mshv: Handle insufficient contiguous memory hypervisor status

The HV_STATUS_INSUFFICIENT_CONTIGUOUS_MEMORY status indicates that the
hypervisor lacks sufficient contiguous memory for its internal allocations.

When this status is encountered, allocate and deposit
HV_MAX_CONTIGUOUS_ALLOCATION_PAGES contiguous pages to the hypervisor.
HV_MAX_CONTIGUOUS_ALLOCATION_PAGES is defined in the hypervisor headers, a
deposit of this size will always satisfy the hypervisor's requirements.

Signed-off-by: Stanislav Kinsburskii <skinsburskii@linux.microsoft.com>
Reviewed-by: Anirudh Rayabharam (Microsoft) <anirudh@anirudhrb.com>
Reviewed-by: Mukesh R <mrathor@linux.microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>

Author: Stanislav Kinsburskii

drivers/hv/hv_common.c

@@ -793,6 +793,7 @@ static const struct hv_status_info hv_status_infos[] = {
 	_STATUS_INFO(HV_STATUS_UNKNOWN_PROPERTY,		-EIO),
 	_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_INVALID_PARTITION_ID,		-EINVAL),
 	_STATUS_INFO(HV_STATUS_INVALID_VP_INDEX,		-EINVAL),
 	_STATUS_INFO(HV_STATUS_NOT_FOUND,			-EIO),

drivers/hv/hv_proc.c

@@ -118,6 +118,9 @@ int hv_deposit_memory_node(int node, u64 partition_id,
 	switch (hv_result(hv_status)) {
 	case HV_STATUS_INSUFFICIENT_MEMORY:
 		break;
+	case HV_STATUS_INSUFFICIENT_CONTIGUOUS_MEMORY:
+		num_pages = HV_MAX_CONTIGUOUS_ALLOCATION_PAGES;
+		break;
 	default:
 		hv_status_err(hv_status, "Unexpected!\n");
 		return -ENOMEM;
@@ -130,6 +133,7 @@ bool hv_result_needs_memory(u64 status)
 {
 	switch (hv_result(status)) {
 	case HV_STATUS_INSUFFICIENT_MEMORY:
+	case HV_STATUS_INSUFFICIENT_CONTIGUOUS_MEMORY:
 		return true;
 	}
 	return false;

include/hyperv/hvgdk_mini.h

@@ -38,6 +38,7 @@ struct hv_u128 {
 #define HV_STATUS_INVALID_LP_INDEX		    0x41
 #define HV_STATUS_INVALID_REGISTER_VALUE	    0x50
 #define HV_STATUS_OPERATION_FAILED		    0x71
+#define HV_STATUS_INSUFFICIENT_CONTIGUOUS_MEMORY    0x75
 #define HV_STATUS_TIME_OUT			    0x78
 #define HV_STATUS_CALL_PENDING			    0x79
 #define HV_STATUS_VTL_ALREADY_ENABLED		    0x86

include/hyperv/hvhdk_mini.h

@@ -7,6 +7,8 @@
 
 #include "hvgdk_mini.h"
 
+#define HV_MAX_CONTIGUOUS_ALLOCATION_PAGES	8
+
 /*
  * Doorbell connection_info flags.
  */