RE: [Xen-devel] oops when access xenstore in hvm guest

[Paul Durrant <Paul.Durrant@xxxxxxxxxx>]

The store *PFN* is called that for a reason… it’s a guest page *frame* number i.e. a physical address. You need to get a kva for it before you can use it.

 

  Paul

 

From: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx [mailto:xen-devel-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of ???
Sent: 03 August 2010 04:33
To: xen-devel@xxxxxxxxxxxxxxxxxxx
Subject: [Xen-devel] oops when access xenstore in hvm guest

 

Hi,
    I use follow code get xenstore ring and event channel, then i wrapped writing and reading function to operate it ,but it came to oops:
    struct xenstore_domain_interface {
    char req[XENSTORE_RING_SIZE]; /* Requests to xenstore daemon. */
    char rsp[XENSTORE_RING_SIZE]; /* Replies and async watch events. */
    XENSTORE_RING_IDX req_cons, req_prod;
    XENSTORE_RING_IDX rsp_cons, rsp_prod;
    };
    struct xenstore_domain_interface *xenstore;
    xen_hvm_param_t param;
    param.domid = DOMID_SELF;
    param.index = HVM_PARAM_STORE_PFN;
    if ( hypercall_hvm_op(HVMOP_get_param, &param) )
        BUG();
    xenstore = (void *) (unsigned long) (param.value << PAGE_SHIFT);
    param.domid = DOMID_SELF;
    param.index = HVM_PARAM_STORE_EVTCHN;
    if ( hypercall_hvm_op(HVMOP_get_param, &param) )
        BUG();
    xenstore_event = param.value;

    I get the xenstore ring whose address is 0xfeffc000, and event channel port 2, but when i read the xenstore->req_prod, it came to "unable to handle kernel paging request at virtual address feffc804", i am using xen-3.4, any idea?Thanks.
 

 

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