diff options
author | Peter Maydell <peter.maydell@linaro.org> | 2016-02-09 19:34:46 +0000 |
---|---|---|
committer | Peter Maydell <peter.maydell@linaro.org> | 2016-02-09 19:34:46 +0000 |
commit | c9f19dff101e2c2cf3fa3967eceec2833e845e40 (patch) | |
tree | 5bcc3ba8281fc7902d3c99bbbf1a7097384c711b /docs | |
parent | f075c89f0a9cb31daf38892371d2822177505706 (diff) | |
parent | 150dcd1aed6f9ebcf370dbb9b666e7d7c6d908e2 (diff) | |
download | qemu-c9f19dff101e2c2cf3fa3967eceec2833e845e40.zip qemu-c9f19dff101e2c2cf3fa3967eceec2833e845e40.tar.gz qemu-c9f19dff101e2c2cf3fa3967eceec2833e845e40.tar.bz2 |
Merge remote-tracking branch 'remotes/bonzini/tags/for-upstream' into staging
* switch to C11 atomics (Alex)
* Coverity fixes for IPMI (Corey), i386 (Paolo), qemu-char (Paolo)
* at long last, fail on wrong .pc files if -m32 is in use (Daniel)
* qemu-char regression fix (Daniel)
* SAS1068 device (Paolo)
* memory region docs improvements (Peter)
* target-i386 cleanups (Richard)
* qemu-nbd docs improvements (Sitsofe)
* thread-safe memory hotplug (Stefan)
# gpg: Signature made Tue 09 Feb 2016 16:09:30 GMT using RSA key ID 78C7AE83
# gpg: Good signature from "Paolo Bonzini <bonzini@gnu.org>"
# gpg: aka "Paolo Bonzini <pbonzini@redhat.com>"
* remotes/bonzini/tags/for-upstream: (33 commits)
qemu-char, io: fix ordering of arguments for UDP socket creation
MAINTAINERS: add all-match entry for qemu-devel@
get_maintainer.pl: fall back to git if only lists are found
target-i386: fix PSE36 mode
docs/memory.txt: Improve list of different memory regions
ipmi_bmc_sim: Add break to correct watchdog NMI check
ipmi_bmc_sim: Fix off by one in check.
ipmi: do not take/drop iothread lock
target-i386: Deconstruct the cpu_T array
target-i386: Tidy gen_add_A0_im
target-i386: Rewrite leave
target-i386: Rewrite gen_enter inline
target-i386: Use gen_lea_v_seg in pusha/popa
target-i386: Access segs via TCG registers
target-i386: Use gen_lea_v_seg in stack subroutines
target-i386: Use gen_lea_v_seg in gen_lea_modrm
target-i386: Introduce mo_stacksize
target-i386: Create gen_lea_v_seg
char: fix repeated registration of tcp chardev I/O handlers
kvm-all: trace: strerror fixup
...
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Diffstat (limited to 'docs')
-rw-r--r-- | docs/memory.txt | 26 |
1 files changed, 25 insertions, 1 deletions
diff --git a/docs/memory.txt b/docs/memory.txt index 2ceb348..8745f76 100644 --- a/docs/memory.txt +++ b/docs/memory.txt @@ -26,14 +26,28 @@ These represent memory as seen from the CPU or a device's viewpoint. Types of regions ---------------- -There are four types of memory regions (all represented by a single C type +There are multiple types of memory regions (all represented by a single C type MemoryRegion): - RAM: a RAM region is simply a range of host memory that can be made available to the guest. + You typically initialize these with memory_region_init_ram(). Some special + purposes require the variants memory_region_init_resizeable_ram(), + memory_region_init_ram_from_file(), or memory_region_init_ram_ptr(). - MMIO: a range of guest memory that is implemented by host callbacks; each read or write causes a callback to be called on the host. + You initialize these with memory_region_io(), passing it a MemoryRegionOps + structure describing the callbacks. + +- ROM: a ROM memory region works like RAM for reads (directly accessing + a region of host memory), but like MMIO for writes (invoking a callback). + You initialize these with memory_region_init_rom_device(). + +- IOMMU region: an IOMMU region translates addresses of accesses made to it + and forwards them to some other target memory region. As the name suggests, + these are only needed for modelling an IOMMU, not for simple devices. + You initialize these with memory_region_init_iommu(). - container: a container simply includes other memory regions, each at a different offset. Containers are useful for grouping several regions @@ -45,12 +59,22 @@ MemoryRegion): can overlay a subregion of RAM with MMIO or ROM, or a PCI controller that does not prevent card from claiming overlapping BARs. + You initialize a pure container with memory_region_init(). + - alias: a subsection of another region. Aliases allow a region to be split apart into discontiguous regions. Examples of uses are memory banks used when the guest address space is smaller than the amount of RAM addressed, or a memory controller that splits main memory to expose a "PCI hole". Aliases may point to any type of region, including other aliases, but an alias may not point back to itself, directly or indirectly. + You initialize these with memory_region_init_alias(). + +- reservation region: a reservation region is primarily for debugging. + It claims I/O space that is not supposed to be handled by QEMU itself. + The typical use is to track parts of the address space which will be + handled by the host kernel when KVM is enabled. + You initialize these with memory_region_init_reservation(), or by + passing a NULL callback parameter to memory_region_init_io(). It is valid to add subregions to a region which is not a pure container (that is, to an MMIO, RAM or ROM region). This means that the region |