On 3/20/20 4:53 AM, Shivaprasad bhat wrote:
On Thu, Mar 12, 2020 at 3:00 AM Daniel Henrique Barboza
<danielhb413@xxxxxxxxx> wrote:
Using the 'uuid' element for ppc64 NVDIMM memory added in the
previous patch, use it in qemuBuildMemoryDeviceStr() to pass
it over to QEMU.
Another ppc64 restriction is the necessity of a mem->labelsize,
given than ppc64 only support label-area backed NVDIMMs.
Finally, we don't want ppc64 NVDIMMs to align up due to the
high risk of going beyond the end of file with a 256MiB
increment that the user didn't predict. Align it down
instead.
Signed-off-by: Daniel Henrique Barboza <danielhb413@xxxxxxxxx>
---
...
+static void
+qemuDomainNVDimmAlignSizePseries(virDomainDefPtr def,
+ virDomainMemoryDefPtr mem)
+{
+ /* For NVDIMMs in ppc64 in we want to align down the guest
+ * visible space, instead of align up, to avoid writing
+ * beyond the end of file by adding a potential 256MiB
+ * to the user specified size.
+ *
+ * The label-size is mandatory for ppc64 as well, meaning that
+ * the guest visible space will be target_size-label_size.
+ *
+ * Finally, target_size must include label_size.
+ *
+ * The above can be summed up as follows:
+ *
+ * target_size = AlignDown(target_size - label_size) + label_size
+ */
+ unsigned long long ppc64AlignSize = qemuDomainGetMemorySizeAlignment(def);
+ unsigned long long guestArea = mem->size - mem->labelsize;
+
+ /* Align down guest_area. 256MiB is the minimum size. */
+ guestArea = (guestArea/ppc64AlignSize) * ppc64AlignSize;
+ guestArea = MAX(guestArea, ppc64AlignSize);
The math is correct, but we need additional checks when a backing file of
size less than 256MB is attempted to be hot-plugged. The qemu errors
out like below if
the backing file is 240MB and MAX of (240, 256) is chosen.
-object memory-backend-file,id=memnvdimm1,prealloc=yes,mem-path
=/tmp/nvdimm,share=yes,size=268566528: backing store size 0xf000000 does
not match 'size' option 0x10020000
Got it. I'll error out in this case.
+
+ mem->size = guestArea + mem->labelsize;
+}
+
+....
+ </label>
</target>
<address type='dimm' slot='0'/>
</memory>
diff --git a/tests/qemuxml2argvtest.c b/tests/qemuxml2argvtest.c
index 35d413d40b..077f7e7650 100644
--- a/tests/qemuxml2argvtest.c
+++ b/tests/qemuxml2argvtest.c
@@ -2790,6 +2790,10 @@ mymain(void)
DO_TEST_CAPS_LATEST("memory-hotplug-nvdimm-align");
DO_TEST_CAPS_LATEST("memory-hotplug-nvdimm-pmem");
DO_TEST_CAPS_LATEST("memory-hotplug-nvdimm-readonly");
+ DO_TEST("memory-hotplug-nvdimm-ppc64", QEMU_CAPS_KVM, QEMU_CAPS_DEVICE_NVDIMM,
I see the qemucapabilitiesdata/caps-5*.ppc64* not updated with the
nvdimm support. Can you update it as well?
Then this can be changed to just DO_TEST_CAPS_LATEST_PPC64, without
this elaborate list of caps.
+ QEMU_CAPS_NUMA, QEMU_CAPS_DEVICE_SPAPR_PCI_HOST_BRIDGE,
+ QEMU_CAPS_OBJECT_MEMORY_RAM,
...
Roger that!
DHB
Thanks,
Shiva
