From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D3267C433FF for ; Tue, 13 Aug 2019 14:35:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A81B42084D for ; Tue, 13 Aug 2019 14:35:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729484AbfHMOfc (ORCPT ); Tue, 13 Aug 2019 10:35:32 -0400 Received: from mail-wm1-f68.google.com ([209.85.128.68]:51302 "EHLO mail-wm1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726637AbfHMOfc (ORCPT ); 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Tue, 13 Aug 2019 07:35:30 -0700 (PDT) Received: from [192.168.10.150] ([93.56.166.5]) by smtp.gmail.com with ESMTPSA id r190sm3362812wmf.0.2019.08.13.07.35.29 (version=TLS1_3 cipher=AEAD-AES128-GCM-SHA256 bits=128/128); Tue, 13 Aug 2019 07:35:29 -0700 (PDT) Subject: Re: [RFC PATCH v6 75/92] kvm: x86: disable gpa_available optimization in emulator_read_write_onepage() To: =?UTF-8?Q?Adalbert_Laz=c4=83r?= , kvm@vger.kernel.org Cc: linux-mm@kvack.org, virtualization@lists.linux-foundation.org, =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= , Konrad Rzeszutek Wilk , Tamas K Lengyel , Mathieu Tarral , =?UTF-8?Q?Samuel_Laur=c3=a9n?= , Patrick Colp , Jan Kiszka , Stefan Hajnoczi , Weijiang Yang , Yu C Zhang , =?UTF-8?Q?Mihai_Don=c8=9bu?= References: <20190809160047.8319-1-alazar@bitdefender.com> <20190809160047.8319-76-alazar@bitdefender.com> <5d52ca22.1c69fb81.4ceb8.e90bSMTPIN_ADDED_BROKEN@mx.google.com> From: Paolo Bonzini Openpgp: preference=signencrypt Message-ID: <5b6f78ca-a5c5-80c4-05af-cbf7fabb96b3@redhat.com> Date: Tue, 13 Aug 2019 16:35:28 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <5d52ca22.1c69fb81.4ceb8.e90bSMTPIN_ADDED_BROKEN@mx.google.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On 13/08/19 16:33, Adalbert Lazăr wrote: > On Tue, 13 Aug 2019 10:47:34 +0200, Paolo Bonzini wrote: >> On 09/08/19 18:00, Adalbert Lazăr wrote: >>> If the EPT violation was caused by an execute restriction imposed by the >>> introspection tool, gpa_available will point to the instruction pointer, >>> not the to the read/write location that has to be used to emulate the >>> current instruction. >>> >>> This optimization should be disabled only when the VM is introspected, >>> not just because the introspection subsystem is present. >>> >>> Signed-off-by: Adalbert Lazăr >> >> The right thing to do is to not set gpa_available for fetch failures in >> kvm_mmu_page_fault instead: >> >> diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c >> index 24843cf49579..1bdca40fa831 100644 >> --- a/arch/x86/kvm/mmu.c >> +++ b/arch/x86/kvm/mmu.c >> @@ -5364,8 +5364,12 @@ int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gva_t cr2, u64 error_code, >> enum emulation_result er; >> bool direct = vcpu->arch.mmu->direct_map; >> >> - /* With shadow page tables, fault_address contains a GVA or nGPA. */ >> - if (vcpu->arch.mmu->direct_map) { >> + /* >> + * With shadow page tables, fault_address contains a GVA or nGPA. >> + * On a fetch fault, fault_address contains the instruction pointer. >> + */ >> + if (vcpu->arch.mmu->direct_map && >> + likely(!(error_code & PFERR_FETCH_MASK)) { >> vcpu->arch.gpa_available = true; >> vcpu->arch.gpa_val = cr2; >> } > > Sure, but I think we'll have to extend the check. > > Searching the logs I've found: > > kvm/x86: re-translate broken translation that caused EPT violation > > Signed-off-by: Mircea Cirjaliu > > arch/x86/kvm/x86.c | 1 + > 1 file changed, 1 insertion(+) > > /home/b/kvmi@9cad844~1/arch/x86/kvm/x86.c:4757,4762 - /home/b/kvmi@9cad844/arch/x86/kvm/x86.c:4757,4763 > */ > if (vcpu->arch.gpa_available && > emulator_can_use_gpa(ctxt) && > + (vcpu->arch.error_code & PFERR_GUEST_FINAL_MASK) && > (addr & ~PAGE_MASK) == (vcpu->arch.gpa_val & ~PAGE_MASK)) { > gpa = vcpu->arch.gpa_val; > ret = vcpu_is_mmio_gpa(vcpu, addr, gpa, write); > Yes, adding that check makes sense as well (still in kvm_mmu_page_fault). Paolo From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paolo Bonzini Subject: Re: [RFC PATCH v6 75/92] kvm: x86: disable gpa_available optimization in emulator_read_write_onepage() Date: Tue, 13 Aug 2019 16:35:28 +0200 Message-ID: <5b6f78ca-a5c5-80c4-05af-cbf7fabb96b3@redhat.com> References: <20190809160047.8319-1-alazar@bitdefender.com> <20190809160047.8319-76-alazar@bitdefender.com> <5d52ca22.1c69fb81.4ceb8.e90bSMTPIN_ADDED_BROKEN@mx.google.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Return-path: In-Reply-To: <5d52ca22.1c69fb81.4ceb8.e90bSMTPIN_ADDED_BROKEN@mx.google.com> Content-Language: en-US List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: =?UTF-8?Q?Adalbert_Laz=c4=83r?= , kvm@vger.kernel.org Cc: Tamas K Lengyel , Weijiang Yang , Yu C Zhang , =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= , Jan Kiszka , =?UTF-8?Q?Samuel_Laur=c3=a9n?= , Konrad Rzeszutek Wilk , virtualization@lists.linux-foundation.org, linux-mm@kvack.org, Patrick Colp , Mathieu Tarral , Stefan Hajnoczi , =?UTF-8?Q?Mihai_Don=c8=9bu?= List-Id: virtualization@lists.linuxfoundation.org T24gMTMvMDgvMTkgMTY6MzMsIEFkYWxiZXJ0IExhesSDciB3cm90ZToKPiBPbiBUdWUsIDEzIEF1 ZyAyMDE5IDEwOjQ3OjM0ICswMjAwLCBQYW9sbyBCb256aW5pIDxwYm9uemluaUByZWRoYXQuY29t PiB3cm90ZToKPj4gT24gMDkvMDgvMTkgMTg6MDAsIEFkYWxiZXJ0IExhesSDciB3cm90ZToKPj4+ IElmIHRoZSBFUFQgdmlvbGF0aW9uIHdhcyBjYXVzZWQgYnkgYW4gZXhlY3V0ZSByZXN0cmljdGlv biBpbXBvc2VkIGJ5IHRoZQo+Pj4gaW50cm9zcGVjdGlvbiB0b29sLCBncGFfYXZhaWxhYmxlIHdp bGwgcG9pbnQgdG8gdGhlIGluc3RydWN0aW9uIHBvaW50ZXIsCj4+PiBub3QgdGhlIHRvIHRoZSBy ZWFkL3dyaXRlIGxvY2F0aW9uIHRoYXQgaGFzIHRvIGJlIHVzZWQgdG8gZW11bGF0ZSB0aGUKPj4+ IGN1cnJlbnQgaW5zdHJ1Y3Rpb24uCj4+Pgo+Pj4gVGhpcyBvcHRpbWl6YXRpb24gc2hvdWxkIGJl IGRpc2FibGVkIG9ubHkgd2hlbiB0aGUgVk0gaXMgaW50cm9zcGVjdGVkLAo+Pj4gbm90IGp1c3Qg YmVjYXVzZSB0aGUgaW50cm9zcGVjdGlvbiBzdWJzeXN0ZW0gaXMgcHJlc2VudC4KPj4+Cj4+PiBT aWduZWQtb2ZmLWJ5OiBBZGFsYmVydCBMYXrEg3IgPGFsYXphckBiaXRkZWZlbmRlci5jb20+Cj4+ Cj4+IFRoZSByaWdodCB0aGluZyB0byBkbyBpcyB0byBub3Qgc2V0IGdwYV9hdmFpbGFibGUgZm9y IGZldGNoIGZhaWx1cmVzIGluIAo+PiBrdm1fbW11X3BhZ2VfZmF1bHQgaW5zdGVhZDoKPj4KPj4g ZGlmZiAtLWdpdCBhL2FyY2gveDg2L2t2bS9tbXUuYyBiL2FyY2gveDg2L2t2bS9tbXUuYwo+PiBp bmRleCAyNDg0M2NmNDk1NzkuLjFiZGNhNDBmYTgzMSAxMDA2NDQKPj4gLS0tIGEvYXJjaC94ODYv a3ZtL21tdS5jCj4+ICsrKyBiL2FyY2gveDg2L2t2bS9tbXUuYwo+PiBAQCAtNTM2NCw4ICs1MzY0 LDEyIEBAIGludCBrdm1fbW11X3BhZ2VfZmF1bHQoc3RydWN0IGt2bV92Y3B1ICp2Y3B1LCBndmFf dCBjcjIsIHU2NCBlcnJvcl9jb2RlLAo+PiAgCWVudW0gZW11bGF0aW9uX3Jlc3VsdCBlcjsKPj4g IAlib29sIGRpcmVjdCA9IHZjcHUtPmFyY2gubW11LT5kaXJlY3RfbWFwOwo+PiAgCj4+IC0JLyog V2l0aCBzaGFkb3cgcGFnZSB0YWJsZXMsIGZhdWx0X2FkZHJlc3MgY29udGFpbnMgYSBHVkEgb3Ig bkdQQS4gICovCj4+IC0JaWYgKHZjcHUtPmFyY2gubW11LT5kaXJlY3RfbWFwKSB7Cj4+ICsJLyoK Pj4gKwkgKiBXaXRoIHNoYWRvdyBwYWdlIHRhYmxlcywgZmF1bHRfYWRkcmVzcyBjb250YWlucyBh IEdWQSBvciBuR1BBLgo+PiArCSAqIE9uIGEgZmV0Y2ggZmF1bHQsIGZhdWx0X2FkZHJlc3MgY29u dGFpbnMgdGhlIGluc3RydWN0aW9uIHBvaW50ZXIuCj4+ICsJICovCj4+ICsJaWYgKHZjcHUtPmFy Y2gubW11LT5kaXJlY3RfbWFwICYmCj4+ICsJICAgIGxpa2VseSghKGVycm9yX2NvZGUgJiBQRkVS Ul9GRVRDSF9NQVNLKSkgewo+PiAgCQl2Y3B1LT5hcmNoLmdwYV9hdmFpbGFibGUgPSB0cnVlOwo+ PiAgCQl2Y3B1LT5hcmNoLmdwYV92YWwgPSBjcjI7Cj4+ICAJfQo+Cj4gU3VyZSwgYnV0IEkgdGhp bmsgd2UnbGwgaGF2ZSB0byBleHRlbmQgdGhlIGNoZWNrLgo+IAo+IFNlYXJjaGluZyB0aGUgbG9n cyBJJ3ZlIGZvdW5kOgo+IAo+ICAgICBrdm0veDg2OiByZS10cmFuc2xhdGUgYnJva2VuIHRyYW5z bGF0aW9uIHRoYXQgY2F1c2VkIEVQVCB2aW9sYXRpb24KPiAgICAgCj4gICAgIFNpZ25lZC1vZmYt Ynk6IE1pcmNlYSBDaXJqYWxpdSA8bWNpcmphbGl1QGJpdGRlZmVuZGVyLmNvbT4KPiAKPiAgYXJj aC94ODYva3ZtL3g4Ni5jIHwgMSArCj4gIDEgZmlsZSBjaGFuZ2VkLCAxIGluc2VydGlvbigrKQo+ IAo+IC9ob21lL2Iva3ZtaUA5Y2FkODQ0fjEvYXJjaC94ODYva3ZtL3g4Ni5jOjQ3NTcsNDc2MiAt IC9ob21lL2Iva3ZtaUA5Y2FkODQ0L2FyY2gveDg2L2t2bS94ODYuYzo0NzU3LDQ3NjMKPiAgIAkg Ki8KPiAgIAlpZiAodmNwdS0+YXJjaC5ncGFfYXZhaWxhYmxlICYmCj4gICAJICAgIGVtdWxhdG9y X2Nhbl91c2VfZ3BhKGN0eHQpICYmCj4gKyAJICAgICh2Y3B1LT5hcmNoLmVycm9yX2NvZGUgJiBQ RkVSUl9HVUVTVF9GSU5BTF9NQVNLKSAmJgo+ICAgCSAgICAoYWRkciAmIH5QQUdFX01BU0spID09 ICh2Y3B1LT5hcmNoLmdwYV92YWwgJiB+UEFHRV9NQVNLKSkgewo+ICAgCQlncGEgPSB2Y3B1LT5h cmNoLmdwYV92YWw7Cj4gICAJCXJldCA9IHZjcHVfaXNfbW1pb19ncGEodmNwdSwgYWRkciwgZ3Bh LCB3cml0ZSk7Cj4gCgpZZXMsIGFkZGluZyB0aGF0IGNoZWNrIG1ha2VzIHNlbnNlIGFzIHdlbGwg KHN0aWxsIGluIGt2bV9tbXVfcGFnZV9mYXVsdCkuCgpQYW9sbwpfX19fX19fX19fX19fX19fX19f X19fX19fX19fX19fX19fX19fX19fX19fX19fXwpWaXJ0dWFsaXphdGlvbiBtYWlsaW5nIGxpc3QK VmlydHVhbGl6YXRpb25AbGlzdHMubGludXgtZm91bmRhdGlvbi5vcmcKaHR0cHM6Ly9saXN0cy5s aW51eGZvdW5kYXRpb24ub3JnL21haWxtYW4vbGlzdGluZm8vdmlydHVhbGl6YXRpb24=