Re: [Xen-devel] [PATCH v2][RFC] libxl: Add AHCI support for upstream qemu

[Fabio Fantoni <fabio.fantoni@xxxxxxx>]

Il 18/05/2015 17:53, Wei Liu ha scritto:
> On Thu, May 14, 2015 at 01:11:13PM +0200, Fabio Fantoni wrote:
> > Usage:
> > ahci=0|1 (default=0)
> >
> > If enabled adds ich9 disk controller in ahci mode and uses it with
> > upstream qemu to emulate disks instead of ide.
> Is ICH9 available in our default setup?
>
> Why do we not always enable AHCI?
ahci seems require ich9 controller (default in q35 but not in older used 
by xen), I think that change it ide->ahci automatically for all cases 
may causes problems, probably in save/restore and more probably in 
windows <=7 without pv where change ide<->ahci require a registry change 
for not have blue screen.
> > It doesn't support cdroms which still use ide (cdroms will use "-device
> > ide-cd" as new qemu parameters)
> > Ahci requires new qemu parameters but for now other emulated disks cases
> > remains with old ones because automatic bus selection seems bugged in
> > qemu using new parameters. (I'll retry)
> Buggy as in? Have you reported to QEMU upstream?
Already reported long time ago in xen-devel and qemu-devel, the only 
reply from qemu-devel was to use fixed bus and is what I did in v2 of 
this patch.
Can someone tell me if can be a problem fixed bus?

> > NOTES:
> > This patch is a only a fast draft for testing.
> > Tested with 1 and 6 disks on ubuntu 15.04 hvm, windows 7 and windows 8
> > domUs.
> > Doc entry and libxl.h define should be added, I'll do.
> > Other emulated disks cases should be converted to use new qemu
> > parameters but probably a fix in qemu is needed.
> >
> > Any comment is appreciated.
> >
> > Signed-off-by: Fabio Fantoni <fabio.fantoni@xxxxxxx>
> >
> > Changes in v2:
> > - libxl_dm.c: manual bus and unit selection (as workaround to qemu bug)
> > to have multiple disks working.
> What's the relation between this patch the other patch you posted later?
>
> > ---
> >   tools/libxl/libxl_create.c  |  1 +
> >   tools/libxl/libxl_dm.c      | 10 +++++++++-
> >   tools/libxl/libxl_types.idl |  1 +
> >   tools/libxl/xl_cmdimpl.c    |  1 +
> >   4 files changed, 12 insertions(+), 1 deletion(-)
> >
> > diff --git a/tools/libxl/libxl_create.c b/tools/libxl/libxl_create.c
> > index f0da7dc..fcfe24a 100644
> > --- a/tools/libxl/libxl_create.c
> > +++ b/tools/libxl/libxl_create.c
> > @@ -322,6 +322,7 @@ int libxl__domain_build_info_setdefault(libxl__gc *gc,
> >           libxl_defbool_setdefault(&b_info->u.hvm.nested_hvm,         false);
> >           libxl_defbool_setdefault(&b_info->u.hvm.usb,                false);
> >           libxl_defbool_setdefault(&b_info->u.hvm.xen_platform_pci,   true);
> > +        libxl_defbool_setdefault(&b_info->u.hvm.ahci,               false);
> >   
> >           libxl_defbool_setdefault(&b_info->u.hvm.spice.enable, false);
> >           if (!libxl_defbool_val(b_info->u.hvm.spice.enable) &&
> > diff --git a/tools/libxl/libxl_dm.c b/tools/libxl/libxl_dm.c
> > index 0c6408d..4bec5ba 100644
> > --- a/tools/libxl/libxl_dm.c
> > +++ b/tools/libxl/libxl_dm.c
> > @@ -804,6 +804,8 @@ static char ** libxl__build_device_model_args_new(libxl__gc 
> > *gc,
> >       flexarray_append(dm_args, libxl__sprintf(gc, "%"PRId64, ram_size));
> >   
> >       if (b_info->type == LIBXL_DOMAIN_TYPE_HVM) {
> > +        if (libxl_defbool_val(b_info->u.hvm.ahci))
> > +            flexarray_append_pair(dm_args, "-device", "ahci,id=ahci0");
> >           for (i = 0; i < num_disks; i++) {
> >               int disk, part;
> >               int dev_number =
> > @@ -858,7 +860,13 @@ static char ** 
> > libxl__build_device_model_args_new(libxl__gc *gc,
> >                       drive = libxl__sprintf
> >                           (gc, 
> > "file=%s,if=scsi,bus=0,unit=%d,format=%s,cache=writeback",
> >                            pdev_path, disk, format);
> > -                else if (disk < 4)
> > +                else if (disk < 6 && libxl_defbool_val(b_info->u.hvm.ahci)){
> And you choose 6 because?
Because the ich9 ahci controller have 6 channel, so is the max, ide 
instead have 2 channel with master/slave.
> Wei.

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel