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2008-12-04Use writeback caching by default with qcow2aliguori1-1/+2
qcow2 writes a cluster reference count on every cluster update. This causes performance to crater when using anything but cache=writeback. This is most noticeable when using savevm. Right now, qcow2 isn't a reliable format regardless of the type of cache your using because metadata is not updated in the correct order. Considering this, I think it's somewhat reasonable to use writeback caching by default with qcow2 files. It at least avoids the massive performance regression for users until we sort out the issues in qcow2. Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5879 c046a42c-6fe2-441c-8c8c-71466251a162
2008-11-25Abstract out geometry detection code from IDE for reusealiguori1-0/+1
Virtio will want to use the geometry detection code. It doesn't belong in ide.c anyway. Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5797 c046a42c-6fe2-441c-8c8c-71466251a162
2008-11-08Use an option rom instead of boot sector for -kernelaliguori1-1/+0
Generate an option rom instead of using a hijacked boot sector for kernel booting. This just requires adding a small option ROM header and a few more instructions to the boot sector to take over the int19 vector and run our boot code. A disk is no longer needed when using -kernel on x86. Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5650 c046a42c-6fe2-441c-8c8c-71466251a162
2008-10-14Expand cache= option and use write-through caching by defaultaliguori1-1/+4
This patch changes the cache= option to accept none, writeback, or writethough to control the host page cache behavior. By default, writethrough caching is now used which internally is implemented by using O_DSYNC to open the disk images. When using -snapshot, writeback is used by default since data integrity it not at all an issue. cache=none has the same behavior as cache=off previously. The later syntax is still supported by now deprecated. I also cleaned up the O_DIRECT implementation to avoid many of the #ifdefs. Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5485 c046a42c-6fe2-441c-8c8c-71466251a162
2008-10-06Add bdrv_flush_all()aliguori1-0/+2
This patch adds a bdrv_flush_all() function. It's necessary to ensure that all IO operations have been flushed to disk before completely a live migration. N.B. we don't actually use this now. We really should flush the block drivers using an live savevm callback to avoid unnecessary guest down time. Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5432 c046a42c-6fe2-441c-8c8c-71466251a162
2008-09-22Refactor AIO to allow multiple AIO implementationsaliguori1-4/+2
This patch refactors the AIO layer to allow multiple AIO implementations. It's only possible because of the recent signalfd() patch. Right now, the AIO infrastructure is pretty specific to the block raw backend. For other block devices to implement AIO, the qemu_aio_wait function must support registration. This patch introduces a new function, qemu_aio_set_fd_handler, which can be used to register a file descriptor to be called back. qemu_aio_wait() now polls a set of file descriptors registered with this function until one becomes readable or writable. This patch should allow the implementation of alternative AIO backends (via a thread pool or linux-aio) and AIO backends in non-traditional block devices (like NBD). Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5297 c046a42c-6fe2-441c-8c8c-71466251a162
2008-09-15Use common objects for qemu-img and qemu-nbdaliguori1-2/+0
Right now, we sprinkle #if defined(QEMU_IMG) && defined(QEMU_NBD) all over the code. It's ugly and causes us to have to build multiple object files for linking against qemu and the tools. This patch introduces a new file, qemu-tool.c which contains enough for qemu-img, qemu-nbd, and QEMU to all share the same objects. This also required getting qemu-nbd to be a bit more Windows friendly. I also changed the Windows block-raw to use normal IO instead of overlapping IO since we don't actually do AIO yet on Windows. I changed the various #if 0's to #if WIN32_AIO to make it easier for someone to eventually fix AIO on Windows. After this patch, there are no longer any #ifdef's related to qemu-img and qemu-nbd. Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5226 c046a42c-6fe2-441c-8c8c-71466251a162
2008-09-10Use signalfd() to work around signal/select racealiguori1-3/+0
This patch introduces signalfd() to work around the signal/select race in checking for AIO completions. For platforms that don't support signalfd(), we emulate it with threads. There was a long discussion about this approach. I don't believe there are any fundamental problems with this approach and I believe eliminating the use of signals is a good thing. I've tested Windows and Linux using Windows and Linux guests. I've also checked for disk IO performance regressions. Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5187 c046a42c-6fe2-441c-8c8c-71466251a162
2008-07-03Allow QEMU to connect directly to an NBD server, by Laurent Vivier.ths1-0/+1
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@4838 c046a42c-6fe2-441c-8c8c-71466251a162
2008-06-05New qemu-img convert -B option, by Marc Bevand.ths1-0/+2
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@4672 c046a42c-6fe2-441c-8c8c-71466251a162
2008-03-11Revert fix for CVE-2008-0928. Will be fixed in a different way later.aurel321-1/+0
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@4041 c046a42c-6fe2-441c-8c8c-71466251a162
2008-03-11Fix CVE-2008-0928 - insufficient block device address range checkingaurel321-0/+1
Qemu 0.9.1 and earlier does not perform range checks for block device read or write requests, which allows guest host users with root privileges to access arbitrary memory and escape the virtual machine. git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@4037 c046a42c-6fe2-441c-8c8c-71466251a162
2007-12-24Real SCSI device passthrough (v4), by Laurent Vivier.ths1-0/+2
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@3851 c046a42c-6fe2-441c-8c8c-71466251a162
2007-12-24Add "cache" parameter to "-drive" (Laurent Vivier).balrog1-0/+1
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@3848 c046a42c-6fe2-441c-8c8c-71466251a162
2007-12-17Fix bdrv_get_geometry to return uint64_t, by Andre Przywara.ths1-1/+1
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@3825 c046a42c-6fe2-441c-8c8c-71466251a162
2007-12-02Collecting block device statistics, by Richard W.M. Jones.ths1-0/+1
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@3760 c046a42c-6fe2-441c-8c8c-71466251a162
2007-11-17Break up vl.h.pbrook1-1/+0
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@3674 c046a42c-6fe2-441c-8c8c-71466251a162
2007-11-11Split block API from vl.h.pbrook1-0/+157
Remove QEMU_TOOL. Replace with QEMU_IMG and NEED_CPU_H. Avoid linking qemu-img against whole system emulatior. git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@3578 c046a42c-6fe2-441c-8c8c-71466251a162
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