>-----Original Message----- >From: Duan, Zhenzhong <[email protected]> >Subject: [PATCH 2/2] intel_iommu: Simplify caching mode check with VFIO >device > >In early days, we have different tricks to ensure caching-mode=on with VFIO >device: > >28cf553afe ("intel_iommu: Sanity check vfio-pci config on machine init done") >c6cbc29d36 ("pc/q35: Disallow vfio-pci hotplug without VT-d caching mode") >b8d78277c0 ("intel-iommu: fail MAP notifier without caching mode") > >Because without caching mode, MAP notifier won't work correctly since >guest >won't send IOTLB update event when it establishes new mappings in the I/O >page >tables. > >Now with host IOMMU device interface between VFIO and vIOMMU, we can >simplify >it with a small check in set_iommu_device(). This also works for future VDPA >implementation which may also need caching mode on. I made a wrong assumption on VDPA, currently VDPA doesn't use hiod interface, so commit b8d78277c0 is still needed for VDPA. I'll have to send a v2, sorry for noise. BRs, Zhenzhong > >For coldplug VFIO device: > >qemu-system-x86_64: -device >vfio-pci,host=0000:3b:00.0,id=hostdev3,bus=root0,iommufd=iommufd0: vfio >0000:3b:00.0: Failed to set vIOMMU: Device assignment is not allowed >without enabling caching-mode=on for Intel IOMMU. > >For hotplug VFIO device: > >Error: vfio 0000:3b:00.0: Failed to set vIOMMU: Device assignment is not >allowed without enabling caching-mode=on for Intel IOMMU. > >Signed-off-by: Zhenzhong Duan <[email protected]> >--- > hw/i386/intel_iommu.c | 47 ++++++------------------------------------- > hw/i386/pc.c | 20 ------------------ > 2 files changed, 6 insertions(+), 61 deletions(-) > >diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c >index f04300022e..5c67b42dde 100644 >--- a/hw/i386/intel_iommu.c >+++ b/hw/i386/intel_iommu.c >@@ -85,13 +85,6 @@ struct vtd_iotlb_key { > static void vtd_address_space_refresh_all(IntelIOMMUState *s); > static void vtd_address_space_unmap(VTDAddressSpace *as, >IOMMUNotifier *n); > >-static void vtd_panic_require_caching_mode(void) >-{ >- error_report("We need to set caching-mode=on for intel-iommu to >enable " >- "device assignment with IOMMU protection."); >- exit(1); >-} >- > static void vtd_define_quad(IntelIOMMUState *s, hwaddr addr, uint64_t val, > uint64_t wmask, uint64_t w1cmask) > { >@@ -3731,13 +3724,6 @@ static int >vtd_iommu_notify_flag_changed(IOMMUMemoryRegion *iommu, > "Snoop Control with vhost or VFIO is not >supported"); > return -ENOTSUP; > } >- if (!s->caching_mode && (new & IOMMU_NOTIFIER_MAP)) { >- error_setg_errno(errp, ENOTSUP, >- "device %02x.%02x.%x requires caching >mode", >- pci_bus_num(vtd_as->bus), >PCI_SLOT(vtd_as->devfn), >- PCI_FUNC(vtd_as->devfn)); >- return -ENOTSUP; >- } > if (!x86_iommu->dt_supported && (new & >IOMMU_NOTIFIER_DEVIOTLB_UNMAP)) { > error_setg_errno(errp, ENOTSUP, > "device %02x.%02x.%x requires device IOTLB >mode", >@@ -4378,6 +4364,12 @@ static bool vtd_dev_set_iommu_device(PCIBus >*bus, void *opaque, int devfn, > > assert(hiod); > >+ if (!s->caching_mode) { >+ error_setg(errp, "Device assignment is not allowed without >enabling " >+ "caching-mode=on for Intel IOMMU."); >+ return false; >+ } >+ > vtd_iommu_lock(s); > > if (g_hash_table_lookup(s->vtd_host_iommu_dev, &key)) { >@@ -4910,32 +4902,6 @@ static bool vtd_decide_config(IntelIOMMUState >*s, Error **errp) > return true; > } > >-static int vtd_machine_done_notify_one(Object *child, void *unused) >-{ >- IntelIOMMUState *iommu = >INTEL_IOMMU_DEVICE(x86_iommu_get_default()); >- >- /* >- * We hard-coded here because vfio-pci is the only special case >- * here. Let's be more elegant in the future when we can, but so >- * far there seems to be no better way. >- */ >- if (object_dynamic_cast(child, "vfio-pci") && !iommu->caching_mode) { >- vtd_panic_require_caching_mode(); >- } >- >- return 0; >-} >- >-static void vtd_machine_done_hook(Notifier *notifier, void *unused) >-{ >- object_child_foreach_recursive(object_get_root(), >- vtd_machine_done_notify_one, >NULL); >-} >- >-static Notifier vtd_machine_done_notify = { >- .notify = vtd_machine_done_hook, >-}; >- > static void vtd_realize(DeviceState *dev, Error **errp) > { > MachineState *ms = MACHINE(qdev_get_machine()); >@@ -4990,7 +4956,6 @@ static void vtd_realize(DeviceState *dev, Error >**errp) > pci_setup_iommu(bus, &vtd_iommu_ops, dev); > /* Pseudo address space under root PCI bus. */ > x86ms->ioapic_as = vtd_host_dma_iommu(bus, s, >Q35_PSEUDO_DEVFN_IOAPIC); >- qemu_add_machine_init_done_notifier(&vtd_machine_done_notify); > } > > static void vtd_class_init(ObjectClass *klass, const void *data) >diff --git a/hw/i386/pc.c b/hw/i386/pc.c >index bc048a6d13..01cd9a67db 100644 >--- a/hw/i386/pc.c >+++ b/hw/i386/pc.c >@@ -1720,25 +1720,6 @@ static void pc_machine_wakeup(MachineState >*machine) > cpu_synchronize_all_post_reset(); > } > >-static bool pc_hotplug_allowed(MachineState *ms, DeviceState *dev, Error >**errp) >-{ >- X86IOMMUState *iommu = x86_iommu_get_default(); >- IntelIOMMUState *intel_iommu; >- >- if (iommu && >- object_dynamic_cast((Object *)iommu, >TYPE_INTEL_IOMMU_DEVICE) && >- object_dynamic_cast((Object *)dev, "vfio-pci")) { >- intel_iommu = INTEL_IOMMU_DEVICE(iommu); >- if (!intel_iommu->caching_mode) { >- error_setg(errp, "Device assignment is not allowed without " >- "enabling caching-mode=on for Intel IOMMU."); >- return false; >- } >- } >- >- return true; >-} >- > static void pc_machine_class_init(ObjectClass *oc, const void *data) > { > MachineClass *mc = MACHINE_CLASS(oc); >@@ -1758,7 +1739,6 @@ static void pc_machine_class_init(ObjectClass *oc, >const void *data) > x86mc->apic_xrupt_override = true; > assert(!mc->get_hotplug_handler); > mc->get_hotplug_handler = pc_get_hotplug_handler; >- mc->hotplug_allowed = pc_hotplug_allowed; > mc->auto_enable_numa_with_memhp = true; > mc->auto_enable_numa_with_memdev = true; > mc->has_hotpluggable_cpus = true; >-- >2.47.1
