Re: [PATCH v6 23/42] nvme: add mapping helpers

[Maxim Levitsky]

On Mon, 2020-03-16 at 07:29 -0700, Klaus Jensen wrote:
> From: Klaus Jensen <address@hidden>
> 
> Add nvme_map_addr, nvme_map_addr_cmb and nvme_addr_to_cmb helpers and
> use them in nvme_map_prp.
> 
> This fixes a bug where in the case of a CMB transfer, the device would
> map to the buffer with a wrong length.
> 
> Fixes: b2b2b67a00574 ("nvme: Add support for Read Data and Write Data in 
> CMBs.")
> Signed-off-by: Klaus Jensen <address@hidden>
> ---
>  hw/block/nvme.c       | 97 +++++++++++++++++++++++++++++++++++--------
>  hw/block/trace-events |  1 +
>  2 files changed, 81 insertions(+), 17 deletions(-)
> 
> diff --git a/hw/block/nvme.c b/hw/block/nvme.c
> index 08267e847671..187c816eb6ad 100644
> --- a/hw/block/nvme.c
> +++ b/hw/block/nvme.c
> @@ -59,6 +59,11 @@
>  
>  static void nvme_process_sq(void *opaque);
>  
> +static inline void *nvme_addr_to_cmb(NvmeCtrl *n, hwaddr addr)
> +{
> +    return &n->cmbuf[addr - n->ctrl_mem.addr];
> +}
> +
>  static inline bool nvme_addr_is_cmb(NvmeCtrl *n, hwaddr addr)
>  {
>      hwaddr low = n->ctrl_mem.addr;
> @@ -70,7 +75,7 @@ static inline bool nvme_addr_is_cmb(NvmeCtrl *n, hwaddr 
> addr)
>  static void nvme_addr_read(NvmeCtrl *n, hwaddr addr, void *buf, int size)
>  {
>      if (n->bar.cmbsz && nvme_addr_is_cmb(n, addr)) {
> -        memcpy(buf, (void *)&n->cmbuf[addr - n->ctrl_mem.addr], size);
> +        memcpy(buf, nvme_addr_to_cmb(n, addr), size);
>          return;
>      }
>  
> @@ -153,29 +158,79 @@ static void nvme_irq_deassert(NvmeCtrl *n, NvmeCQueue 
> *cq)
>      }
>  }
>  
> +static uint16_t nvme_map_addr_cmb(NvmeCtrl *n, QEMUIOVector *iov, hwaddr 
> addr,
> +                                  size_t len)
> +{
> +    if (!nvme_addr_is_cmb(n, addr) || !nvme_addr_is_cmb(n, addr + len)) {
> +        return NVME_DATA_TRAS_ERROR;
> +    }

I just noticed that
in theory (not that it really matters) but addr+len refers to the byte which is 
already 
not the part of the transfer.


> +
> +    qemu_iovec_add(iov, nvme_addr_to_cmb(n, addr), len);
Also intersting is we can add 0 sized iovec.


> +
> +    return NVME_SUCCESS;
> +}
> +
> +static uint16_t nvme_map_addr(NvmeCtrl *n, QEMUSGList *qsg, QEMUIOVector 
> *iov,
> +                              hwaddr addr, size_t len)
> +{
> +    if (nvme_addr_is_cmb(n, addr)) {
> +        if (qsg && qsg->sg) {
> +            return NVME_INVALID_USE_OF_CMB | NVME_DNR;
> +        }
> +
> +        assert(iov);
> +
> +        if (!iov->iov) {
> +            qemu_iovec_init(iov, 1);
> +        }
> +
> +        return nvme_map_addr_cmb(n, iov, addr, len);
> +    }
> +
> +    if (iov && iov->iov) {
> +        return NVME_INVALID_USE_OF_CMB | NVME_DNR;
> +    }
> +
> +    assert(qsg);
> +
> +    if (!qsg->sg) {
> +        pci_dma_sglist_init(qsg, &n->parent_obj, 1);
> +    }
> +
> +    qemu_sglist_add(qsg, addr, len);
> +
> +    return NVME_SUCCESS;
> +}
Looks very good.

> +
>  static uint16_t nvme_map_prp(QEMUSGList *qsg, QEMUIOVector *iov, uint64_t 
> prp1,
>                               uint64_t prp2, uint32_t len, NvmeCtrl *n)
>  {
>      hwaddr trans_len = n->page_size - (prp1 % n->page_size);
>      trans_len = MIN(len, trans_len);
>      int num_prps = (len >> n->page_bits) + 1;
> +    uint16_t status;
>  
>      if (unlikely(!prp1)) {
>          trace_nvme_dev_err_invalid_prp();
>          return NVME_INVALID_FIELD | NVME_DNR;
> -    } else if (n->bar.cmbsz && prp1 >= n->ctrl_mem.addr &&
> -               prp1 < n->ctrl_mem.addr + int128_get64(n->ctrl_mem.size)) {
> -        qsg->nsg = 0;
> +    }
> +
> +    if (nvme_addr_is_cmb(n, prp1)) {
>          qemu_iovec_init(iov, num_prps);
> -        qemu_iovec_add(iov, (void *)&n->cmbuf[prp1 - n->ctrl_mem.addr], 
> trans_len);
>      } else {
>          pci_dma_sglist_init(qsg, &n->parent_obj, num_prps);
> -        qemu_sglist_add(qsg, prp1, trans_len);
>      }
> +
> +    status = nvme_map_addr(n, qsg, iov, prp1, trans_len);
> +    if (status) {
> +        goto unmap;
> +    }
> +
>      len -= trans_len;
>      if (len) {
>          if (unlikely(!prp2)) {
>              trace_nvme_dev_err_invalid_prp2_missing();
> +            status = NVME_INVALID_FIELD | NVME_DNR;
>              goto unmap;
>          }
>          if (len > n->page_size) {
> @@ -192,6 +247,7 @@ static uint16_t nvme_map_prp(QEMUSGList *qsg, 
> QEMUIOVector *iov, uint64_t prp1,
>                  if (i == n->max_prp_ents - 1 && len > n->page_size) {
>                      if (unlikely(!prp_ent || prp_ent & (n->page_size - 1))) {
>                          trace_nvme_dev_err_invalid_prplist_ent(prp_ent);
> +                        status = NVME_INVALID_FIELD | NVME_DNR;
>                          goto unmap;
>                      }
>  
> @@ -205,14 +261,14 @@ static uint16_t nvme_map_prp(QEMUSGList *qsg, 
> QEMUIOVector *iov, uint64_t prp1,
>  
>                  if (unlikely(!prp_ent || prp_ent & (n->page_size - 1))) {
>                      trace_nvme_dev_err_invalid_prplist_ent(prp_ent);
> +                    status = NVME_INVALID_FIELD | NVME_DNR;
>                      goto unmap;
>                  }
>  
>                  trans_len = MIN(len, n->page_size);
> -                if (qsg->nsg){
> -                    qemu_sglist_add(qsg, prp_ent, trans_len);
> -                } else {
> -                    qemu_iovec_add(iov, (void *)&n->cmbuf[prp_ent - 
> n->ctrl_mem.addr], trans_len);
> +                status = nvme_map_addr(n, qsg, iov, prp_ent, trans_len);
> +                if (status) {
> +                    goto unmap;
>                  }
>                  len -= trans_len;
>                  i++;
> @@ -220,20 +276,27 @@ static uint16_t nvme_map_prp(QEMUSGList *qsg, 
> QEMUIOVector *iov, uint64_t prp1,
>          } else {
>              if (unlikely(prp2 & (n->page_size - 1))) {
>                  trace_nvme_dev_err_invalid_prp2_align(prp2);
> +                status = NVME_INVALID_FIELD | NVME_DNR;
>                  goto unmap;
>              }
> -            if (qsg->nsg) {
> -                qemu_sglist_add(qsg, prp2, len);
> -            } else {
> -                qemu_iovec_add(iov, (void *)&n->cmbuf[prp2 - 
> n->ctrl_mem.addr], trans_len);
> +            status = nvme_map_addr(n, qsg, iov, prp2, len);
> +            if (status) {
> +                goto unmap;
>              }
>          }
>      }
>      return NVME_SUCCESS;
>  
> - unmap:
> -    qemu_sglist_destroy(qsg);
> -    return NVME_INVALID_FIELD | NVME_DNR;
> +unmap:
> +    if (iov && iov->iov) {
> +        qemu_iovec_destroy(iov);
> +    }
> +
> +    if (qsg && qsg->sg) {
> +        qemu_sglist_destroy(qsg);
> +    }
> +
> +    return status;
>  }
>  
>  static uint16_t nvme_dma_write_prp(NvmeCtrl *n, uint8_t *ptr, uint32_t len,
> diff --git a/hw/block/trace-events b/hw/block/trace-events
> index 4cde0844ef64..adf11313f956 100644
> --- a/hw/block/trace-events
> +++ b/hw/block/trace-events
> @@ -33,6 +33,7 @@ nvme_dev_irq_msix(uint32_t vector) "raising MSI-X IRQ 
> vector %u"
>  nvme_dev_irq_pin(void) "pulsing IRQ pin"
>  nvme_dev_irq_masked(void) "IRQ is masked"
>  nvme_dev_dma_read(uint64_t prp1, uint64_t prp2) "DMA read, prp1=0x%"PRIx64" 
> prp2=0x%"PRIx64""
> +nvme_dev_map_prp(uint16_t cid, uint8_t opc, uint64_t trans_len, uint32_t 
> len, uint64_t prp1, uint64_t prp2, int num_prps) "cid %"PRIu16" opc 
> 0x%"PRIx8" trans_len %"PRIu64" len %"PRIu32" prp1
> 0x%"PRIx64" prp2 0x%"PRIx64" num_prps %d"
>  nvme_dev_rw(const char *verb, uint32_t blk_count, uint64_t byte_count, 
> uint64_t lba) "%s %"PRIu32" blocks (%"PRIu64" bytes) from LBA %"PRIu64""
>  nvme_dev_create_sq(uint64_t addr, uint16_t sqid, uint16_t cqid, uint16_t 
> qsize, uint16_t qflags) "create submission queue, addr=0x%"PRIx64", 
> sqid=%"PRIu16", cqid=%"PRIu16", qsize=%"PRIu16",
> qflags=%"PRIu16""
>  nvme_dev_create_cq(uint64_t addr, uint16_t cqid, uint16_t vector, uint16_t 
> size, uint16_t qflags, int ien) "create completion queue, addr=0x%"PRIx64", 
> cqid=%"PRIu16", vector=%"PRIu16",
> qsize=%"PRIu16", qflags=%"PRIu16", ien=%d"


Looks very good overall,

Best regards,
        Maxim Levitsky