On Wed, Dec 15, 2021 at 10:35:35AM -0500, Jagannathan Raman wrote: > Assign separate address space for each device in the remote processes. If I understand correctly this isn't really an IOMMU. It's abusing the IOMMU APIs to create isolated address spaces for each device. This way memory regions added by the vfio-user client do not conflict when there are multiple vfio-user servers. Calling pci_root_bus_new() and keeping one PCI bus per VfuObject might be a cleaner approach: - Lets you isolate both PCI Memory Space and IO Space. - Isolates the PCIDevices and their addresses on the bus. - Isolates irqs. - No more need to abuse the IOMMU API. I might be missing something because I haven't investigated how to do this myself. > Signed-off-by: Elena Ufimtseva > Signed-off-by: John G Johnson > Signed-off-by: Jagannathan Raman > --- > include/hw/pci/pci.h | 2 + > include/hw/remote/iommu.h | 24 ++++++++ > hw/pci/pci.c | 2 +- > hw/remote/iommu.c | 117 ++++++++++++++++++++++++++++++++++++++ > hw/remote/machine.c | 5 ++ > hw/remote/vfio-user-obj.c | 20 ++++++- > MAINTAINERS | 2 + > hw/remote/meson.build | 1 + > 8 files changed, 169 insertions(+), 4 deletions(-) > create mode 100644 include/hw/remote/iommu.h > create mode 100644 hw/remote/iommu.c > > diff --git a/include/hw/pci/pci.h b/include/hw/pci/pci.h > index 5c4016b995..f2fc2d5375 100644 > --- a/include/hw/pci/pci.h > +++ b/include/hw/pci/pci.h > @@ -734,6 +734,8 @@ void lsi53c8xx_handle_legacy_cmdline(DeviceState *lsi_dev); > qemu_irq pci_allocate_irq(PCIDevice *pci_dev); > void pci_set_irq(PCIDevice *pci_dev, int level); > > +void pci_init_bus_master(PCIDevice *pci_dev); This function isn't used in this patch. Why make it public? > + > static inline void pci_irq_assert(PCIDevice *pci_dev) > { > pci_set_irq(pci_dev, 1); > diff --git a/include/hw/remote/iommu.h b/include/hw/remote/iommu.h > new file mode 100644 > index 0000000000..42ce0ca383 > --- /dev/null > +++ b/include/hw/remote/iommu.h > @@ -0,0 +1,24 @@ > +/* > + * IOMMU for remote device > + * > + * Copyright © 2021 Oracle and/or its affiliates. > + * > + * This work is licensed under the terms of the GNU GPL, version 2 or later. > + * See the COPYING file in the top-level directory. > + * > + */ > + > +#ifndef REMOTE_IOMMU_H > +#define REMOTE_IOMMU_H > + > +#include "hw/pci/pci_bus.h" > + > +void remote_iommu_free(PCIDevice *pci_dev); > + > +void remote_iommu_init(void); > + > +void remote_iommu_set(PCIBus *bus); > + > +MemoryRegion *remote_iommu_get_ram(PCIDevice *pci_dev); > + > +#endif > diff --git a/hw/pci/pci.c b/hw/pci/pci.c > index 4a84e478ce..57d561cc03 100644 > --- a/hw/pci/pci.c > +++ b/hw/pci/pci.c > @@ -95,7 +95,7 @@ static const VMStateDescription vmstate_pcibus = { > } > }; > > -static void pci_init_bus_master(PCIDevice *pci_dev) > +void pci_init_bus_master(PCIDevice *pci_dev) > { > AddressSpace *dma_as = pci_device_iommu_address_space(pci_dev); > > diff --git a/hw/remote/iommu.c b/hw/remote/iommu.c > new file mode 100644 > index 0000000000..30c866badb > --- /dev/null > +++ b/hw/remote/iommu.c > @@ -0,0 +1,117 @@ > +/* > + * Remote IOMMU > + * > + * Copyright © 2021 Oracle and/or its affiliates. > + * > + * This work is licensed under the terms of the GNU GPL, version 2 or later. > + * See the COPYING file in the top-level directory. > + * > + */ > + > +#include "qemu/osdep.h" > +#include "qemu-common.h" > + > +#include "hw/remote/iommu.h" > +#include "hw/pci/pci_bus.h" > +#include "exec/memory.h" > +#include "exec/address-spaces.h" > +#include "trace.h" > + > +struct VFUIOMMU { > + AddressSpace as; > + MemoryRegion mr; I guess this is the root MemoryRegion container? Calling it "root" or "root_mr" instead of "mr" would make that clearer. > +}; > + > +typedef struct VFUPciBus { There is no uppercase/lowercase consistency between VfuObject vs VFUIOMMU vs VFUPciBus. Although the coding standard doesn't dictate ABC vs Abc, please be consistent. I suggest following the VfuObject convention started in the previous patches. The names would be VfuIommu and VfuPciBus. > + PCIBus *bus; > + struct VFUIOMMU *iommu[]; > +} VFUPciBus; > + > +GHashTable *remote_as_table; > + > +static AddressSpace *remote_iommu_get_as(PCIBus *bus, void *opaque, int devfn) > +{ > + VFUPciBus *vfu_pci_bus = NULL; > + struct VFUIOMMU *iommu = NULL; > + > + if (!remote_as_table) { > + return &address_space_memory; > + } > + > + vfu_pci_bus = g_hash_table_lookup(remote_as_table, bus); > + > + if (!vfu_pci_bus) { > + vfu_pci_bus = g_malloc0(sizeof(VFUPciBus)); > + vfu_pci_bus->bus = bus; > + g_hash_table_insert(remote_as_table, bus, vfu_pci_bus); > + } > + > + iommu = vfu_pci_bus->iommu[devfn]; > + > + if (!iommu) { > + g_autofree char *mr_name = g_strdup_printf("vfu-ram-%d", devfn); > + g_autofree char *as_name = g_strdup_printf("vfu-as-%d", devfn); > + > + iommu = g_malloc0(sizeof(struct VFUIOMMU)); > + > + memory_region_init(&iommu->mr, NULL, mr_name, UINT64_MAX); > + address_space_init(&iommu->as, &iommu->mr, as_name); > + > + vfu_pci_bus->iommu[devfn] = iommu; > + } > + > + return &iommu->as; > +} > + > +void remote_iommu_free(PCIDevice *pci_dev) > +{ > + VFUPciBus *vfu_pci_bus = NULL; > + struct VFUIOMMU *iommu = NULL; > + > + if (!remote_as_table) { > + return; > + } > + > + vfu_pci_bus = g_hash_table_lookup(remote_as_table, pci_get_bus(pci_dev)); > + > + if (!vfu_pci_bus) { > + return; > + } > + > + iommu = vfu_pci_bus->iommu[pci_dev->devfn]; > + > + vfu_pci_bus->iommu[pci_dev->devfn] = NULL; > + > + if (iommu) { > + memory_region_unref(&iommu->mr); > + address_space_destroy(&iommu->as); > + g_free(iommu); > + } > +} > + > +void remote_iommu_init(void) > +{ > + remote_as_table = g_hash_table_new_full(NULL, NULL, NULL, NULL); > +} > + > +void remote_iommu_set(PCIBus *bus) > +{ > + pci_setup_iommu(bus, remote_iommu_get_as, NULL); > +} > + > +MemoryRegion *remote_iommu_get_ram(PCIDevice *pci_dev) > +{ > + PCIBus *bus = pci_get_bus(pci_dev); > + VFUPciBus *vfu_pci_bus; > + > + if (!remote_as_table) { > + return get_system_memory(); > + } > + > + vfu_pci_bus = g_hash_table_lookup(remote_as_table, bus); > + if (!vfu_pci_bus) { > + return get_system_memory(); > + } > + > + return &vfu_pci_bus->iommu[pci_dev->devfn]->mr; > +} > diff --git a/hw/remote/machine.c b/hw/remote/machine.c > index 952105eab5..023be0491e 100644 > --- a/hw/remote/machine.c > +++ b/hw/remote/machine.c > @@ -21,6 +21,7 @@ > #include "qapi/error.h" > #include "hw/pci/pci_host.h" > #include "hw/remote/iohub.h" > +#include "hw/remote/iommu.h" > > static void remote_machine_init(MachineState *machine) > { > @@ -52,6 +53,10 @@ static void remote_machine_init(MachineState *machine) > > remote_iohub_init(&s->iohub); > > + remote_iommu_init(); > + > + remote_iommu_set(pci_host->bus); > + > pci_bus_irqs(pci_host->bus, remote_iohub_set_irq, remote_iohub_map_irq, > &s->iohub, REMOTE_IOHUB_NB_PIRQS); > } > diff --git a/hw/remote/vfio-user-obj.c b/hw/remote/vfio-user-obj.c > index 9399e87cbe..ae375e69b9 100644 > --- a/hw/remote/vfio-user-obj.c > +++ b/hw/remote/vfio-user-obj.c > @@ -49,6 +49,7 @@ > #include "hw/qdev-core.h" > #include "hw/pci/pci.h" > #include "qemu/timer.h" > +#include "hw/remote/iommu.h" > > #define TYPE_VFU_OBJECT "x-vfio-user-server" > OBJECT_DECLARE_TYPE(VfuObject, VfuObjectClass, VFU_OBJECT) > @@ -210,6 +211,7 @@ static ssize_t vfu_object_cfg_access(vfu_ctx_t *vfu_ctx, char * const buf, > > static void dma_register(vfu_ctx_t *vfu_ctx, vfu_dma_info_t *info) > { > + VfuObject *o = vfu_get_private(vfu_ctx); > MemoryRegion *subregion = NULL; > g_autofree char *name = NULL; > static unsigned int suffix; > @@ -226,14 +228,15 @@ static void dma_register(vfu_ctx_t *vfu_ctx, vfu_dma_info_t *info) > memory_region_init_ram_ptr(subregion, NULL, name, > iov->iov_len, info->vaddr); > > - memory_region_add_subregion(get_system_memory(), (hwaddr)iov->iov_base, > - subregion); > + memory_region_add_subregion(remote_iommu_get_ram(o->pci_dev), > + (hwaddr)iov->iov_base, subregion); > > trace_vfu_dma_register((uint64_t)iov->iov_base, iov->iov_len); > } > > static void dma_unregister(vfu_ctx_t *vfu_ctx, vfu_dma_info_t *info) > { > + VfuObject *o = vfu_get_private(vfu_ctx); > MemoryRegion *mr = NULL; > ram_addr_t offset; > > @@ -242,7 +245,7 @@ static void dma_unregister(vfu_ctx_t *vfu_ctx, vfu_dma_info_t *info) > return; > } > > - memory_region_del_subregion(get_system_memory(), mr); > + memory_region_del_subregion(remote_iommu_get_ram(o->pci_dev), mr); > > object_unparent((OBJECT(mr))); > > @@ -320,6 +323,7 @@ static vfu_region_access_cb_t *vfu_object_bar_handlers[PCI_NUM_REGIONS] = { > */ > static void vfu_object_register_bars(vfu_ctx_t *vfu_ctx, PCIDevice *pdev) > { > + VfuObject *o = vfu_get_private(vfu_ctx); > int i; > > for (i = 0; i < PCI_NUM_REGIONS; i++) { > @@ -332,6 +336,12 @@ static void vfu_object_register_bars(vfu_ctx_t *vfu_ctx, PCIDevice *pdev) > vfu_object_bar_handlers[i], > VFU_REGION_FLAG_RW, NULL, 0, -1, 0); > > + if ((o->pci_dev->io_regions[i].type & PCI_BASE_ADDRESS_SPACE) == 0) { > + memory_region_unref(o->pci_dev->io_regions[i].address_space); > + o->pci_dev->io_regions[i].address_space = > + remote_iommu_get_ram(o->pci_dev); > + } This looks hacky. If you create a separate PCIHost for each device instead then the BARs will be created in the MemoryRegion (confusingly named "address_space" in the PCI code) of your choosing. Also, why is PCI Memory Space isolated via VFUIOMMU but PCI IO Space is not?