From: Nuno Das Neves <nunodasne...@linux.microsoft.com> Sent: Friday, March 14,
2025 12:29 PM
>
> Provide a set of IOCTLs for creating and managing child partitions when
> running as root partition on Hyper-V. The new driver is enabled via
> CONFIG_MSHV_ROOT.
>
[snip]
> +
> +int
> +hv_call_clear_virtual_interrupt(u64 partition_id)
> +{
> + unsigned long flags;
This local variable is now unused and will generate a compile warning.
> + int status;
> +
> + status = hv_do_fast_hypercall8(HVCALL_CLEAR_VIRTUAL_INTERRUPT,
> + partition_id);
> +
> + return hv_result_to_errno(status);
> +}
> +
> +int
> +hv_call_create_port(u64 port_partition_id, union hv_port_id port_id,
> + u64 connection_partition_id,
> + struct hv_port_info *port_info,
> + u8 port_vtl, u8 min_connection_vtl, int node)
> +{
> + struct hv_input_create_port *input;
> + unsigned long flags;
> + int ret = 0;
> + int status;
> +
> + do {
> + local_irq_save(flags);
> + input = *this_cpu_ptr(hyperv_pcpu_input_arg);
> + memset(input, 0, sizeof(*input));
> +
> + input->port_partition_id = port_partition_id;
> + input->port_id = port_id;
> + input->connection_partition_id = connection_partition_id;
> + input->port_info = *port_info;
> + input->port_vtl = port_vtl;
> + input->min_connection_vtl = min_connection_vtl;
> + input->proximity_domain_info = hv_numa_node_to_pxm_info(node);
> + status = hv_do_hypercall(HVCALL_CREATE_PORT, input, NULL);
> + local_irq_restore(flags);
> + if (hv_result_success(status))
> + break;
> +
> + if (hv_result(status) != HV_STATUS_INSUFFICIENT_MEMORY) {
> + ret = hv_result_to_errno(status);
> + break;
> + }
> + ret = hv_call_deposit_pages(NUMA_NO_NODE, port_partition_id, 1);
> +
> + } while (!ret);
> +
> + return ret;
> +}
> +
> +int
> +hv_call_delete_port(u64 port_partition_id, union hv_port_id port_id)
> +{
> + union hv_input_delete_port input = { 0 };
> + unsigned long flags;
Unused local variable.
> + int status;
> +
> + input.port_partition_id = port_partition_id;
> + input.port_id = port_id;
> + status = hv_do_fast_hypercall16(HVCALL_DELETE_PORT,
> + input.as_uint64[0],
> + input.as_uint64[1]);
> +
> + return hv_result_to_errno(status);
> +}
> +
> +int
> +hv_call_connect_port(u64 port_partition_id, union hv_port_id port_id,
> + u64 connection_partition_id,
> + union hv_connection_id connection_id,
> + struct hv_connection_info *connection_info,
> + u8 connection_vtl, int node)
> +{
> + struct hv_input_connect_port *input;
> + unsigned long flags;
> + int ret = 0, status;
> +
> + do {
> + local_irq_save(flags);
> + input = *this_cpu_ptr(hyperv_pcpu_input_arg);
> + memset(input, 0, sizeof(*input));
> + input->port_partition_id = port_partition_id;
> + input->port_id = port_id;
> + input->connection_partition_id = connection_partition_id;
> + input->connection_id = connection_id;
> + input->connection_info = *connection_info;
> + input->connection_vtl = connection_vtl;
> + input->proximity_domain_info = hv_numa_node_to_pxm_info(node);
> + status = hv_do_hypercall(HVCALL_CONNECT_PORT, input, NULL);
> +
> + local_irq_restore(flags);
> + if (hv_result_success(status))
> + break;
> +
> + if (hv_result(status) != HV_STATUS_INSUFFICIENT_MEMORY) {
> + ret = hv_result_to_errno(status);
> + break;
> + }
> + ret = hv_call_deposit_pages(NUMA_NO_NODE,
> + connection_partition_id, 1);
> + } while (!ret);
> +
> + return ret;
> +}
> +
> +int
> +hv_call_disconnect_port(u64 connection_partition_id,
> + union hv_connection_id connection_id)
> +{
> + union hv_input_disconnect_port input = { 0 };
> + unsigned long flags;
Unused local variable.
> + int status;
> +
> + input.connection_partition_id = connection_partition_id;
> + input.connection_id = connection_id;
> + input.is_doorbell = 1;
> + status = hv_do_fast_hypercall16(HVCALL_DISCONNECT_PORT,
> + input.as_uint64[0],
> + input.as_uint64[1]);
> +
> + return hv_result_to_errno(status);
> +}
> +
> +int
> +hv_call_notify_port_ring_empty(u32 sint_index)
> +{
> + union hv_input_notify_port_ring_empty input = { 0 };
> + unsigned long flags;
Unused.
> + int status;
> +
> + input.sint_index = sint_index;
> + status = hv_do_fast_hypercall8(HVCALL_NOTIFY_PORT_RING_EMPTY,
> + input.as_uint64);
> +
> + return hv_result_to_errno(status);
> +}
> +
> +int hv_call_map_stat_page(enum hv_stats_object_type type,
> + const union hv_stats_object_identity *identity,
> + void **addr)
> +{
> + unsigned long flags;
> + struct hv_input_map_stats_page *input;
> + struct hv_output_map_stats_page *output;
> + u64 status, pfn;
> + int ret;
> +
> + do {
> + 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->type = type;
> + input->identity = *identity;
> +
> + status = hv_do_hypercall(HVCALL_MAP_STATS_PAGE, input, output);
> + pfn = output->map_location;
> +
> + local_irq_restore(flags);
> + if (hv_result(status) != HV_STATUS_INSUFFICIENT_MEMORY) {
> + if (hv_result_success(status))
> + break;
If this "break" is taken, "ret" may be uninitialized and the return value is
stack garbage. This bug was also in v5 and I didn't notice it in my
previous review.
> + return hv_result_to_errno(status);
> + }
> +
> + ret = hv_call_deposit_pages(NUMA_NO_NODE,
> + hv_current_partition_id, 1);
> + if (ret)
> + return ret;
> + } while (!ret);
> +
> + *addr = page_address(pfn_to_page(pfn));
> +
> + return ret;
> +}
> +
> +int hv_call_unmap_stat_page(enum hv_stats_object_type type,
> + const union hv_stats_object_identity *identity)
> +{
> + unsigned long flags;
> + struct hv_input_unmap_stats_page *input;
> + u64 status;
> +
> + local_irq_save(flags);
> + input = *this_cpu_ptr(hyperv_pcpu_input_arg);
> +
> + memset(input, 0, sizeof(*input));
> + input->type = type;
> + input->identity = *identity;
> +
> + status = hv_do_hypercall(HVCALL_UNMAP_STATS_PAGE, input, NULL);
> + local_irq_restore(flags);
> +
> + return hv_result_to_errno(status);
> +}
> +
> +int hv_call_modify_spa_host_access(u64 partition_id, struct page **pages,
> + u64 page_struct_count, u32 host_access,
> + u32 flags, u8 acquire)
> +{
> + struct hv_input_modify_sparse_spa_page_host_access *input_page;
> + u64 status;
> + int done = 0;
> + unsigned long irq_flags, large_shift = 0;
> + u64 page_count = page_struct_count;
> + u16 code = acquire ? HVCALL_ACQUIRE_SPARSE_SPA_PAGE_HOST_ACCESS :
> + HVCALL_RELEASE_SPARSE_SPA_PAGE_HOST_ACCESS;
> +
> + if (page_count == 0)
> + return -EINVAL;
> +
> + if (flags & HV_MODIFY_SPA_PAGE_HOST_ACCESS_LARGE_PAGE) {
> + if (!HV_PAGE_COUNT_2M_ALIGNED(page_count))
> + return -EINVAL;
> + large_shift = HV_HYP_LARGE_PAGE_SHIFT - HV_HYP_PAGE_SHIFT;
> + page_count >>= large_shift;
> + }
> +
> + while (done < page_count) {
> + ulong i, completed, remain = page_count - done;
> + int rep_count = min(remain,
> +
> HV_MODIFY_SPARSE_SPA_PAGE_HOST_ACCESS_MAX_PAGE_COUNT);
> +
> + local_irq_save(irq_flags);
> + input_page = *this_cpu_ptr(hyperv_pcpu_input_arg);
> +
> + memset(input_page, 0, sizeof(*input_page));
> + /* Only set the partition id if you are making the pages
> + * exclusive
> + */
> + if (flags & HV_MODIFY_SPA_PAGE_HOST_ACCESS_MAKE_EXCLUSIVE)
> + input_page->partition_id = partition_id;
> + input_page->flags = flags;
> + input_page->host_access = host_access;
> +
> + for (i = 0; i < rep_count; i++) {
> + u64 index = (done + i) << large_shift;
> +
> + if (index >= page_struct_count)
> + return -EINVAL;
> +
> + input_page->spa_page_list[i] =
> + page_to_pfn(pages[index]);
> + }
> +
> + status = hv_do_rep_hypercall(code, rep_count, 0, input_page,
> + NULL);
> + local_irq_restore(irq_flags);
> +
> + completed = hv_repcomp(status);
> +
> + if (!hv_result_success(status))
> + return hv_result_to_errno(status);
> +
> + done += completed;
> + }
> +
> + return 0;
> +}
Stopping here because that's where I stopped in Part 1 of my v5 review
of this patch.
Michael
