Re: [Xen-devel] [PATCH RFC 14/14] xen: tools: Added xen-subpage tool.

[Yi Zhang <yi.z.zhang@xxxxxxxxxxxxxxx>]

On 2017-10-19 at 11:42:17 +0300, Razvan Cojocaru wrote:
> > +#include <errno.h>
> > +#include <inttypes.h>
> > +#include <stdlib.h>
> > +#include <stdarg.h>
> > +#include <stdbool.h>
> > +#include <string.h>
> > +#include <time.h>
> > +#include <signal.h>
> > +#include <unistd.h>
> > +#include <sys/mman.h>
> > +#include <poll.h>
> > +
> > +#include <xenctrl.h>
> > +
> > +#define DPRINTF(a, b...) fprintf(stderr, a, ## b)
> > +#define ERROR(a, b...) fprintf(stderr, a "\n", ## b)
> > +#define PERROR(a, b...) fprintf(stderr, a ": %s\n", ## b, strerror(errno))
> > +
> > +void usage(char* progname)
> > +{
> > +    fprintf(stderr, "Usage: %s [-m] <domain_id> get|set [gfn] [bit_map]", 
> > progname);
> > +
> > +            fprintf(stderr,
> > +            "\n"
> > +            "set - set gfn bitmap.\n"
> > +            "\n"
> > +            "-m requires this program to run\n");
> > +}
> > +
> > +int main(int argc, char *argv[])
> > +{
> > +    domid_t domain_id;
> > +    xc_interface *xch;
> > +    xen_pfn_t gfn = 0;
> > +    uint32_t access = 0;
> > +    int required = 0;
> > +    int rc = 0;
> > +
> > +    char* progname = argv[0];
> > +    argv++;
> > +    argc--;
> > +
> > +    if ( argc == 5 && argv[0][0] == '-' )
> > +    {
> > +        if ( !strcmp(argv[0], "-m") )
> > +            required = 1;
> > +        else
> > +        {
> > +            usage(progname);
> > +            return -1;
> > +        }
> > +        argv++;
> > +        argc--;
> > +    }
> > +
> > +    if ( argc != 4 )
> > +    {
> > +        usage(progname);
> > +        return -1;
> > +    }
> > +
> > +    domain_id = atoi(argv[0]);
> > +    argv++;
> > +    argc--;
> > +
> > +    if ( !strcmp(argv[0], "set") )
> > +    {
> > +        gfn = strtoul(argv[1], 0, 0);
> > +        access = strtoul(argv[2], 0, 0);
> > +        DPRINTF("set subpage gfn:0x%lx -- map:0x%x\n", gfn, access);
> > +        xch = xc_interface_open(NULL, NULL, 0);
> > +        if ( !xch )
> > +        {
> > +            ERROR("get interface error\n");
> > +            return -1;
> > +        }
> > +        xc_mem_set_subpage(xch, domain_id, gfn, access);
> > +        xc_interface_close(xch);
> > +    }
> > +    else
> > +    {
> > +        usage(argv[0]);
> > +        return -1;
> > +    }
> > +
> > +    return rc;
> > +}
> 
> As far as I understand, this example just calls the new hypercall and exits.
> 
> Should there be another vm_event-subscribed application that will be
> affected by the changes? If so, doesn't this rather belong in the
> xen-access.c test?

There will not be other related app on domain0 at that time, the
hypercall will prepare everything we need.
We will run a write test on a HVM guest, it will tell us if a sub page
will be write-protected or not.

> 
> Also, no explanation is given in comments in the source code or the
> displayed help for useful values of the access parameter, and what it
> stands for.

Yes, Thanks Rezvan, will add some explanation.

> 
> 
> Thanks,
> Razvan

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
https://lists.xen.org/xen-devel