Re: [Xen-devel] [PATCH v16 03/10] tools: provide interface for generic resource access

[Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>]

On Thu, Sep 25, 2014 at 06:19:03PM +0800, Chao Peng wrote:
> Xen added a new platform_op hypercall for generic MSR access, and this
> is the the tool side change to wrapper the hypercall into xc APIs.
> 
> Signed-off-by: Dongxiao Xu <dongxiao.xu@xxxxxxxxx>
> Signed-off-by: Chao Peng <chao.p.peng@xxxxxxxxxxxxxxx>
> Acked-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
> ---
>  tools/libxc/Makefile      |    1 +
>  tools/libxc/xc_private.h  |   52 +++++++++++++++++
>  tools/libxc/xc_resource.c |  143 
> +++++++++++++++++++++++++++++++++++++++++++++
>  tools/libxc/xenctrl.h     |   13 +++++
>  4 files changed, 209 insertions(+)
>  create mode 100644 tools/libxc/xc_resource.c
> 
> diff --git a/tools/libxc/Makefile b/tools/libxc/Makefile
> index 3b04027..dde6109 100644
> --- a/tools/libxc/Makefile
> +++ b/tools/libxc/Makefile
> @@ -34,6 +34,7 @@ CTRL_SRCS-y       += xc_foreign_memory.c
>  CTRL_SRCS-y       += xc_kexec.c
>  CTRL_SRCS-y       += xtl_core.c
>  CTRL_SRCS-y       += xtl_logger_stdio.c
> +CTRL_SRCS-y       += xc_resource.c
>  CTRL_SRCS-$(CONFIG_X86) += xc_pagetab.c
>  CTRL_SRCS-$(CONFIG_Linux) += xc_linux.c xc_linux_osdep.c
>  CTRL_SRCS-$(CONFIG_FreeBSD) += xc_freebsd.c xc_freebsd_osdep.c
> diff --git a/tools/libxc/xc_private.h b/tools/libxc/xc_private.h
> index 94df688..fbdfe79 100644
> --- a/tools/libxc/xc_private.h
> +++ b/tools/libxc/xc_private.h
> @@ -46,6 +46,7 @@
>  #define DECLARE_SYSCTL struct xen_sysctl sysctl
>  #define DECLARE_PHYSDEV_OP struct physdev_op physdev_op
>  #define DECLARE_FLASK_OP struct xen_flask_op op
> +#define DECLARE_PLATFORM_OP struct xen_platform_op platform_op
>  
>  #undef PAGE_SHIFT
>  #undef PAGE_SIZE
> @@ -310,6 +311,57 @@ static inline int do_sysctl(xc_interface *xch, struct 
> xen_sysctl *sysctl)
>      return ret;
>  }
>  
> +static inline int do_platform_op(xc_interface *xch,
> +                                 struct xen_platform_op *platform_op)
> +{
> +    int ret = -1;
> +    DECLARE_HYPERCALL;
> +    DECLARE_HYPERCALL_BOUNCE(platform_op, sizeof(*platform_op),
> +                             XC_HYPERCALL_BUFFER_BOUNCE_BOTH);
> +
> +    platform_op->interface_version = XENPF_INTERFACE_VERSION;
> +
> +    if ( xc_hypercall_bounce_pre(xch, platform_op) )
> +    {
> +        PERROR("Could not bounce buffer for platform_op hypercall");
> +        goto out1;

Just return -1;
> +    }
> +
> +    hypercall.op     = __HYPERVISOR_platform_op;
> +    hypercall.arg[0] = HYPERCALL_BUFFER_AS_ARG(platform_op);
> +    if ( (ret = do_xen_hypercall(xch, &hypercall)) < 0 )
> +    {
> +        if ( errno == EACCES )
> +            DPRINTF("platform operation failed -- need to"
> +                    " rebuild the user-space tool set?\n");
> +    }
> +
> +    xc_hypercall_bounce_post(xch, platform_op);
> + out1:

And remove this label.

> +    return ret;
> +}
> +
> +static inline int do_multicall_op(xc_interface *xch,
> +                                  xc_hypercall_buffer_t *call_list,
> +                                  uint32_t nr_calls)
> +{
> +    int ret = -1;
> +    DECLARE_HYPERCALL;
> +    DECLARE_HYPERCALL_BUFFER_ARGUMENT(call_list);
> +
> +    hypercall.op     = __HYPERVISOR_multicall;
> +    hypercall.arg[0] = HYPERCALL_BUFFER_AS_ARG(call_list);
> +    hypercall.arg[1] = nr_calls;
> +    if ( (ret = do_xen_hypercall(xch, &hypercall)) < 0 )
> +    {
> +        if ( errno == EACCES )
> +            DPRINTF("multicall operation failed -- need to"
> +                    " rebuild the user-space tool set?\n");
> +    }
> +
> +    return ret;
> +}
> +
>  int do_memory_op(xc_interface *xch, int cmd, void *arg, size_t len);
>  
>  void *xc_map_foreign_ranges(xc_interface *xch, uint32_t dom,
> diff --git a/tools/libxc/xc_resource.c b/tools/libxc/xc_resource.c
> new file mode 100644
> index 0000000..c92910b
> --- /dev/null
> +++ b/tools/libxc/xc_resource.c
> @@ -0,0 +1,143 @@
> +/*
> + * xc_resource.c
> + *
> + * Generic resource access API
> + *
> + * Copyright (C) 2014      Intel Corporation
> + * Author Dongxiao Xu <dongxiao.xu@xxxxxxxxx>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU Lesser General Public License as published
> + * by the Free Software Foundation; version 2.1 only. with the special
> + * exception on linking described in file LICENSE.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU Lesser General Public License for more details.
> + */
> +
> +#include "xc_private.h"
> +
> +static int xc_resource_op_one(xc_interface *xch, xc_resource_op_t *op)
> +{
> +    int rc;
> +    DECLARE_PLATFORM_OP;
> +    DECLARE_NAMED_HYPERCALL_BOUNCE(data, op->entries,
> +                                op->nr_entries * sizeof(*op->entries),
> +                                XC_HYPERCALL_BUFFER_BOUNCE_BOTH);
> +
> +    if ( xc_hypercall_bounce_pre(xch, data) )
> +        return -1;
> +
> +    platform_op.cmd = XENPF_resource_op;
> +    platform_op.u.resource_op.nr = op->nr_entries;
> +    platform_op.u.resource_op.cpu = op->cpu;
> +    set_xen_guest_handle(platform_op.u.resource_op.data, data);
> +
> +    rc = do_platform_op(xch, &platform_op);
> +
> +    xc_hypercall_bounce_post(xch, data);
> +
> +    return rc;
> +}
> +
> +static int xc_resource_op_multi(xc_interface *xch, uint32_t nr_ops, 
> xc_resource_op_t *ops)
> +{
> +    int rc, i, entries_size;
> +    xc_resource_op_t *op;
> +    multicall_entry_t *call;
> +    DECLARE_HYPERCALL_BUFFER(multicall_entry_t, call_list);
> +    xc_hypercall_buffer_array_t *platform_ops, *entries_list = NULL;
> +
> +    call_list = xc_hypercall_buffer_alloc(xch, call_list,
> +                                          sizeof(*call_list) * nr_ops);
> +    if ( !call_list )
> +        return -1;
> +
> +    platform_ops = xc_hypercall_buffer_array_create(xch, nr_ops);
> +    if ( !platform_ops ) {

In the previous file you had '{' on an new-line. Can you make it uniform please?

> +        rc = -1;
> +        goto out;
> +    }
> +
> +    entries_list = xc_hypercall_buffer_array_create(xch, nr_ops);
> +    if ( !entries_list ) {

Ditto.
> +        rc = -1;
> +        goto out;
> +    }
> +
> +    for ( i = 0; i < nr_ops; i++ ) {

And here?

> +        DECLARE_HYPERCALL_BUFFER(xen_platform_op_t, platform_op);
> +        DECLARE_HYPERCALL_BUFFER(xc_resource_data_t, entries);
> +
> +        op = ops + i;
> +
> +        platform_op = xc_hypercall_buffer_array_alloc(xch, platform_ops, i,
> +                        platform_op, sizeof(xen_platform_op_t));
> +        if ( !platform_op ) {

?
> +            rc = -1;
> +            goto out;
> +        }
> +
> +        entries_size = sizeof(xc_resource_data_t) * op->nr_entries;
> +        entries = xc_hypercall_buffer_array_alloc(xch, entries_list, i,
> +                   entries, entries_size);
> +        if ( !entries) {

?
> +            rc = -1;
> +            goto out;
> +        }
> +        memcpy(entries, op->entries, entries_size);
> +
> +        call = call_list + i;
> +        call->op = __HYPERVISOR_platform_op;
> +        call->args[0] = HYPERCALL_BUFFER_AS_ARG(platform_op);
> +
> +        platform_op->interface_version = XENPF_INTERFACE_VERSION;
> +        platform_op->cmd = XENPF_resource_op;
> +        platform_op->u.resource_op.cpu = op->cpu;
> +        platform_op->u.resource_op.nr = op->nr_entries;
> +        set_xen_guest_handle(platform_op->u.resource_op.data, entries);
> +    }
> +
> +    rc = do_multicall_op(xch, HYPERCALL_BUFFER(call_list), nr_ops);
> +
> +    for ( i = 0; i < nr_ops; i++ ) {
> +        DECLARE_HYPERCALL_BUFFER(xc_resource_data_t, entries);
> +        op = ops + i;
> +
> +        call = call_list + i;
> +        op->result = call->result;
> +
> +        entries_size = sizeof(xc_resource_data_t) * op->nr_entries;
> +        entries = xc_hypercall_buffer_array_get(xch, entries_list, i,
> +                   entries, entries_size);
> +        memcpy(op->entries, entries, entries_size);
> +    }
> +
> +out:
> +    xc_hypercall_buffer_array_destroy(xch, entries_list);
> +    xc_hypercall_buffer_array_destroy(xch, platform_ops);
> +    xc_hypercall_buffer_free(xch, call_list);
> +    return rc;
> +}
> +
> +int xc_resource_op(xc_interface *xch, uint32_t nr_ops, xc_resource_op_t *ops)
> +{
> +    if ( nr_ops == 1 )
> +        return xc_resource_op_one(xch, ops);
> +    else if ( nr_ops > 1 )
> +        return xc_resource_op_multi(xch, nr_ops, ops);
> +    else
> +        return -1;
> +}
> +
> +/*
> + * Local variables:
> + * mode: C
> + * c-file-style: "BSD"
> + * c-basic-offset: 4
> + * tab-width: 4
> + * indent-tabs-mode: nil
> + * End:
> + */
> diff --git a/tools/libxc/xenctrl.h b/tools/libxc/xenctrl.h
> index 514b241..fb58c44 100644
> --- a/tools/libxc/xenctrl.h
> +++ b/tools/libxc/xenctrl.h
> @@ -47,6 +47,7 @@
>  #include <xen/xsm/flask_op.h>
>  #include <xen/tmem.h>
>  #include <xen/kexec.h>
> +#include <xen/platform.h>
>  
>  #include "xentoollog.h"
>  
> @@ -2655,6 +2656,18 @@ int xc_kexec_load(xc_interface *xch, uint8_t type, 
> uint16_t arch,
>   */
>  int xc_kexec_unload(xc_interface *xch, int type);
>  
> +typedef xenpf_resource_data_t xc_resource_data_t;
> +

A comment would be nice.
> +struct xc_resource_op {
> +    uint64_t result;
> +    uint32_t cpu;
> +    uint32_t nr_entries;
> +    xc_resource_data_t *entries;
> +};
> +
> +typedef struct xc_resource_op xc_resource_op_t;
> +int xc_resource_op(xc_interface *xch, uint32_t nr_ops, xc_resource_op_t 
> *ops);
> +
>  #endif /* XENCTRL_H */
>  
>  /*
> -- 
> 1.7.9.5
> 
> 
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> Xen-devel@xxxxxxxxxxxxx
> http://lists.xen.org/xen-devel

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