Re: [Qemu-devel] [PATCH v1 06/12] net: cadence_gem: Add support for selecting the DMA MemoryRegion

[Philippe Mathieu-Daudé]

Hi Edgar,

On 03/10/2018 17:07, Edgar E. Iglesias wrote:
> From: "Edgar E. Iglesias" <address@hidden>
> 
> Add support for selecting the Memory Region that the GEM
> will do DMA to.
> 
> Signed-off-by: Edgar E. Iglesias <address@hidden>
> ---
>  hw/net/cadence_gem.c         | 63 
> ++++++++++++++++++++++++++++----------------
>  include/hw/net/cadence_gem.h |  2 ++
>  2 files changed, 43 insertions(+), 22 deletions(-)
> 
> diff --git a/hw/net/cadence_gem.c b/hw/net/cadence_gem.c
> index 759c1d7..ab02515 100644
> --- a/hw/net/cadence_gem.c
> +++ b/hw/net/cadence_gem.c
> @@ -28,6 +28,7 @@
>  #include "hw/net/cadence_gem.h"
>  #include "qapi/error.h"
>  #include "qemu/log.h"
> +#include "sysemu/dma.h"
>  #include "net/checksum.h"
>  
>  #ifdef CADENCE_GEM_ERR_DEBUG
> @@ -835,9 +836,9 @@ static void gem_get_rx_desc(CadenceGEMState *s, int q)
>  {
>      DB_PRINT("read descriptor 0x%x\n", (unsigned)s->rx_desc_addr[q]);
>      /* read current descriptor */
> -    cpu_physical_memory_read(s->rx_desc_addr[q],
> -                             (uint8_t *)s->rx_desc[q],
> -                             sizeof(uint32_t) * gem_get_desc_len(s, true));
> +    address_space_read(s->dma_as, s->rx_desc_addr[q], MEMTXATTRS_UNSPECIFIED,
> +                       (uint8_t *)s->rx_desc[q],
> +                       sizeof(uint32_t) * gem_get_desc_len(s, true));
>  
>      /* Descriptor owned by software ? */
>      if (rx_desc_get_ownership(s->rx_desc[q]) == 1) {
> @@ -956,10 +957,10 @@ static ssize_t gem_receive(NetClientState *nc, const 
> uint8_t *buf, size_t size)
>                  rx_desc_get_buffer(s->rx_desc[q]));
>  
>          /* Copy packet data to emulated DMA buffer */
> -        cpu_physical_memory_write(rx_desc_get_buffer(s, s->rx_desc[q]) +
> +        address_space_write(s->dma_as, rx_desc_get_buffer(s, s->rx_desc[q]) +
>                                                                    
> rxbuf_offset,
> -                                  rxbuf_ptr,
> -                                  MIN(bytes_to_copy, rxbufsize));
> +                            MEMTXATTRS_UNSPECIFIED, rxbuf_ptr,
> +                            MIN(bytes_to_copy, rxbufsize));
>          rxbuf_ptr += MIN(bytes_to_copy, rxbufsize);
>          bytes_to_copy -= MIN(bytes_to_copy, rxbufsize);
>  
> @@ -993,9 +994,10 @@ static ssize_t gem_receive(NetClientState *nc, const 
> uint8_t *buf, size_t size)
>          }
>  
>          /* Descriptor write-back.  */
> -        cpu_physical_memory_write(s->rx_desc_addr[q],
> -                                  (uint8_t *)s->rx_desc[q],
> -                                  sizeof(uint32_t) * gem_get_desc_len(s, 
> true));
> +        address_space_write(s->dma_as, s->rx_desc_addr[q],
> +                            MEMTXATTRS_UNSPECIFIED,
> +                            (uint8_t *)s->rx_desc[q],
> +                            sizeof(uint32_t) * gem_get_desc_len(s, true));
>  
>          /* Next descriptor */
>          if (rx_desc_get_wrap(s->rx_desc[q])) {
> @@ -1099,9 +1101,9 @@ static void gem_transmit(CadenceGEMState *s)
>          packet_desc_addr = s->tx_desc_addr[q];
>  
>          DB_PRINT("read descriptor 0x%" HWADDR_PRIx "\n", packet_desc_addr);
> -        cpu_physical_memory_read(packet_desc_addr,
> -                                 (uint8_t *)desc,
> -                                 sizeof(uint32_t) * gem_get_desc_len(s, 
> false));
> +        address_space_read(s->dma_as, packet_desc_addr,
> +                           MEMTXATTRS_UNSPECIFIED, (uint8_t *)desc,
> +                           sizeof(uint32_t) * gem_get_desc_len(s, false));
>          /* Handle all descriptors owned by hardware */
>          while (tx_desc_get_used(desc) == 0) {
>  
> @@ -1133,8 +1135,9 @@ static void gem_transmit(CadenceGEMState *s)
>              /* Gather this fragment of the packet from "dma memory" to our
>               * contig buffer.
>               */
> -            cpu_physical_memory_read(tx_desc_get_buffer(s, desc), p,
> -                                     tx_desc_get_length(desc));
> +            address_space_read(s->dma_as, tx_desc_get_buffer(s, desc),
> +                               MEMTXATTRS_UNSPECIFIED,
> +                               p, tx_desc_get_length(desc));
>              p += tx_desc_get_length(desc);
>              total_bytes += tx_desc_get_length(desc);
>  
> @@ -1145,13 +1148,15 @@ static void gem_transmit(CadenceGEMState *s)
>                  /* Modify the 1st descriptor of this packet to be owned by
>                   * the processor.
>                   */
> -                cpu_physical_memory_read(s->tx_desc_addr[q],
> -                                         (uint8_t *)desc_first,
> -                                         sizeof(desc_first));
> +                address_space_read(s->dma_as, s->tx_desc_addr[q],
> +                                   MEMTXATTRS_UNSPECIFIED,
> +                                   (uint8_t *)desc_first,
> +                                   sizeof(desc_first));
>                  tx_desc_set_used(desc_first);
> -                cpu_physical_memory_write(s->tx_desc_addr[q],
> -                                          (uint8_t *)desc_first,
> -                                          sizeof(desc_first));
> +                address_space_write(s->dma_as, s->tx_desc_addr[q],
> +                                  MEMTXATTRS_UNSPECIFIED,
> +                                  (uint8_t *)desc_first,
> +                                   sizeof(desc_first));
>                  /* Advance the hardware current descriptor past this packet 
> */
>                  if (tx_desc_get_wrap(desc)) {
>                      s->tx_desc_addr[q] = s->regs[GEM_TXQBASE];
> @@ -1204,8 +1209,9 @@ static void gem_transmit(CadenceGEMState *s)
>                  packet_desc_addr += 4 * gem_get_desc_len(s, false);
>              }
>              DB_PRINT("read descriptor 0x%" HWADDR_PRIx "\n", 
> packet_desc_addr);
> -            cpu_physical_memory_read(packet_desc_addr, (uint8_t *)desc,
> -                                sizeof(uint32_t) * gem_get_desc_len(s, 
> false));
> +            address_space_read(s->dma_as, packet_desc_addr,
> +                              MEMTXATTRS_UNSPECIFIED, (uint8_t *)desc,
> +                              sizeof(uint32_t) * gem_get_desc_len(s, false));
>          }
>  
>          if (tx_desc_get_used(desc)) {
> @@ -1500,6 +1506,13 @@ static void gem_realize(DeviceState *dev, Error **errp)
>      CadenceGEMState *s = CADENCE_GEM(dev);
>      int i;
>  
> +    if (s->dma_mr) {
> +        s->dma_as = g_malloc0(sizeof(AddressSpace));
> +        address_space_init(s->dma_as, s->dma_mr, NULL);
> +    } else {
> +        s->dma_as = &address_space_memory;
> +    }

This is not the first time I see this if() block.

Should we consider refactor it?

Anyway:
Reviewed-by: Philippe Mathieu-Daudé <address@hidden>


> +
>      if (s->num_priority_queues == 0 ||
>          s->num_priority_queues > MAX_PRIORITY_QUEUES) {
>          error_setg(errp, "Invalid num-priority-queues value: %" PRIx8,
> @@ -1537,6 +1550,12 @@ static void gem_init(Object *obj)
>                            "enet", sizeof(s->regs));
>  
>      sysbus_init_mmio(SYS_BUS_DEVICE(dev), &s->iomem);
> +
> +    object_property_add_link(obj, "dma", TYPE_MEMORY_REGION,
> +                             (Object **)&s->dma_mr,
> +                             qdev_prop_allow_set_link_before_realize,
> +                             OBJ_PROP_LINK_STRONG,
> +                             &error_abort);
>  }
>  
>  static const VMStateDescription vmstate_cadence_gem = {
> diff --git a/include/hw/net/cadence_gem.h b/include/hw/net/cadence_gem.h
> index 00dbf4f..c8f0751 100644
> --- a/include/hw/net/cadence_gem.h
> +++ b/include/hw/net/cadence_gem.h
> @@ -45,6 +45,8 @@ typedef struct CadenceGEMState {
>  
>      /*< public >*/
>      MemoryRegion iomem;
> +    MemoryRegion *dma_mr;
> +    AddressSpace *dma_as;
>      NICState *nic;
>      NICConf conf;
>      qemu_irq irq[MAX_PRIORITY_QUEUES];
>