When trying to map an alias of a ram region, where the alias starts at
address A and we map it into address B, and A > B, we had an arithmetic
underflow. Because we use unsigned arithmetic, the underflow converted
into a large number which failed addrrange_intersects() tests.
The concrete example which triggered this was cirrus vga mapping
the framebuffer at offsets 0xc0000-0xc7fff (relative to the start of
the framebuffer) into offsets 0xa0000 (relative to system addres space
start).
With our favorite analogy of a windowing system, this is equivalent to
dragging a subwindow off the left edge of the screen, and failing to clip
it into its parent window which is on screen.
Fix by switching to signed arithmetic.
Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
When a range is being unmapped, ask accelerators (e.g. kvm) to synchronize the
dirty bitmap to avoid losing information forever.
Fixes grub2 screen update.
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Allow changes to the memory hierarchy to be accumulated and
made visible all at once. This reduces computational effort,
especially when an accelerator (e.g. kvm) is involved.
Useful when a single register update causes multiple changes
to an address space.
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Instead of adding and deleting regions in one pass, do a delete
pass followed by an add pass. This fixes the following case:
from:
0x0000-0x0fff ram (a1)
0x1000-0x1fff mmio (a2)
0x2000-0x2fff ram (a3)
to:
0x0000-0x2fff ram (b1)
The single pass algorithm removed a1, added b2, then removed a2 and a3,
which caused the wrong memory map to be built. The two pass algorithm
removes a1, a2, and a3, then adds b1.
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
As with the rest of the memory API, the caller associates an eventfd
with an address, and the memory API takes care of registering or
unregistering when the address is made visible or invisible to the
guest.
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
This eases the transition to the new API.
Reviewed-by: Anthony Liguori <aliguori@us.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Allow registering I/O ports via the same mechanism as mmio ranges.
Reviewed-by: Anthony Liguori <aliguori@us.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
For non-RAM memory regions, we cannot tell whether this is an I/O region
or an MMIO region. Since the qemu backing registration is different for
the two, we have to defer initialization until we know which address
space we are in.
These shenanigans will be removed once the backing registration is unified
with the memory API.
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
I/O regions will not have ram_addrs, so this is a better name.
Reviewed-by: Anthony Liguori <aliguori@us.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Prepare for multiple address space support by abstracting away the details
of registering a memory range with qemu's flat representation into an
AddressSpace object.
Note operations which are memory specific are not abstracted, since they will
never be called on I/O address spaces anyway.
Reviewed-by: Anthony Liguori <aliguori@us.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
get_system_memory() provides the root of the memory hierarchy.
This interface is intended to be private between memory.c and exec.c.
If this file is included elsewhere, it should be regarded as a bug (or
TODO item). However, it will be temporarily needed for the conversion
to hierarchical memory routing.
Reviewed-by: Anthony Liguori <aliguori@us.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Simple implementations of memory routers, for example the Cirrus VGA memory banks
or the 440FX PAM registers can generate adjacent memory regions which are contiguous.
Detect these and merge them; this saves kvm memory slots and shortens lookup times.
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Currently dirty tracking is implemented by passing through
all calls to the underlying cpu_physical_memory_*() calls.
Reviewed-by: Anthony Liguori <aliguori@us.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
The memory API separates the attributes of a memory region (its size, how
reads or writes are handled, dirty logging, and coalescing) from where it
is mapped and whether it is enabled. This allows a device to configure
a memory region once, then hand it off to its parent bus to map it according
to the bus configuration.
Hierarchical registration also allows a device to compose a region out of
a number of sub-regions with different properties; for example some may be
RAM while others may be MMIO.
Reviewed-by: Anthony Liguori <aliguori@us.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
