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Re: [Qemu-devel] [RFC] net: 'Remove vhostforce option in addition to vho
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From: |
Pankaj Gupta |
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Subject: |
Re: [Qemu-devel] [RFC] net: 'Remove vhostforce option in addition to vhost param' |
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Date: |
Thu, 19 Feb 2015 07:02:43 -0500 (EST) |
Hi,
Could you please help/guide me here. As suggested by Jason I did other changes
also.
But when I did testing still virtio-net.c functions like 'receive()' gets
called when vhost is 'ON'.
I want to know is there anything I am missing here or is this expected
behaviour?
I was also searching for "kvm eventfd support for injecting level-triggered
interrupts", For non-MSIX
guests, can we remove vhost-force unless we have this feature?
Best regards,
Pankaj
----- Original Message -----
> From: "Jason Wang" <address@hidden>
> To: "Pankaj Gupta" <address@hidden>
> Cc: "Michael S. Tsirkin" <address@hidden>, address@hidden, address@hidden,
> address@hidden
> Sent: Sunday, February 15, 2015 8:11:29 AM
> Subject: Re: [Qemu-devel] [RFC] net: 'Remove vhostforce option in
> addition to vhost param'
>
>
>
> On Thu, Feb 12, 2015 at 11:41 PM, Pankaj Gupta <address@hidden>
> wrote:
> >
> >>
> >> > On Thu, Feb 12, 2015 at 11:50:05AM +0530, Pankaj Gupta wrote:
> >> > > vhostforce was added to enable use of vhost when
> >> > > guest don't have MSI-X support.
> >> > > Now, we have scenarios which dont use interrupts
> >> > > like DPDK and still use vhost. Also, performance of
> >> > > guests without MSI-X support is getting less popular.
> >> > >
> >> > > Its ok to remove this extra option and enable vhost
> >> > > on the basis of vhost=ON/OFF.
> >> > >
> >> > > Signed-off-by: Pankaj Gupta <address@hidden>
> >> >
> >> > The patch doesn't seem to do what it says.
> >> > Did you try with a non MSIX guest and vhost=on, to check that
> >> > it actually runs vhost and not userspace virtio?
> >>
> >> No, I have not. I just did basic tested a new guest without
> >> vhostforce.
> >> I will test non-MSIX guest and share the result.
> >
> > I tested this with RHEL 4 guest which don't have MSI-X. Though vhost
> > gets
> > created but still userspace virtio-net code executes.
> >
> > So, vhostforce was added to disable vhost for non-MSI guest?
>
> In fact to enable vhost.
> >
> > I took the idea from KVM/Networking todo list.
> >
> > Do we have some other dependency before we want to remove vhostforce?
> >
>
> You may want to take a look at the vhost_dev->force and
> vhost_dev_query().
> >
> >>
> >> >
> >> > > ---
> >> > > net/tap.c | 4 +---
> >> > > net/vhost-user.c | 16 ++--------------
> >> > > 2 files changed, 3 insertions(+), 17 deletions(-)
> >> > >
> >> > > diff --git a/net/tap.c b/net/tap.c
> >> > > index 1fe0edf..bd2efa9 100644
> >> > > --- a/net/tap.c
> >> > > +++ b/net/tap.c
> >> > > @@ -634,13 +634,11 @@ static int net_init_tap_one(const
> >> NetdevTapOptions
> >> > > *tap, NetClientState *peer,
> >> > > }
> >> > > }
> >> > >
> >> > > - if (tap->has_vhost ? tap->vhost :
> >> > > - vhostfdname || (tap->has_vhostforce &&
> >> tap->vhostforce)) {
> >> > > + if (tap->has_vhost ? tap->vhost : vhostfdname) {
> >> > > VhostNetOptions options;
> >> > >
> >> > > options.backend_type = VHOST_BACKEND_TYPE_KERNEL;
> >> > > options.net_backend = &s->nc;
> >> > > - options.force = tap->has_vhostforce && tap->vhostforce;
> >> > >
> >> > > if (tap->has_vhostfd || tap->has_vhostfds) {
> >> > > vhostfd = monitor_handle_fd_param(cur_mon,
> >> vhostfdname);
> >> > > diff --git a/net/vhost-user.c b/net/vhost-user.c
> >> > > index 24e050c..d2d7bf2 100644
> >> > > --- a/net/vhost-user.c
> >> > > +++ b/net/vhost-user.c
> >> > > @@ -18,7 +18,6 @@
> >> > > typedef struct VhostUserState {
> >> > > NetClientState nc;
> >> > > CharDriverState *chr;
> >> > > - bool vhostforce;
> >> > > VHostNetState *vhost_net;
> >> > > } VhostUserState;
> >> > >
> >> > > @@ -51,7 +50,6 @@ static int vhost_user_start(VhostUserState *s)
> >> > > options.backend_type = VHOST_BACKEND_TYPE_USER;
> >> > > options.net_backend = &s->nc;
> >> > > options.opaque = s->chr;
> >> > > - options.force = s->vhostforce;
> >> > >
> >> > > s->vhost_net = vhost_net_init(&options);
> >> > >
> >> > > @@ -133,8 +131,7 @@ static void net_vhost_user_event(void
> >> *opaque, int
> >> > > event)
> >> > > }
> >> > >
> >> > > static int net_vhost_user_init(NetClientState *peer, const
> >> char *device,
> >> > > - const char *name,
> >> CharDriverState *chr,
> >> > > - bool vhostforce)
> >> > > + const char *name,
> >> CharDriverState *chr)
> >> > > {
> >> > > NetClientState *nc;
> >> > > VhostUserState *s;
> >> > > @@ -149,7 +146,6 @@ static int
> >> net_vhost_user_init(NetClientState *peer,
> >> > > const char *device,
> >> > > /* We don't provide a receive callback */
> >> > > s->nc.receive_disabled = 1;
> >> > > s->chr = chr;
> >> > > - s->vhostforce = vhostforce;
> >> > >
> >> > > qemu_chr_add_handlers(s->chr, NULL, NULL,
> >> net_vhost_user_event, s);
> >> > >
> >> > > @@ -230,7 +226,6 @@ int net_init_vhost_user(const
> >> NetClientOptions *opts,
> >> > > const char *name,
> >> > > {
> >> > > const NetdevVhostUserOptions *vhost_user_opts;
> >> > > CharDriverState *chr;
> >> > > - bool vhostforce;
> >> > >
> >> > > assert(opts->kind == NET_CLIENT_OPTIONS_KIND_VHOST_USER);
> >> > > vhost_user_opts = opts->vhost_user;
> >> > > @@ -247,12 +242,5 @@ int net_init_vhost_user(const
> >> NetClientOptions
> >> > > *opts,
> >> > > const char *name,
> >> > > return -1;
> >> > > }
> >> > >
> >> > > - /* vhostforce for non-MSIX */
> >> > > - if (vhost_user_opts->has_vhostforce) {
> >> > > - vhostforce = vhost_user_opts->vhostforce;
> >> > > - } else {
> >> > > - vhostforce = false;
> >> > > - }
> >> > > -
> >> > > - return net_vhost_user_init(peer, "vhost_user", name, chr,
> >> > > vhostforce);
> >> > > + return net_vhost_user_init(peer, "vhost_user", name, chr);
> >> > > }
> >> > > --
> >> > > 1.8.3.1
> >> >
> >> >
> >>
> >
>
>