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Thu, 12 Nov 2020 19:31:08 GMT Received: from aserv0121.oracle.com (aserv0121.oracle.com [141.146.126.235]) by userp3030.oracle.com with ESMTP id 34rtks9ybc-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 12 Nov 2020 19:31:07 +0000 Received: from abhmp0020.oracle.com (abhmp0020.oracle.com [141.146.116.26]) by aserv0121.oracle.com (8.14.4/8.13.8) with ESMTP id 0ACJV4Vp029843; Thu, 12 Nov 2020 19:31:04 GMT Received: from char.us.oracle.com (/10.152.32.25) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Thu, 12 Nov 2020 11:31:04 -0800 Received: by char.us.oracle.com (Postfix, from userid 1000) id E12FC6A0109; Thu, 12 Nov 2020 14:32:53 -0500 (EST) Date: Thu, 12 Nov 2020 14:32:53 -0500 From: Konrad Rzeszutek Wilk To: "Tian, Kevin" Cc: "Raj, Ashok" , Thomas Gleixner , Jason Gunthorpe , "Williams, Dan J" , "Jiang, Dave" , Bjorn Helgaas , "vkoul@kernel.org" , "Dey, Megha" , "maz@kernel.org" , "bhelgaas@google.com" , "alex.williamson@redhat.com" , "Pan, Jacob jun" , "Liu, Yi L" , "Lu, Baolu" , "Kumar, Sanjay K" , "Luck, Tony" , "kwankhede@nvidia.com" , "eric.auger@redhat.com" , "parav@mellanox.com" , "rafael@kernel.org" , "netanelg@mellanox.com" , "shahafs@mellanox.com" , "yan.y.zhao@linux.intel.com" , "pbonzini@redhat.com" , "Ortiz, Samuel" , "Hossain, Mona" , "dmaengine@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-pci@vger.kernel.org" , "kvm@vger.kernel.org" Subject: Re: [PATCH v4 06/17] PCI: add SIOV and IMS capability detection Message-ID: <20201112193253.GG19638@char.us.oracle.com> References: <20201107001207.GA2620339@nvidia.com> <87pn4nk7nn.fsf@nanos.tec.linutronix.de> <20201108235852.GC32074@araj-mobl1.jf.intel.com> <874klykc7h.fsf@nanos.tec.linutronix.de> <20201109173034.GG2620339@nvidia.com> <87pn4mi23u.fsf@nanos.tec.linutronix.de> <20201110051412.GA20147@otc-nc-03> <875z6dik1a.fsf@nanos.tec.linutronix.de> <20201110141323.GB22336@otc-nc-03> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.1 (2017-09-22) X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9803 signatures=668682 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 mlxscore=0 phishscore=0 suspectscore=0 bulkscore=0 malwarescore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2011120116 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9803 signatures=668682 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 lowpriorityscore=0 priorityscore=1501 clxscore=1011 malwarescore=0 mlxscore=0 spamscore=0 suspectscore=0 mlxlogscore=999 impostorscore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2011120116 Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org .monster snip.. > 4. Using CPUID to detect running as guest. But as Thomas pointed out, this > approach is less reliable as not all hypervisors do this way. Is that truly true? It is the first time I see the argument that extra steps are needed and that checking for X86_FEATURE_HYPERVISOR is not enough. Or is it more "Some hypervisor probably forgot about it, so lets make sure we patch over that possible hole?" Also is there anything in this spec that precludes this from working on non-X86 architectures, say ARM systems?