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Fri, 26 Jun 2026 17:56:34 +0000 (GMT) Received: from Mac.ibm.com (unknown [9.61.243.21]) by smtpav04.wdc07v.mail.ibm.com (Postfix) with ESMTP; Fri, 26 Jun 2026 17:56:34 +0000 (GMT) From: Omar Elghoul To: linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: oelghoul@linux.ibm.com, hca@linux.ibm.com, gor@linux.ibm.com, agordeev@linux.ibm.com, borntraeger@linux.ibm.com, svens@linux.ibm.com, schnelle@linux.ibm.com, mjrosato@linux.ibm.com, alifm@linux.ibm.com, farman@linux.ibm.com, gbayer@linux.ibm.com, alex@shazbot.org Subject: [PATCH v5 2/4] s390/pci: Preserve FMB state in device re-enablement Date: Fri, 26 Jun 2026 13:55:23 -0400 Message-ID: <20260626175525.37370-3-oelghoul@linux.ibm.com> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260626175525.37370-1-oelghoul@linux.ibm.com> References: <20260626175525.37370-1-oelghoul@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: bs13FM0vJ2-RA-u3buSvXrSZd9x1MMCm X-Proofpoint-GUID: bs13FM0vJ2-RA-u3buSvXrSZd9x1MMCm X-Authority-Analysis: v=2.4 cv=Y4XIdBeN c=1 sm=1 tr=0 ts=6a3ebd57 cx=c_pps a=bLidbwmWQ0KltjZqbj+ezA==:117 a=bLidbwmWQ0KltjZqbj+ezA==:17 a=FelO9ux0wxsA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=Y2IxJ9c9Rs8Kov3niI8_:22 a=VnNF1IyMAAAA:8 a=oGupVoiG_xs3DRKMqNIA:9 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNjI2MDE0OCBTYWx0ZWRfX/yrZCOuMNzVw b1NSRgtQ2sDifzjAecug2q80O0/IM2bDfu9+x7/fqYixBJ7xV3uAhSrsawXX5FE9NKemt1va3+B FoNNGopPj1aV9RNmTLuK3bBDbRagCf10inP7qSf7B6hUpueR8fpPEn05EiLt16zBoMuMmQEW/eZ cxYzBH0B/hF39CV+A6UU0hMe9t9LsoYHt7Ym3JH5AerKDP/sd/mp0gCQQ60EqZOjbNXoH2iVq/Y gYkB1DpWm5gUxkxMGEze5U5/xiqxzlEIlevlP/WIBSJyx9d1Dss61gUa5ILI8G0L1XMjXF26FCW uuvtZ7HADVsDU7cq5QSutndoFJtnQGkH5QtXVgUUx9sHV4Eh0/OlUX+/L9Bw6Zv0cvfpZP2xdiR aVldK6XzTyJIwaU5SmwpHSL3m8sq/Gp5PxWI1d+Ns9ptfGnBHN7XQYu17amVpcDjKv3Fwtn7f8K imkGVRYotq5ZeAOey+A== X-Proofpoint-Spam-Info: AW1haW4tMjYwNjI2MDE0OCBTYWx0ZWRfXxEnG+aKVqDkU sxRz0zJ1E8PWcIOoPWhz2Bn5g/eb1e6F4PLyb2vVLn8odxY9hHZ/sAvJMbmrdUHZZWJ3PH2PKfw BmWlvQkZ2tdj+fR9so4U2/FOUnsRQrg= X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.125,FMLib:17.12.100.49 definitions=2026-06-26_04,2026-06-26_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 adultscore=0 priorityscore=1501 malwarescore=0 lowpriorityscore=0 spamscore=0 clxscore=1015 suspectscore=0 impostorscore=0 phishscore=0 bulkscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2606260148 Introduce a function zpci_fmb_reenable_device() that checks the state of the FMB and ensures it is enabled. Reset the counters to zero, disable, and re-enable the FMB if it was already enabled. Call this function during a zPCI device re-enablement, which in turn implicitly ensures that the FMB is enabled for host devices during their KVM registration. Signed-off-by: Omar Elghoul --- arch/s390/include/asm/pci.h | 1 + arch/s390/pci/pci.c | 34 +++++++++++++++++++++++++++++++++- 2 files changed, 34 insertions(+), 1 deletion(-) diff --git a/arch/s390/include/asm/pci.h b/arch/s390/include/asm/pci.h index 5dcf35f0f325..65014e52d559 100644 --- a/arch/s390/include/asm/pci.h +++ b/arch/s390/include/asm/pci.h @@ -323,6 +323,7 @@ void zpci_remove_parent_msi_domain(struct zpci_bus *zbus); /* FMB */ int zpci_fmb_enable_device(struct zpci_dev *); int zpci_fmb_disable_device(struct zpci_dev *); +int zpci_fmb_reenable_device(struct zpci_dev *zdev); /* Debug */ int zpci_debug_init(void); diff --git a/arch/s390/pci/pci.c b/arch/s390/pci/pci.c index 2910d4038d39..1eb6aa772eb3 100644 --- a/arch/s390/pci/pci.c +++ b/arch/s390/pci/pci.c @@ -231,6 +231,34 @@ int zpci_fmb_disable_device(struct zpci_dev *zdev) } return cc ? -EIO : 0; } +EXPORT_SYMBOL_GPL(zpci_fmb_disable_device); + +int zpci_fmb_reenable_device(struct zpci_dev *zdev) +{ + u64 req = ZPCI_CREATE_REQ(zdev->fh, 0, ZPCI_MOD_FC_SET_MEASURE); + struct zpci_fib fib = {0}; + u8 cc, status; + + lockdep_assert_held(&zdev->fmb_lock); + + if (!zdev->fmb) + return zpci_fmb_enable_device(zdev); + + fib.gd = zdev->gisa; + cc = zpci_mod_fc(req, &fib, &status); /* Disable function measurement */ + + /* Unlike in zpci_fmb_disable_device(), cc == 3 is not a valid state here + * because we are re-enabling function measurement for the same function + * handle. + */ + if (cc) + return -EIO; + + kmem_cache_free(zdev_fmb_cache, zdev->fmb); + zdev->fmb = NULL; + return zpci_fmb_enable_device(zdev); +} +EXPORT_SYMBOL_GPL(zpci_fmb_reenable_device); static int zpci_cfg_load(struct zpci_dev *zdev, int offset, u32 *val, u8 len) { @@ -737,9 +765,13 @@ int zpci_reenable_device(struct zpci_dev *zdev) } rc = zpci_iommu_register_ioat(zdev, &status); - if (rc) + if (rc) { zpci_disable_device(zdev); + return rc; + } + guard(mutex)(&zdev->fmb_lock); + zpci_fmb_reenable_device(zdev); return rc; } EXPORT_SYMBOL_GPL(zpci_reenable_device); -- 2.54.0