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Re: [Xen-devel] [PATCH v2 03/13] xen/xsplice: Hypervisor implementation of XEN_XSPLICE_op (v7)



>>> On 06.02.16 at 23:35, <cardoe@xxxxxxxxxx> wrote:

(Just to demonstrate the effect - please go right to the end.)

> On 1/14/16 3:47 PM, Konrad Rzeszutek Wilk wrote:
>> The implementation does not actually do any patching.
>> 
>> It just adds the framework for doing the hypercalls,
>> keeping track of ELF payloads, and the basic operations:
>>  - query which payloads exist,
>>  - query for specific payloads,
>>  - check*1, apply*1, replace*1, and unload payloads.
>> 
>> *1: Which of course in this patch are nops.
>> 
>> Acked-by: Daniel De Graaf <dgdegra@xxxxxxxxxxxxx>
>> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
>> Signed-off-by: Ross Lagerwall <ross.lagerwall@xxxxxxxxxx>
>> 
>> ---
>> v2: Rebased on keyhandler: rework keyhandler infrastructure
>> v3: Fixed XSM.
>> v4: Removed REVERTED state.
>>     Split status and error code.
>>     Add REPLACE action.
>>     Separate payload data from the payload structure.
>>     s/XSPLICE_ID_../XSPLICE_NAME_../
>> v5: Add xsplice and CONFIG_XSPLICE build toption.
>>     Fix code per Jan's review.
>>     Update the sysctl.h (change bits to enum like)
>> v6: Rebase on Kconfig changes.
>> v7: Add missing pad checks. Re-order keyhandler.h to build on ARM.
>> 
>> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
>> ---
>>  tools/flask/policy/policy/modules/xen/xen.te |   1 +
>>  xen/arch/arm/Kconfig                         |   1 +
>>  xen/arch/x86/Kconfig                         |   1 +
>>  xen/common/Kconfig                           |  14 +
>>  xen/common/Makefile                          |   2 +
>>  xen/common/sysctl.c                          |   8 +
>>  xen/common/xsplice.c                         | 386 
> +++++++++++++++++++++++++++
>>  xen/include/public/sysctl.h                  | 156 +++++++++++
>>  xen/include/xen/xsplice.h                    |   7 +
>>  xen/xsm/flask/hooks.c                        |   6 +
>>  xen/xsm/flask/policy/access_vectors          |   2 +
>>  11 files changed, 584 insertions(+)
>>  create mode 100644 xen/common/xsplice.c
>>  create mode 100644 xen/include/xen/xsplice.h
>> 
>> diff --git a/tools/flask/policy/policy/modules/xen/xen.te 
> b/tools/flask/policy/policy/modules/xen/xen.te
>> index d35ae22..542c3e1 100644
>> --- a/tools/flask/policy/policy/modules/xen/xen.te
>> +++ b/tools/flask/policy/policy/modules/xen/xen.te
>> @@ -72,6 +72,7 @@ allow dom0_t xen_t:xen2 {
>>  allow dom0_t xen_t:xen2 {
>>      pmu_ctrl
>>      get_symbol
>> +    xsplice_op
>>  };
>>  allow dom0_t xen_t:mmu memorymap;
>>  
>> diff --git a/xen/arch/arm/Kconfig b/xen/arch/arm/Kconfig
>> index 60e923c..3780949 100644
>> --- a/xen/arch/arm/Kconfig
>> +++ b/xen/arch/arm/Kconfig
>> @@ -23,6 +23,7 @@ config ARM
>>      select HAS_PASSTHROUGH
>>      select HAS_PDX
>>      select HAS_VIDEO
>> +    select HAS_XSPLICE
>>  
>>  config ARCH_DEFCONFIG
>>      string
>> diff --git a/xen/arch/x86/Kconfig b/xen/arch/x86/Kconfig
>> index 4781b34..2b6c832 100644
>> --- a/xen/arch/x86/Kconfig
>> +++ b/xen/arch/x86/Kconfig
>> @@ -18,6 +18,7 @@ config X86
>>      select HAS_PCI
>>      select HAS_PDX
>>      select HAS_VGA
>> +    select HAS_XSPLICE
>>  
>>  config ARCH_DEFCONFIG
>>      string
>> diff --git a/xen/common/Kconfig b/xen/common/Kconfig
>> index eadfc3b..aaf4053 100644
>> --- a/xen/common/Kconfig
>> +++ b/xen/common/Kconfig
>> @@ -51,6 +51,9 @@ config HAS_GDBSX
>>  config HAS_IOPORTS
>>      bool
>>  
>> +config HAS_XSPLICE
>> +    bool
>> +
>>  # Enable/Disable kexec support
>>  config KEXEC
>>      bool "kexec support"
>> @@ -97,4 +100,15 @@ config XSM
>>  
>>        If unsure, say N.
>>  
>> +# Enable/Disable xsplice support
>> +config XSPLICE
>> +    bool "xsplice support"
>> +    default y
>> +    depends on HAS_XSPLICE
>> +    ---help---
>> +      Allows a running Xen hypervisor to be patched without rebooting.
>> +      This is primarily used to patch an hypervisor with XSA fixes.
>> +
>> +      If unsure, say Y.
>> +
>>  endmenu
> 
> I'm indifferent on the HAS_XSPLICE, you can drop that if you want to
> simply stuff.
> 
> 
>> diff --git a/xen/common/Makefile b/xen/common/Makefile
>> index 9f8b214..6fdeccf 100644
>> --- a/xen/common/Makefile
>> +++ b/xen/common/Makefile
>> @@ -71,3 +71,5 @@ subdir-$(coverage) += gcov
>>  
>>  subdir-y += libelf
>>  subdir-$(CONFIG_HAS_DEVICE_TREE) += libfdt
>> +
>> +obj-$(CONFIG_XSPLICE) += xsplice.o
>> diff --git a/xen/common/sysctl.c b/xen/common/sysctl.c
>> index a3007b8..55e6cfa 100644
>> --- a/xen/common/sysctl.c
>> +++ b/xen/common/sysctl.c
>> @@ -28,6 +28,7 @@
>>  #include <xsm/xsm.h>
>>  #include <xen/pmstat.h>
>>  #include <xen/gcov.h>
>> +#include <xen/xsplice.h>
>>  
>>  long do_sysctl(XEN_GUEST_HANDLE_PARAM(xen_sysctl_t) u_sysctl)
>>  {
>> @@ -460,6 +461,13 @@ long do_sysctl(XEN_GUEST_HANDLE_PARAM(xen_sysctl_t) 
> u_sysctl)
>>          ret = tmem_control(&op->u.tmem_op);
>>          break;
>>  
>> +#ifdef CONFIG_XSPLICE
>> +    case XEN_SYSCTL_xsplice_op:
>> +        ret = xsplice_control(&op->u.xsplice);
>> +        copyback = 1;
>> +        break;
>> +#endif
> 
> Should the case statement still exist and not just return -ENOSYS?
> Otherwise we're needlessly going into arch_do_sysctl() just to get the
> same result.
> 
> 
>> +
>>      default:
>>          ret = arch_do_sysctl(op, u_sysctl);
>>          copyback = 0;
>> diff --git a/xen/common/xsplice.c b/xen/common/xsplice.c
>> new file mode 100644
>> index 0000000..3c6acc3
>> --- /dev/null
>> +++ b/xen/common/xsplice.c
>> @@ -0,0 +1,386 @@
>> +/*
>> + * Copyright (c) 2016 Oracle and/or its affiliates. All rights reserved.
>> + *
>> + */
>> +
>> +#include <xen/guest_access.h>
>> +#include <xen/keyhandler.h>
>> +#include <xen/lib.h>
>> +#include <xen/list.h>
>> +#include <xen/mm.h>
>> +#include <xen/sched.h>
>> +#include <xen/smp.h>
>> +#include <xen/spinlock.h>
>> +#include <xen/xsplice.h>
>> +
>> +#include <asm/event.h>
>> +#include <public/sysctl.h>
>> +
>> +static DEFINE_SPINLOCK(payload_list_lock);
>> +static LIST_HEAD(payload_list);
>> +
>> +static unsigned int payload_cnt;
>> +static unsigned int payload_version = 1;
>> +
>> +struct payload {
>> +    int32_t state;                       /* One of the XSPLICE_STATE_*. */
>> +    int32_t rc;                          /* 0 or -XEN_EXX. */
>> +    struct list_head list;               /* Linked to 'payload_list'. */
>> +    char name[XEN_XSPLICE_NAME_SIZE + 1];/* Name of it. */
>> +};
>> +
>> +static const char *state2str(int32_t state)
>> +{
>> +#define STATE(x) [XSPLICE_STATE_##x] = #x
>> +    static const char *const names[] = {
>> +            STATE(LOADED),
>> +            STATE(CHECKED),
>> +            STATE(APPLIED),
>> +    };
>> +#undef STATE
>> +
>> +    if (state >= ARRAY_SIZE(names))
>> +        return "unknown";
>> +
>> +    if (state < 0)
>> +        return "-EXX";
>> +
>> +    if (!names[state])
>> +        return "unknown";
>> +
>> +    return names[state];
>> +}
>> +
>> +static void xsplice_printall(unsigned char key)
>> +{
>> +    struct payload *data;
>> +
>> +    spin_lock(&payload_list_lock);
>> +
>> +    list_for_each_entry ( data, &payload_list, list )
>> +        printk(" name=%s state=%s(%d)\n", data->name,
>> +               state2str(data->state), data->state);
>> +
>> +    spin_unlock(&payload_list_lock);
>> +}
>> +
>> +static int verify_name(xen_xsplice_name_t *name)
>> +{
>> +    if ( name->size == 0 || name->size > XEN_XSPLICE_NAME_SIZE )
>> +        return -EINVAL;
>> +
>> +    if ( name->pad[0] || name->pad[1] || name->pad[2] )
>> +        return -EINVAL;
>> +
>> +    if ( !guest_handle_okay(name->name, name->size) )
>> +        return -EINVAL;
>> +
>> +    return 0;
>> +}
>> +
>> +static int find_payload(xen_xsplice_name_t *name, bool_t need_lock,
>> +                        struct payload **f)
>> +{
>> +    struct payload *data;
>> +    XEN_GUEST_HANDLE_PARAM(char) str;
>> +    char n[XEN_XSPLICE_NAME_SIZE + 1] = { 0 };
>> +    int rc = -EINVAL;
>> +
>> +    rc = verify_name(name);
>> +    if ( rc )
>> +        return rc;
>> +
>> +    str = guest_handle_cast(name->name, char);
>> +    if ( copy_from_guest(n, str, name->size) )
>> +        return -EFAULT;
>> +
>> +    if ( need_lock )
>> +        spin_lock(&payload_list_lock);
>> +
>> +    rc = -ENOENT;
>> +    list_for_each_entry ( data, &payload_list, list )
>> +    {
>> +        if ( !strcmp(data->name, n) )
>> +        {
>> +            *f = data;
>> +            rc = 0;
>> +            break;
>> +        }
>> +    }
>> +
>> +    if ( need_lock )
>> +        spin_unlock(&payload_list_lock);
>> +
>> +    return rc;
>> +}
>> +
>> +static int verify_payload(xen_sysctl_xsplice_upload_t *upload)
>> +{
>> +    if ( verify_name(&upload->name) )
>> +        return -EINVAL;
>> +
>> +    if ( upload->size == 0 )
>> +        return -EINVAL;
>> +
>> +    if ( !guest_handle_okay(upload->payload, upload->size) )
>> +        return -EFAULT;
>> +
>> +    return 0;
>> +}
>> +
>> +/*
>> + * We MUST be holding the payload_list_lock spinlock.
>> + */
>> +static void free_payload(struct payload *data)
>> +{
>> +    list_del(&data->list);
>> +    payload_cnt--;
>> +    payload_version++;
>> +    xfree(data);
>> +}
>> +
>> +static int xsplice_upload(xen_sysctl_xsplice_upload_t *upload)
>> +{
>> +    struct payload *data = NULL;
>> +    uint8_t *raw_data;
>> +    int rc;
>> +
>> +    rc = verify_payload(upload);
>> +    if ( rc )
>> +        return rc;
>> +
>> +    rc = find_payload(&upload->name, 1 /* true. */, &data);
>> +    if ( rc == 0 /* Found. */ )
>> +        return -EEXIST;
>> +
>> +    if ( rc != -ENOENT )
>> +        return rc;
>> +
>> +    data = xzalloc(struct payload);
>> +    if ( !data )
>> +        return -ENOMEM;
>> +
>> +    memset(data, 0, sizeof *data);
>> +    rc = -EFAULT;
>> +    if ( copy_from_guest(data->name, upload->name.name, upload->name.size) )
>> +        goto err_data;
>> +
>> +    rc = -ENOMEM;
>> +    raw_data = alloc_xenheap_pages(get_order_from_bytes(upload->size), 0);
>> +    if ( !raw_data )
>> +        goto err_data;
>> +
>> +    rc = -EFAULT;
>> +    if ( copy_from_guest(raw_data, upload->payload, upload->size) )
>> +        goto err_raw;
>> +
>> +    data->state = XSPLICE_STATE_LOADED;
>> +    data->rc = 0;
>> +    INIT_LIST_HEAD(&data->list);
>> +
>> +    spin_lock(&payload_list_lock);
>> +    list_add_tail(&data->list, &payload_list);
>> +    payload_cnt++;
>> +    payload_version++;
>> +    spin_unlock(&payload_list_lock);
>> +
>> +    free_xenheap_pages(raw_data, get_order_from_bytes(upload->size));
>> +    return 0;
>> +
>> + err_raw:
>> +    free_xenheap_pages(raw_data, get_order_from_bytes(upload->size));
>> + err_data:
>> +    xfree(data);
>> +    return rc;
>> +}
>> +
>> +static int xsplice_get(xen_sysctl_xsplice_summary_t *summary)
>> +{
>> +    struct payload *data;
>> +    int rc;
>> +
>> +    if ( summary->status.state )
>> +        return -EINVAL;
>> +
>> +    if ( summary->status.rc != 0 )
>> +        return -EINVAL;
>> +
>> +    rc = verify_name(&summary->name);
>> +    if ( rc )
>> +        return rc;
>> +
>> +    rc = find_payload(&summary->name, 1 /* true. */, &data);
>> +    if ( rc )
>> +        return rc;
>> +
>> +    summary->status.state = data->state;
>> +    summary->status.rc = data->rc;
>> +
>> +    return 0;
>> +}
>> +
>> +static int xsplice_list(xen_sysctl_xsplice_list_t *list)
>> +{
>> +    xen_xsplice_status_t status;
>> +    struct payload *data;
>> +    unsigned int idx = 0, i = 0;
>> +    int rc = 0;
>> +
>> +    if ( list->nr > 1024 )
>> +        return -E2BIG;
>> +
>> +    if ( list->pad != 0 )
>> +        return -EINVAL;
>> +
>> +    if ( !guest_handle_okay(list->status, sizeof(status) * list->nr) ||
>> +         !guest_handle_okay(list->name, XEN_XSPLICE_NAME_SIZE * list->nr) ||
>> +         !guest_handle_okay(list->len, sizeof(uint32_t) * list->nr) )
>> +        return -EINVAL;
>> +
>> +    spin_lock(&payload_list_lock);
>> +    if ( list->idx > payload_cnt || !list->nr )
>> +    {
>> +        spin_unlock(&payload_list_lock);
>> +        return -EINVAL;
>> +    }
>> +
>> +    list_for_each_entry( data, &payload_list, list )
>> +    {
>> +        uint32_t len;
>> +
>> +        if ( list->idx > i++ )
>> +            continue;
>> +
>> +        status.state = data->state;
>> +        status.rc = data->rc;
>> +        len = strlen(data->name);
>> +
>> +        /* N.B. 'idx' != 'i'. */
>> +        if ( __copy_to_guest_offset(list->name, idx * XEN_XSPLICE_NAME_SIZE,
>> +                                    data->name, len) ||
>> +             __copy_to_guest_offset(list->len, idx, &len, 1) ||
>> +             __copy_to_guest_offset(list->status, idx, &status, 1) )
>> +        {
>> +            rc = -EFAULT;
>> +            break;
>> +        }
>> +        idx++;
>> +        if ( hypercall_preempt_check() || (idx + 1 > list->nr) )
>> +            break;
>> +    }
>> +    list->nr = payload_cnt - i; /* Remaining amount. */
>> +    list->version = payload_version;
>> +    spin_unlock(&payload_list_lock);
>> +
>> +    /* And how many we have processed. */
>> +    return rc ? : idx;
>> +}
>> +
>> +static int xsplice_action(xen_sysctl_xsplice_action_t *action)
>> +{
>> +    struct payload *data;
>> +    int rc;
>> +
>> +    rc = verify_name(&action->name);
>> +    if ( rc )
>> +        return rc;
>> +
>> +    spin_lock(&payload_list_lock);
>> +    rc = find_payload(&action->name, 0 /* We are holding the lock. */, 
>> &data);
>> +    if ( rc )
>> +        goto out;
>> +
>> +    switch ( action->cmd )
>> +    {
>> +    case XSPLICE_ACTION_CHECK:
>> +        if ( (data->state == XSPLICE_STATE_LOADED) ||
>> +             (data->state == XSPLICE_STATE_CHECKED) )
>> +        {
>> +            /* No implementation yet. */
>> +            data->state = XSPLICE_STATE_CHECKED;
>> +            data->rc = 0;
>> +            rc = 0;
>> +        }
>> +        break;
>> +    case XSPLICE_ACTION_UNLOAD:
>> +        if ( (data->state == XSPLICE_STATE_LOADED) ||
>> +             (data->state == XSPLICE_STATE_CHECKED) )
>> +        {
>> +            free_payload(data);
>> +            /* No touching 'data' from here on! */
>> +            rc = 0;
>> +        }
>> +        break;
>> +    case XSPLICE_ACTION_REVERT:
>> +        if ( data->state == XSPLICE_STATE_APPLIED )
>> +        {
>> +            /* No implementation yet. */
>> +            data->state = XSPLICE_STATE_CHECKED;
>> +            data->rc = 0;
>> +            rc = 0;
>> +        }
>> +        break;
>> +    case XSPLICE_ACTION_APPLY:
>> +        if ( (data->state == XSPLICE_STATE_CHECKED) )
>> +        {
>> +            /* No implementation yet. */
>> +            data->state = XSPLICE_STATE_APPLIED;
>> +            data->rc = 0;
>> +            rc = 0;
>> +        }
>> +        break;
>> +    case XSPLICE_ACTION_REPLACE:
>> +        if ( data->state == XSPLICE_STATE_CHECKED )
>> +        {
>> +            /* No implementation yet. */
>> +            data->state = XSPLICE_STATE_CHECKED;
>> +            data->rc = 0;
>> +            rc = 0;
>> +        }
>> +        break;
>> +    default:
>> +        rc = -EOPNOTSUPP;
>> +        break;
>> +    }
>> +
>> + out:
>> +    spin_unlock(&payload_list_lock);
>> +
>> +    return rc;
>> +}
>> +
>> +int xsplice_control(xen_sysctl_xsplice_op_t *xsplice)
>> +{
>> +    int rc;
>> +
>> +    if ( xsplice->pad != 0 )
>> +        return -EINVAL;
>> +
>> +    switch ( xsplice->cmd )
>> +    {
>> +    case XEN_SYSCTL_XSPLICE_UPLOAD:
>> +        rc = xsplice_upload(&xsplice->u.upload);
>> +        break;
>> +    case XEN_SYSCTL_XSPLICE_GET:
>> +        rc = xsplice_get(&xsplice->u.get);
>> +        break;
>> +    case XEN_SYSCTL_XSPLICE_LIST:
>> +        rc = xsplice_list(&xsplice->u.list);
>> +        break;
>> +    case XEN_SYSCTL_XSPLICE_ACTION:
>> +        rc = xsplice_action(&xsplice->u.action);
>> +        break;
>> +    default:
>> +        rc = -EOPNOTSUPP;
>> +        break;
>> +   }
>> +
>> +    return rc;
>> +}
>> +
>> +static int __init xsplice_init(void)
>> +{
>> +    register_keyhandler('x', xsplice_printall, "print xsplicing info", 1);
>> +    return 0;
>> +}
>> +__initcall(xsplice_init);
>> diff --git a/xen/include/public/sysctl.h b/xen/include/public/sysctl.h
>> index 96680eb..0b0b879 100644
>> --- a/xen/include/public/sysctl.h
>> +++ b/xen/include/public/sysctl.h
>> @@ -766,6 +766,160 @@ struct xen_sysctl_tmem_op {
>>  typedef struct xen_sysctl_tmem_op xen_sysctl_tmem_op_t;
>>  DEFINE_XEN_GUEST_HANDLE(xen_sysctl_tmem_op_t);
>>  
>> +/*
>> + * XEN_SYSCTL_XSPLICE_op
>> + *
>> + * Refer to the 
> http://xenbits.xenproject.org/docs/unstable/misc/xsplice.html 
>> + * for the design details of this hyprcall.
>> + */
>> +
>> +/*
>> + * Structure describing an ELF payload. Uniquely identifies the
>> + * payload. Should be human readable.
>> + * Recommended length is upto XEN_XSPLICE_NAME_SIZE.
>> + */
>> +#define XEN_XSPLICE_NAME_SIZE 128
>> +struct xen_xsplice_name {
>> +    XEN_GUEST_HANDLE_64(char) name;         /* IN: pointer to name. */
>> +    uint16_t size;                          /* IN: size of name. May be 
> upto
>> +                                               XEN_XSPLICE_NAME_SIZE. */
>> +    uint16_t pad[3];                        /* IN: MUST be zero. */
>> +};
>> +typedef struct xen_xsplice_name xen_xsplice_name_t;
>> +DEFINE_XEN_GUEST_HANDLE(xen_xsplice_name_t);
>> +
>> +/*
>> + * Upload a payload to the hypervisor. The payload is verified
>> + * against basic checks and if there are any issues the proper return code
>> + * will be returned. The payload is not applied at this time - that is
>> + * controlled by XEN_SYSCTL_XSPLICE_ACTION.
>> + *
>> + * The return value is zero if the payload was succesfully uploaded.
>> + * Otherwise an EXX return value is provided. Duplicate `name` are not
>> + * supported.
>> + *
>> + * The payload at this point is verified against the basic checks.
>> + *
>> + * The `payload` is the ELF payload as mentioned in the `Payload format`
>> + * section in the xSplice design document.
>> + */
>> +#define XEN_SYSCTL_XSPLICE_UPLOAD 0
>> +struct xen_sysctl_xsplice_upload {
>> +    xen_xsplice_name_t name;                /* IN, name of the patch. */
>> +    uint64_t size;                          /* IN, size of the ELF file. */
>> +    XEN_GUEST_HANDLE_64(uint8) payload;     /* IN, the ELF file. */
>> +};
>> +typedef struct xen_sysctl_xsplice_upload xen_sysctl_xsplice_upload_t;
>> +DEFINE_XEN_GUEST_HANDLE(xen_sysctl_xsplice_upload_t);
>> +
>> +/*
>> + * Retrieve an status of an specific payload.
>> + *
>> + * Upon completion the `struct xen_xsplice_status` is updated.
>> + *
>> + * The return value is zero on success and XEN_EXX on failure. This 
> operation
>> + * is synchronous and does not require preemption.
>> + */
>> +#define XEN_SYSCTL_XSPLICE_GET 1
>> +
>> +struct xen_xsplice_status {
>> +#define XSPLICE_STATE_LOADED       1
>> +#define XSPLICE_STATE_CHECKED      2
>> +#define XSPLICE_STATE_APPLIED      3
>> +    int32_t state;                 /* OUT: XSPLICE_STATE_*. IN: MUST be 
> zero. */
>> +    int32_t rc;                    /* OUT: 0 if no error, otherwise 
> -XEN_EXX. */
>> +                                   /* IN: MUST be zero. */
>> +};
>> +typedef struct xen_xsplice_status xen_xsplice_status_t;
>> +DEFINE_XEN_GUEST_HANDLE(xen_xsplice_status_t);
>> +
>> +struct xen_sysctl_xsplice_summary {
>> +    xen_xsplice_name_t name;                /* IN, name of the payload. */
>> +    xen_xsplice_status_t status;            /* IN/OUT, state of it. */
>> +};
>> +typedef struct xen_sysctl_xsplice_summary xen_sysctl_xsplice_summary_t;
>> +DEFINE_XEN_GUEST_HANDLE(xen_sysctl_xsplice_summary_t);
>> +
>> +/*
>> + * Retrieve an array of abbreviated status and names of payloads that are
>> + * loaded in the hypervisor.
>> + *
>> + * If the hypercall returns an positive number, it is the number (up to 
> `nr`)
>> + * of the payloads returned, along with `nr` updated with the number of 
> remaining
>> + * payloads, `version` updated (it may be the same across hypercalls. If it
>> + * varies the data is stale and further calls could fail). The `status`,
>> + * `name`, and `len`' are updated at their designed index value (`idx`) 
> with
>> + * the returned value of data.
>> + *
>> + * If the hypercall returns E2BIG the `nr` is too big and should be
>> + * lowered.
>> + *
>> + * This operation can be preempted by the hypercall returning EAGAIN.
>> + * Retry.
>> + *
>> + * Note that due to the asynchronous nature of hypercalls the domain might 
> have
>> + * added or removed the number of payloads making this information stale. 
> It is
>> + * the responsibility of the toolstack to use the `version` field to check
>> + * between each invocation. if the version differs it should discard the 
> stale
>> + * data and start from scratch. It is OK for the toolstack to use the new
>> + * `version` field.
>> + */
>> +#define XEN_SYSCTL_XSPLICE_LIST 2
>> +struct xen_sysctl_xsplice_list {
>> +    uint32_t version;                       /* IN/OUT: Initially *MUST* be 
> zero.
>> +                                               On subsequent calls reuse 
> value.
>> +                                               If varies between calls, we 
> are
>> +                                             * getting stale data. */
>> +    uint32_t idx;                           /* IN/OUT: Index into array. */
>> +    uint32_t nr;                            /* IN: How many status, id, and 
> len
>> +                                               should fill out.
>> +                                               OUT: How many payloads left. 
> */
>> +    uint32_t pad;                           /* IN: Must be zero. */
>> +    XEN_GUEST_HANDLE_64(xen_xsplice_status_t) status;  /* OUT. Must have 
> enough
>> +                                               space allocate for nr of 
> them. */
>> +    XEN_GUEST_HANDLE_64(char) name;         /* OUT: Array of ids. Each 
> member
>> +                                               MUST XEN_XSPLICE_NAME_SIZE 
> in size.
>> +                                               Must have nr of them. */
>> +    XEN_GUEST_HANDLE_64(uint32) len;        /* OUT: Array of lengths of 
> ids.
>> +                                               Must have nr of them. */
>> +};
>> +typedef struct xen_sysctl_xsplice_list xen_sysctl_xsplice_list_t;
>> +DEFINE_XEN_GUEST_HANDLE(xen_sysctl_xsplice_list_t);
>> +
>> +/*
>> + * Perform an operation on the payload structure referenced by the `name` 
> field.
>> + * The operation request is asynchronous and the status should be retrieved
>> + * by using either XEN_SYSCTL_XSPLICE_GET or XEN_SYSCTL_XSPLICE_LIST 
> hypercall.
>> + */
>> +#define XEN_SYSCTL_XSPLICE_ACTION 3
>> +struct xen_sysctl_xsplice_action {
>> +    xen_xsplice_name_t name;                /* IN, name of the patch. */
>> +#define XSPLICE_ACTION_CHECK        1
>> +#define XSPLICE_ACTION_UNLOAD       2
>> +#define XSPLICE_ACTION_REVERT       3
>> +#define XSPLICE_ACTION_APPLY        4
>> +#define XSPLICE_ACTION_REPLACE      5
>> +    uint32_t cmd;                           /* IN: XSPLICE_ACTION_*. */
>> +    uint32_t timeout;                       /* IN: Zero if no timeout. */
>> +                                            /* Or upper bound of time (ms) 
> */
>> +                                            /* for operation to take. */
>> +};
>> +typedef struct xen_sysctl_xsplice_action xen_sysctl_xsplice_action_t;
>> +DEFINE_XEN_GUEST_HANDLE(xen_sysctl_xsplice_action_t);
>> +
>> +struct xen_sysctl_xsplice_op {
>> +    uint32_t cmd;                           /* IN: XEN_SYSCTL_XSPLICE_*. */
>> +    uint32_t pad;                           /* IN: Always zero. */
>> +    union {
>> +        xen_sysctl_xsplice_upload_t upload;
>> +        xen_sysctl_xsplice_list_t list;
>> +        xen_sysctl_xsplice_summary_t get;
>> +        xen_sysctl_xsplice_action_t action;
>> +    } u;
>> +};
>> +typedef struct xen_sysctl_xsplice_op xen_sysctl_xsplice_op_t;
>> +DEFINE_XEN_GUEST_HANDLE(xen_sysctl_xsplice_op_t);
>> +
>>  struct xen_sysctl {
>>      uint32_t cmd;
>>  #define XEN_SYSCTL_readconsole                    1
>> @@ -791,6 +945,7 @@ struct xen_sysctl {
>>  #define XEN_SYSCTL_pcitopoinfo                   22
>>  #define XEN_SYSCTL_psr_cat_op                    23
>>  #define XEN_SYSCTL_tmem_op                       24
>> +#define XEN_SYSCTL_xsplice_op                    25
>>      uint32_t interface_version; /* XEN_SYSCTL_INTERFACE_VERSION */
>>      union {
>>          struct xen_sysctl_readconsole       readconsole;
>> @@ -816,6 +971,7 @@ struct xen_sysctl {
>>          struct xen_sysctl_psr_cmt_op        psr_cmt_op;
>>          struct xen_sysctl_psr_cat_op        psr_cat_op;
>>          struct xen_sysctl_tmem_op           tmem_op;
>> +        struct xen_sysctl_xsplice_op        xsplice;
>>          uint8_t                             pad[128];
>>      } u;
>>  };
>> diff --git a/xen/include/xen/xsplice.h b/xen/include/xen/xsplice.h
>> new file mode 100644
>> index 0000000..2cb2035
>> --- /dev/null
>> +++ b/xen/include/xen/xsplice.h
>> @@ -0,0 +1,7 @@
>> +#ifndef __XEN_XSPLICE_H__
>> +#define __XEN_XSPLICE_H__
>> +
>> +struct xen_sysctl_xsplice_op;
>> +int xsplice_control(struct xen_sysctl_xsplice_op *);
>> +
>> +#endif /* __XEN_XSPLICE_H__ */
>> diff --git a/xen/xsm/flask/hooks.c b/xen/xsm/flask/hooks.c
>> index 9b7de30..5346dcf 100644
>> --- a/xen/xsm/flask/hooks.c
>> +++ b/xen/xsm/flask/hooks.c
>> @@ -807,6 +807,12 @@ static int flask_sysctl(int cmd)
>>      case XEN_SYSCTL_tmem_op:
>>          return domain_has_xen(current->domain, XEN__TMEM_CONTROL);
>>  
>> +#ifdef CONFIG_XSPLICE
>> +    case XEN_SYSCTL_xsplice_op:
>> +        return avc_current_has_perm(SECINITSID_XEN, SECCLASS_XEN2,
>> +                                    XEN2__XSPLICE_OP, NULL);
>> +#endif
>> +
>>      default:
>>          printk("flask_sysctl: Unknown op %d\n", cmd);
>>          return -EPERM;
>> diff --git a/xen/xsm/flask/policy/access_vectors 
> b/xen/xsm/flask/policy/access_vectors
>> index effb59f..5f08d05 100644
>> --- a/xen/xsm/flask/policy/access_vectors
>> +++ b/xen/xsm/flask/policy/access_vectors
>> @@ -93,6 +93,8 @@ class xen2
>>      pmu_ctrl
>>  # PMU use (domains, including unprivileged ones, will be using this 
> operation)
>>      pmu_use
>> +# XEN_SYSCTL_xsplice_op
>> +    xsplice_op
>>  }
>>  
>>  # Classes domain and domain2 consist of operations that a domain performs 
> on
>> 
> 
> 
> -- 
> Doug Goldstein

Please trim your replies.

Thanks, Jan

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