Re: [PATCH v6 29/42] nvme: refactor request bounds checking

[Maxim Levitsky]

On Mon, 2020-03-16 at 07:29 -0700, Klaus Jensen wrote:
> From: Klaus Jensen <address@hidden>
> 
> Signed-off-by: Klaus Jensen <address@hidden>
> ---
>  hw/block/nvme.c | 28 ++++++++++++++++++++++------
>  1 file changed, 22 insertions(+), 6 deletions(-)
> 
> diff --git a/hw/block/nvme.c b/hw/block/nvme.c
> index eecfad694bf8..ba520c76bae5 100644
> --- a/hw/block/nvme.c
> +++ b/hw/block/nvme.c
> @@ -491,6 +491,20 @@ static void nvme_clear_events(NvmeCtrl *n, uint8_t 
> event_type)
>      }
>  }
>  
> +static inline uint16_t nvme_check_bounds(NvmeCtrl *n, NvmeNamespace *ns,
> +                                         uint64_t slba, uint32_t nlb,
> +                                         NvmeRequest *req)
> +{
> +    uint64_t nsze = le64_to_cpu(ns->id_ns.nsze);
> +
> +    if (unlikely(UINT64_MAX - slba < nlb || slba + nlb > nsze)) {
> +        trace_nvme_dev_err_invalid_lba_range(slba, nlb, nsze);
> +        return NVME_LBA_RANGE | NVME_DNR;
> +    }
> +
> +    return NVME_SUCCESS;
> +}
Looks good.

> +
>  static void nvme_rw_cb(void *opaque, int ret)
>  {
>      NvmeRequest *req = opaque;
> @@ -536,10 +550,11 @@ static uint16_t nvme_write_zeros(NvmeCtrl *n, 
> NvmeNamespace *ns, NvmeCmd *cmd,
>      uint32_t nlb  = le16_to_cpu(rw->nlb) + 1;
>      uint64_t offset = slba << data_shift;
>      uint32_t count = nlb << data_shift;
> +    uint16_t status;
>  
> -    if (unlikely(slba + nlb > ns->id_ns.nsze)) {
> -        trace_nvme_dev_err_invalid_lba_range(slba, nlb, ns->id_ns.nsze);
> -        return NVME_LBA_RANGE | NVME_DNR;
> +    status = nvme_check_bounds(n, ns, slba, nlb, req);
> +    if (status) {
> +        return status;
>      }
>  
>      block_acct_start(blk_get_stats(n->conf.blk), &req->acct, 0,
> @@ -562,13 +577,14 @@ static uint16_t nvme_rw(NvmeCtrl *n, NvmeNamespace *ns, 
> NvmeCmd *cmd,
>      uint64_t data_offset = slba << data_shift;
>      int is_write = rw->opcode == NVME_CMD_WRITE ? 1 : 0;
>      enum BlockAcctType acct = is_write ? BLOCK_ACCT_WRITE : BLOCK_ACCT_READ;
> +    uint16_t status;
>  
>      trace_nvme_dev_rw(is_write ? "write" : "read", nlb, data_size, slba);
>  
> -    if (unlikely((slba + nlb) > ns->id_ns.nsze)) {
> +    status = nvme_check_bounds(n, ns, slba, nlb, req);
> +    if (status) {
>          block_acct_invalid(blk_get_stats(n->conf.blk), acct);
> -        trace_nvme_dev_err_invalid_lba_range(slba, nlb, ns->id_ns.nsze);
> -        return NVME_LBA_RANGE | NVME_DNR;
> +        return status;
>      }
>  
>      if (nvme_map(n, cmd, &req->qsg, &req->iov, data_size, req)) {
Looks good as well, once we get support for discard, it will
use this as well, but for now indeed only write zeros and read/write
need bounds checking on the IO path.

Reviewed-by: Maxim Levitsky <address@hidden>

Best regards,
        Maxim Levitsky