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charset="UTF-8" Content-Transfer-Encoding: quoted-printable Date: Mon, 22 Jun 2026 20:54:00 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Evolution 3.60.2 (3.60.2-1.fc44) X-TM-AS-GCONF: 00 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNjIyMDE4MyBTYWx0ZWRfX/Ab0WOWCIMRF xKSPb6hHxZIo7if8Rvz73C8nhCjSgDlzKxqgqS+9gqgLJ/XTjLBb5D2L+FBn/CFZtPKI+mzzBr7 TmpqPQ9VpTGA8Ebsy7DuLMwlXIgd9pGiVF/J9EjCSO0dLiihgEk4Pxt6a26uNv1AgJC7gyq8R7A dIlnygM+9/CeqZCJ/WSCxy2w/N3DmQOdQIItW+j6zlY33/73DmSwGbyBWeoC81MxauxCq6eaZ/q WUrJNaNa1GASjrerfBPWP4+AOAuZatejeByW0rDiaNk2eJ4zPIxyxNFRdlGVP5vjpOBq/fZmuem 74iFNz+wrdBtu4MLbjzpbj7nv0JK9aK3AoI7906QSRiXmtqtP3d/JHsmdvPmHJnx4aSrks7qe2A tqH0Q+sLoVmUiYmeV9s6TPdGa8RixaMloS2/lEhE+EZGZIewFKKFBKUdW4ZAKWM53ebYvQKQg7/ h9krnBE5K3wbRG4oRzQ== X-Proofpoint-GUID: 6iFd2jrksA3ygvB0LqZBMoXdvRdXjb61 X-Proofpoint-Spam-Info: AW1haW4tMjYwNjIyMDE4MyBTYWx0ZWRfXx+xyDBTcAPRC f0llpjB+lojbvpsZT/N/8BNehpjrReFW7CtGZ/FWLYv9/El4xCcXYLknQwPjqgXCA6JEbRsXAjB lilLOMfRKJuLQELHqe2yhUq9yMGm/xg= X-Authority-Analysis: v=2.4 cv=I/lVgtgg c=1 sm=1 tr=0 ts=6a39850a cx=c_pps a=aDMHemPKRhS1OARIsFnwRA==:117 a=aDMHemPKRhS1OARIsFnwRA==:17 a=IkcTkHD0fZMA:10 a=FelO9ux0wxsA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=RzCfie-kr_QcCd8fBx8p:22 a=VnNF1IyMAAAA:8 a=AWd1BeZrjBnSaHBDTCkA:9 a=QEXdDO2ut3YA:10 X-Proofpoint-ORIG-GUID: 6iFd2jrksA3ygvB0LqZBMoXdvRdXjb61 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=2026-06-22_03,2026-06-22_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 lowpriorityscore=0 spamscore=0 phishscore=0 clxscore=1015 priorityscore=1501 adultscore=0 impostorscore=0 bulkscore=0 suspectscore=0 malwarescore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2606220183 On Mon, 2026-06-22 at 10:18 -0700, Farhan Ali wrote: > The current MSI-X restoration path assumes the Command register Memory bi= t > is enabled when writing MSI-X messages. But its possible the last saved a= nd SpellingL "it's" > restored state of device may not have the Memory bit enabled, even if a Missing "a" in "of a device" > device driver later enables Memory bit and MSI-X. Attempting to access > Memory space without Memory bit enabled can lead to Unsupported Request > (UR) from the device. Fix this by enabling Memory bit and restore > it afterwards. The official spec term is "Memory Space Enable" and I think "can lead to" is actually underselling it, as the PCIe spec says that accesses are "caused to be handled as Unsupported Requests". Also as I understand you did see this in practice. Maybe we even want a Fixes tag? >=20 > Signed-off-by: Farhan Ali > --- > drivers/pci/msi/msi.c | 4 ++++ > 1 file changed, 4 insertions(+) >=20 > diff --git a/drivers/pci/msi/msi.c b/drivers/pci/msi/msi.c > index 81d24a270a79..46a0d9f68a57 100644 > --- a/drivers/pci/msi/msi.c > +++ b/drivers/pci/msi/msi.c > @@ -874,6 +874,7 @@ void __pci_restore_msix_state(struct pci_dev *dev) > { > struct msi_desc *entry; > bool write_msg; > + u16 cmd; > =20 > if (!dev->msix_enabled) > return; > @@ -882,6 +883,8 @@ void __pci_restore_msix_state(struct pci_dev *dev) > pci_intx_for_msi(dev, 0); > pci_msix_clear_and_set_ctrl(dev, 0, > PCI_MSIX_FLAGS_ENABLE | PCI_MSIX_FLAGS_MASKALL); > + pci_read_config_word(dev, PCI_COMMAND, &cmd); > + pci_write_config_word(dev, PCI_COMMAND, cmd | PCI_COMMAND_MEMORY); > =20 > write_msg =3D arch_restore_msi_irqs(dev); > =20 > @@ -893,6 +896,7 @@ void __pci_restore_msix_state(struct pci_dev *dev) > } > } > =20 > + pci_write_config_word(dev, PCI_COMMAND, cmd); > pci_msix_clear_and_set_ctrl(dev, PCI_MSIX_FLAGS_MASKALL, 0); > } > =20 Code wise this all looks good to me so feel free to add. Reviewed-by: Niklas Schnelle Thanks, Niklas