memory: introduce memory_region_present

This new API will avoid having too many memory_region_ref/unref
in paths that currently use memory_region_find.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
memory: add ref/unref calls

Add ref/unref calls at the following places:

- places where memory regions are stashed by a listener and
  used outside the BQL (including in Xen or KVM).

- memory_region_find callsites

- creation of aliases and containers (only the aliased/contained
  region gets a reference to avoid loops)

- around calls to del_subregion/add_subregion, where the region
  could disappear after the first call

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
exec: check MRU in qemu_ram_addr_from_host

This function is not used outside the iothread mutex, so it
can use ram_list.mru_block.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
exec: move qemu_ram_addr_from_host_nofail to cputlb.c

After the next patch it would not be used elsewhere anyway.  Also,
the _nofail and the standard versions of this function return different
things, which is confusing.  Removing the function from the public headers
limits the confusion.

Reviewed-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
memory: return MemoryRegion from qemu_ram_addr_from_host

It will be needed in the next patch.

Reviewed-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
exec: reorganize address_space_map

First of all, rename "todo" to "done".

Second, clearly separate the case of done == 0 with the case of done != 0.
This will help handling reference counting in the next patch.

Third, this test:

             if (memory_region_get_ram_addr(mr) + xlat != raddr + todo) {

does not guarantee that the memory region is the same across two iterations
of the while loop.  For example, you could have two blocks:

A) size 640 K, mapped at physical address 0, ram_addr_t 0
B) size 64 K, mapped at physical address 0xa0000, ram_addr_t 0xa0000

then mapping 1 M starting at physical address zero will erroneously treat
B as the continuation of block A.  qemu_ram_ptr_length ensures that no
invalid memory is accessed, but it is still a pointless complication of
the algorithm.  The patch makes the logic clearer with an explicit test
that the memory region is the same.

Reviewed-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
memory: ref/unref memory across address_space_map/unmap

The iothread mutex might be released between map and unmap, so the
mapped region might disappear.

Reviewed-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
escc: rename struct to ESCCState

We are using the same struct name for two devices.  8250 is widespread
enough that this causes some confusion, rename the other instance.

Reviewed-by: Andreas Faerber <afaerber@suse.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
vga: pass owner to vga_init

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
vga: pass owner to vga_common_init

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
vga: pass owner to cirrus_init_common

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
vga: pass owner to vga_init_vbe

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
vga: pass owner to vga_init_io

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
vga: set owner in vga_update_memory_access

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
ne2000: pass device to ne2000_setup_io, use it as owner

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
vfio: pass device to vfio_mmap_bar and use it to set owner

Cc: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
spapr_iommu: pass device to spapr_tce_new_table and use it to set owner

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
pam: pass device to init_pam and use it to set owner

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
piolist: add owner argument to initialization functions and pass devices

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
hw/a*: pass owner to memory_region_init* functions

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>