VFIO update 2018-08-17
- Enhance balloon inhibitor for multiple users and use around vfio device assignment (Alex Williamson) -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.14 (GNU/Linux) iQIcBAABAgAGBQJbdvs5AAoJECObm247sIsioA4QAKWqKWnqOu4AwIdADzOEKTv+ jSG+M6S6uEBbhk6hC+scnIlyA6MwiTmh8uJYDOTPy/4S9kv4+Bj/LykoJxk1T3UI jREP+EHMUe13YfG//5yIb0HLIBEI7VJeBteyksboZ8KTO4kMt4RCnk1lpfARxIjB ouMIngGq9ltOWAann9tcjGaPXfKjB9LSSYyhQMlqSzl7LckOsGAgmdFU7uurlTrq a5kB2oRNP7CSbF/fDTsWd8nsCGy357Cou42KpsTRQN+TeLmqExQXguCQLszBup3H VYwS0FzpR1ix7jOuafHLcBh9VgSEFYWf71oznMoPDiv2vVjKGsDG3Tzu5Xqz0vsI ynKXCXNbXZhpazZzw8ThXoLs8mWLWSrtqvjQItDmrl0kboY6ZwOZc8m+PQmIqtHQ RDcVlCT0TecwYXBZ5G930JpcEsUFBKfZrla+v2W0ON6HVA6eVBweSata5r08XvHK P2rbHgO6NSDZTMZUOborh/sbINb61PNW7h7inigHzpDJxjseIz/vO+mVjfsCZMed dSu/0VYCbA0cS2IK21zZFsR4LNlL4yzFzhONdBqbZD7zhiZL25IcZV/TVzHJE+zS su7uDSLNihJYOXAXO7s0Ne2vO5lZzpYykVFOAmQQicxcYZz+u8LxXY+NlTjKJhEv x3fobaflymrG7xkRy3xq =JQ6k -----END PGP SIGNATURE----- Merge remote-tracking branch 'remotes/awilliam/tags/vfio-update-20180817.0' into staging VFIO update 2018-08-17 - Enhance balloon inhibitor for multiple users and use around vfio device assignment (Alex Williamson) # gpg: Signature made Fri 17 Aug 2018 17:43:37 BST # gpg: using RSA key 239B9B6E3BB08B22 # gpg: Good signature from "Alex Williamson <alex.williamson@redhat.com>" # gpg: aka "Alex Williamson <alex@shazbot.org>" # gpg: aka "Alex Williamson <alwillia@redhat.com>" # gpg: aka "Alex Williamson <alex.l.williamson@gmail.com>" # Primary key fingerprint: 42F6 C04E 540B D1A9 9E7B 8A90 239B 9B6E 3BB0 8B22 * remotes/awilliam/tags/vfio-update-20180817.0: vfio/ccw/pci: Allow devices to opt-in for ballooning vfio: Inhibit ballooning based on group attachment to a container kvm: Use inhibit to prevent ballooning without synchronous mmu balloon: Allow multiple inhibit users Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
This commit is contained in:
commit
a544c9110d
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@ -39,6 +39,7 @@
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#include "trace.h"
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#include "hw/irq.h"
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#include "sysemu/sev.h"
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#include "sysemu/balloon.h"
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#include "hw/boards.h"
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@ -1698,6 +1699,9 @@ static int kvm_init(MachineState *ms)
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s->many_ioeventfds = kvm_check_many_ioeventfds();
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s->sync_mmu = !!kvm_vm_check_extension(kvm_state, KVM_CAP_SYNC_MMU);
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if (!s->sync_mmu) {
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qemu_balloon_inhibit(true);
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}
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return 0;
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13
balloon.c
13
balloon.c
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@ -26,6 +26,7 @@
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#include "qemu/osdep.h"
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#include "qemu-common.h"
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#include "qemu/atomic.h"
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#include "exec/cpu-common.h"
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#include "sysemu/kvm.h"
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#include "sysemu/balloon.h"
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@ -37,16 +38,22 @@
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static QEMUBalloonEvent *balloon_event_fn;
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static QEMUBalloonStatus *balloon_stat_fn;
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static void *balloon_opaque;
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static bool balloon_inhibited;
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static int balloon_inhibit_count;
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bool qemu_balloon_is_inhibited(void)
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{
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return balloon_inhibited;
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return atomic_read(&balloon_inhibit_count) > 0;
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}
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void qemu_balloon_inhibit(bool state)
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{
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balloon_inhibited = state;
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if (state) {
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atomic_inc(&balloon_inhibit_count);
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} else {
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atomic_dec(&balloon_inhibit_count);
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}
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assert(atomic_read(&balloon_inhibit_count) >= 0);
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}
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static bool have_balloon(Error **errp)
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@ -349,6 +349,15 @@ static void vfio_ccw_get_device(VFIOGroup *group, VFIOCCWDevice *vcdev,
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}
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}
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/*
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* All vfio-ccw devices are believed to operate in a way compatible with
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* memory ballooning, ie. pages pinned in the host are in the current
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* working set of the guest driver and therefore never overlap with pages
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* available to the guest balloon driver. This needs to be set before
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* vfio_get_device() for vfio common to handle the balloon inhibitor.
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*/
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vcdev->vdev.balloon_allowed = true;
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if (vfio_get_device(group, vcdev->cdev.mdevid, &vcdev->vdev, errp)) {
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goto out_err;
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}
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@ -32,6 +32,7 @@
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#include "hw/hw.h"
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#include "qemu/error-report.h"
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#include "qemu/range.h"
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#include "sysemu/balloon.h"
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#include "sysemu/kvm.h"
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#include "trace.h"
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#include "qapi/error.h"
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@ -1044,6 +1045,33 @@ static int vfio_connect_container(VFIOGroup *group, AddressSpace *as,
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space = vfio_get_address_space(as);
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/*
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* VFIO is currently incompatible with memory ballooning insofar as the
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* madvise to purge (zap) the page from QEMU's address space does not
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* interact with the memory API and therefore leaves stale virtual to
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* physical mappings in the IOMMU if the page was previously pinned. We
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* therefore add a balloon inhibit for each group added to a container,
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* whether the container is used individually or shared. This provides
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* us with options to allow devices within a group to opt-in and allow
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* ballooning, so long as it is done consistently for a group (for instance
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* if the device is an mdev device where it is known that the host vendor
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* driver will never pin pages outside of the working set of the guest
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* driver, which would thus not be ballooning candidates).
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*
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* The first opportunity to induce pinning occurs here where we attempt to
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* attach the group to existing containers within the AddressSpace. If any
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* pages are already zapped from the virtual address space, such as from a
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* previous ballooning opt-in, new pinning will cause valid mappings to be
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* re-established. Likewise, when the overall MemoryListener for a new
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* container is registered, a replay of mappings within the AddressSpace
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* will occur, re-establishing any previously zapped pages as well.
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*
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* NB. Balloon inhibiting does not currently block operation of the
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* balloon driver or revoke previously pinned pages, it only prevents
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* calling madvise to modify the virtual mapping of ballooned pages.
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*/
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qemu_balloon_inhibit(true);
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QLIST_FOREACH(container, &space->containers, next) {
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if (!ioctl(group->fd, VFIO_GROUP_SET_CONTAINER, &container->fd)) {
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group->container = container;
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@ -1232,6 +1260,7 @@ close_fd_exit:
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close(fd);
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put_space_exit:
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qemu_balloon_inhibit(false);
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vfio_put_address_space(space);
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return ret;
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@ -1352,6 +1381,9 @@ void vfio_put_group(VFIOGroup *group)
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return;
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}
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if (!group->balloon_allowed) {
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qemu_balloon_inhibit(false);
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}
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vfio_kvm_device_del_group(group);
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vfio_disconnect_container(group);
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QLIST_REMOVE(group, next);
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@ -1387,6 +1419,25 @@ int vfio_get_device(VFIOGroup *group, const char *name,
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return ret;
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}
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/*
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* Clear the balloon inhibitor for this group if the driver knows the
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* device operates compatibly with ballooning. Setting must be consistent
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* per group, but since compatibility is really only possible with mdev
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* currently, we expect singleton groups.
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*/
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if (vbasedev->balloon_allowed != group->balloon_allowed) {
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if (!QLIST_EMPTY(&group->device_list)) {
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error_setg(errp,
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"Inconsistent device balloon setting within group");
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return -1;
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}
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if (!group->balloon_allowed) {
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group->balloon_allowed = true;
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qemu_balloon_inhibit(false);
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}
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}
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vbasedev->fd = fd;
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vbasedev->group = group;
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QLIST_INSERT_HEAD(&group->device_list, vbasedev, next);
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@ -2804,12 +2804,13 @@ static void vfio_realize(PCIDevice *pdev, Error **errp)
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VFIOPCIDevice *vdev = DO_UPCAST(VFIOPCIDevice, pdev, pdev);
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VFIODevice *vbasedev_iter;
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VFIOGroup *group;
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char *tmp, group_path[PATH_MAX], *group_name;
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char *tmp, *subsys, group_path[PATH_MAX], *group_name;
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Error *err = NULL;
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ssize_t len;
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struct stat st;
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int groupid;
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int i, ret;
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bool is_mdev;
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if (!vdev->vbasedev.sysfsdev) {
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if (!(~vdev->host.domain || ~vdev->host.bus ||
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}
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}
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/*
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* Mediated devices *might* operate compatibly with memory ballooning, but
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* we cannot know for certain, it depends on whether the mdev vendor driver
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* stays in sync with the active working set of the guest driver. Prevent
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* the x-balloon-allowed option unless this is minimally an mdev device.
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*/
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tmp = g_strdup_printf("%s/subsystem", vdev->vbasedev.sysfsdev);
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subsys = realpath(tmp, NULL);
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g_free(tmp);
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is_mdev = (strcmp(subsys, "/sys/bus/mdev") == 0);
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free(subsys);
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trace_vfio_mdev(vdev->vbasedev.name, is_mdev);
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if (vdev->vbasedev.balloon_allowed && !is_mdev) {
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error_setg(errp, "x-balloon-allowed only potentially compatible "
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"with mdev devices");
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vfio_put_group(group);
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goto error;
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}
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ret = vfio_get_device(group, vdev->vbasedev.name, &vdev->vbasedev, errp);
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if (ret) {
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vfio_put_group(group);
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@ -3170,6 +3192,8 @@ static Property vfio_pci_dev_properties[] = {
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DEFINE_PROP_BIT("x-igd-opregion", VFIOPCIDevice, features,
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VFIO_FEATURE_ENABLE_IGD_OPREGION_BIT, false),
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DEFINE_PROP_BOOL("x-no-mmap", VFIOPCIDevice, vbasedev.no_mmap, false),
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DEFINE_PROP_BOOL("x-balloon-allowed", VFIOPCIDevice,
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vbasedev.balloon_allowed, false),
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DEFINE_PROP_BOOL("x-no-kvm-intx", VFIOPCIDevice, no_kvm_intx, false),
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DEFINE_PROP_BOOL("x-no-kvm-msi", VFIOPCIDevice, no_kvm_msi, false),
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DEFINE_PROP_BOOL("x-no-kvm-msix", VFIOPCIDevice, no_kvm_msix, false),
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@ -39,6 +39,7 @@ vfio_pci_hot_reset_result(const char *name, const char *result) "%s hot reset: %
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vfio_populate_device_config(const char *name, unsigned long size, unsigned long offset, unsigned long flags) "Device %s config:\n size: 0x%lx, offset: 0x%lx, flags: 0x%lx"
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vfio_populate_device_get_irq_info_failure(void) "VFIO_DEVICE_GET_IRQ_INFO failure: %m"
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vfio_realize(const char *name, int group_id) " (%s) group %d"
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vfio_mdev(const char *name, bool is_mdev) " (%s) is_mdev %d"
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vfio_add_ext_cap_dropped(const char *name, uint16_t cap, uint16_t offset) "%s 0x%x@0x%x"
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vfio_pci_reset(const char *name) " (%s)"
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vfio_pci_reset_flr(const char *name) "%s FLR/VFIO_DEVICE_RESET"
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@ -21,7 +21,6 @@
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#include "hw/mem/pc-dimm.h"
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#include "sysemu/balloon.h"
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#include "hw/virtio/virtio-balloon.h"
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#include "sysemu/kvm.h"
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#include "exec/address-spaces.h"
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#include "qapi/error.h"
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#include "qapi/qapi-events-misc.h"
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static void balloon_page(void *addr, int deflate)
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{
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if (!qemu_balloon_is_inhibited() && (!kvm_enabled() ||
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kvm_has_sync_mmu())) {
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if (!qemu_balloon_is_inhibited()) {
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qemu_madvise(addr, BALLOON_PAGE_SIZE,
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deflate ? QEMU_MADV_WILLNEED : QEMU_MADV_DONTNEED);
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}
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@ -112,6 +112,7 @@ typedef struct VFIODevice {
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bool reset_works;
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bool needs_reset;
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bool no_mmap;
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bool balloon_allowed;
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VFIODeviceOps *ops;
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unsigned int num_irqs;
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unsigned int num_regions;
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QLIST_HEAD(, VFIODevice) device_list;
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QLIST_ENTRY(VFIOGroup) next;
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QLIST_ENTRY(VFIOGroup) container_next;
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bool balloon_allowed;
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} VFIOGroup;
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typedef struct VFIODMABuf {
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