On 8/28/2025 7:43 PM, Nuno Das Neves wrote:
From: Purna Pavan Chandra Aekkaladevi <[email protected]>
Some versions of the hypervisor do not support HV_STATUS_AREA_PARENT and
return HV_STATUS_INVALID_PARAMETER for the second stats page mapping
request.
Is this behavior limited to VP stats? Or does it extend to other
stats (hypervisor, partition, etc) as well?
This results a failure in module init. Instead of failing, gracefully
nit: s/This results in a failure during module init/> fall back to
populating stats_pages[HV_STATS_AREA_PARENT] with the
already-mapped stats_pages[HV_STATS_AREA_SELF].
Signed-off-by: Purna Pavan Chandra Aekkaladevi
<[email protected]>
Signed-off-by: Nuno Das Neves <[email protected]>
---
drivers/hv/mshv_root_hv_call.c | 43 ++++++++++++++++++++++++++++++----
drivers/hv/mshv_root_main.c | 3 +++
2 files changed, 42 insertions(+), 4 deletions(-)
diff --git a/drivers/hv/mshv_root_hv_call.c b/drivers/hv/mshv_root_hv_call.c
index c9c274f29c3c..1c38576a673c 100644
--- a/drivers/hv/mshv_root_hv_call.c
+++ b/drivers/hv/mshv_root_hv_call.c
@@ -724,6 +724,24 @@ hv_call_notify_port_ring_empty(u32 sint_index)
return hv_result_to_errno(status);
}
+static int
+hv_stats_get_area_type(enum hv_stats_object_type type,
+ const union hv_stats_object_identity *identity)
+{
+ switch (type) {
+ case HV_STATS_OBJECT_HYPERVISOR:
+ return identity->hv.stats_area_type;
+ case HV_STATS_OBJECT_LOGICAL_PROCESSOR:
+ return identity->lp.stats_area_type;
+ case HV_STATS_OBJECT_PARTITION:
+ return identity->partition.stats_area_type;
+ case HV_STATS_OBJECT_VP:
+ return identity->vp.stats_area_type;
+ }
+
+ return -EINVAL;
+}
+
int hv_call_map_stat_page(enum hv_stats_object_type type,
const union hv_stats_object_identity *identity,
void **addr)
@@ -732,7 +750,7 @@ int hv_call_map_stat_page(enum hv_stats_object_type type,
struct hv_input_map_stats_page *input;
struct hv_output_map_stats_page *output;
u64 status, pfn;
- int ret = 0;
+ int hv_status, ret = 0;
do {
local_irq_save(flags);
@@ -747,11 +765,28 @@ int hv_call_map_stat_page(enum hv_stats_object_type type,
pfn = output->map_location;
local_irq_restore(flags);
- if (hv_result(status) != HV_STATUS_INSUFFICIENT_MEMORY) {
- ret = hv_result_to_errno(status);
+
+ hv_status = hv_result(status);
+ if (hv_status != HV_STATUS_INSUFFICIENT_MEMORY) {
if (hv_result_success(status))
break;
- return ret;
+
+ /*
+ * Some versions of the hypervisor do not support the
+ * PARENT stats area. In this case return "success" but
+ * set the page to NULL. The caller checks for this
+ * case instead just uses the SELF area.
+ */
+ if (hv_stats_get_area_type(type, identity) ==
HV_STATS_AREA_PARENT &&
+ hv_status == HV_STATUS_INVALID_PARAMETER) {
+ pr_debug_once("%s: PARENT area type is
unsupported\n",
+ __func__);
+ *addr = NULL;
+ return 0;
+ }
+
+ hv_status_debug(status, "\n");
+ return hv_result_to_errno(status);
}
ret = hv_call_deposit_pages(NUMA_NO_NODE,
diff --git a/drivers/hv/mshv_root_main.c b/drivers/hv/mshv_root_main.c
index bbdefe8a2e9c..56ababab57ce 100644
--- a/drivers/hv/mshv_root_main.c
+++ b/drivers/hv/mshv_root_main.c
@@ -929,6 +929,9 @@ static int mshv_vp_stats_map(u64 partition_id, u32 vp_index,
if (err)
goto unmap_self;
+ if (!stats_pages[HV_STATS_AREA_PARENT])
+ stats_pages[HV_STATS_AREA_PARENT] =
stats_pages[HV_STATS_AREA_SELF];
+
return 0;
unmap_self:
--
Regards,
Praveen K Paladugu
