| Message ID | 1459762426-18440-12-git-send-email-aik@ozlabs.ru (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Mon, Apr 04, 2016 at 07:33:40PM +1000, Alexey Kardashevskiy wrote: > This makes use of the new "memory registering" feature. The idea is > to provide the userspace ability to notify the host kernel about pages > which are going to be used for DMA. Having this information, the host > kernel can pin them all once per user process, do locked pages > accounting (once) and not spent time on doing that in real time with > possible failures which cannot be handled nicely in some cases. > > This adds a prereg memory listener which listens on address_space_memory > and notifies a VFIO container about memory which needs to be > pinned/unpinned. VFIO MMIO regions (i.e. "skip dump" regions) are skipped. > > As there is no per-IOMMU-type release() callback anymore, this stores > the IOMMU type in the container so vfio_listener_release() can device s/device/determine/ ? > if it needs to unregister @prereg_listener. > > The feature is only enabled for SPAPR IOMMU v2. The host kernel changes > are required. Since v2 does not need/support VFIO_IOMMU_ENABLE, this does > not call it when v2 is detected and enabled. > > This does not change the guest visible interface. > > Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru> > --- > Changes: > v15: > * banned unaligned sections > * added an vfio_prereg_gpa_to_ua() helper > > v14: > * s/free_container_exit/listener_release_exit/g > * added "if memory_region_is_iommu()" to vfio_prereg_listener_skipped_section > --- > hw/vfio/Makefile.objs | 1 + > hw/vfio/common.c | 38 +++++++++--- > hw/vfio/prereg.c | 138 ++++++++++++++++++++++++++++++++++++++++++ > include/hw/vfio/vfio-common.h | 4 ++ > trace-events | 2 + > 5 files changed, 173 insertions(+), 10 deletions(-) > create mode 100644 hw/vfio/prereg.c > > diff --git a/hw/vfio/Makefile.objs b/hw/vfio/Makefile.objs > index ceddbb8..5800e0e 100644 > --- a/hw/vfio/Makefile.objs > +++ b/hw/vfio/Makefile.objs > @@ -4,4 +4,5 @@ obj-$(CONFIG_PCI) += pci.o pci-quirks.o > obj-$(CONFIG_SOFTMMU) += platform.o > obj-$(CONFIG_SOFTMMU) += calxeda-xgmac.o > obj-$(CONFIG_SOFTMMU) += amd-xgbe.o > +obj-$(CONFIG_SOFTMMU) += prereg.o > endif > diff --git a/hw/vfio/common.c b/hw/vfio/common.c > index 6bec419..3e9c579 100644 > --- a/hw/vfio/common.c > +++ b/hw/vfio/common.c > @@ -493,6 +493,9 @@ static const MemoryListener vfio_memory_listener = { > static void vfio_listener_release(VFIOContainer *container) > { > memory_listener_unregister(&container->listener); > + if (container->iommu_type == VFIO_SPAPR_TCE_v2_IOMMU) { > + memory_listener_unregister(&container->prereg_listener); > + } > } > > int vfio_region_setup(Object *obj, VFIODevice *vbasedev, VFIORegion *region, > @@ -800,8 +803,8 @@ static int vfio_connect_container(VFIOGroup *group, AddressSpace *as) > goto free_container_exit; > } > > - ret = ioctl(fd, VFIO_SET_IOMMU, > - v2 ? VFIO_TYPE1v2_IOMMU : VFIO_TYPE1_IOMMU); > + container->iommu_type = v2 ? VFIO_TYPE1v2_IOMMU : VFIO_TYPE1_IOMMU; > + ret = ioctl(fd, VFIO_SET_IOMMU, container->iommu_type); > if (ret) { > error_report("vfio: failed to set iommu for container: %m"); > ret = -errno; > @@ -826,8 +829,10 @@ static int vfio_connect_container(VFIOGroup *group, AddressSpace *as) > if ((ret == 0) && (info.flags & VFIO_IOMMU_INFO_PGSIZES)) { > container->iova_pgsizes = info.iova_pgsizes; > } > - } else if (ioctl(fd, VFIO_CHECK_EXTENSION, VFIO_SPAPR_TCE_IOMMU)) { > + } else if (ioctl(fd, VFIO_CHECK_EXTENSION, VFIO_SPAPR_TCE_IOMMU) || > + ioctl(fd, VFIO_CHECK_EXTENSION, VFIO_SPAPR_TCE_v2_IOMMU)) { > struct vfio_iommu_spapr_tce_info info; > + bool v2 = !!ioctl(fd, VFIO_CHECK_EXTENSION, VFIO_SPAPR_TCE_v2_IOMMU); > > ret = ioctl(group->fd, VFIO_GROUP_SET_CONTAINER, &fd); > if (ret) { > @@ -835,7 +840,9 @@ static int vfio_connect_container(VFIOGroup *group, AddressSpace *as) > ret = -errno; > goto free_container_exit; > } > - ret = ioctl(fd, VFIO_SET_IOMMU, VFIO_SPAPR_TCE_IOMMU); > + container->iommu_type = > + v2 ? VFIO_SPAPR_TCE_v2_IOMMU : VFIO_SPAPR_TCE_IOMMU; > + ret = ioctl(fd, VFIO_SET_IOMMU, container->iommu_type); > if (ret) { > error_report("vfio: failed to set iommu for container: %m"); > ret = -errno; > @@ -847,11 +854,22 @@ static int vfio_connect_container(VFIOGroup *group, AddressSpace *as) > * when container fd is closed so we do not call it explicitly > * in this file. > */ > - ret = ioctl(fd, VFIO_IOMMU_ENABLE); > - if (ret) { > - error_report("vfio: failed to enable container: %m"); > - ret = -errno; > - goto free_container_exit; > + if (!v2) { > + ret = ioctl(fd, VFIO_IOMMU_ENABLE); > + if (ret) { > + error_report("vfio: failed to enable container: %m"); > + ret = -errno; > + goto free_container_exit; > + } > + } else { > + container->prereg_listener = vfio_prereg_listener; > + > + memory_listener_register(&container->prereg_listener, > + &address_space_memory); > + if (container->error) { > + error_report("vfio: RAM memory listener initialization failed for container"); > + goto listener_release_exit; > + } > } > > /* > @@ -864,7 +882,7 @@ static int vfio_connect_container(VFIOGroup *group, AddressSpace *as) > if (ret) { > error_report("vfio: VFIO_IOMMU_SPAPR_TCE_GET_INFO failed: %m"); > ret = -errno; > - goto free_container_exit; > + goto listener_release_exit; > } > container->min_iova = info.dma32_window_start; > container->max_iova = container->min_iova + info.dma32_window_size - 1; > diff --git a/hw/vfio/prereg.c b/hw/vfio/prereg.c > new file mode 100644 > index 0000000..5f7fa30 > --- /dev/null > +++ b/hw/vfio/prereg.c > @@ -0,0 +1,138 @@ > +/* > + * DMA memory preregistration > + * > + * Authors: > + * Alexey Kardashevskiy <aik@ozlabs.ru> > + * > + * This work is licensed under the terms of the GNU GPL, version 2. See > + * the COPYING file in the top-level directory. > + */ > + > +#include "qemu/osdep.h" > +#include <sys/ioctl.h> > +#include <linux/vfio.h> > + > +#include "hw/vfio/vfio-common.h" > +#include "qemu/error-report.h" > +#include "trace.h" > + > +static bool vfio_prereg_listener_skipped_section(MemoryRegionSection *section) > +{ > + if (memory_region_is_iommu(section->mr)) { > + error_report("Cannot possibly preregister IOMMU memory"); > + return true; > + } > + > + return !memory_region_is_ram(section->mr) || > + memory_region_is_skip_dump(section->mr); > +} > + > +static void *vfio_prereg_gpa_to_ua(MemoryRegionSection *section, hwaddr gpa) > +{ > + return memory_region_get_ram_ptr(section->mr) + > + section->offset_within_region + > + (gpa - section->offset_within_address_space); > +} > + > +static void vfio_prereg_listener_region_add(MemoryListener *listener, > + MemoryRegionSection *section) > +{ > + VFIOContainer *container = container_of(listener, VFIOContainer, > + prereg_listener); > + const hwaddr gpa = section->offset_within_address_space; > + Int128 llend; > + int ret; > + hwaddr page_mask = qemu_real_host_page_mask; > + struct vfio_iommu_spapr_register_memory reg = { > + .argsz = sizeof(reg), > + .flags = 0, > + }; > + > + if (vfio_prereg_listener_skipped_section(section)) { > + trace_vfio_listener_region_add_skip( > + section->offset_within_address_space, > + section->offset_within_address_space + > + int128_get64(int128_sub(section->size, int128_one()))); > + return; > + } > + > + if (unlikely((section->offset_within_address_space & ~page_mask) || > + (section->offset_within_region & ~page_mask) || > + (int128_get64(section->size) & ~page_mask))) { > + error_report("%s received unaligned region", __func__); > + return; > + } You could round out the range to pre-register rather than just failing here, but that can be changed later if we need it. > + llend = int128_make64(section->offset_within_address_space); > + llend = int128_add(llend, section->size); > + > + g_assert(!int128_ge(int128_make64(gpa), llend)); > + > + memory_region_ref(section->mr); > + > + reg.vaddr = (__u64) vfio_prereg_gpa_to_ua(section, gpa); > + reg.size = int128_get64(llend) - gpa; > + > + ret = ioctl(container->fd, VFIO_IOMMU_SPAPR_REGISTER_MEMORY, ®); > + trace_vfio_ram_register(reg.vaddr, reg.size, ret ? -errno : 0); > + if (ret) { > + /* > + * On the initfn path, store the first error in the container so we > + * can gracefully fail. Runtime, there's not much we can do other > + * than throw a hardware error. > + */ > + if (!container->initialized) { > + if (!container->error) { > + container->error = ret; > + } > + } else { > + hw_error("vfio: Memory registering failed, unable to continue"); > + } > + } > +} > + > +static void vfio_prereg_listener_region_del(MemoryListener *listener, > + MemoryRegionSection *section) > +{ > + VFIOContainer *container = container_of(listener, VFIOContainer, > + prereg_listener); > + const hwaddr gpa = section->offset_within_address_space; > + hwaddr end; > + int ret; > + hwaddr page_mask = qemu_real_host_page_mask; > + struct vfio_iommu_spapr_register_memory reg = { > + .argsz = sizeof(reg), > + .flags = 0, > + }; > + > + if (vfio_prereg_listener_skipped_section(section)) { > + trace_vfio_listener_region_del_skip( > + section->offset_within_address_space, > + section->offset_within_address_space + > + int128_get64(int128_sub(section->size, int128_one()))); > + return; > + } > + > + if (unlikely((section->offset_within_address_space & ~page_mask) || > + (section->offset_within_region & ~page_mask) || > + (int128_get64(section->size) & ~page_mask))) { > + error_report("%s received unaligned region", __func__); > + return; > + } > + > + end = section->offset_within_address_space + int128_get64(section->size); Why 64-bit math here, but 128 bit math in the region_add path? > + if (gpa >= end) { > + return; > + } > + > + reg.vaddr = (__u64) vfio_prereg_gpa_to_ua(section, gpa); > + reg.size = end - gpa; > + > + ret = ioctl(container->fd, VFIO_IOMMU_SPAPR_UNREGISTER_MEMORY, ®); > + trace_vfio_ram_unregister(reg.vaddr, reg.size, ret ? -errno : 0); > +} > + > +const MemoryListener vfio_prereg_listener = { > + .region_add = vfio_prereg_listener_region_add, > + .region_del = vfio_prereg_listener_region_del, > +}; > diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h > index c9b6622..c72e45a 100644 > --- a/include/hw/vfio/vfio-common.h > +++ b/include/hw/vfio/vfio-common.h > @@ -73,6 +73,8 @@ typedef struct VFIOContainer { > VFIOAddressSpace *space; > int fd; /* /dev/vfio/vfio, empowered by the attached groups */ > MemoryListener listener; > + MemoryListener prereg_listener; > + unsigned iommu_type; > int error; > bool initialized; > /* > @@ -156,4 +158,6 @@ extern QLIST_HEAD(vfio_as_head, VFIOAddressSpace) vfio_address_spaces; > int vfio_get_region_info(VFIODevice *vbasedev, int index, > struct vfio_region_info **info); > #endif > +extern const MemoryListener vfio_prereg_listener; > + > #endif /* !HW_VFIO_VFIO_COMMON_H */ > diff --git a/trace-events b/trace-events > index 4335b9b..23ca0b9 100644 > --- a/trace-events > +++ b/trace-events > @@ -1736,6 +1736,8 @@ vfio_region_mmap(const char *name, unsigned long offset, unsigned long end) "Reg > vfio_region_exit(const char *name, int index) "Device %s, region %d" > vfio_region_finalize(const char *name, int index) "Device %s, region %d" > vfio_region_mmaps_set_enabled(const char *name, bool enabled) "Region %s mmaps enabled: %d" > +vfio_ram_register(uint64_t va, uint64_t size, int ret) "va=%"PRIx64" size=%"PRIx64" ret=%d" > +vfio_ram_unregister(uint64_t va, uint64_t size, int ret) "va=%"PRIx64" size=%"PRIx64" ret=%d" > > # hw/vfio/platform.c > vfio_platform_base_device_init(char *name, int groupid) "%s belongs to group #%d"
On 04/06/2016 04:05 PM, David Gibson wrote: > On Mon, Apr 04, 2016 at 07:33:40PM +1000, Alexey Kardashevskiy wrote: >> This makes use of the new "memory registering" feature. The idea is >> to provide the userspace ability to notify the host kernel about pages >> which are going to be used for DMA. Having this information, the host >> kernel can pin them all once per user process, do locked pages >> accounting (once) and not spent time on doing that in real time with >> possible failures which cannot be handled nicely in some cases. >> >> This adds a prereg memory listener which listens on address_space_memory >> and notifies a VFIO container about memory which needs to be >> pinned/unpinned. VFIO MMIO regions (i.e. "skip dump" regions) are skipped. >> >> As there is no per-IOMMU-type release() callback anymore, this stores >> the IOMMU type in the container so vfio_listener_release() can device > > s/device/determine/ ? That was supposed to be "decide" but "determine" will also do :) > >> if it needs to unregister @prereg_listener. >> >> The feature is only enabled for SPAPR IOMMU v2. The host kernel changes >> are required. Since v2 does not need/support VFIO_IOMMU_ENABLE, this does >> not call it when v2 is detected and enabled. >> >> This does not change the guest visible interface. >> >> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru> >> --- >> Changes: >> v15: >> * banned unaligned sections >> * added an vfio_prereg_gpa_to_ua() helper >> >> v14: >> * s/free_container_exit/listener_release_exit/g >> * added "if memory_region_is_iommu()" to vfio_prereg_listener_skipped_section >> --- >> hw/vfio/Makefile.objs | 1 + >> hw/vfio/common.c | 38 +++++++++--- >> hw/vfio/prereg.c | 138 ++++++++++++++++++++++++++++++++++++++++++ >> include/hw/vfio/vfio-common.h | 4 ++ >> trace-events | 2 + >> 5 files changed, 173 insertions(+), 10 deletions(-) >> create mode 100644 hw/vfio/prereg.c >> >> diff --git a/hw/vfio/Makefile.objs b/hw/vfio/Makefile.objs >> index ceddbb8..5800e0e 100644 >> --- a/hw/vfio/Makefile.objs >> +++ b/hw/vfio/Makefile.objs >> @@ -4,4 +4,5 @@ obj-$(CONFIG_PCI) += pci.o pci-quirks.o >> obj-$(CONFIG_SOFTMMU) += platform.o >> obj-$(CONFIG_SOFTMMU) += calxeda-xgmac.o >> obj-$(CONFIG_SOFTMMU) += amd-xgbe.o >> +obj-$(CONFIG_SOFTMMU) += prereg.o >> endif >> diff --git a/hw/vfio/common.c b/hw/vfio/common.c >> index 6bec419..3e9c579 100644 >> --- a/hw/vfio/common.c >> +++ b/hw/vfio/common.c >> @@ -493,6 +493,9 @@ static const MemoryListener vfio_memory_listener = { >> static void vfio_listener_release(VFIOContainer *container) >> { >> memory_listener_unregister(&container->listener); >> + if (container->iommu_type == VFIO_SPAPR_TCE_v2_IOMMU) { >> + memory_listener_unregister(&container->prereg_listener); >> + } >> } >> >> int vfio_region_setup(Object *obj, VFIODevice *vbasedev, VFIORegion *region, >> @@ -800,8 +803,8 @@ static int vfio_connect_container(VFIOGroup *group, AddressSpace *as) >> goto free_container_exit; >> } >> >> - ret = ioctl(fd, VFIO_SET_IOMMU, >> - v2 ? VFIO_TYPE1v2_IOMMU : VFIO_TYPE1_IOMMU); >> + container->iommu_type = v2 ? VFIO_TYPE1v2_IOMMU : VFIO_TYPE1_IOMMU; >> + ret = ioctl(fd, VFIO_SET_IOMMU, container->iommu_type); >> if (ret) { >> error_report("vfio: failed to set iommu for container: %m"); >> ret = -errno; >> @@ -826,8 +829,10 @@ static int vfio_connect_container(VFIOGroup *group, AddressSpace *as) >> if ((ret == 0) && (info.flags & VFIO_IOMMU_INFO_PGSIZES)) { >> container->iova_pgsizes = info.iova_pgsizes; >> } >> - } else if (ioctl(fd, VFIO_CHECK_EXTENSION, VFIO_SPAPR_TCE_IOMMU)) { >> + } else if (ioctl(fd, VFIO_CHECK_EXTENSION, VFIO_SPAPR_TCE_IOMMU) || >> + ioctl(fd, VFIO_CHECK_EXTENSION, VFIO_SPAPR_TCE_v2_IOMMU)) { >> struct vfio_iommu_spapr_tce_info info; >> + bool v2 = !!ioctl(fd, VFIO_CHECK_EXTENSION, VFIO_SPAPR_TCE_v2_IOMMU); >> >> ret = ioctl(group->fd, VFIO_GROUP_SET_CONTAINER, &fd); >> if (ret) { >> @@ -835,7 +840,9 @@ static int vfio_connect_container(VFIOGroup *group, AddressSpace *as) >> ret = -errno; >> goto free_container_exit; >> } >> - ret = ioctl(fd, VFIO_SET_IOMMU, VFIO_SPAPR_TCE_IOMMU); >> + container->iommu_type = >> + v2 ? VFIO_SPAPR_TCE_v2_IOMMU : VFIO_SPAPR_TCE_IOMMU; >> + ret = ioctl(fd, VFIO_SET_IOMMU, container->iommu_type); >> if (ret) { >> error_report("vfio: failed to set iommu for container: %m"); >> ret = -errno; >> @@ -847,11 +854,22 @@ static int vfio_connect_container(VFIOGroup *group, AddressSpace *as) >> * when container fd is closed so we do not call it explicitly >> * in this file. >> */ >> - ret = ioctl(fd, VFIO_IOMMU_ENABLE); >> - if (ret) { >> - error_report("vfio: failed to enable container: %m"); >> - ret = -errno; >> - goto free_container_exit; >> + if (!v2) { >> + ret = ioctl(fd, VFIO_IOMMU_ENABLE); >> + if (ret) { >> + error_report("vfio: failed to enable container: %m"); >> + ret = -errno; >> + goto free_container_exit; >> + } >> + } else { >> + container->prereg_listener = vfio_prereg_listener; >> + >> + memory_listener_register(&container->prereg_listener, >> + &address_space_memory); >> + if (container->error) { >> + error_report("vfio: RAM memory listener initialization failed for container"); >> + goto listener_release_exit; >> + } >> } >> >> /* >> @@ -864,7 +882,7 @@ static int vfio_connect_container(VFIOGroup *group, AddressSpace *as) >> if (ret) { >> error_report("vfio: VFIO_IOMMU_SPAPR_TCE_GET_INFO failed: %m"); >> ret = -errno; >> - goto free_container_exit; >> + goto listener_release_exit; >> } >> container->min_iova = info.dma32_window_start; >> container->max_iova = container->min_iova + info.dma32_window_size - 1; >> diff --git a/hw/vfio/prereg.c b/hw/vfio/prereg.c >> new file mode 100644 >> index 0000000..5f7fa30 >> --- /dev/null >> +++ b/hw/vfio/prereg.c >> @@ -0,0 +1,138 @@ >> +/* >> + * DMA memory preregistration >> + * >> + * Authors: >> + * Alexey Kardashevskiy <aik@ozlabs.ru> >> + * >> + * This work is licensed under the terms of the GNU GPL, version 2. See >> + * the COPYING file in the top-level directory. >> + */ >> + >> +#include "qemu/osdep.h" >> +#include <sys/ioctl.h> >> +#include <linux/vfio.h> >> + >> +#include "hw/vfio/vfio-common.h" >> +#include "qemu/error-report.h" >> +#include "trace.h" >> + >> +static bool vfio_prereg_listener_skipped_section(MemoryRegionSection *section) >> +{ >> + if (memory_region_is_iommu(section->mr)) { >> + error_report("Cannot possibly preregister IOMMU memory"); >> + return true; >> + } >> + >> + return !memory_region_is_ram(section->mr) || >> + memory_region_is_skip_dump(section->mr); >> +} >> + >> +static void *vfio_prereg_gpa_to_ua(MemoryRegionSection *section, hwaddr gpa) >> +{ >> + return memory_region_get_ram_ptr(section->mr) + >> + section->offset_within_region + >> + (gpa - section->offset_within_address_space); >> +} >> + >> +static void vfio_prereg_listener_region_add(MemoryListener *listener, >> + MemoryRegionSection *section) >> +{ >> + VFIOContainer *container = container_of(listener, VFIOContainer, >> + prereg_listener); >> + const hwaddr gpa = section->offset_within_address_space; >> + Int128 llend; >> + int ret; >> + hwaddr page_mask = qemu_real_host_page_mask; >> + struct vfio_iommu_spapr_register_memory reg = { >> + .argsz = sizeof(reg), >> + .flags = 0, >> + }; >> + >> + if (vfio_prereg_listener_skipped_section(section)) { >> + trace_vfio_listener_region_add_skip( >> + section->offset_within_address_space, >> + section->offset_within_address_space + >> + int128_get64(int128_sub(section->size, int128_one()))); >> + return; >> + } >> + >> + if (unlikely((section->offset_within_address_space & ~page_mask) || >> + (section->offset_within_region & ~page_mask) || >> + (int128_get64(section->size) & ~page_mask))) { >> + error_report("%s received unaligned region", __func__); >> + return; >> + } > > You could round out the range to pre-register rather than just failing > here, but that can be changed later if we need it. Do we really want to support non-host-page-aligned guest RAM size? I'd prefer less automated decisions at this stage really, regardless. > >> + llend = int128_make64(section->offset_within_address_space); >> + llend = int128_add(llend, section->size); >> + >> + g_assert(!int128_ge(int128_make64(gpa), llend)); >> + >> + memory_region_ref(section->mr); >> + >> + reg.vaddr = (__u64) vfio_prereg_gpa_to_ua(section, gpa); >> + reg.size = int128_get64(llend) - gpa; >> + >> + ret = ioctl(container->fd, VFIO_IOMMU_SPAPR_REGISTER_MEMORY, ®); >> + trace_vfio_ram_register(reg.vaddr, reg.size, ret ? -errno : 0); >> + if (ret) { >> + /* >> + * On the initfn path, store the first error in the container so we >> + * can gracefully fail. Runtime, there's not much we can do other >> + * than throw a hardware error. >> + */ >> + if (!container->initialized) { >> + if (!container->error) { >> + container->error = ret; >> + } >> + } else { >> + hw_error("vfio: Memory registering failed, unable to continue"); >> + } >> + } >> +} >> + >> +static void vfio_prereg_listener_region_del(MemoryListener *listener, >> + MemoryRegionSection *section) >> +{ >> + VFIOContainer *container = container_of(listener, VFIOContainer, >> + prereg_listener); >> + const hwaddr gpa = section->offset_within_address_space; >> + hwaddr end; >> + int ret; >> + hwaddr page_mask = qemu_real_host_page_mask; >> + struct vfio_iommu_spapr_register_memory reg = { >> + .argsz = sizeof(reg), >> + .flags = 0, >> + }; >> + >> + if (vfio_prereg_listener_skipped_section(section)) { >> + trace_vfio_listener_region_del_skip( >> + section->offset_within_address_space, >> + section->offset_within_address_space + >> + int128_get64(int128_sub(section->size, int128_one()))); >> + return; >> + } >> + >> + if (unlikely((section->offset_within_address_space & ~page_mask) || >> + (section->offset_within_region & ~page_mask) || >> + (int128_get64(section->size) & ~page_mask))) { >> + error_report("%s received unaligned region", __func__); >> + return; >> + } >> + >> + end = section->offset_within_address_space + int128_get64(section->size); > > Why 64-bit math here, but 128 bit math in the region_add path? Hm. Good question. It has been copied from the common VFIO code where it was since 7532d3cbf1, back those days I did not even think of VFIO devices hot(un)plugging so region_del() was never executed so this seems to be a bug there and here. Yet another patch is coming then. > >> + if (gpa >= end) { >> + return; >> + } >> + >> + reg.vaddr = (__u64) vfio_prereg_gpa_to_ua(section, gpa); >> + reg.size = end - gpa; >> + >> + ret = ioctl(container->fd, VFIO_IOMMU_SPAPR_UNREGISTER_MEMORY, ®); >> + trace_vfio_ram_unregister(reg.vaddr, reg.size, ret ? -errno : 0); >> +} >> + >> +const MemoryListener vfio_prereg_listener = { >> + .region_add = vfio_prereg_listener_region_add, >> + .region_del = vfio_prereg_listener_region_del, >> +}; >> diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h >> index c9b6622..c72e45a 100644 >> --- a/include/hw/vfio/vfio-common.h >> +++ b/include/hw/vfio/vfio-common.h >> @@ -73,6 +73,8 @@ typedef struct VFIOContainer { >> VFIOAddressSpace *space; >> int fd; /* /dev/vfio/vfio, empowered by the attached groups */ >> MemoryListener listener; >> + MemoryListener prereg_listener; >> + unsigned iommu_type; >> int error; >> bool initialized; >> /* >> @@ -156,4 +158,6 @@ extern QLIST_HEAD(vfio_as_head, VFIOAddressSpace) vfio_address_spaces; >> int vfio_get_region_info(VFIODevice *vbasedev, int index, >> struct vfio_region_info **info); >> #endif >> +extern const MemoryListener vfio_prereg_listener; >> + >> #endif /* !HW_VFIO_VFIO_COMMON_H */ >> diff --git a/trace-events b/trace-events >> index 4335b9b..23ca0b9 100644 >> --- a/trace-events >> +++ b/trace-events >> @@ -1736,6 +1736,8 @@ vfio_region_mmap(const char *name, unsigned long offset, unsigned long end) "Reg >> vfio_region_exit(const char *name, int index) "Device %s, region %d" >> vfio_region_finalize(const char *name, int index) "Device %s, region %d" >> vfio_region_mmaps_set_enabled(const char *name, bool enabled) "Region %s mmaps enabled: %d" >> +vfio_ram_register(uint64_t va, uint64_t size, int ret) "va=%"PRIx64" size=%"PRIx64" ret=%d" >> +vfio_ram_unregister(uint64_t va, uint64_t size, int ret) "va=%"PRIx64" size=%"PRIx64" ret=%d" >> >> # hw/vfio/platform.c >> vfio_platform_base_device_init(char *name, int groupid) "%s belongs to group #%d" >
diff --git a/hw/vfio/Makefile.objs b/hw/vfio/Makefile.objs index ceddbb8..5800e0e 100644 --- a/hw/vfio/Makefile.objs +++ b/hw/vfio/Makefile.objs @@ -4,4 +4,5 @@ obj-$(CONFIG_PCI) += pci.o pci-quirks.o obj-$(CONFIG_SOFTMMU) += platform.o obj-$(CONFIG_SOFTMMU) += calxeda-xgmac.o obj-$(CONFIG_SOFTMMU) += amd-xgbe.o +obj-$(CONFIG_SOFTMMU) += prereg.o endif diff --git a/hw/vfio/common.c b/hw/vfio/common.c index 6bec419..3e9c579 100644 --- a/hw/vfio/common.c +++ b/hw/vfio/common.c @@ -493,6 +493,9 @@ static const MemoryListener vfio_memory_listener = { static void vfio_listener_release(VFIOContainer *container) { memory_listener_unregister(&container->listener); + if (container->iommu_type == VFIO_SPAPR_TCE_v2_IOMMU) { + memory_listener_unregister(&container->prereg_listener); + } } int vfio_region_setup(Object *obj, VFIODevice *vbasedev, VFIORegion *region, @@ -800,8 +803,8 @@ static int vfio_connect_container(VFIOGroup *group, AddressSpace *as) goto free_container_exit; } - ret = ioctl(fd, VFIO_SET_IOMMU, - v2 ? VFIO_TYPE1v2_IOMMU : VFIO_TYPE1_IOMMU); + container->iommu_type = v2 ? VFIO_TYPE1v2_IOMMU : VFIO_TYPE1_IOMMU; + ret = ioctl(fd, VFIO_SET_IOMMU, container->iommu_type); if (ret) { error_report("vfio: failed to set iommu for container: %m"); ret = -errno; @@ -826,8 +829,10 @@ static int vfio_connect_container(VFIOGroup *group, AddressSpace *as) if ((ret == 0) && (info.flags & VFIO_IOMMU_INFO_PGSIZES)) { container->iova_pgsizes = info.iova_pgsizes; } - } else if (ioctl(fd, VFIO_CHECK_EXTENSION, VFIO_SPAPR_TCE_IOMMU)) { + } else if (ioctl(fd, VFIO_CHECK_EXTENSION, VFIO_SPAPR_TCE_IOMMU) || + ioctl(fd, VFIO_CHECK_EXTENSION, VFIO_SPAPR_TCE_v2_IOMMU)) { struct vfio_iommu_spapr_tce_info info; + bool v2 = !!ioctl(fd, VFIO_CHECK_EXTENSION, VFIO_SPAPR_TCE_v2_IOMMU); ret = ioctl(group->fd, VFIO_GROUP_SET_CONTAINER, &fd); if (ret) { @@ -835,7 +840,9 @@ static int vfio_connect_container(VFIOGroup *group, AddressSpace *as) ret = -errno; goto free_container_exit; } - ret = ioctl(fd, VFIO_SET_IOMMU, VFIO_SPAPR_TCE_IOMMU); + container->iommu_type = + v2 ? VFIO_SPAPR_TCE_v2_IOMMU : VFIO_SPAPR_TCE_IOMMU; + ret = ioctl(fd, VFIO_SET_IOMMU, container->iommu_type); if (ret) { error_report("vfio: failed to set iommu for container: %m"); ret = -errno; @@ -847,11 +854,22 @@ static int vfio_connect_container(VFIOGroup *group, AddressSpace *as) * when container fd is closed so we do not call it explicitly * in this file. */ - ret = ioctl(fd, VFIO_IOMMU_ENABLE); - if (ret) { - error_report("vfio: failed to enable container: %m"); - ret = -errno; - goto free_container_exit; + if (!v2) { + ret = ioctl(fd, VFIO_IOMMU_ENABLE); + if (ret) { + error_report("vfio: failed to enable container: %m"); + ret = -errno; + goto free_container_exit; + } + } else { + container->prereg_listener = vfio_prereg_listener; + + memory_listener_register(&container->prereg_listener, + &address_space_memory); + if (container->error) { + error_report("vfio: RAM memory listener initialization failed for container"); + goto listener_release_exit; + } } /* @@ -864,7 +882,7 @@ static int vfio_connect_container(VFIOGroup *group, AddressSpace *as) if (ret) { error_report("vfio: VFIO_IOMMU_SPAPR_TCE_GET_INFO failed: %m"); ret = -errno; - goto free_container_exit; + goto listener_release_exit; } container->min_iova = info.dma32_window_start; container->max_iova = container->min_iova + info.dma32_window_size - 1; diff --git a/hw/vfio/prereg.c b/hw/vfio/prereg.c new file mode 100644 index 0000000..5f7fa30 --- /dev/null +++ b/hw/vfio/prereg.c @@ -0,0 +1,138 @@ +/* + * DMA memory preregistration + * + * Authors: + * Alexey Kardashevskiy <aik@ozlabs.ru> + * + * This work is licensed under the terms of the GNU GPL, version 2. See + * the COPYING file in the top-level directory. + */ + +#include "qemu/osdep.h" +#include <sys/ioctl.h> +#include <linux/vfio.h> + +#include "hw/vfio/vfio-common.h" +#include "qemu/error-report.h" +#include "trace.h" + +static bool vfio_prereg_listener_skipped_section(MemoryRegionSection *section) +{ + if (memory_region_is_iommu(section->mr)) { + error_report("Cannot possibly preregister IOMMU memory"); + return true; + } + + return !memory_region_is_ram(section->mr) || + memory_region_is_skip_dump(section->mr); +} + +static void *vfio_prereg_gpa_to_ua(MemoryRegionSection *section, hwaddr gpa) +{ + return memory_region_get_ram_ptr(section->mr) + + section->offset_within_region + + (gpa - section->offset_within_address_space); +} + +static void vfio_prereg_listener_region_add(MemoryListener *listener, + MemoryRegionSection *section) +{ + VFIOContainer *container = container_of(listener, VFIOContainer, + prereg_listener); + const hwaddr gpa = section->offset_within_address_space; + Int128 llend; + int ret; + hwaddr page_mask = qemu_real_host_page_mask; + struct vfio_iommu_spapr_register_memory reg = { + .argsz = sizeof(reg), + .flags = 0, + }; + + if (vfio_prereg_listener_skipped_section(section)) { + trace_vfio_listener_region_add_skip( + section->offset_within_address_space, + section->offset_within_address_space + + int128_get64(int128_sub(section->size, int128_one()))); + return; + } + + if (unlikely((section->offset_within_address_space & ~page_mask) || + (section->offset_within_region & ~page_mask) || + (int128_get64(section->size) & ~page_mask))) { + error_report("%s received unaligned region", __func__); + return; + } + + llend = int128_make64(section->offset_within_address_space); + llend = int128_add(llend, section->size); + + g_assert(!int128_ge(int128_make64(gpa), llend)); + + memory_region_ref(section->mr); + + reg.vaddr = (__u64) vfio_prereg_gpa_to_ua(section, gpa); + reg.size = int128_get64(llend) - gpa; + + ret = ioctl(container->fd, VFIO_IOMMU_SPAPR_REGISTER_MEMORY, ®); + trace_vfio_ram_register(reg.vaddr, reg.size, ret ? -errno : 0); + if (ret) { + /* + * On the initfn path, store the first error in the container so we + * can gracefully fail. Runtime, there's not much we can do other + * than throw a hardware error. + */ + if (!container->initialized) { + if (!container->error) { + container->error = ret; + } + } else { + hw_error("vfio: Memory registering failed, unable to continue"); + } + } +} + +static void vfio_prereg_listener_region_del(MemoryListener *listener, + MemoryRegionSection *section) +{ + VFIOContainer *container = container_of(listener, VFIOContainer, + prereg_listener); + const hwaddr gpa = section->offset_within_address_space; + hwaddr end; + int ret; + hwaddr page_mask = qemu_real_host_page_mask; + struct vfio_iommu_spapr_register_memory reg = { + .argsz = sizeof(reg), + .flags = 0, + }; + + if (vfio_prereg_listener_skipped_section(section)) { + trace_vfio_listener_region_del_skip( + section->offset_within_address_space, + section->offset_within_address_space + + int128_get64(int128_sub(section->size, int128_one()))); + return; + } + + if (unlikely((section->offset_within_address_space & ~page_mask) || + (section->offset_within_region & ~page_mask) || + (int128_get64(section->size) & ~page_mask))) { + error_report("%s received unaligned region", __func__); + return; + } + + end = section->offset_within_address_space + int128_get64(section->size); + if (gpa >= end) { + return; + } + + reg.vaddr = (__u64) vfio_prereg_gpa_to_ua(section, gpa); + reg.size = end - gpa; + + ret = ioctl(container->fd, VFIO_IOMMU_SPAPR_UNREGISTER_MEMORY, ®); + trace_vfio_ram_unregister(reg.vaddr, reg.size, ret ? -errno : 0); +} + +const MemoryListener vfio_prereg_listener = { + .region_add = vfio_prereg_listener_region_add, + .region_del = vfio_prereg_listener_region_del, +}; diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h index c9b6622..c72e45a 100644 --- a/include/hw/vfio/vfio-common.h +++ b/include/hw/vfio/vfio-common.h @@ -73,6 +73,8 @@ typedef struct VFIOContainer { VFIOAddressSpace *space; int fd; /* /dev/vfio/vfio, empowered by the attached groups */ MemoryListener listener; + MemoryListener prereg_listener; + unsigned iommu_type; int error; bool initialized; /* @@ -156,4 +158,6 @@ extern QLIST_HEAD(vfio_as_head, VFIOAddressSpace) vfio_address_spaces; int vfio_get_region_info(VFIODevice *vbasedev, int index, struct vfio_region_info **info); #endif +extern const MemoryListener vfio_prereg_listener; + #endif /* !HW_VFIO_VFIO_COMMON_H */ diff --git a/trace-events b/trace-events index 4335b9b..23ca0b9 100644 --- a/trace-events +++ b/trace-events @@ -1736,6 +1736,8 @@ vfio_region_mmap(const char *name, unsigned long offset, unsigned long end) "Reg vfio_region_exit(const char *name, int index) "Device %s, region %d" vfio_region_finalize(const char *name, int index) "Device %s, region %d" vfio_region_mmaps_set_enabled(const char *name, bool enabled) "Region %s mmaps enabled: %d" +vfio_ram_register(uint64_t va, uint64_t size, int ret) "va=%"PRIx64" size=%"PRIx64" ret=%d" +vfio_ram_unregister(uint64_t va, uint64_t size, int ret) "va=%"PRIx64" size=%"PRIx64" ret=%d" # hw/vfio/platform.c vfio_platform_base_device_init(char *name, int groupid) "%s belongs to group #%d"
This makes use of the new "memory registering" feature. The idea is to provide the userspace ability to notify the host kernel about pages which are going to be used for DMA. Having this information, the host kernel can pin them all once per user process, do locked pages accounting (once) and not spent time on doing that in real time with possible failures which cannot be handled nicely in some cases. This adds a prereg memory listener which listens on address_space_memory and notifies a VFIO container about memory which needs to be pinned/unpinned. VFIO MMIO regions (i.e. "skip dump" regions) are skipped. As there is no per-IOMMU-type release() callback anymore, this stores the IOMMU type in the container so vfio_listener_release() can device if it needs to unregister @prereg_listener. The feature is only enabled for SPAPR IOMMU v2. The host kernel changes are required. Since v2 does not need/support VFIO_IOMMU_ENABLE, this does not call it when v2 is detected and enabled. This does not change the guest visible interface. Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru> --- Changes: v15: * banned unaligned sections * added an vfio_prereg_gpa_to_ua() helper v14: * s/free_container_exit/listener_release_exit/g * added "if memory_region_is_iommu()" to vfio_prereg_listener_skipped_section --- hw/vfio/Makefile.objs | 1 + hw/vfio/common.c | 38 +++++++++--- hw/vfio/prereg.c | 138 ++++++++++++++++++++++++++++++++++++++++++ include/hw/vfio/vfio-common.h | 4 ++ trace-events | 2 + 5 files changed, 173 insertions(+), 10 deletions(-) create mode 100644 hw/vfio/prereg.c