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Re: [PATCH 05/16] hw/block/nvme: refactor dma read/write
From: |
Klaus Jensen |
Subject: |
Re: [PATCH 05/16] hw/block/nvme: refactor dma read/write |
Date: |
Wed, 29 Jul 2020 20:38:13 +0200 |
On Jul 29 20:35, Maxim Levitsky wrote:
> On Mon, 2020-07-20 at 13:37 +0200, Klaus Jensen wrote:
> > From: Klaus Jensen <k.jensen@samsung.com>
> >
> > Refactor the nvme_dma_{read,write}_prp functions into a common function
> > taking a DMADirection parameter.
> >
> > Signed-off-by: Klaus Jensen <k.jensen@samsung.com>
> > Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
> > ---
> > hw/block/nvme.c | 88 ++++++++++++++++++++++++-------------------------
> > 1 file changed, 43 insertions(+), 45 deletions(-)
> >
> > diff --git a/hw/block/nvme.c b/hw/block/nvme.c
> > index 6a1a1626b87b..d314a604db81 100644
> > --- a/hw/block/nvme.c
> > +++ b/hw/block/nvme.c
> > @@ -361,55 +361,50 @@ unmap:
> > return status;
> > }
> >
> > -static uint16_t nvme_dma_write_prp(NvmeCtrl *n, uint8_t *ptr, uint32_t len,
> > - uint64_t prp1, uint64_t prp2)
> > +static uint16_t nvme_dma_prp(NvmeCtrl *n, uint8_t *ptr, uint32_t len,
> > + uint64_t prp1, uint64_t prp2, DMADirection
> > dir)
> > {
> > QEMUSGList qsg;
> > QEMUIOVector iov;
> > uint16_t status = NVME_SUCCESS;
> >
> > - if (nvme_map_prp(&qsg, &iov, prp1, prp2, len, n)) {
> > - return NVME_INVALID_FIELD | NVME_DNR;
> > + status = nvme_map_prp(&qsg, &iov, prp1, prp2, len, n);
> > + if (status) {
> > + return status;
> > }
> > +
> > if (qsg.nsg > 0) {
> > - if (dma_buf_write(ptr, len, &qsg)) {
> > - status = NVME_INVALID_FIELD | NVME_DNR;
> > + uint64_t residual;
> > +
> > + if (dir == DMA_DIRECTION_TO_DEVICE) {
> > + residual = dma_buf_write(ptr, len, &qsg);
> > + } else {
> > + residual = dma_buf_read(ptr, len, &qsg);
> > }
> > - qemu_sglist_destroy(&qsg);
> > - } else {
> > - if (qemu_iovec_to_buf(&iov, 0, ptr, len) != len) {
> > - status = NVME_INVALID_FIELD | NVME_DNR;
> > - }
> > - qemu_iovec_destroy(&iov);
> > - }
> > - return status;
> > -}
> >
> > -static uint16_t nvme_dma_read_prp(NvmeCtrl *n, uint8_t *ptr, uint32_t len,
> > - uint64_t prp1, uint64_t prp2)
> > -{
> > - QEMUSGList qsg;
> > - QEMUIOVector iov;
> > - uint16_t status = NVME_SUCCESS;
> > -
> > - trace_pci_nvme_dma_read(prp1, prp2);
> > -
> > - if (nvme_map_prp(&qsg, &iov, prp1, prp2, len, n)) {
> > - return NVME_INVALID_FIELD | NVME_DNR;
> > - }
> > - if (qsg.nsg > 0) {
> > - if (unlikely(dma_buf_read(ptr, len, &qsg))) {
> > + if (unlikely(residual)) {
> > trace_pci_nvme_err_invalid_dma();
> > status = NVME_INVALID_FIELD | NVME_DNR;
> > }
> > +
> > qemu_sglist_destroy(&qsg);
> > } else {
> > - if (unlikely(qemu_iovec_from_buf(&iov, 0, ptr, len) != len)) {
> > + size_t bytes;
> > +
> > + if (dir == DMA_DIRECTION_TO_DEVICE) {
> > + bytes = qemu_iovec_to_buf(&iov, 0, ptr, len);
> > + } else {
> > + bytes = qemu_iovec_from_buf(&iov, 0, ptr, len);
> > + }
> > +
> > + if (unlikely(bytes != len)) {
> > trace_pci_nvme_err_invalid_dma();
> > status = NVME_INVALID_FIELD | NVME_DNR;
> > }
> > +
> > qemu_iovec_destroy(&iov);
> > }
> > +
> I know I reviewed this, but thinking now, why not to add an assert here
> that we don't have both iov and qsg with data.
>
Good point. I added it after the nvme_map_prp call.
[PATCH 04/16] hw/block/nvme: remove redundant has_sg member, Klaus Jensen, 2020/07/20