Re: [PATCH-for-8.0 v2 4/6] hw/virtio: Constify qmp_virtio_feature_map_t[]

[Jonah Palmer]

On 12/13/22 06:17, Philippe Mathieu-Daudé wrote:

> These arrays are only accessed read-only, move them to .rodata.
>
> Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
> ---
>  hw/virtio/virtio.c | 34 +++++++++++++++++-----------------
>  1 file changed, 17 insertions(+), 17 deletions(-)
>
> diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
> index b35480be8f..f2298bb437 100644
> --- a/hw/virtio/virtio.c
> +++ b/hw/virtio/virtio.c
> @@ -80,7 +80,7 @@ enum VhostUserProtocolFeature {
>  };
>  
>  /* Virtio transport features mapping */
> -static qmp_virtio_feature_map_t virtio_transport_map[] = {
> +static const qmp_virtio_feature_map_t virtio_transport_map[] = {
>      /* Virtio device transport features */
>  #ifndef VIRTIO_CONFIG_NO_LEGACY
>      FEATURE_ENTRY(VIRTIO_F_NOTIFY_ON_EMPTY, \
> @@ -111,7 +111,7 @@ static qmp_virtio_feature_map_t virtio_transport_map[] = {
>  };
>  
>  /* Vhost-user protocol features mapping */
> -static qmp_virtio_feature_map_t vhost_user_protocol_map[] = {
> +static const qmp_virtio_feature_map_t vhost_user_protocol_map[] = {
>      FEATURE_ENTRY(VHOST_USER_PROTOCOL_F_MQ, \
>              "VHOST_USER_PROTOCOL_F_MQ: Multiqueue protocol supported"),
>      FEATURE_ENTRY(VHOST_USER_PROTOCOL_F_LOG_SHMFD, \
> @@ -161,7 +161,7 @@ static qmp_virtio_feature_map_t vhost_user_protocol_map[] = {
>  };
>  
>  /* virtio device configuration statuses */
> -static qmp_virtio_feature_map_t virtio_config_status_map[] = {
> +static const qmp_virtio_feature_map_t virtio_config_status_map[] = {
>      FEATURE_ENTRY(VIRTIO_CONFIG_S_DRIVER_OK, \
>              "VIRTIO_CONFIG_S_DRIVER_OK: Driver setup and ready"),
>      FEATURE_ENTRY(VIRTIO_CONFIG_S_FEATURES_OK, \
> @@ -180,7 +180,7 @@ static qmp_virtio_feature_map_t virtio_config_status_map[] = {
>  
>  /* virtio-blk features mapping */
>  #ifdef CONFIG_VIRTIO_BLK
> -static qmp_virtio_feature_map_t virtio_blk_feature_map[] = {
> +static const qmp_virtio_feature_map_t virtio_blk_feature_map[] = {
>      FEATURE_ENTRY(VIRTIO_BLK_F_SIZE_MAX, \
>              "VIRTIO_BLK_F_SIZE_MAX: Max segment size is size_max"),
>      FEATURE_ENTRY(VIRTIO_BLK_F_SEG_MAX, \
> @@ -221,7 +221,7 @@ static qmp_virtio_feature_map_t virtio_blk_feature_map[] = {
>  
>  /* virtio-serial features mapping */
>  #ifdef CONFIG_VIRTIO_SERIAL
> -static qmp_virtio_feature_map_t virtio_serial_feature_map[] = {
> +static const qmp_virtio_feature_map_t virtio_serial_feature_map[] = {
>      FEATURE_ENTRY(VIRTIO_CONSOLE_F_SIZE, \
>              "VIRTIO_CONSOLE_F_SIZE: Host providing console size"),
>      FEATURE_ENTRY(VIRTIO_CONSOLE_F_MULTIPORT, \
> @@ -234,7 +234,7 @@ static qmp_virtio_feature_map_t virtio_serial_feature_map[] = {
>  
>  /* virtio-gpu features mapping */
>  #ifdef CONFIG_VIRTIO_GPU
> -static qmp_virtio_feature_map_t virtio_gpu_feature_map[] = {
> +static const qmp_virtio_feature_map_t virtio_gpu_feature_map[] = {
>      FEATURE_ENTRY(VIRTIO_GPU_F_VIRGL, \
>              "VIRTIO_GPU_F_VIRGL: Virgl 3D mode supported"),
>      FEATURE_ENTRY(VIRTIO_GPU_F_EDID, \
> @@ -257,7 +257,7 @@ static qmp_virtio_feature_map_t virtio_gpu_feature_map[] = {
>  
>  /* virtio-input features mapping */
>  #ifdef CONFIG_VIRTIO_INPUT
> -static qmp_virtio_feature_map_t virtio_input_feature_map[] = {
> +static const qmp_virtio_feature_map_t virtio_input_feature_map[] = {
>      FEATURE_ENTRY(VHOST_F_LOG_ALL, \
>              "VHOST_F_LOG_ALL: Logging write descriptors supported"),
>      FEATURE_ENTRY(VHOST_USER_F_PROTOCOL_FEATURES, \
> @@ -269,7 +269,7 @@ static qmp_virtio_feature_map_t virtio_input_feature_map[] = {
>  
>  /* virtio-net features mapping */
>  #ifdef CONFIG_VIRTIO_NET
> -static qmp_virtio_feature_map_t virtio_net_feature_map[] = {
> +static const qmp_virtio_feature_map_t virtio_net_feature_map[] = {
>      FEATURE_ENTRY(VIRTIO_NET_F_CSUM, \
>              "VIRTIO_NET_F_CSUM: Device handling packets with partial checksum "
>              "supported"),
> @@ -349,7 +349,7 @@ static qmp_virtio_feature_map_t virtio_net_feature_map[] = {
>  
>  /* virtio-scsi features mapping */
>  #ifdef CONFIG_VIRTIO_SCSI
> -static qmp_virtio_feature_map_t virtio_scsi_feature_map[] = {
> +static const qmp_virtio_feature_map_t virtio_scsi_feature_map[] = {
>      FEATURE_ENTRY(VIRTIO_SCSI_F_INOUT, \
>              "VIRTIO_SCSI_F_INOUT: Requests including read and writable data "
>              "buffers suppoted"),
> @@ -372,7 +372,7 @@ static qmp_virtio_feature_map_t virtio_scsi_feature_map[] = {
>  
>  /* virtio/vhost-user-fs features mapping */
>  #ifdef CONFIG_VHOST_USER_FS
> -static qmp_virtio_feature_map_t virtio_fs_feature_map[] = {
> +static const qmp_virtio_feature_map_t virtio_fs_feature_map[] = {
>      FEATURE_ENTRY(VHOST_F_LOG_ALL, \
>              "VHOST_F_LOG_ALL: Logging write descriptors supported"),
>      FEATURE_ENTRY(VHOST_USER_F_PROTOCOL_FEATURES, \
> @@ -384,7 +384,7 @@ static qmp_virtio_feature_map_t virtio_fs_feature_map[] = {
>  
>  /* virtio/vhost-user-i2c features mapping */
>  #ifdef CONFIG_VIRTIO_I2C_ADAPTER
> -static qmp_virtio_feature_map_t virtio_i2c_feature_map[] = {
> +static const qmp_virtio_feature_map_t virtio_i2c_feature_map[] = {
>      FEATURE_ENTRY(VIRTIO_I2C_F_ZERO_LENGTH_REQUEST, \
>              "VIRTIO_I2C_F_ZERO_LEGNTH_REQUEST: Zero length requests supported"),
>      FEATURE_ENTRY(VHOST_F_LOG_ALL, \
> @@ -398,7 +398,7 @@ static qmp_virtio_feature_map_t virtio_i2c_feature_map[] = {
>  
>  /* virtio/vhost-vsock features mapping */
>  #ifdef CONFIG_VHOST_VSOCK
> -static qmp_virtio_feature_map_t virtio_vsock_feature_map[] = {
> +static const qmp_virtio_feature_map_t virtio_vsock_feature_map[] = {
>      FEATURE_ENTRY(VIRTIO_VSOCK_F_SEQPACKET, \
>              "VIRTIO_VSOCK_F_SEQPACKET: SOCK_SEQPACKET supported"),
>      FEATURE_ENTRY(VHOST_F_LOG_ALL, \
> @@ -412,7 +412,7 @@ static qmp_virtio_feature_map_t virtio_vsock_feature_map[] = {
>  
>  /* virtio-balloon features mapping */
>  #ifdef CONFIG_VIRTIO_BALLOON
> -static qmp_virtio_feature_map_t virtio_balloon_feature_map[] = {
> +static const qmp_virtio_feature_map_t virtio_balloon_feature_map[] = {
>      FEATURE_ENTRY(VIRTIO_BALLOON_F_MUST_TELL_HOST, \
>              "VIRTIO_BALLOON_F_MUST_TELL_HOST: Tell host before reclaiming "
>              "pages"),
> @@ -432,7 +432,7 @@ static qmp_virtio_feature_map_t virtio_balloon_feature_map[] = {
>  
>  /* virtio-crypto features mapping */
>  #ifdef CONFIG_VIRTIO_CRYPTO
> -static qmp_virtio_feature_map_t virtio_crypto_feature_map[] = {
> +static const qmp_virtio_feature_map_t virtio_crypto_feature_map[] = {
>      FEATURE_ENTRY(VHOST_F_LOG_ALL, \
>              "VHOST_F_LOG_ALL: Logging write descriptors supported"),
>      { -1, "" }
> @@ -441,7 +441,7 @@ static qmp_virtio_feature_map_t virtio_crypto_feature_map[] = {
>  
>  /* virtio-iommu features mapping */
>  #ifdef CONFIG_VIRTIO_IOMMU
> -static qmp_virtio_feature_map_t virtio_iommu_feature_map[] = {
> +static const qmp_virtio_feature_map_t virtio_iommu_feature_map[] = {
>      FEATURE_ENTRY(VIRTIO_IOMMU_F_INPUT_RANGE, \
>              "VIRTIO_IOMMU_F_INPUT_RANGE: Range of available virtual addrs. "
>              "available"),
> @@ -466,7 +466,7 @@ static qmp_virtio_feature_map_t virtio_iommu_feature_map[] = {
>  
>  /* virtio-mem features mapping */
>  #ifdef CONFIG_VIRTIO_MEM
> -static qmp_virtio_feature_map_t virtio_mem_feature_map[] = {
> +static const qmp_virtio_feature_map_t virtio_mem_feature_map[] = {
>  #ifndef CONFIG_ACPI
>      FEATURE_ENTRY(VIRTIO_MEM_F_ACPI_PXM, \
>              "VIRTIO_MEM_F_ACPI_PXM: node_id is an ACPI PXM and is valid"),
> @@ -480,7 +480,7 @@ static qmp_virtio_feature_map_t virtio_mem_feature_map[] = {
>  
>  /* virtio-rng features mapping */
>  #ifdef CONFIG_VIRTIO_RNG
> -static qmp_virtio_feature_map_t virtio_rng_feature_map[] = {
> +static const qmp_virtio_feature_map_t virtio_rng_feature_map[] = {
>      FEATURE_ENTRY(VHOST_F_LOG_ALL, \
>              "VHOST_F_LOG_ALL: Logging write descriptors supported"),
>      FEATURE_ENTRY(VHOST_USER_F_PROTOCOL_FEATURES, \
>     
Also a good catch. These maps should not change after being initialized,
since they're just definitions. Adding const here appears to be appropriate.

Reviewed-by: Jonah Palmer <jonah.palmer@oracle.com>