[Qemu-devel] Re: [PATCH 23/26] Implement PAPR CRQ hypercalls

[Alexander Graf <agraf@suse.de>]

On 03/16/2011 05:57 AM, David Gibson wrote:
> From: Ben Herrenschmidt<benh@kernel.crashing.org>
>
> This patch implements the infrastructure and hypercalls necessary for the
> PAPR specified CRQ (Command Request Queue) mechanism.  This general
> request queueing system is used by many of the PAPR virtual IO devices,
> including the virtual scsi adapter.
>
> Signed-off-by: Ben Herrenschmidt<benh@kernel.crashing.org>
> Signed-off-by: David Gibson<dwg@au1.ibm.com>
> ---
>   hw/spapr.c     |    2 +-
>   hw/spapr_vio.c |  159 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>   hw/spapr_vio.h |   12 ++++
>   3 files changed, 172 insertions(+), 1 deletions(-)
>
> diff --git a/hw/spapr.c b/hw/spapr.c
> index 44cf3cc..cb97a16 100644
> --- a/hw/spapr.c
> +++ b/hw/spapr.c
> @@ -64,7 +64,7 @@ static void *spapr_create_fdt(int *fdt_size, ram_addr_t ramsize,
>       uint32_t end_prop = cpu_to_be32(initrd_base + initrd_size);
>       uint32_t pft_size_prop[] = {0, cpu_to_be32(hash_shift)};
>       char hypertas_prop[] = "hcall-pft\0hcall-term\0hcall-dabr\0hcall-interrupt"
> -        "\0hcall-tce";
> +        "\0hcall-tce\0hcall-vio";
>       uint32_t interrupt_server_ranges_prop[] = {0, cpu_to_be32(smp_cpus)};
>       int i;
>       char *modelname;
> diff --git a/hw/spapr_vio.c b/hw/spapr_vio.c
> index 37cf51e..96668f3 100644
> --- a/hw/spapr_vio.c
> +++ b/hw/spapr_vio.c
> @@ -352,6 +352,159 @@ uint64_t ldq_tce(VIOsPAPRDevice *dev, uint64_t taddr)
>       return tswap64(val);
>   }
>
> +/*
> + * CRQ handling
> + */
> +static target_ulong h_reg_crq(CPUState *env, sPAPREnvironment *spapr,
> +                              target_ulong opcode, target_ulong *args)
> +{
> +    target_ulong reg = args[0];
> +    target_ulong queue_addr = args[1];
> +    target_ulong queue_len = args[2];
> +    VIOsPAPRDevice *dev = spapr_vio_find_by_reg(spapr->vio_bus, reg);
> +
> +    if (!dev) {
> +        fprintf(stderr, "h_reg_crq on non-existent unit 0x"
> +                TARGET_FMT_lx "\n", reg);
> +        return H_PARAMETER;
> +    }
> +
> +    /* We can't grok a queue size bigger than 256M for now */
> +    if (queue_len<  0x1000 || queue_len>  0x10000000) {
> +        fprintf(stderr, "h_reg_crq, queue size too small or too big (0x%llx)\n",
> +                (unsigned long long)queue_len);
> +        return H_PARAMETER;
> +    }
> +
> +    /* Check queue alignment */
> +    if (queue_addr&  0xfff) {
> +        fprintf(stderr, "h_reg_crq, queue not aligned (0x%llx)\n",
> +                (unsigned long long)queue_addr);
> +        return H_PARAMETER;
> +    }
> +
> +    /* Check if device supports CRQs */
> +    if (!dev->crq.SendFunc) {
> +        return H_NOT_FOUND;
> +    }
> +
> +
> +    /* Already a queue ? */
> +    if (dev->crq.qsize) {
> +        return H_RESOURCE;
> +    }
> +    dev->crq.qladdr = queue_addr;
> +    dev->crq.qsize = queue_len;
> +    dev->crq.qnext = 0;
> +
> +    dprintf("CRQ for dev 0x" TARGET_FMT_lx " registered at 0x"
> +            TARGET_FMT_lx "/0x" TARGET_FMT_lx "\n",
> +            reg, queue_addr, queue_len);
> +    return H_SUCCESS;
> +}
> +
> +static target_ulong h_free_crq(CPUState *env, sPAPREnvironment *spapr,
> +                               target_ulong opcode, target_ulong *args)
> +{
> +    target_ulong reg = args[0];
> +    VIOsPAPRDevice *dev = spapr_vio_find_by_reg(spapr->vio_bus, reg);
> +
> +    if (!dev) {
> +        fprintf(stderr, "h_free_crq on non-existent unit 0x"
> +                TARGET_FMT_lx "\n", reg);
> +        return H_PARAMETER;
> +    }
> +
> +    dev->crq.qladdr = 0;
> +    dev->crq.qsize = 0;
> +    dev->crq.qnext = 0;
> +
> +    dprintf("CRQ for dev 0x" TARGET_FMT_lx " freed\n", reg);
> +
> +    return H_SUCCESS;
> +}
> +
> +static target_ulong h_send_crq(CPUState *env, sPAPREnvironment *spapr,
> +                               target_ulong opcode, target_ulong *args)
> +{
> +    target_ulong reg = args[0];
> +    target_ulong msg_hi = args[1];
> +    target_ulong msg_lo = args[2];
> +    VIOsPAPRDevice *dev = spapr_vio_find_by_reg(spapr->vio_bus, reg);
> +    uint64_t crq_mangle[2];
> +
> +    if (!dev) {
> +        fprintf(stderr, "h_send_crq on non-existent unit 0x"
> +                TARGET_FMT_lx "\n", reg);
> +        return H_PARAMETER;
> +    }
> +    crq_mangle[0] = cpu_to_be64(msg_hi);
> +    crq_mangle[1] = cpu_to_be64(msg_lo);
> +
> +    if (dev->crq.SendFunc) {
> +        return dev->crq.SendFunc(dev, (uint8_t *)crq_mangle);
> +    }
> +
> +    return H_HARDWARE;
> +}
> +
> +static target_ulong h_enable_crq(CPUState *env, sPAPREnvironment *spapr,
> +                                 target_ulong opcode, target_ulong *args)
> +{
> +    target_ulong reg = args[0];
> +    VIOsPAPRDevice *dev = spapr_vio_find_by_reg(spapr->vio_bus, reg);
> +
> +    if (!dev) {
> +        fprintf(stderr, "h_enable_crq on non-existent unit 0x"
> +                TARGET_FMT_lx "\n", reg);
> +        return H_PARAMETER;
> +    }
> +
> +    return 0;
> +}
> +
> +/* Returns negative error, 0 success, or positive: queue full */
> +int spapr_vio_send_crq(VIOsPAPRDevice *dev, uint8_t *crq)
> +{
> +    int rc;
> +    uint8_t byte;
> +
> +    if (!dev->crq.qsize) {
> +        fprintf(stderr, "spapr_vio_send_creq on uninitialized queue\n");
> +        return -1;
> +    }
> +
> +    /* Maybe do a fast path for KVM just writing to the pages */
> +    rc = spapr_tce_dma_read(dev, dev->crq.qladdr + dev->crq.qnext,&byte, 1);
> +    if (rc) {
> +        return rc;
> +    }
> +    if (byte != 0) {
> +        return 1;
> +    }
> +
> +    rc = spapr_tce_dma_write(dev, dev->crq.qladdr + dev->crq.qnext + 8,&crq[8], 8);
> +    if (rc) {
> +        return rc;
> +    }
> +#ifdef __powerpc__
> +    /* Really only needed for kvm... */

Create a kvm helper function for this in target-ppc/kvm.c please that is 
just a nop when !kvm.

> +    asm volatile("eieio" : : : "memory");
> +#endif

Alex