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| From: | Marcel Apfelbaum |
| Subject: | Re: [Qemu-devel] [PATCH v9 1/9] memory: add section range info for IOMMU notifier |
| Date: | Tue, 18 Apr 2017 18:20:11 +0300 |
| User-agent: | Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.1.1 |
On 04/10/2017 10:09 AM, Peter Xu wrote:
On Mon, Apr 10, 2017 at 02:39:22PM +1000, David Gibson wrote:On Fri, Apr 07, 2017 at 06:59:07PM +0800, Peter Xu wrote:In this patch, IOMMUNotifier.{start|end} are introduced to store section information for a specific notifier. When notification occurs, we not only check the notification type (MAP|UNMAP), but also check whether the notified iova range overlaps with the range of specific IOMMU notifier, and skip those notifiers if not in the listened range. When removing an region, we need to make sure we removed the correct VFIOGuestIOMMU by checking the IOMMUNotifier.start address as well. This patch is solving the problem that vfio-pci devices receive duplicated UNMAP notification on x86 platform when vIOMMU is there. The issue is that x86 IOMMU has a (0, 2^64-1) IOMMU region, which is splitted by the (0xfee00000, 0xfeefffff) IRQ region. AFAIK this (splitted IOMMU region) is only happening on x86. This patch also helps vhost to leverage the new interface as well, so that vhost won't get duplicated cache flushes. In that sense, it's an slight performance improvement. Suggested-by: David Gibson <address@hidden> Reviewed-by: Eric Auger <address@hidden> Reviewed-by: Michael S. Tsirkin <address@hidden> Acked-by: Alex Williamson <address@hidden> Signed-off-by: Peter Xu <address@hidden> --- hw/vfio/common.c | 12 +++++++++--- hw/virtio/vhost.c | 10 ++++++++-- include/exec/memory.h | 19 ++++++++++++++++++- memory.c | 9 +++++++++ 4 files changed, 44 insertions(+), 6 deletions(-) diff --git a/hw/vfio/common.c b/hw/vfio/common.c index f3ba9b9..6b33b9f 100644 --- a/hw/vfio/common.c +++ b/hw/vfio/common.c @@ -478,8 +478,13 @@ static void vfio_listener_region_add(MemoryListener *listener, giommu->iommu_offset = section->offset_within_address_space - section->offset_within_region; giommu->container = container; - giommu->n.notify = vfio_iommu_map_notify; - giommu->n.notifier_flags = IOMMU_NOTIFIER_ALL; + llend = int128_add(int128_make64(section->offset_within_region), + section->size); + llend = int128_sub(llend, int128_one()); + iommu_notifier_init(&giommu->n, vfio_iommu_map_notify, + IOMMU_NOTIFIER_ALL, + section->offset_within_region, + int128_get64(llend));Seems to me it would make sense to put the fiddling around to convert the MemoryRegionSection into the necessary values would make sense to go inside iommu_notifier_init().But will we always get one MemoryRegionSection if we are not in any of the region_{add|del} callback? E.g., what if we want to init an IOMMU notifier that covers just the whole IOMMU region range? Considering above, I would still slightly prefer current interface.QLIST_INSERT_HEAD(&container->giommu_list, giommu, giommu_next); memory_region_register_iommu_notifier(giommu->iommu, &giommu->n); @@ -550,7 +555,8 @@ static void vfio_listener_region_del(MemoryListener *listener, VFIOGuestIOMMU *giommu; QLIST_FOREACH(giommu, &container->giommu_list, giommu_next) { - if (giommu->iommu == section->mr) { + if (giommu->iommu == section->mr && + giommu->n.start == section->offset_within_region) {This test should be sufficient, but I'd be a bit more comfortable if there was a test and assert() that the end matches as well. I also wonder if remove-matching-notifier helper would be useful here. Although vhost doesn't appear to ever remove, so maybe it's premature.Oh... vhost does remove it, but I just forgot to touch it up :( ... Thanks for pointing out. Marcel, if this is the only comment, would you mind squash below change into current patch? Thanks,
Hi Peter, I asked Eduardo to merge the series through this machine tree since I don't have a tree yet. He already squashed the change, thanks Eduardo! Marcel
----8<---- diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c index 185b95b..0001e60 100644 --- a/hw/virtio/vhost.c +++ b/hw/virtio/vhost.c @@ -771,7 +771,8 @@ static void vhost_iommu_region_del(MemoryListener *listener, } QLIST_FOREACH(iommu, &dev->iommu_list, iommu_next) { - if (iommu->mr == section->mr) { + if (iommu->mr == section->mr && + iommu->n.start == section->offset_within_region) { memory_region_unregister_iommu_notifier(iommu->mr, &iommu->n); QLIST_REMOVE(iommu, iommu_next); ---->8----memory_region_unregister_iommu_notifier(giommu->iommu, &giommu->n); QLIST_REMOVE(giommu, giommu_next); diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c index 613494d..185b95b 100644 --- a/hw/virtio/vhost.c +++ b/hw/virtio/vhost.c @@ -736,14 +736,20 @@ static void vhost_iommu_region_add(MemoryListener *listener, struct vhost_dev *dev = container_of(listener, struct vhost_dev, iommu_listener); struct vhost_iommu *iommu; + Int128 end; if (!memory_region_is_iommu(section->mr)) { return; } iommu = g_malloc0(sizeof(*iommu)); - iommu->n.notify = vhost_iommu_unmap_notify; - iommu->n.notifier_flags = IOMMU_NOTIFIER_UNMAP; + end = int128_add(int128_make64(section->offset_within_region), + section->size); + end = int128_sub(end, int128_one()); + iommu_notifier_init(&iommu->n, vhost_iommu_unmap_notify, + IOMMU_NOTIFIER_UNMAP, + section->offset_within_region, + int128_get64(end)); iommu->mr = section->mr; iommu->iommu_offset = section->offset_within_address_space - section->offset_within_region; diff --git a/include/exec/memory.h b/include/exec/memory.h index f20b191..0840c89 100644 --- a/include/exec/memory.h +++ b/include/exec/memory.h @@ -77,13 +77,30 @@ typedef enum { #define IOMMU_NOTIFIER_ALL (IOMMU_NOTIFIER_MAP | IOMMU_NOTIFIER_UNMAP) +struct IOMMUNotifier; +typedef void (*IOMMUNotify)(struct IOMMUNotifier *notifier, + IOMMUTLBEntry *data); + struct IOMMUNotifier { - void (*notify)(struct IOMMUNotifier *notifier, IOMMUTLBEntry *data); + IOMMUNotify notify; IOMMUNotifierFlag notifier_flags; + /* Notify for address space range start <= addr <= end */ + hwaddr start; + hwaddr end; QLIST_ENTRY(IOMMUNotifier) node; }; typedef struct IOMMUNotifier IOMMUNotifier; +static inline void iommu_notifier_init(IOMMUNotifier *n, IOMMUNotify fn, + IOMMUNotifierFlag flags, + hwaddr start, hwaddr end) +{ + n->notify = fn; + n->notifier_flags = flags; + n->start = start; + n->end = end; +} + /* New-style MMIO accessors can indicate that the transaction failed. * A zero (MEMTX_OK) response means success; anything else is a failure * of some kind. The memory subsystem will bitwise-OR together results diff --git a/memory.c b/memory.c index 4c95aaf..75ac595 100644 --- a/memory.c +++ b/memory.c @@ -1606,6 +1606,7 @@ void memory_region_register_iommu_notifier(MemoryRegion *mr, /* We need to register for at least one bitfield */ assert(n->notifier_flags != IOMMU_NOTIFIER_NONE); + assert(n->start <= n->end); QLIST_INSERT_HEAD(&mr->iommu_notify, n, node); memory_region_update_iommu_notify_flags(mr); } @@ -1667,6 +1668,14 @@ void memory_region_notify_iommu(MemoryRegion *mr, } QLIST_FOREACH(iommu_notifier, &mr->iommu_notify, node) { + /* + * Skip the notification if the notification does not overlap + * with registered range. + */ + if (iommu_notifier->start > entry.iova + entry.addr_mask + 1 || + iommu_notifier->end < entry.iova) { + continue; + } if (iommu_notifier->notifier_flags & request_flags) { iommu_notifier->notify(iommu_notifier, &entry); }-- 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-- peterx
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