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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id AA8EACE7A89 for ; Sat, 23 Sep 2023 16:44:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232051AbjIWQoa (ORCPT ); Sat, 23 Sep 2023 12:44:30 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56080 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229965AbjIWQo3 (ORCPT ); Sat, 23 Sep 2023 12:44:29 -0400 Received: from smtp-fw-33001.amazon.com (smtp-fw-33001.amazon.com [207.171.190.10]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 15668139; Sat, 23 Sep 2023 09:44:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.de; i=@amazon.de; q=dns/txt; s=amazon201209; t=1695487458; x=1727023458; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=2xx3LLBKBr2Twnx9PDcMEphhMOW9wkJNY6OBiL1LK0c=; b=eovHWO/qP3zZBHv7nsDMk9sNiZdHRp7KsQ10W2JEoFS+Kllo9p6HC7FI dSADKeXtrOuhZ51ElOELu2ctFLfdSK8P//rAWX0XVCl+HpSM2Cwzym2MC eT1HV32fdPDniZpaiNwe1IQrY8+Oe2n1T1H7e3URDn2f2wMLQB4nvoHwF A=; X-IronPort-AV: E=Sophos;i="6.03,171,1694736000"; d="scan'208";a="305729342" Received: from iad12-co-svc-p1-lb1-vlan3.amazon.com (HELO email-inbound-relay-iad-1e-m6i4x-9694bb9e.us-east-1.amazon.com) ([10.43.8.6]) by smtp-border-fw-33001.sea14.amazon.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 Sep 2023 16:44:12 +0000 Received: from EX19MTAUWC001.ant.amazon.com (iad12-ws-svc-p26-lb9-vlan2.iad.amazon.com [10.40.163.34]) by email-inbound-relay-iad-1e-m6i4x-9694bb9e.us-east-1.amazon.com (Postfix) with ESMTPS id 36B84805FB; Sat, 23 Sep 2023 16:43:36 +0000 (UTC) Received: from EX19D020UWC004.ant.amazon.com (10.13.138.149) by EX19MTAUWC001.ant.amazon.com (10.250.64.174) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1118.37; Sat, 23 Sep 2023 16:43:34 +0000 Received: from [0.0.0.0] (10.253.83.51) by EX19D020UWC004.ant.amazon.com (10.13.138.149) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1118.37; Sat, 23 Sep 2023 16:43:31 +0000 Message-ID: Date: Sat, 23 Sep 2023 18:43:29 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC] KVM: x86: Allow userspace exit on HLT and MWAIT, else yield on MWAIT Content-Language: en-GB To: Paolo Bonzini , David Woodhouse CC: , Peter Zijlstra , "Sean Christopherson" , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , , "H. Peter Anvin" , , Nicolas Saenz Julienne , "Griffoul, Fred" References: <1b52b557beb6606007f7ec5672eab0adf1606a34.camel@infradead.org> <3dc66987-49c7-abda-eb70-1898181ef3fe@redhat.com> From: Alexander Graf In-Reply-To: <3dc66987-49c7-abda-eb70-1898181ef3fe@redhat.com> X-Originating-IP: [10.253.83.51] X-ClientProxiedBy: EX19D037UWC001.ant.amazon.com (10.13.139.197) To EX19D020UWC004.ant.amazon.com (10.13.138.149) Content-Type: text/plain; charset="utf-8"; format="flowed" Content-Transfer-Encoding: base64 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Ck9uIDIzLjA5LjIzIDExOjI0LCBQYW9sbyBCb256aW5pIHdyb3RlOgo+Cj4gT24gOS8yMy8yMyAw OToyMiwgRGF2aWQgV29vZGhvdXNlIHdyb3RlOgo+PiBPbiBGcmksIDIwMjMtMDktMjIgYXQgMTQ6 MDAgKzAyMDAsIFBhb2xvIEJvbnppbmkgd3JvdGU6Cj4+PiBUbyBhdm9pZCByYWNlcyB5b3UgbmVl ZCB0d28gZmxhZ3MgdGhvdWdoOyB0aGVyZSBuZWVkcyB0byBiZSBhbHNvIGEKPj4+IGtlcm5lbC0+ dXNlcnNwYWNlIGNvbW11bmljYXRpb24gb2Ygd2hldGhlciB0aGUgdkNQVSBpcyBjdXJyZW50bHkg aW4KPj4+IEhMVCBvciBNV0FJVCwgdXNpbmcgdGhlICJmbGFncyIgZmllbGQgZm9yIGV4YW1wbGUu IElmIGl0IHdhcyBITFQgb25seSwKPj4+IG1vdmluZyB0aGUgbXBfc3RhdGUgaW4ga3ZtX3J1biB3 b3VsZCBzZWVtIGxpa2UgYSBnb29kIGlkZWE7IGJ1dCBub3QgaWYKPj4+IE1XQUlUIG9yIFBBVVNF IGFyZSBhbHNvIGluY2x1ZGVkLgo+Pgo+PiBSaWdodC4gV2hlbiB3b3JrIGlzIGFkZGVkIHRvIGFu IGVtcHR5IHdvcmtxdWV1ZSwgdGhlIFZNTSB3aWxsIHdhbnQgdG8KPj4gaHVudCBmb3IgYSB2Q1BV IHdoaWNoIGlzIGN1cnJlbnRseSBpZGxlIGFuZCB0aGVuIHNpZ25hbCBpdCB0byBleGl0Lgo+Pgo+ PiBBcyB5b3Ugc2F5LCBmb3IgSExUIGl0J3Mgc2ltcGxlIGVub3VnaCB0byBsb29rIGF0IHRoZSBt cF9zdGF0ZSwgYW5kIHdlCj4+IGNhbiBtb3ZlIHRoYXQgaW50byBrdm1fcnVuIHNvIGl0IGRvZXNu J3QgbmVlZCBhbiBpb2N0bC4uLgo+Cj4gTG9va2luZyBhdCBpdCBhZ2Fpbjogbm90IHNvIGVhc3kg YmVjYXVzZSB0aGUgbXBzdGF0ZSBpcyBjaGFuZ2VkIGluIHRoZQo+IHZDUFUgdGhyZWFkIGJ5IHZj cHVfYmxvY2soKSBpdHNlbGYuCj4KPj4gYWx0aG91Z2ggaXQKPj4gd291bGQgYWxzbyBiZSBuaWNl IHRvIGdldCBhbiAqZXZlbnQqIG9uIGFuIGV2ZW50ZmQgd2hlbiB0aGUgdkNQVQo+PiBiZWNvbWVz IHJ1bm5hYmxlIChhcyBub3RlZCwgd2Ugd2FudCB0aGF0IGZvciBWU00gYW55d2F5KS4gT3IgcGVy aGFwcwo+PiBldmVuIHRvIGJlIGFibGUgdG8gcG9sbCgpIG9uIHRoZSB2Q1BVIGZkLgo+Cj4gV2h5 IGRvIHlvdSBuZWVkIGl0P8KgIFlvdSBjYW4ganVzdCB1c2UgS1ZNX1JVTiB0byBnbyB0byBzbGVl cCwgYW5kIGlmIHlvdQo+IGdldCBhbm90aGVyIGpvYiB5b3Uga2ljayBvdXQgdGhlIHZDUFUgd2l0 aCBwdGhyZWFkX2tpbGwuwqAgKEkgYWxzbyBkaWRuJ3QKPiBnZXQgdGhlIFZTTSByZWZlcmVuY2Up LgoKCldpdGggdGhlIG9yaWdpbmFsIFZTTSBwYXRjaGVzLCB3ZSB1c2VkIHRvIG1ha2UgYSB2Q1BV IGF3YXJlIG9mIHRoZSBmYWN0IAp0aGF0IGl0IGNhbiBtb3JwaCBpbnRvIG9uZSBvZiBtYW55IFZU THMuIFRoYXQgYXBwcm9hY2ggdHVybmVkIG91dCB0byBiZSAKaW5zYW5lbHkgaW50cnVzaXZlIGFu ZCBmcmFnaWxlIGFuZCBzbyB3ZSdyZSBjdXJyZW50bHkgcmVpbXBsZW1lbnRpbmcgCmV2ZXJ5dGhp bmcgYXMgVlRMcyBhcyB2Q1BVcy4gVGhhdCBhbGxvd3MgdXMgdG8gbW92ZSB0aGUgbWFqb3JpdHkg b2YgVlNNIApmdW5jdGlvbmFsaXR5IHRvIHVzZXIgc3BhY2UuIEV2ZXJ5dGhpbmcgd2UndmUgc2Vl biBzbyBmYXIgbG9va3MgYXMgaWYgCnRoZXJlIGlzIG5vIHJlYWwgcGVyZm9ybWFuY2UgbG9zcyB3 aXRoIHRoYXQgYXBwcm9hY2guCgpPbmUgc21hbGwgcHJvYmxlbSB3aXRoIHRoYXQgaXMgdGhhdCBu b3cgdXNlciBzcGFjZSBpcyByZXNwb25zaWJsZSBmb3IgCnN3aXRjaGluZyBiZXR3ZWVuIFZUTHM6 IEl0IGRldGVybWluZXMgd2hpY2ggVlRMIGlzIGN1cnJlbnRseSBydW5uaW5nIGFuZCAKbGVhdmVz IGFsbCBvdGhlcnMgKHJlYWQ6IGFsbCBvdGhlciB2Q1BVcykgYXMgc3RvcHBlZC4gVGhhdCBtZWFu cyBpZiB5b3UgCmFyZSBydW5uaW5nIGhhcHBpbHkgaW4gS1ZNX1JVTiBpbiBWVEwwIGFuZCBWVEwx IGdldHMgYW4gaW50ZXJydXB0LCB1c2VyIApzcGFjZSBuZWVkcyB0byBzdG9wIFZUTDAgYW5kIHVu cGF1c2UgVlRMMSB1bnRpbCBpdCB0cmlnZ2VycyBWVExfUkVUVVJOIAphdCB3aGljaCBwb2ludCBW VEwxIHN0b3BzIGV4ZWN1dGlvbiBhbmQgVlRMMCBydW5zIGFnYWluLgoKTmljb2xhcyBidWlsdCBh IHBhdGNoIHRoYXQgZXhwb3NlcyAiaW50ZXJydXB0IG9uIHZDUFUgaXMgcGVuZGluZyIgYXMgYW4g CmlvZXZlbnRmZCB1c2VyIHNwYWNlIGNhbiByZXF1ZXN0LiBUaGF0IHdheSwgdXNlciBzcGFjZSBj YW4ga25vdyB3aGVuZXZlciAKYSBjdXJyZW50bHkgcGF1c2VkIHZDUFUgaGFzIGEgcGVuZGluZyBp bnRlcnJ1cHQgYW5kIGNhbiBhY3QgYWNjb3JkaW5nbHkuIApZb3UgY291bGQgdXNlIHRoZSBzYW1l IG1lY2hhbmlzbSBpZiB5b3Ugd2FudGVkIHRvIGltcGxlbWVudCBITFQgaW4gdXNlciAKc3BhY2Us IGJ1dCBzdGlsbCB1c2UgYW4gaW4ta2VybmVsIExBUElDLgoKCkFsZXgKCgoKCkFtYXpvbiBEZXZl bG9wbWVudCBDZW50ZXIgR2VybWFueSBHbWJICktyYXVzZW5zdHIuIDM4CjEwMTE3IEJlcmxpbgpH ZXNjaGFlZnRzZnVlaHJ1bmc6IENocmlzdGlhbiBTY2hsYWVnZXIsIEpvbmF0aGFuIFdlaXNzCkVp bmdldHJhZ2VuIGFtIEFtdHNnZXJpY2h0IENoYXJsb3R0ZW5idXJnIHVudGVyIEhSQiAxNDkxNzMg QgpTaXR6OiBCZXJsaW4KVXN0LUlEOiBERSAyODkgMjM3IDg3OQoKCg==