From: Stanislav Kinsburskii <[email protected]> Sent: Thursday, February 5, 2026 10:42 AM > To: [email protected]; [email protected]; [email protected]; > [email protected]; [email protected] > Cc: [email protected]; [email protected] > Subject: [PATCH v3 4/4] mshv: Handle insufficient root memory hypervisor > statuses > > When creating guest partition objects, the hypervisor may fail to > allocate root partition pages and return an insufficient memory status. > In this case, deposit memory using the root partition ID instead. > > Note: This error should never occur in a guest of L1VH partition context. > > Signed-off-by: Stanislav Kinsburskii <[email protected]> > --- > drivers/hv/hv_common.c | 2 + > drivers/hv/hv_proc.c | 14 ++++++++++ > include/hyperv/hvgdk_mini.h | 58 > ++++++++++++++++++++++--------------------- > 3 files changed, 46 insertions(+), 28 deletions(-) > > diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c > index f20596276662..6b67ac616789 100644 > --- a/drivers/hv/hv_common.c > +++ b/drivers/hv/hv_common.c > @@ -794,6 +794,8 @@ static const struct hv_status_info hv_status_infos[] = { > _STATUS_INFO(HV_STATUS_PROPERTY_VALUE_OUT_OF_RANGE, -EIO), > _STATUS_INFO(HV_STATUS_INSUFFICIENT_MEMORY, -ENOMEM), > _STATUS_INFO(HV_STATUS_INSUFFICIENT_CONTIGUOUS_MEMORY, -ENOMEM), > + _STATUS_INFO(HV_STATUS_INSUFFICIENT_ROOT_MEMORY, -ENOMEM), > + _STATUS_INFO(HV_STATUS_INSUFFICIENT_CONTIGUOUS_ROOT_MEMORY, > -ENOMEM), > _STATUS_INFO(HV_STATUS_INVALID_PARTITION_ID, -EINVAL), > _STATUS_INFO(HV_STATUS_INVALID_VP_INDEX, -EINVAL), > _STATUS_INFO(HV_STATUS_NOT_FOUND, -EIO), > diff --git a/drivers/hv/hv_proc.c b/drivers/hv/hv_proc.c > index 181f6d02bce3..5f4fd9c3231c 100644 > --- a/drivers/hv/hv_proc.c > +++ b/drivers/hv/hv_proc.c > @@ -121,6 +121,18 @@ int hv_deposit_memory_node(int node, u64 partition_id, > case HV_STATUS_INSUFFICIENT_CONTIGUOUS_MEMORY: > num_pages = HV_MAX_CONTIGUOUS_ALLOCATION_PAGES; > break; > + > + case HV_STATUS_INSUFFICIENT_CONTIGUOUS_ROOT_MEMORY: > + num_pages = HV_MAX_CONTIGUOUS_ALLOCATION_PAGES; > + fallthrough; > + case HV_STATUS_INSUFFICIENT_ROOT_MEMORY: > + if (!hv_root_partition()) { > + hv_status_err(hv_status, "Unexpected root memory > deposit\n"); > + return -ENOMEM; > + } > + partition_id = HV_PARTITION_ID_SELF; > + break; > +
Per the discussion in v1 of this patch set, if the number of pages that should be deposited in a particular situation is different from what this function provides, the fallback is to use hv_call_deposit_pages() directly. From what I see, there's only one such fallback case after a hypercall failure -- in hv_do_map_gpa_hcall(). The other uses of hv_call_deposit_pages() are initial deposits when creating a VP or partition. But if hv_call_deposit_pages() is used directly, the logic added here to detect insufficient root memory and deposit to HV_PARTITION_ID_SELF isn't applied. So if the hypercall in hv_do_map_gpa_hcall() fails with insufficient root memory, the deposit is done to the wrong partition ID. If that case can actually happen, then some additional logic is needed in hv_do_map_gpa_hcall() to handle it. Or there needs to be a fallback function that contains the logic. Other than that, everything else in this patch set looks good to me. Michael > default: > hv_status_err(hv_status, "Unexpected!\n"); > return -ENOMEM;
