From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:39935) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aiDXp-00063V-27 for qemu-devel@nongnu.org; Tue, 22 Mar 2016 00:03:51 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1aiDXn-0002Xw-0t for qemu-devel@nongnu.org; Tue, 22 Mar 2016 00:03:49 -0400 Date: Tue, 22 Mar 2016 15:04:51 +1100 From: David Gibson Message-ID: <20160322040451.GC23586@voom.redhat.com> References: <1458546426-26222-1-git-send-email-aik@ozlabs.ru> <1458546426-26222-14-git-send-email-aik@ozlabs.ru> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="nG7dHWd/DOCuxGWF" Content-Disposition: inline In-Reply-To: <1458546426-26222-14-git-send-email-aik@ozlabs.ru> Subject: Re: [Qemu-devel] [PATCH qemu v14 13/18] vfio: spapr: Add SPAPR IOMMU v2 support (DMA memory preregistering) List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Alexey Kardashevskiy Cc: Alex Williamson , qemu-ppc@nongnu.org, qemu-devel@nongnu.org --nG7dHWd/DOCuxGWF Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Mar 21, 2016 at 06:47:01PM +1100, 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. >=20 > 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. >=20 > 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. >=20 > 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. >=20 > This does not change the guest visible interface. >=20 > Signed-off-by: Alexey Kardashevskiy > --- > Changes: > v14: > * s/free_container_exit/listener_release_exit/g > * added "if memory_region_is_iommu()" to vfio_prereg_listener_skipped_sec= tion > --- > hw/vfio/Makefile.objs | 1 + > hw/vfio/common.c | 38 +++++++++--- > hw/vfio/prereg.c | 137 ++++++++++++++++++++++++++++++++++++= ++++++ > include/hw/vfio/vfio-common.h | 4 ++ > trace-events | 2 + > 5 files changed, 172 insertions(+), 10 deletions(-) > create mode 100644 hw/vfio/prereg.c >=20 > 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-$(CONFIG_PCI) +=3D pci.o pci-quirks.o > obj-$(CONFIG_SOFTMMU) +=3D platform.o > obj-$(CONFIG_SOFTMMU) +=3D calxeda-xgmac.o > obj-$(CONFIG_SOFTMMU) +=3D amd-xgbe.o > +obj-$(CONFIG_SOFTMMU) +=3D prereg.o > endif > diff --git a/hw/vfio/common.c b/hw/vfio/common.c > index 9587c25..a8deb16 100644 > --- a/hw/vfio/common.c > +++ b/hw/vfio/common.c > @@ -493,6 +493,9 @@ static const MemoryListener vfio_memory_listener =3D { > static void vfio_listener_release(VFIOContainer *container) > { > memory_listener_unregister(&container->listener); > + if (container->iommu_type =3D=3D VFIO_SPAPR_TCE_v2_IOMMU) { > + memory_listener_unregister(&container->prereg_listener); > + } > } > =20 > int vfio_region_setup(Object *obj, VFIODevice *vbasedev, VFIORegion *reg= ion, > @@ -800,8 +803,8 @@ static int vfio_connect_container(VFIOGroup *group, A= ddressSpace *as) > goto free_container_exit; > } > =20 > - ret =3D ioctl(fd, VFIO_SET_IOMMU, > - v2 ? VFIO_TYPE1v2_IOMMU : VFIO_TYPE1_IOMMU); > + container->iommu_type =3D v2 ? VFIO_TYPE1v2_IOMMU : VFIO_TYPE1_I= OMMU; > + ret =3D ioctl(fd, VFIO_SET_IOMMU, container->iommu_type); > if (ret) { > error_report("vfio: failed to set iommu for container: %m"); > ret =3D -errno; > @@ -826,8 +829,10 @@ static int vfio_connect_container(VFIOGroup *group, = AddressSpace *as) > if ((ret =3D=3D 0) && (info.flags & VFIO_IOMMU_INFO_PGSIZES)) { > container->iova_pgsizes =3D 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 =3D !!ioctl(fd, VFIO_CHECK_EXTENSION, VFIO_SPAPR_TCE_v2_= IOMMU); > =20 > ret =3D ioctl(group->fd, VFIO_GROUP_SET_CONTAINER, &fd); > if (ret) { > @@ -835,7 +840,9 @@ static int vfio_connect_container(VFIOGroup *group, A= ddressSpace *as) > ret =3D -errno; > goto free_container_exit; > } > - ret =3D ioctl(fd, VFIO_SET_IOMMU, VFIO_SPAPR_TCE_IOMMU); > + container->iommu_type =3D > + v2 ? VFIO_SPAPR_TCE_v2_IOMMU : VFIO_SPAPR_TCE_IOMMU; > + ret =3D ioctl(fd, VFIO_SET_IOMMU, container->iommu_type); > if (ret) { > error_report("vfio: failed to set iommu for container: %m"); > ret =3D -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 =3D ioctl(fd, VFIO_IOMMU_ENABLE); > - if (ret) { > - error_report("vfio: failed to enable container: %m"); > - ret =3D -errno; > - goto free_container_exit; > + if (!v2) { > + ret =3D ioctl(fd, VFIO_IOMMU_ENABLE); > + if (ret) { > + error_report("vfio: failed to enable container: %m"); > + ret =3D -errno; > + goto free_container_exit; > + } > + } else { > + container->prereg_listener =3D vfio_prereg_listener; > + > + memory_listener_register(&container->prereg_listener, > + &address_space_memory); > + if (container->error) { > + error_report("vfio: RAM memory listener initialization f= ailed for container"); > + goto listener_release_exit; > + } > } > =20 > /* > @@ -864,7 +882,7 @@ static int vfio_connect_container(VFIOGroup *group, A= ddressSpace *as) > if (ret) { > error_report("vfio: VFIO_IOMMU_SPAPR_TCE_GET_INFO failed: %m= "); > ret =3D -errno; > - goto free_container_exit; > + goto listener_release_exit; > } > container->min_iova =3D info.dma32_window_start; > container->max_iova =3D 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..36c9ff5 > --- /dev/null > +++ b/hw/vfio/prereg.c > @@ -0,0 +1,137 @@ > +/* > + * DMA memory preregistration > + * > + * Authors: > + * Alexey Kardashevskiy > + * > + * 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 > +#include > + > +#include "hw/vfio/vfio-common.h" > +#include "qemu/error-report.h" > +#include "trace.h" > + > +static bool vfio_prereg_listener_skipped_section(MemoryRegionSection *se= ction) > +{ > + 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_listener_region_add(MemoryListener *listener, > + MemoryRegionSection *section) > +{ > + VFIOContainer *container =3D container_of(listener, VFIOContainer, > + prereg_listener); > + hwaddr gpa; > + Int128 llend; > + int ret; > + hwaddr page_mask =3D qemu_real_host_page_mask; > + struct vfio_iommu_spapr_register_memory reg =3D { > + .argsz =3D sizeof(reg), > + .flags =3D 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) !=3D > + (section->offset_within_region & ~page_mask))) { > + error_report("%s received unaligned region", __func__); > + return; > + } > + > + gpa =3D ROUND_UP(section->offset_within_address_space, ~page_mask + = 1); If offset_within_address_space is not aligned to page_mask, you could fail to preregister a little bit of the section. Sounds like you either want to prohibit that entirely (change the test above) or round down to preregister a bit more than just the section. > + llend =3D int128_make64(section->offset_within_address_space); > + llend =3D int128_add(llend, section->size); > + llend =3D int128_and(llend, int128_exts64(page_mask)); Likewise here you round the end of the section down, which could leave a bit un-preregistered. Sounds like you want to ban that, or round up. > + g_assert(!int128_ge(int128_make64(gpa), llend)); > + > + memory_region_ref(section->mr); > + > + reg.vaddr =3D (__u64) memory_region_get_ram_ptr(section->mr) + > + section->offset_within_region + > + (gpa - section->offset_within_address_space); > + reg.size =3D int128_get64(llend) - gpa; > + > + ret =3D 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 oth= er > + * than throw a hardware error. > + */ > + if (!container->initialized) { > + if (!container->error) { > + container->error =3D ret; > + } > + } else { > + hw_error("vfio: Memory registering failed, unable to continu= e"); > + } > + } > +} > + > +static void vfio_prereg_listener_region_del(MemoryListener *listener, > + MemoryRegionSection *section) > +{ > + VFIOContainer *container =3D container_of(listener, VFIOContainer, > + prereg_listener); > + hwaddr gpa, end; > + int ret; > + hwaddr page_mask =3D qemu_real_host_page_mask; > + struct vfio_iommu_spapr_register_memory reg =3D { > + .argsz =3D sizeof(reg), > + .flags =3D 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) !=3D > + (section->offset_within_region & ~page_mask))) { > + error_report("%s received unaligned region", __func__); > + return; > + } > + > + gpa =3D ROUND_UP(section->offset_within_address_space, ~page_mask + = 1); > + end =3D (section->offset_within_address_space + int128_get64(section= ->size)) & > + page_mask; > + > + if (gpa >=3D end) { > + return; > + } > + > + reg.vaddr =3D (__u64) memory_region_get_ram_ptr(section->mr) + > + section->offset_within_region + > + (gpa - section->offset_within_address_space); > + reg.size =3D end - gpa; Might be useful to have a helper function that does the address calculations, so you can use the same one for region_add and region_del. > + ret =3D ioctl(container->fd, VFIO_IOMMU_SPAPR_UNREGISTER_MEMORY, &re= g); > + trace_vfio_ram_unregister(reg.vaddr, reg.size, ret ? -errno : 0); > +} > + > +const MemoryListener vfio_prereg_listener =3D { > + .region_add =3D vfio_prereg_listener_region_add, > + .region_del =3D vfio_prereg_listener_region_del, > +}; > diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h > index 5341e05..b861eec 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) vfi= o_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 6a94736..cc619e1 100644 > --- a/trace-events > +++ b/trace-events > @@ -1734,6 +1734,8 @@ vfio_region_mmap(const char *name, unsigned long of= fset, 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=3D%"PRIx64" s= ize=3D%"PRIx64" ret=3D%d" > +vfio_ram_unregister(uint64_t va, uint64_t size, int ret) "va=3D%"PRIx64"= size=3D%"PRIx64" ret=3D%d" > =20 > # hw/vfio/platform.c > vfio_platform_base_device_init(char *name, int groupid) "%s belongs to g= roup #%d" --=20 David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson --nG7dHWd/DOCuxGWF Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAEBAgAGBQJW8MRjAAoJEGw4ysog2bOS6OYP/0BmsjSJRyEnEpQ55iQ0pT2b cmLPhjaDADrkV+qUSgszBo8lNQolIFGZqC5no7pHvLhF61AohknhzqJ2AtMCI58b OCsrm1gHT+aTMLsjIilWDpc7lPYL+qgqNnBmfuIODvpyT37wlqIrdRXlzfdbc8BM QChZt01scwrOgZMhlZxAF0JFRNnxWBVG90eMinIGygSc8tsElhpaYiZ/jHblK3AI Oh9r3UwrNcAqe2MmZ0U5KoNFFnkUeErNRJYEqQ+W3bpLhNh4131ACKOUsnCVbrTu KSdFEB9V0cJtVDcQm0Xh0iHuqHqzYNobSTuQWrGtBSNELmHmOfuyOOWd3/T+nDfY DFGKZrgkQmrR9oTlY6p3KKwDKLsN9iyF387oZwXrgKrTgqleLbdgsBtgOjXDTcAO MkuoKuguTmpzkipnwyTMhP0WW/4rMzdYdZzXijD2IW5SsR1rPKlc/5O6D7QDgDKw tbmXbwiUmLwuVfLUOhalQdrdSYClUTT4hbSO3prZMQem1Lg1Vv0a12Ife5qc7aGN kIj0+gTG+4xgZHdYd3Sy84F7h3O/kETtVq1d5AZ7PAxWTC01KSZUOOZBwLKUKgao vUXWXWLFqZk/aT5GpwG55c7rTJY0BXIZj3Cs0RXvRTtu1kzeTaSbaRHtMjRe6FDq aWLfedgR780qiErXAOs7 =exN1 -----END PGP SIGNATURE----- --nG7dHWd/DOCuxGWF--