM and VMX are pretty close in regards to > event injection, this allowed us to move a lot of logic into the common= > code. It's a type relevant for event delivery, see 24-16. I think we only handle what we can possibly generate. This assumption would have to be checked and potentially resolved before we can use the standard code for nesting as well. Jan ------enig2MUVTQMHPDADQSSWCXWEI Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.16 (GNU/Linux) Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iEYEARECAAYFAlEhFecACgkQitSsb3rl5xRjFwCgpHWabnJAceK+D6ey/zG0gBf7 u6gAoKfi7e2AmgJDBTZfSRZ5J3jKBfV6 =lgrK -----END PGP SIGNATURE----- ------enig2MUVTQMHPDADQSSWCXWEI--