From: David Hildenbrand <david@redhat.com>
To: qemu-devel@nongnu.org
Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com>,
Wei Yang <richard.weiyang@linux.alibaba.com>,
"Michael S . Tsirkin" <mst@redhat.com>,
David Hildenbrand <david@redhat.com>,
"Dr . David Alan Gilbert" <dgilbert@redhat.com>,
Peter Xu <peterx@redhat.com>, Auger Eric <eric.auger@redhat.com>,
Alex Williamson <alex.williamson@redhat.com>,
teawater <teawaterz@linux.alibaba.com>,
Igor Mammedov <imammedo@redhat.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Marek Kedzierski <mkedzier@redhat.com>
Subject: [PATCH v6 12/12] vfio: Disable only uncoordinated discards for VFIO_TYPE1 iommus
Date: Mon, 22 Feb 2021 12:57:08 +0100 [thread overview]
Message-ID: <20210222115708.7623-13-david@redhat.com> (raw)
In-Reply-To: <20210222115708.7623-1-david@redhat.com>
We support coordinated discarding of RAM using the RamDiscardMgr for
the VFIO_TYPE1 iommus. Let's unlock support for coordinated discards,
keeping uncoordinated discards (e.g., via virtio-balloon) disabled if
possible.
This unlocks virtio-mem + vfio on x86-64. Note that vfio used via "nvme://"
by the block layer has to be implemented/unlocked separately. For now,
virtio-mem only supports x86-64; we don't restrict RamDiscardMgr to x86-64,
though: arm64 and s390x are supposed to work as well, and we'll test
once unlocking virtio-mem support. The spapr IOMMUs will need special
care, to be tackled later, e.g.., once supporting virtio-mem.
Note: The block size of a virtio-mem device has to be set to sane sizes,
depending on the maximum hotplug size - to not run out of vfio mappings.
The default virtio-mem block size is usually in the range of a couple of
MBs. The maximum number of mapping is 64k, shared with other users.
Assume you want to hotplug 256GB using virtio-mem - the block size would
have to be set to at least 8 MiB (resulting in 32768 separate mappings).
Acked-by: Alex Williamson <alex.williamson@redhat.com>
Reviewed-by: Alex Williamson <alex.williamson@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Dr. David Alan Gilbert <dgilbert@redhat.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Auger Eric <eric.auger@redhat.com>
Cc: Wei Yang <richard.weiyang@linux.alibaba.com>
Cc: teawater <teawaterz@linux.alibaba.com>
Cc: Marek Kedzierski <mkedzier@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
hw/vfio/common.c | 63 +++++++++++++++++++++++++++++++++++++++---------
1 file changed, 51 insertions(+), 12 deletions(-)
diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index 15ecd05a4b..d879b8ab92 100644
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -135,6 +135,27 @@ static const char *index_to_str(VFIODevice *vbasedev, int index)
}
}
+static int vfio_ram_block_discard_disable(VFIOContainer *container, bool state)
+{
+ switch (container->iommu_type) {
+ case VFIO_TYPE1v2_IOMMU:
+ case VFIO_TYPE1_IOMMU:
+ /* We support coordinated discarding of RAM via the RamDiscardMgr. */
+ return ram_block_uncoordinated_discard_disable(state);
+ default:
+ /*
+ * VFIO_SPAPR_TCE_IOMMU most probably works just fine with
+ * RamDiscardMgr, however, it is completely untested.
+ *
+ * VFIO_SPAPR_TCE_v2_IOMMU with "DMA memory preregistering" does
+ * completely the opposite of managing mapping/pinning dynamically as
+ * required by RamDiscardMgr. We would have to special-case sections
+ * with a RamDiscardMgr.
+ */
+ return ram_block_discard_disable(state);
+ }
+}
+
int vfio_set_irq_signaling(VFIODevice *vbasedev, int index, int subindex,
int action, int fd, Error **errp)
{
@@ -1979,15 +2000,25 @@ static int vfio_connect_container(VFIOGroup *group, AddressSpace *as,
* new memory, it will not yet set ram_block_discard_set_required() and
* therefore, neither stops us here or deals with the sudden memory
* consumption of inflated memory.
+ *
+ * We do support discarding of memory coordinated via the RamDiscardMgr
+ * with some IOMMU types. vfio_ram_block_discard_disable() handles the
+ * details once we know which type of IOMMU we are using.
*/
- ret = ram_block_discard_disable(true);
- if (ret) {
- error_setg_errno(errp, -ret, "Cannot set discarding of RAM broken");
- return ret;
- }
QLIST_FOREACH(container, &space->containers, next) {
if (!ioctl(group->fd, VFIO_GROUP_SET_CONTAINER, &container->fd)) {
+ ret = vfio_ram_block_discard_disable(container, true);
+ if (ret) {
+ error_setg_errno(errp, -ret,
+ "Cannot set discarding of RAM broken");
+ if (ioctl(group->fd, VFIO_GROUP_UNSET_CONTAINER,
+ &container->fd)) {
+ error_report("vfio: error disconnecting group %d from"
+ " container", group->groupid);
+ }
+ return ret;
+ }
group->container = container;
QLIST_INSERT_HEAD(&container->group_list, group, container_next);
vfio_kvm_device_add_group(group);
@@ -2025,6 +2056,12 @@ static int vfio_connect_container(VFIOGroup *group, AddressSpace *as,
goto free_container_exit;
}
+ ret = vfio_ram_block_discard_disable(container, true);
+ if (ret) {
+ error_setg_errno(errp, -ret, "Cannot set discarding of RAM broken");
+ goto free_container_exit;
+ }
+
switch (container->iommu_type) {
case VFIO_TYPE1v2_IOMMU:
case VFIO_TYPE1_IOMMU:
@@ -2072,7 +2109,7 @@ static int vfio_connect_container(VFIOGroup *group, AddressSpace *as,
if (ret) {
error_setg_errno(errp, errno, "failed to enable container");
ret = -errno;
- goto free_container_exit;
+ goto enable_discards_exit;
}
} else {
container->prereg_listener = vfio_prereg_listener;
@@ -2084,7 +2121,7 @@ static int vfio_connect_container(VFIOGroup *group, AddressSpace *as,
ret = -1;
error_propagate_prepend(errp, container->error,
"RAM memory listener initialization failed: ");
- goto free_container_exit;
+ goto enable_discards_exit;
}
}
@@ -2097,7 +2134,7 @@ static int vfio_connect_container(VFIOGroup *group, AddressSpace *as,
if (v2) {
memory_listener_unregister(&container->prereg_listener);
}
- goto free_container_exit;
+ goto enable_discards_exit;
}
if (v2) {
@@ -2112,7 +2149,7 @@ static int vfio_connect_container(VFIOGroup *group, AddressSpace *as,
if (ret) {
error_setg_errno(errp, -ret,
"failed to remove existing window");
- goto free_container_exit;
+ goto enable_discards_exit;
}
} else {
/* The default table uses 4K pages */
@@ -2153,6 +2190,9 @@ listener_release_exit:
vfio_kvm_device_del_group(group);
vfio_listener_release(container);
+enable_discards_exit:
+ vfio_ram_block_discard_disable(container, false);
+
free_container_exit:
g_free(container);
@@ -2160,7 +2200,6 @@ close_fd_exit:
close(fd);
put_space_exit:
- ram_block_discard_disable(false);
vfio_put_address_space(space);
return ret;
@@ -2282,7 +2321,7 @@ void vfio_put_group(VFIOGroup *group)
}
if (!group->ram_block_discard_allowed) {
- ram_block_discard_disable(false);
+ vfio_ram_block_discard_disable(group->container, false);
}
vfio_kvm_device_del_group(group);
vfio_disconnect_container(group);
@@ -2336,7 +2375,7 @@ int vfio_get_device(VFIOGroup *group, const char *name,
if (!group->ram_block_discard_allowed) {
group->ram_block_discard_allowed = true;
- ram_block_discard_disable(false);
+ vfio_ram_block_discard_disable(group->container, false);
}
}
--
2.29.2
prev parent reply other threads:[~2021-02-22 12:08 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-22 11:56 [PATCH v6 00/12] virtio-mem: vfio support David Hildenbrand
2021-02-22 11:56 ` [PATCH v6 01/12] memory: Introduce RamDiscardMgr for RAM memory regions David Hildenbrand
2021-02-22 13:27 ` Paolo Bonzini
2021-02-22 14:03 ` David Hildenbrand
2021-02-22 14:18 ` Paolo Bonzini
2021-02-22 14:53 ` David Hildenbrand
2021-02-22 17:37 ` Paolo Bonzini
2021-02-22 17:48 ` David Hildenbrand
2021-02-22 19:43 ` David Hildenbrand
2021-02-23 10:50 ` David Hildenbrand
2021-02-23 15:03 ` Paolo Bonzini
2021-02-23 15:09 ` David Hildenbrand
2021-02-22 11:56 ` [PATCH v6 02/12] virtio-mem: Factor out traversing unplugged ranges David Hildenbrand
2021-02-22 11:56 ` [PATCH v6 03/12] virtio-mem: Don't report errors when ram_block_discard_range() fails David Hildenbrand
2021-02-22 11:57 ` [PATCH v6 04/12] virtio-mem: Implement RamDiscardMgr interface David Hildenbrand
2021-02-22 11:57 ` [PATCH v6 05/12] vfio: Support for RamDiscardMgr in the !vIOMMU case David Hildenbrand
2021-02-22 13:20 ` Paolo Bonzini
2021-02-22 14:43 ` David Hildenbrand
2021-02-22 17:29 ` Paolo Bonzini
2021-02-22 17:34 ` David Hildenbrand
2021-02-22 11:57 ` [PATCH v6 06/12] vfio: Query and store the maximum number of possible DMA mappings David Hildenbrand
2021-02-22 11:57 ` [PATCH v6 07/12] vfio: Sanity check maximum number of DMA mappings with RamDiscardMgr David Hildenbrand
2021-02-22 11:57 ` [PATCH v6 08/12] vfio: Support for RamDiscardMgr in the vIOMMU case David Hildenbrand
2021-02-22 11:57 ` [PATCH v6 09/12] softmmu/physmem: Don't use atomic operations in ram_block_discard_(disable|require) David Hildenbrand
2021-02-22 13:14 ` Paolo Bonzini
2021-02-22 13:33 ` David Hildenbrand
2021-02-22 14:02 ` Paolo Bonzini
2021-02-22 15:38 ` David Hildenbrand
2021-02-22 17:32 ` Paolo Bonzini
2021-02-23 9:02 ` David Hildenbrand
2021-02-23 15:02 ` Paolo Bonzini
2021-02-22 11:57 ` [PATCH v6 10/12] softmmu/physmem: Extend ram_block_discard_(require|disable) by two discard types David Hildenbrand
2021-02-22 11:57 ` [PATCH v6 11/12] virtio-mem: Require only coordinated discards David Hildenbrand
2021-02-22 11:57 ` David Hildenbrand [this message]
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