Re: [Xen-devel] [PATCH] xen: additionally restrict xenforeignmemory operations

[Paul Durrant <Paul.Durrant@xxxxxxxxxx>]

> -----Original Message-----
[snip]
> 
> This is OK but the file is growing too entangled. What do you think of
> the following, which moves the if CONFIG_XEN_CTRL_INTERFACE_VERSION
> <
> 40701 at the top? This way we don't have to add yet another ifdef.
> 

Yes, this looks better and appears to DTRT. I assume you will just apply this 
version and don't want be to resubmit?

Cheers,

  Paul

> diff --git a/include/hw/xen/xen_common.h
> b/include/hw/xen/xen_common.h
> index 4f3bd35..624fb86 100644
> --- a/include/hw/xen/xen_common.h
> +++ b/include/hw/xen/xen_common.h
> @@ -27,6 +27,58 @@ extern xc_interface *xen_xc;
>   * We don't support Xen prior to 4.2.0.
>   */
> 
> +/* Xen 4.2 through 4.6 */
> +#if CONFIG_XEN_CTRL_INTERFACE_VERSION < 40701
> +
> +typedef xc_interface xenforeignmemory_handle;
> +typedef xc_evtchn xenevtchn_handle;
> +typedef xc_gnttab xengnttab_handle;
> +
> +#define xenevtchn_open(l, f) xc_evtchn_open(l, f);
> +#define xenevtchn_close(h) xc_evtchn_close(h)
> +#define xenevtchn_fd(h) xc_evtchn_fd(h)
> +#define xenevtchn_pending(h) xc_evtchn_pending(h)
> +#define xenevtchn_notify(h, p) xc_evtchn_notify(h, p)
> +#define xenevtchn_bind_interdomain(h, d, p)
> xc_evtchn_bind_interdomain(h, d, p)
> +#define xenevtchn_unmask(h, p) xc_evtchn_unmask(h, p)
> +#define xenevtchn_unbind(h, p) xc_evtchn_unbind(h, p)
> +
> +#define xengnttab_open(l, f) xc_gnttab_open(l, f)
> +#define xengnttab_close(h) xc_gnttab_close(h)
> +#define xengnttab_set_max_grants(h, n) xc_gnttab_set_max_grants(h, n)
> +#define xengnttab_map_grant_ref(h, d, r, p) xc_gnttab_map_grant_ref(h,
> d, r, p)
> +#define xengnttab_unmap(h, a, n) xc_gnttab_munmap(h, a, n)
> +#define xengnttab_map_grant_refs(h, c, d, r, p) \
> +    xc_gnttab_map_grant_refs(h, c, d, r, p)
> +#define xengnttab_map_domain_grant_refs(h, c, d, r, p) \
> +    xc_gnttab_map_domain_grant_refs(h, c, d, r, p)
> +
> +#define xenforeignmemory_open(l, f) xen_xc
> +#define xenforeignmemory_close(h)
> +
> +static inline void *xenforeignmemory_map(xc_interface *h, uint32_t dom,
> +                                         int prot, size_t pages,
> +                                         const xen_pfn_t arr[/*pages*/],
> +                                         int err[/*pages*/])
> +{
> +    if (err)
> +        return xc_map_foreign_bulk(h, dom, prot, arr, err, pages);
> +    else
> +        return xc_map_foreign_pages(h, dom, prot, arr, pages);
> +}
> +
> +#define xenforeignmemory_unmap(h, p, s) munmap(p, s * XC_PAGE_SIZE)
> +
> +#else /* CONFIG_XEN_CTRL_INTERFACE_VERSION >= 40701 */
> +
> +#include <xenevtchn.h>
> +#include <xengnttab.h>
> +#include <xenforeignmemory.h>
> +
> +#endif
> +
> +extern xenforeignmemory_handle *xen_fmem;
> +
>  #if CONFIG_XEN_CTRL_INTERFACE_VERSION < 40900
> 
>  typedef xc_interface xendevicemodel_handle;
> @@ -159,6 +211,13 @@ static inline int xendevicemodel_restrict(
>      return -1;
>  }
> 
> +static inline int xenforeignmemory_restrict(
> +    xenforeignmemory_handle *fmem, domid_t domid)
> +{
> +    errno = ENOTTY;
> +    return -1;
> +}
> +
>  #else /* CONFIG_XEN_CTRL_INTERFACE_VERSION >= 40900 */
> 
>  #include <xendevicemodel.h>
> @@ -215,69 +274,32 @@ static inline int xen_modified_memory(domid_t
> domid, uint64_t first_pfn,
> 
>  static inline int xen_restrict(domid_t domid)
>  {
> -    int rc = xendevicemodel_restrict(xen_dmod, domid);
> +    int rc;
> 
> -    trace_xen_domid_restrict(errno);
> +    /* Attempt to restrict devicemodel operations */
> +    rc = xendevicemodel_restrict(xen_dmod, domid);
> +    trace_xen_domid_restrict(rc ? errno : 0);
> 
> -    if (errno == ENOTTY) {
> -        return 0;
> +    if (rc < 0) {
> +        /*
> +         * If errno is ENOTTY then restriction is not implemented so
> +         * there's no point in trying to restrict other types of
> +         * operation, but it should not be treated as a failure.
> +         */
> +        if (errno == ENOTTY) {
> +            return 0;
> +        }
> +
> +        return rc;
>      }
> 
> -    return rc;
> -}
> -
> -/* Xen 4.2 through 4.6 */
> -#if CONFIG_XEN_CTRL_INTERFACE_VERSION < 40701
> -
> -typedef xc_interface xenforeignmemory_handle;
> -typedef xc_evtchn xenevtchn_handle;
> -typedef xc_gnttab xengnttab_handle;
> -
> -#define xenevtchn_open(l, f) xc_evtchn_open(l, f);
> -#define xenevtchn_close(h) xc_evtchn_close(h)
> -#define xenevtchn_fd(h) xc_evtchn_fd(h)
> -#define xenevtchn_pending(h) xc_evtchn_pending(h)
> -#define xenevtchn_notify(h, p) xc_evtchn_notify(h, p)
> -#define xenevtchn_bind_interdomain(h, d, p)
> xc_evtchn_bind_interdomain(h, d, p)
> -#define xenevtchn_unmask(h, p) xc_evtchn_unmask(h, p)
> -#define xenevtchn_unbind(h, p) xc_evtchn_unbind(h, p)
> -
> -#define xengnttab_open(l, f) xc_gnttab_open(l, f)
> -#define xengnttab_close(h) xc_gnttab_close(h)
> -#define xengnttab_set_max_grants(h, n) xc_gnttab_set_max_grants(h, n)
> -#define xengnttab_map_grant_ref(h, d, r, p) xc_gnttab_map_grant_ref(h,
> d, r, p)
> -#define xengnttab_unmap(h, a, n) xc_gnttab_munmap(h, a, n)
> -#define xengnttab_map_grant_refs(h, c, d, r, p) \
> -    xc_gnttab_map_grant_refs(h, c, d, r, p)
> -#define xengnttab_map_domain_grant_refs(h, c, d, r, p) \
> -    xc_gnttab_map_domain_grant_refs(h, c, d, r, p)
> -
> -#define xenforeignmemory_open(l, f) xen_xc
> -#define xenforeignmemory_close(h)
> +    /* Restrict foreignmemory operations */
> +    rc = xenforeignmemory_restrict(xen_fmem, domid);
> +    trace_xen_domid_restrict(rc ? errno : 0);
> 
> -static inline void *xenforeignmemory_map(xc_interface *h, uint32_t dom,
> -                                         int prot, size_t pages,
> -                                         const xen_pfn_t arr[/*pages*/],
> -                                         int err[/*pages*/])
> -{
> -    if (err)
> -        return xc_map_foreign_bulk(h, dom, prot, arr, err, pages);
> -    else
> -        return xc_map_foreign_pages(h, dom, prot, arr, pages);
> +    return rc;
>  }
> 
> -#define xenforeignmemory_unmap(h, p, s) munmap(p, s * XC_PAGE_SIZE)
> -
> -#else /* CONFIG_XEN_CTRL_INTERFACE_VERSION >= 40701 */
> -
> -#include <xenevtchn.h>
> -#include <xengnttab.h>
> -#include <xenforeignmemory.h>
> -
> -#endif
> -
> -extern xenforeignmemory_handle *xen_fmem;
> -
>  void destroy_hvm_domain(bool reboot);
> 
>  /* shutdown/destroy current domain because of an error */

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