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Mon, 24 Jun 2019 12:58:19 +0000 Received: from abhmp0016.oracle.com (abhmp0016.oracle.com [141.146.116.22]) by userv0121.oracle.com (8.14.4/8.13.8) with ESMTP id x5OCwHri010630; Mon, 24 Jun 2019 12:58:17 GMT Received: from z2.cn.oracle.com (/10.182.69.87) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Mon, 24 Jun 2019 05:58:16 -0700 From: Zhenzhong Duan To: linux-kernel@vger.kernel.org Date: Sun, 23 Jun 2019 21:01:40 +0800 Message-Id: <1561294903-6166-3-git-send-email-zhenzhong.duan@oracle.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1561294903-6166-1-git-send-email-zhenzhong.duan@oracle.com> References: <1561294903-6166-1-git-send-email-zhenzhong.duan@oracle.com> X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9297 signatures=668687 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=1 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1906240106 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9297 signatures=668687 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=1 phishscore=0 bulkscore=0 spamscore=0 clxscore=1011 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1906240105 Subject: [Xen-devel] [PATCH 3/6] x86: Add nopv parameter to disable PV extensions X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Cc: jgross@suse.com, sstabellini@kernel.org, Zhenzhong Duan , mingo@kernel.org, bp@alien8.de, hpa@zytor.com, xen-devel@lists.xenproject.org, boris.ostrovsky@oracle.com, tglx@linutronix.de MIME-Version: 1.0 Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" X-Virus-Scanned: ClamAV using ClamSMTP In virtualization environment, PV extensions (drivers, interrupts, timers, etc) are enabled in the majority of use cases which is the best option. However, in some cases (kexec not fully working, benchmarking) we want to disable PV extensions. As such introduce the 'nopv' parameter that will do it. There is already 'xen_nopv' parameter for XEN platform but not for others. 'xen_nopv' can then be removed with this change. Signed-off-by: Zhenzhong Duan Cc: xen-devel@lists.xenproject.org --- Documentation/admin-guide/kernel-parameters.txt | 4 ++++ arch/x86/kernel/cpu/hypervisor.c | 11 +++++++++++ 2 files changed, 15 insertions(+) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 138f666..b352f36 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -5268,6 +5268,10 @@ improve timer resolution at the expense of processing more timer interrupts. + nopv= [X86] + Disables the PV optimizations forcing the guest to run + as generic guest with no PV drivers. + xirc2ps_cs= [NET,PCMCIA] Format: ,,,,,[,[,[,]]] diff --git a/arch/x86/kernel/cpu/hypervisor.c b/arch/x86/kernel/cpu/hypervisor.c index 479ca47..4f2c875 100644 --- a/arch/x86/kernel/cpu/hypervisor.c +++ b/arch/x86/kernel/cpu/hypervisor.c @@ -85,10 +85,21 @@ static void __init copy_array(const void *src, void *target, unsigned int size) to[i] = from[i]; } +static bool nopv; +static __init int xen_parse_nopv(char *arg) +{ + nopv = true; + return 0; +} +early_param("nopv", xen_parse_nopv); + void __init init_hypervisor_platform(void) { const struct hypervisor_x86 *h; + if (nopv) + return; + h = detect_hypervisor_vendor(); if (!h)