Commit 5efc3564 authored by Dr. David Alan Gilbert's avatar Dr. David Alan Gilbert Committed by Michael S. Tsirkin
Browse files

postcopy: helper for waking shared 



Provide a helper to send a 'wake' request on a userfaultfd for
a shared process.
The address in the clients address space is specified together
with the RAMBlock it was resolved to.

Signed-off-by: default avatarDr. David Alan Gilbert <dgilbert@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 375318d0

migration/postcopy-ram.c

+26 −0
Original line number Diff line number Diff line
@@ -525,6 +525,25 @@ static int ram_block_enable_notify(const char *block_name, void *host_addr, 
    return 0;

}



int postcopy_wake_shared(struct PostCopyFD *pcfd,

                         uint64_t client_addr,

                         RAMBlock *rb)

{

    size_t pagesize = qemu_ram_pagesize(rb);

    struct uffdio_range range;

    int ret;

    trace_postcopy_wake_shared(client_addr, qemu_ram_get_idstr(rb));

    range.start = client_addr & ~(pagesize - 1);

    range.len = pagesize;

    ret = ioctl(pcfd->fd, UFFDIO_WAKE, &range);

    if (ret) {

        error_report("%s: Failed to wake: %zx in %s (%s)",

                     __func__, (size_t)client_addr, qemu_ram_get_idstr(rb),

                     strerror(errno));

    }

    return ret;

}



/*

 * Callback from shared fault handlers to ask for a page,

 * the page must be specified by a RAMBlock and an offset in that rb
@@ -961,6 +980,13 @@ void *postcopy_get_tmp_page(MigrationIncomingState *mis) 
    return NULL;

}



int postcopy_wake_shared(struct PostCopyFD *pcfd,

                         uint64_t client_addr,

                         RAMBlock *rb)

{

    assert(0);

    return -1;

}

#endif



/* ------------------------------------------------------------------------- */

migration/postcopy-ram.h

+10 −0
Original line number Diff line number Diff line
@@ -164,6 +164,16 @@ struct PostCopyFD { 
 */

void postcopy_register_shared_ufd(struct PostCopyFD *pcfd);

void postcopy_unregister_shared_ufd(struct PostCopyFD *pcfd);

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

 *

 * Returns 0 on success

 *

 * @pcfd: Structure with fd, handler and name as above

 * @client_addr: Address in the client program, not QEMU

 * @rb: The RAMBlock the page is in

 */

int postcopy_wake_shared(struct PostCopyFD *pcfd, uint64_t client_addr,

                         RAMBlock *rb);

/* Callback from shared fault handlers to ask for a page */

int postcopy_request_shared_page(struct PostCopyFD *pcfd, RAMBlock *rb,

                                 uint64_t client_addr, uint64_t offset);

migration/trace-events

+1 −0
Original line number Diff line number Diff line
@@ -199,6 +199,7 @@ postcopy_ram_incoming_cleanup_entry(void) "" 
postcopy_ram_incoming_cleanup_exit(void) ""

postcopy_ram_incoming_cleanup_join(void) ""

postcopy_request_shared_page(const char *sharer, const char *rb, uint64_t rb_offset) "for %s in %s offset 0x%"PRIx64

postcopy_wake_shared(uint64_t client_addr, const char *rb) "at 0x%"PRIx64" in %s"



save_xbzrle_page_skipping(void) ""

save_xbzrle_page_overflow(void) ""