[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH RFC 2/2] tools/libxc: Make the mem_access APIs generic
>On Wed, 2014-04-09 at 09:58 +0100, Jan Beulich wrote: >> >>> On 09.04.14 at 10:23, <Ian.Campbell@xxxxxxxxxx> wrote: >> >> int xc_hvm_set_mem_access( >> >> - xc_interface *xch, domid_t dom, hvmmem_access_t mem_access, >uint64_t first_pfn, uint64_t nr) >> >> + xc_interface *xch, domid_t dom, hvmmem_access_t mem_access, >> >> + uint64_t first_pfn, uint64_t nr) >> >> { >> >> - DECLARE_HYPERCALL; >> >> - DECLARE_HYPERCALL_BUFFER(struct xen_hvm_set_mem_access, >arg); >> >> - int rc; >> >> - >> >> - arg = xc_hypercall_buffer_alloc(xch, arg, sizeof(*arg)); >> >> - if ( arg == NULL ) >> >> - { >> >> - PERROR("Could not allocate memory for xc_hvm_set_mem_access >hypercall"); >> >> - return -1; >> >> - } >> >> - >> >> - arg->domid = dom; >> >> - arg->hvmmem_access = mem_access; >> >> - arg->first_pfn = first_pfn; >> >> - arg->nr = nr; >> >> - >> >> - hypercall.op = __HYPERVISOR_hvm_op; >> >> - hypercall.arg[0] = HVMOP_set_mem_access; >> >> - hypercall.arg[1] = HYPERCALL_BUFFER_AS_ARG(arg); >> >> - >> >> - rc = do_xen_hypercall(xch, &hypercall); >> >> - >> >> - xc_hypercall_buffer_free(xch, arg); >> >> - >> >> - return rc; >> >> + if ( nr > UINT_MAX ) >> >> + return -EINVAL; >> > >> > I guess the hypervisor must also make a similar check? >> > >> >> + return xc_set_mem_access(xch, dom, mem_access, first_pfn, nr); >> > >> > This will return -1 and set errno, while the EINVAL above returns a >> > -errno value. >> > >> > Personally I would just drop the limit check and rely on the hypervisor >> > to return an error, but if you want to keep the check then please make >> > it use the -1 and set errno pattern. >> >> Actually the hypervisor can't do that check, since it only sees the >> truncated (32-bit) value. Question rather is why to retain a 64-bit >> function parameter - I recently suggested switching it to 32 bits, and >> I think this should definitely be done while anyway fiddling with the >> interface. > >Ah, nr is correct in xc_set_mem_access() so this is just briding the gap >between the old and new interfaces. THis would be solved by nuking this >now pointless wrapper. OK, I will nuke the wrappers. Thanks, Aravindh _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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