From patchwork Fri Aug 5 06:57:04 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: [v6,4/4] Qemu: Add commandline -drive option 'hostcache' Date: Thu, 04 Aug 2011 20:57:04 -0000 From: Supriya Kannery X-Patchwork-Id: 108614 Message-Id: <20110805065704.5829.84280.sendpatchset@skannery> To: qemu-devel@nongnu.org Cc: Kevin Wolf , Stefan Hajnoczi , Christoph Hellwig qemu command option 'hostcache' added to -drive for block devices. While starting a VM from qemu commandline, this option can be used for setting host cache usage for block data access. It is not allowed to specify both 'hostcache' and 'cache' options in the same commandline. Signed-off-by: Supriya Kannery --- blockdev.c | 13 +++++++++++++ qemu-config.c | 4 ++++ qemu-options.hx | 2 +- 3 files changed, 18 insertions(+), 1 deletion(-) Index: qemu/blockdev.c =================================================================== --- qemu.orig/blockdev.c +++ qemu/blockdev.c @@ -238,6 +238,7 @@ DriveInfo *drive_init(QemuOpts *opts, in DriveInfo *dinfo; int snapshot = 0; int ret; + int hostcache = 0; translation = BIOS_ATA_TRANSLATION_AUTO; media = MEDIA_DISK; @@ -320,7 +321,19 @@ DriveInfo *drive_init(QemuOpts *opts, in } } + if ((hostcache = qemu_opt_get_bool(opts, "hostcache", -1)) != -1) { + if (!hostcache) { + bdrv_flags |= BDRV_O_NOCACHE; + } else { + bdrv_flags &= ~BDRV_O_NOCACHE; + } + } + if ((buf = qemu_opt_get(opts, "cache")) != NULL) { + if (hostcache != -1) { + error_report("'hostcache' and 'cache' cannot co-exist"); + return NULL; + } if (!strcmp(buf, "off") || !strcmp(buf, "none")) { bdrv_flags |= BDRV_O_NOCACHE | BDRV_O_CACHE_WB; } else if (!strcmp(buf, "writeback")) { Index: qemu/qemu-options.hx =================================================================== --- qemu.orig/qemu-options.hx +++ qemu/qemu-options.hx @@ -135,7 +135,7 @@ DEF("drive", HAS_ARG, QEMU_OPTION_drive, " [,cyls=c,heads=h,secs=s[,trans=t]][,snapshot=on|off]\n" " [,cache=writethrough|writeback|none|unsafe][,format=f]\n" " [,serial=s][,addr=A][,id=name][,aio=threads|native]\n" - " [,readonly=on|off]\n" + " [,readonly=on|off][,hostcache=on|off]\n" " use 'file' as a drive image\n", QEMU_ARCH_ALL) STEXI @item -drive @var{option}[,@var{option}[,@var{option}[,...]]] Index: qemu/qemu-config.c =================================================================== --- qemu.orig/qemu-config.c +++ qemu/qemu-config.c @@ -84,6 +84,10 @@ static QemuOptsList qemu_drive_opts = { .name = "readonly", .type = QEMU_OPT_BOOL, .help = "open drive file as read-only", + },{ + .name = "hostcache", + .type = QEMU_OPT_BOOL, + .help = "set or reset hostcache (on/off)" }, { /* end of list */ } },