On 8/28/2025 7:43 PM, Nuno Das Neves wrote:
From: Purna Pavan Chandra Aekkaladevi <paekkalad...@linux.microsoft.com>

This hypercall can be used to fetch extended properties of a
partition. Extended properties are properties with values larger than
a u64. Some of these also need additional input arguments.

Add helper function for using the hypercall in the mshv_root driver.

Signed-off-by: Purna Pavan Chandra Aekkaladevi 
<paekkalad...@linux.microsoft.com>
Signed-off-by: Nuno Das Neves <nunodasne...@linux.microsoft.com>
---
  drivers/hv/mshv_root.h         |  2 ++
  drivers/hv/mshv_root_hv_call.c | 31 ++++++++++++++++++++++++++
  include/hyperv/hvgdk_mini.h    |  1 +
  include/hyperv/hvhdk.h         | 40 ++++++++++++++++++++++++++++++++++
  include/hyperv/hvhdk_mini.h    | 26 ++++++++++++++++++++++
  5 files changed, 100 insertions(+)

diff --git a/drivers/hv/mshv_root.h b/drivers/hv/mshv_root.h
index e3931b0f1269..4aeb03bea6b6 100644
--- a/drivers/hv/mshv_root.h
+++ b/drivers/hv/mshv_root.h
@@ -303,6 +303,8 @@ int hv_call_unmap_stat_page(enum hv_stats_object_type type,
  int hv_call_modify_spa_host_access(u64 partition_id, struct page **pages,
                                   u64 page_struct_count, u32 host_access,
                                   u32 flags, u8 acquire);
+int hv_call_get_partition_property_ex(u64 partition_id, u64 property_code, u64 
arg,
+                                     void *property_value, size_t 
property_value_sz);
extern struct mshv_root mshv_root;
  extern enum hv_scheduler_type hv_scheduler_type;
diff --git a/drivers/hv/mshv_root_hv_call.c b/drivers/hv/mshv_root_hv_call.c
index 1c38576a673c..7589b1ff3515 100644
--- a/drivers/hv/mshv_root_hv_call.c
+++ b/drivers/hv/mshv_root_hv_call.c
@@ -590,6 +590,37 @@ int hv_call_unmap_vp_state_page(u64 partition_id, u32 
vp_index, u32 type,
        return hv_result_to_errno(status);
  }
+int
+hv_call_get_partition_property_ex(u64 partition_id, u64 property_code, u64 arg,
+                                 void *property_value, size_t 
property_value_sz)
+{
+       u64 status;
+       unsigned long flags;
+       struct hv_input_get_partition_property_ex *input;
+       struct hv_output_get_partition_property_ex *output;
+
+       local_irq_save(flags);
+       input = *this_cpu_ptr(hyperv_pcpu_input_arg);
+       output = *this_cpu_ptr(hyperv_pcpu_output_arg);
+
+       memset(input, 0, sizeof(*input));
+       input->partition_id = partition_id;
+       input->property_code = property_code;
+       input->arg = arg;
+       status = hv_do_hypercall(HVCALL_GET_PARTITION_PROPERTY_EX, input, 
output);
+
+       if (!hv_result_success(status)) {
+               hv_status_debug(status, "\n");
+               local_irq_restore(flags);
+               return hv_result_to_errno(status);
+       }
+       memcpy(property_value, &output->property_value, property_value_sz);
+
+       local_irq_restore(flags);
+
+       return 0;
+}
+
  int
  hv_call_clear_virtual_interrupt(u64 partition_id)
  {
diff --git a/include/hyperv/hvgdk_mini.h b/include/hyperv/hvgdk_mini.h
index 79b7324e4ef5..1bde0aa102ec 100644
--- a/include/hyperv/hvgdk_mini.h
+++ b/include/hyperv/hvgdk_mini.h
@@ -490,6 +490,7 @@ union hv_vp_assist_msr_contents {    /* 
HV_REGISTER_VP_ASSIST_PAGE */
  #define HVCALL_GET_VP_STATE                           0x00e3
  #define HVCALL_SET_VP_STATE                           0x00e4
  #define HVCALL_GET_VP_CPUID_VALUES                    0x00f4
+#define HVCALL_GET_PARTITION_PROPERTY_EX               0x0101
  #define HVCALL_MMIO_READ                              0x0106
  #define HVCALL_MMIO_WRITE                             0x0107
diff --git a/include/hyperv/hvhdk.h b/include/hyperv/hvhdk.h
index 57f3f9c2a685..fd3555def008 100644
--- a/include/hyperv/hvhdk.h
+++ b/include/hyperv/hvhdk.h
@@ -411,6 +411,46 @@ struct hv_input_set_partition_property {
        u64 property_value;
  } __packed;
+union hv_partition_property_arg {
+       u64 as_uint64;
+       struct {
+               union {
+                       u32 arg;
+                       u32 vp_index;
+               };
+               u16 reserved0;
+               u8 reserved1;
+               u8 object_type;
+       };
+} __packed;
+
+struct hv_input_get_partition_property_ex {
+       u64 partition_id;
+       u32 property_code; /* enum hv_partition_property_code */
+       u32 padding;
+       union {
+               union hv_partition_property_arg arg_data;
+               u64 arg;
+       };
+} __packed;
+
+/*
+ * NOTE: Should use hv_input_set_partition_property_ex_header to compute this
+ * size, but hv_input_get_partition_property_ex is identical so it suffices
+ */
+#define HV_PARTITION_PROPERTY_EX_MAX_VAR_SIZE \
+       (HV_HYP_PAGE_SIZE - sizeof(struct hv_input_get_partition_property_ex))
+
+union hv_partition_property_ex {
+       u8 buffer[HV_PARTITION_PROPERTY_EX_MAX_VAR_SIZE];
+       struct hv_partition_property_vmm_capabilities vmm_capabilities;
+       /* More fields to be filled in when needed */
+} __packed;
+
+struct hv_output_get_partition_property_ex {
+       union hv_partition_property_ex property_value;
+} __packed;
+
  enum hv_vp_state_page_type {
        HV_VP_STATE_PAGE_REGISTERS = 0,
        HV_VP_STATE_PAGE_INTERCEPT_MESSAGE = 1,
diff --git a/include/hyperv/hvhdk_mini.h b/include/hyperv/hvhdk_mini.h
index 858f6a3925b3..bf2ce27dfcc5 100644
--- a/include/hyperv/hvhdk_mini.h
+++ b/include/hyperv/hvhdk_mini.h
@@ -96,8 +96,34 @@ enum hv_partition_property_code {
        HV_PARTITION_PROPERTY_XSAVE_STATES                      = 0x00060007,
        HV_PARTITION_PROPERTY_MAX_XSAVE_DATA_SIZE               = 0x00060008,
        HV_PARTITION_PROPERTY_PROCESSOR_CLOCK_FREQUENCY         = 0x00060009,
+
+       /* Extended properties with larger property values */
+       HV_PARTITION_PROPERTY_VMM_CAPABILITIES                  = 0x00090007,
  };
+#define HV_PARTITION_VMM_CAPABILITIES_BANK_COUNT 1
+#define HV_PARTITION_VMM_CAPABILITIES_RESERVED_BITFIELD_COUNT  59
+
+struct hv_partition_property_vmm_capabilities {
+       u16 bank_count;
+       u16 reserved[3];
+       union {
+               u64 as_uint64[HV_PARTITION_VMM_CAPABILITIES_BANK_COUNT];
+               struct {
+                       u64 map_gpa_preserve_adjustable: 1;
+                       u64 vmm_can_provide_overlay_gpfn: 1;
+                       u64 vp_affinity_property: 1;
+#if IS_ENABLED(CONFIG_ARM64)
+                       u64 vmm_can_provide_gic_overlay_locations: 1;
+#else
+                       u64 reservedbit3: 1;
+#endif
+                       u64 assignable_synthetic_proc_features: 1;
+                       u64 reserved0: 
HV_PARTITION_VMM_CAPABILITIES_RESERVED_BITFIELD_COUNT;
+               } __packed;
+       };
+} __packed;
+
  enum hv_snp_status {
        HV_SNP_STATUS_NONE = 0,
        HV_SNP_STATUS_AVAILABLE = 1,

Reviewed-by: Praveen K Paladugu <pra...@linux.microsoft.com>

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