Re: [libvirt] [PATCH v1 19/31] qemu: Take NVMe disks into account when calculating memlock limit
On Thu, Jul 11, 2019 at 17:54:06 +0200, Michal Privoznik wrote:
We have this beautiful function that does crystal ball
divination. The function is named
qemuDomainGetMemLockLimitBytes() and it calculates the upper
limit of how much locked memory is given guest going to need. The
function bases its guess on devices defined for a domain. For
instance, if there is a VFIO hostdev defined then it adds 1GiB to
the guessed maximum. Since NVMe disks are pretty much VFIO
hostdevs (but not quite), we have to do the same sorcery.
Signed-off-by: Michal Privoznik <mprivozn(a)redhat.com>
---
src/qemu/qemu_domain.c | 15 +++++++++++++++
1 file changed, 15 insertions(+)
diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
index f09abc8a73..09e5ee37f4 100644
--- a/src/qemu/qemu_domain.c
+++ b/src/qemu/qemu_domain.c
preceeding hunk
for (i = 0; i < def->nhostdevs; i++) {
virDomainHostdevSubsysPtr subsys = &def->hostdevs[i]->source.subsys;
if (def->hostdevs[i]->mode == VIR_DOMAIN_HOSTDEV_MODE_SUBSYS &&
(subsys->type == VIR_DOMAIN_HOSTDEV_SUBSYS_TYPE_MDEV ||
(subsys->type == VIR_DOMAIN_HOSTDEV_SUBSYS_TYPE_PCI &&
subsys->u.pci.backend == VIR_DOMAIN_HOSTDEV_PCI_BACKEND_VFIO))) {
memKB = virDomainDefGetMemoryTotal(def) + 1024 * 1024;
goto done;
}
}
@@ -10950,6 +10950,21 @@
qemuDomainGetMemLockLimitBytes(virDomainDefPtr def)
}
}
+ for (i = 0; i < def->ndisks; i++) {
+ virDomainDiskDefPtr disk = def->disks[i];
+ virStorageSourcePtr n;
+
+ if (!disk->src)
+ continue;
+
+ for (n = disk->src; virStorageSourceIsBacking(n); n = n->backingStore) {
+ if (n->type == VIR_STORAGE_TYPE_NVME) {
+ memKB = virDomainDefGetMemoryTotal(def) + 1024 * 1024;
+ goto done;
+ }
+ }
+ }
Please set a booleand such as 'needVFIO' in the above hunk and here and
do the calculation once based on that boolean.
This implementation creates two instancess needing fixing in case when
we'd need to ever change the number.
ACK with that change
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