Re: [Qemu-devel] [V4 Patch 4/4 - Updated]Qemu: Add commandline -drive option 'hostcache'

[Supriya Kannery <supriyak@in.ibm.com>]

On 07/05/2011 04:35 PM, Supriya Kannery wrote:
> Updated patch to use qemu_opt_get_bool() instead of qemu_opt_get()
> to read 'hostcache'
>
> -------------------------------------------------------------------
> 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. User has to specify only one among these.
>
> Signed-off-by: Supriya Kannery <supriyak@in.ibm.com>
>
> ---
> 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;
>
> @@ -324,7 +325,19 @@ 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
> @@ -120,7 +120,7 @@ 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
> @@ -78,6 +78,10 @@ static QemuOptsList qemu_drive_opts = {
> },{
> .name = "readonly",
> .type = QEMU_OPT_BOOL,
> + },{
> + .name = "hostcache",
> + .type = QEMU_OPT_BOOL,
> + .help = "set or reset hostcache (on/off)"
> },
> { /* end of list */ }
> },
>
Please review..