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a="430953889" X-IronPort-AV: E=Sophos;i="6.01,199,1684825200"; d="scan'208";a="430953889" X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10768"; a="835024184" X-IronPort-AV: E=Sophos;i="6.01,199,1684825200"; d="scan'208";a="835024184" From: Zhenzhong Duan To: qemu-devel@nongnu.org Cc: alex.williamson@redhat.com, clg@redhat.com, jgg@nvidia.com, nicolinc@nvidia.com, eric.auger@redhat.com, peterx@redhat.com, jasonwang@redhat.com, kevin.tian@intel.com, yi.l.liu@intel.com, yi.y.sun@intel.com, chao.p.peng@intel.com, Zhenzhong Duan Subject: [RFC PATCH v4 24/24] vfio/iommufd: Make vfio cdev pre-openable by passing a file handle Date: Wed, 12 Jul 2023 15:25:28 +0800 Message-Id: <20230712072528.275577-25-zhenzhong.duan@intel.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230712072528.275577-1-zhenzhong.duan@intel.com> References: <20230712072528.275577-1-zhenzhong.duan@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=134.134.136.100; envelope-from=zhenzhong.duan@intel.com; helo=mga07.intel.com X-Spam_score_int: -43 X-Spam_score: -4.4 X-Spam_bar: ---- X-Spam_report: (-4.4 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZohoMail-DKIM: pass (identity @intel.com) X-ZM-MESSAGEID: 1689147683898100009 Content-Type: text/plain; charset="utf-8" This gives management tools like libvirt a chance to open the vfio cdev with privilege and pass FD to qemu. This way qemu never needs to have privilege to open a VFIO or iommu cdev node. There is no easy way to check if a device is mdev with FD passing, so fail the x-balloon-allowed check unconditionally in this case. There is also no easy way to get BDF as name with FD passing, so we fake a name by VFIO_FD[fd]. Signed-off-by: Zhenzhong Duan --- hw/vfio/iommufd.c | 12 +++++++---- hw/vfio/pci.c | 53 +++++++++++++++++++++++++++++++++++++++++------ 2 files changed, 55 insertions(+), 10 deletions(-) diff --git a/hw/vfio/iommufd.c b/hw/vfio/iommufd.c index e532eed2ac..87f1960eed 100644 --- a/hw/vfio/iommufd.c +++ b/hw/vfio/iommufd.c @@ -343,11 +343,15 @@ static int iommufd_attach_device(char *name, VFIODevi= ce *vbasedev, uint32_t ioas_id; Error *err =3D NULL; =20 - devfd =3D vfio_get_devicefd(vbasedev->sysfsdev, errp); - if (devfd < 0) { - return devfd; + if (vbasedev->fd < 0) { + devfd =3D vfio_get_devicefd(vbasedev->sysfsdev, errp); + if (devfd < 0) { + return devfd; + } + vbasedev->fd =3D devfd; + } else { + devfd =3D vbasedev->fd; } - vbasedev->fd =3D devfd; =20 space =3D vfio_get_address_space(as); =20 diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c index 9aa6c21200..6429172f30 100644 --- a/hw/vfio/pci.c +++ b/hw/vfio/pci.c @@ -44,6 +44,7 @@ #include "migration/qemu-file.h" #include "linux/iommufd.h" #include "sysemu/iommufd.h" +#include "monitor/monitor.h" =20 #define TYPE_VFIO_PCI_NOHOTPLUG "vfio-pci-nohotplug" =20 @@ -3185,12 +3186,18 @@ static void vfio_realize(PCIDevice *pdev, Error **e= rrp) } #endif =20 - if (!vbasedev->sysfsdev) { + if (vbasedev->fd < 0 && !vbasedev->sysfsdev) { if (!(~vdev->host.domain || ~vdev->host.bus || ~vdev->host.slot || ~vdev->host.function)) { error_setg(errp, "No provided host device"); +#ifdef CONFIG_IOMMUFD + error_append_hint(errp, "Use -device vfio-pci,host=3DDDDD:BB:D= D.F, " + "-device vfio-pci,sysfsdev=3DPATH_TO_DEVICE " + "or -device vfio-pci,fd=3DDEVICE_FD\n"); +#else error_append_hint(errp, "Use -device vfio-pci,host=3DDDDD:BB:D= D.F " "or -device vfio-pci,sysfsdev=3DPATH_TO_DEVI= CE\n"); +#endif return; } vbasedev->sysfsdev =3D @@ -3199,13 +3206,28 @@ static void vfio_realize(PCIDevice *pdev, Error **e= rrp) vdev->host.slot, vdev->host.function); } =20 - if (stat(vbasedev->sysfsdev, &st) < 0) { - error_setg_errno(errp, errno, "no such host device"); - error_prepend(errp, VFIO_MSG_PREFIX, vbasedev->sysfsdev); - return; + if (vbasedev->fd < 0) { + if (stat(vbasedev->sysfsdev, &st) < 0) { + error_setg_errno(errp, errno, "no such host device"); + error_prepend(errp, VFIO_MSG_PREFIX, vbasedev->sysfsdev); + return; + } + vbasedev->name =3D g_path_get_basename(vbasedev->sysfsdev); + } +#ifdef CONFIG_IOMMUFD + else { + if (!vbasedev->iommufd) { + error_setg(errp, "Use FD passing only with iommufd backend"); + return; + } + /* + * Give a name with fd so any function printing out vbasedev->name + * will not break. + */ + vbasedev->name =3D g_strdup_printf("VFIO_FD%d", vbasedev->fd); } +#endif =20 - vbasedev->name =3D g_path_get_basename(vbasedev->sysfsdev); vbasedev->ops =3D &vfio_pci_ops; vbasedev->type =3D VFIO_DEVICE_TYPE_PCI; vbasedev->dev =3D DEVICE(vdev); @@ -3574,6 +3596,7 @@ static void vfio_instance_init(Object *obj) vdev->host.bus =3D ~0U; vdev->host.slot =3D ~0U; vdev->host.function =3D ~0U; + vdev->vbasedev.fd =3D -1; =20 vdev->nv_gpudirect_clique =3D 0xFF; =20 @@ -3634,6 +3657,21 @@ static Property vfio_pci_dev_properties[] =3D { DEFINE_PROP_END_OF_LIST(), }; =20 +#ifdef CONFIG_IOMMUFD +static void vfio_pci_set_fd(Object *obj, const char *str, Error **errp) +{ + VFIOPCIDevice *vdev =3D VFIO_PCI(obj); + int fd =3D -1; + + fd =3D monitor_fd_param(monitor_cur(), str, errp); + if (fd =3D=3D -1) { + error_prepend(errp, "Could not parse remote object fd %s:", str); + return; + } + vdev->vbasedev.fd =3D fd; +} +#endif + static void vfio_pci_dev_class_init(ObjectClass *klass, void *data) { DeviceClass *dc =3D DEVICE_CLASS(klass); @@ -3641,6 +3679,9 @@ static void vfio_pci_dev_class_init(ObjectClass *klas= s, void *data) =20 dc->reset =3D vfio_pci_reset; device_class_set_props(dc, vfio_pci_dev_properties); +#ifdef CONFIG_IOMMUFD + object_class_property_add_str(klass, "fd", NULL, vfio_pci_set_fd); +#endif dc->desc =3D "VFIO-based PCI device assignment"; set_bit(DEVICE_CATEGORY_MISC, dc->categories); pdc->realize =3D vfio_realize; --=20 2.34.1