Commit d488b349 authored by Dr. David Alan Gilbert's avatar Dr. David Alan Gilbert Committed by Michael S. Tsirkin
Browse files

postcopy: postcopy_notify_shared_wake 



Add a hook to allow a client userfaultfd to be 'woken'
when a page arrives, and a walker that calls that
hook for relevant clients given a RAMBlock and offset.

Signed-off-by: default avatarDr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: default avatarPeter Xu <peterx@redhat.com>
Reviewed-by: default avatarMarc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
parent 5efc3564

migration/postcopy-ram.c

+16 −0
Original line number Diff line number Diff line
@@ -827,6 +827,22 @@ static int qemu_ufd_copy_ioctl(int userfault_fd, void *host_addr, 
    return ret;

}



int postcopy_notify_shared_wake(RAMBlock *rb, uint64_t offset)

{

    int i;

    MigrationIncomingState *mis = migration_incoming_get_current();

    GArray *pcrfds = mis->postcopy_remote_fds;



    for (i = 0; i < pcrfds->len; i++) {

        struct PostCopyFD *cur = &g_array_index(pcrfds, struct PostCopyFD, i);

        int ret = cur->waker(cur, rb, offset);

        if (ret) {

            return ret;

        }

    }

    return 0;

}



/*

 * Place a host page (from) at (host) atomically

 * returns 0 on success

migration/postcopy-ram.h

+10 −0
Original line number Diff line number Diff line
@@ -148,6 +148,10 @@ struct PostCopyFD; 


/* ufd is a pointer to the struct uffd_msg *TODO: more Portable! */

typedef int (*pcfdhandler)(struct PostCopyFD *pcfd, void *ufd);

/* Notification to wake, either on place or on reception of

 * a fault on something that's already arrived (race)

 */

typedef int (*pcfdwake)(struct PostCopyFD *pcfd, RAMBlock *rb, uint64_t offset);



struct PostCopyFD {

    int fd;
@@ -155,6 +159,8 @@ struct PostCopyFD { 
    void *data;

    /* Handler to be called whenever we get a poll event */

    pcfdhandler handler;

    /* Notification to wake shared client */

    pcfdwake waker;

    /* A string to use in error messages */

    const char *idstr;

};
@@ -164,6 +170,10 @@ struct PostCopyFD { 
 */

void postcopy_register_shared_ufd(struct PostCopyFD *pcfd);

void postcopy_unregister_shared_ufd(struct PostCopyFD *pcfd);

/* Call each of the shared 'waker's registerd telling them of

 * availability of a block.

 */

int postcopy_notify_shared_wake(RAMBlock *rb, uint64_t offset);

/* postcopy_wake_shared: Notify a client ufd that a page is available

 *

 * Returns 0 on success