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Mon, 5 Oct 2020 16:51:59 +0000 (GMT) Received: from yukon.ibmuc.com (sig-9-145-2-207.uk.ibm.com [9.145.2.207]) by smtp.tlslab.ibm.com (Postfix) with ESMTP id 95A85220155; Mon, 5 Oct 2020 18:51:58 +0200 (CEST) From: =?utf-8?q?C=C3=A9dric_Le_Goater?= To: David Gibson Subject: [PATCH v2 3/6] spapr/xive: Add a warning when StoreEOI is activated on POWER9 CPUs Date: Mon, 5 Oct 2020 18:51:44 +0200 Message-Id: <20201005165147.526426-4-clg@kaod.org> X-Mailer: git-send-email 2.25.4 In-Reply-To: <20201005165147.526426-1-clg@kaod.org> References: <20201005165147.526426-1-clg@kaod.org> MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.235, 18.0.687 definitions=2020-10-05_11:2020-10-05, 2020-10-05 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxlogscore=731 malwarescore=0 lowpriorityscore=0 adultscore=0 spamscore=0 bulkscore=0 impostorscore=0 priorityscore=1501 phishscore=0 mlxscore=0 clxscore=1034 suspectscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2010050117 Received-SPF: softfail client-ip=148.163.156.1; envelope-from=clg@kaod.org; helo=mx0a-001b2d01.pphosted.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/10/05 12:52:09 X-ACL-Warn: Detected OS = Linux 3.x [generic] [fuzzy] X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_SOFTFAIL=0.665 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: qemu-devel@nongnu.org, =?utf-8?q?C=C3=A9dric_Le_Goater?= , qemu-ppc@nongnu.org, Greg Kurz , Gustavo Romero Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" StoreEOI on POWER9 CPUs is racy because load-after-store ordering is not enforced. Signed-off-by: Cédric Le Goater --- hw/ppc/spapr_caps.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/hw/ppc/spapr_caps.c b/hw/ppc/spapr_caps.c index b0a9d0227db2..9251badbdc27 100644 --- a/hw/ppc/spapr_caps.c +++ b/hw/ppc/spapr_caps.c @@ -549,6 +549,15 @@ static void cap_storeeoi_apply(SpaprMachineState *spapr, uint8_t val, error_setg(errp, "StoreEOI not supported by KVM"); return; } + + /* + * load-after-store ordering is not enforced on POWER9 CPUs + * and StoreEOI can be racy. + */ + if (!ppc_type_check_compat(machine->cpu_type, CPU_POWERPC_LOGICAL_3_10, + 0, spapr->max_compat_pvr)) { + warn_report("StoreEOI on a POWER9 CPU is unsafe on KVM."); + } } }