• Kevin Wolf's avatar
    block: Don't use guest sector size for qemu_blockalign() · 339064d5
    Kevin Wolf authored
    bs->buffer_alignment is set by the device emulation and contains the
    logical block size of the guest device. This isn't something that the
    block layer should know, and even less something to use for determining
    the right alignment of buffers to be used for the host.
    
    The new BlockLimits field opt_mem_alignment tells the qemu block layer
    the optimal alignment to be used so that no bounce buffer must be used
    in the driver.
    
    This patch may change the buffer alignment from 4k to 512 for all
    callers that used qemu_blockalign() with the top-level image format
    BlockDriverState. The value was never propagated to other levels in the
    tree, so in particular raw-posix never required anything else than 512.
    
    While on disks with 4k sectors direct I/O requires a 4k alignment,
    memory may still be okay when aligned to 512 byte boundaries. This is
    what must have happened in practice, because otherwise this would
    already have failed earlier. Therefore I don't expect regressions even
    with this intermediate state. Later, raw-posix can implement the hook
    and expose a different memory alignment requirement.
    Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
    Reviewed-by: default avatarWenchao Xia <xiawenc@linux.vnet.ibm.com>
    Reviewed-by: default avatarMax Reitz <mreitz@redhat.com>
    339064d5
Name
Last commit
Last update
audio Loading commit data...
backends Loading commit data...
block Loading commit data...
bsd-user Loading commit data...
default-configs Loading commit data...
disas Loading commit data...
docs Loading commit data...
dtc @ bc895d6d Loading commit data...
fpu Loading commit data...
fsdev Loading commit data...
gdb-xml Loading commit data...
hw Loading commit data...
include Loading commit data...
libcacard Loading commit data...
linux-headers Loading commit data...
linux-user Loading commit data...
net Loading commit data...
pc-bios Loading commit data...
pixman @ 97336fad Loading commit data...
po Loading commit data...
qapi Loading commit data...
qga Loading commit data...
qobject Loading commit data...
qom Loading commit data...
roms Loading commit data...
scripts Loading commit data...
slirp Loading commit data...
stubs Loading commit data...
sysconfigs/target Loading commit data...
target-alpha Loading commit data...
target-arm Loading commit data...
target-cris Loading commit data...
target-i386 Loading commit data...
target-lm32 Loading commit data...
target-m68k Loading commit data...
target-microblaze Loading commit data...
target-mips Loading commit data...
target-moxie Loading commit data...
target-openrisc Loading commit data...
target-ppc Loading commit data...
target-s390x Loading commit data...
target-sh4 Loading commit data...
target-sparc Loading commit data...
target-unicore32 Loading commit data...
target-xtensa Loading commit data...
tcg Loading commit data...
tests Loading commit data...
trace Loading commit data...
ui Loading commit data...
util Loading commit data...
.exrc Loading commit data...
.gitignore Loading commit data...
.gitmodules Loading commit data...
.mailmap Loading commit data...
.travis.yml Loading commit data...
CODING_STYLE Loading commit data...
COPYING Loading commit data...
COPYING.LIB Loading commit data...
Changelog Loading commit data...
HACKING Loading commit data...
LICENSE Loading commit data...
MAINTAINERS Loading commit data...
Makefile Loading commit data...
Makefile.objs Loading commit data...
Makefile.target Loading commit data...
README Loading commit data...
VERSION Loading commit data...
aio-posix.c Loading commit data...
aio-win32.c Loading commit data...
arch_init.c Loading commit data...
async.c Loading commit data...
balloon.c Loading commit data...
block-migration.c Loading commit data...
block.c Loading commit data...
blockdev-nbd.c Loading commit data...
blockdev.c Loading commit data...
blockjob.c Loading commit data...
bt-host.c Loading commit data...
bt-vhci.c Loading commit data...
configure Loading commit data...
coroutine-gthread.c Loading commit data...
coroutine-sigaltstack.c Loading commit data...
coroutine-ucontext.c Loading commit data...
coroutine-win32.c Loading commit data...
cpu-exec.c Loading commit data...
cpus.c Loading commit data...
cputlb.c Loading commit data...
device-hotplug.c Loading commit data...
device_tree.c Loading commit data...
disas.c Loading commit data...
dma-helpers.c Loading commit data...
dump.c Loading commit data...
exec.c Loading commit data...
gdbstub.c Loading commit data...
hmp-commands.hx Loading commit data...
hmp.c Loading commit data...
hmp.h Loading commit data...
iohandler.c Loading commit data...
ioport.c Loading commit data...
kvm-all.c Loading commit data...
kvm-stub.c Loading commit data...
main-loop.c Loading commit data...
memory.c Loading commit data...
memory_mapping.c Loading commit data...
migration-exec.c Loading commit data...
migration-fd.c Loading commit data...
migration-rdma.c Loading commit data...
migration-tcp.c Loading commit data...
migration-unix.c Loading commit data...
migration.c Loading commit data...
monitor.c Loading commit data...
nbd.c Loading commit data...
os-posix.c Loading commit data...
os-win32.c Loading commit data...
page_cache.c Loading commit data...
qapi-schema.json Loading commit data...
qdev-monitor.c Loading commit data...
qdict-test-data.txt Loading commit data...
qemu-bridge-helper.c Loading commit data...
qemu-char.c Loading commit data...
qemu-coroutine-io.c Loading commit data...
qemu-coroutine-lock.c Loading commit data...
qemu-coroutine-sleep.c Loading commit data...
qemu-coroutine.c Loading commit data...
qemu-doc.texi Loading commit data...
qemu-file.c Loading commit data...
qemu-img-cmds.hx Loading commit data...
qemu-img.c Loading commit data...
qemu-img.texi Loading commit data...
qemu-io-cmds.c Loading commit data...
qemu-io.c Loading commit data...
qemu-log.c Loading commit data...
qemu-nbd.c Loading commit data...
qemu-nbd.texi Loading commit data...
qemu-options-wrapper.h Loading commit data...
qemu-options.h Loading commit data...
qemu-options.hx Loading commit data...
qemu-seccomp.c Loading commit data...
qemu-tech.texi Loading commit data...
qemu-timer.c Loading commit data...
qemu.nsi Loading commit data...
qemu.sasl Loading commit data...
qmp-commands.hx Loading commit data...
qmp.c Loading commit data...
qtest.c Loading commit data...
rules.mak Loading commit data...
savevm.c Loading commit data...
spice-qemu-char.c Loading commit data...
tcg-runtime.c Loading commit data...
tci.c Loading commit data...
thread-pool.c Loading commit data...
thunk.c Loading commit data...
tpm.c Loading commit data...
trace-events Loading commit data...
translate-all.c Loading commit data...
translate-all.h Loading commit data...
user-exec.c Loading commit data...
version.rc Loading commit data...
vl.c Loading commit data...
vmstate.c Loading commit data...
xbzrle.c Loading commit data...
xen-all.c Loading commit data...
xen-mapcache.c Loading commit data...
xen-stub.c Loading commit data...