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Re: [Qemu-devel] [PATCH v6 wave 2 1/3] hw/isa/lpc_ich9: add SMI feature
From: |
Igor Mammedov |
Subject: |
Re: [Qemu-devel] [PATCH v6 wave 2 1/3] hw/isa/lpc_ich9: add SMI feature negotiation via fw_cfg |
Date: |
Tue, 17 Jan 2017 09:42:39 +0100 |
On Mon, 16 Jan 2017 21:51:34 +0100
Laszlo Ersek <address@hidden> wrote:
> On 01/13/17 14:34, Igor Mammedov wrote:
> > On Thu, 12 Jan 2017 19:24:44 +0100
> > Laszlo Ersek <address@hidden> wrote:
> >
> > [...]
> >> +static void smi_features_ok_callback(void *opaque)
> >> +{
> >> + ICH9LPCState *lpc = opaque;
> >> + uint64_t guest_features;
> >> +
> >> + if (lpc->smi_features_ok) {
> >> + /* negotiation already complete, features locked */
> >> + return;
> >> + }
> >> +
> >> + memcpy(&guest_features, lpc->smi_guest_features_le, sizeof
> >> guest_features);
> >> + le64_to_cpus(&guest_features);
> >> + if (guest_features & ~lpc->smi_host_features) {
> >> + /* guest requests invalid features, leave @features_ok at zero */
> >> + return;
> >> + }
> >> +
> >> + /* valid feature subset requested, lock it down, report success */
> >> + lpc->smi_negotiated_features = guest_features;
> >> + lpc->smi_features_ok = 1;
> >> +}
> > [...]
> >
> >> + .fields = (VMStateField[]) {
> >> + VMSTATE_UINT8_ARRAY(smi_guest_features_le, ICH9LPCState,
> >> + sizeof(uint64_t)),
> >> + VMSTATE_UINT8(smi_features_ok, ICH9LPCState),
> >> + VMSTATE_UINT64(smi_negotiated_features, ICH9LPCState),
> >
> > Couldn't smi_negotiated_features be derived from
> > smi_guest_features_le on target side?
>
> No, that's something we must expressly not do.
>
> The "guest-features" file remains writeable (and back-readable) to the
> guest after feature validation/lockdown (i.e., after selecting
> "features-ok"), it just has no effect on QEMU.
>
> And, if the guest rewrites "guest-features" between feature lockdown and
> migration, that must have no effect on the target host either. Hence we
> must carry forward the negotiated features originally computed on the
> source host.
ok,
patch looks good to me, so
Reviewed-by: Igor Mammedov <address@hidden>
> Thanks
> Laszlo
>
> >
> >
> >> + VMSTATE_END_OF_LIST()
> >> + }
> >> +};
> >> +
> >> static const VMStateDescription vmstate_ich9_lpc = {
> >> .name = "ICH9LPC",
> >> .version_id = 1,
> >> @@ -683,6 +761,7 @@ static const VMStateDescription vmstate_ich9_lpc = {
> >> },
> >> .subsections = (const VMStateDescription*[]) {
> >> &vmstate_ich9_rst_cnt,
> >> + &vmstate_ich9_smi_feat,
> >> NULL
> >> }
> >> };
> >
>
>
- [Qemu-devel] [PATCH v6 wave 2 0/3] q35: add negotiable broadcast SMI, Laszlo Ersek, 2017/01/12
- [Qemu-devel] [PATCH v6 wave 2 3/3] hw/isa/lpc_ich9: negotiate SMI broadcast on pc-q35-2.9+ machine types, Laszlo Ersek, 2017/01/12
- [Qemu-devel] [PATCH v6 wave 2 2/3] hw/isa/lpc_ich9: add broadcast SMI feature, Laszlo Ersek, 2017/01/12
- Re: [Qemu-devel] [PATCH v6 wave 2 2/3] hw/isa/lpc_ich9: add broadcast SMI feature, Igor Mammedov, 2017/01/13
- Re: [Qemu-devel] [PATCH v6 wave 2 2/3] hw/isa/lpc_ich9: add broadcast SMI feature, Laszlo Ersek, 2017/01/16
- Re: [Qemu-devel] [PATCH v6 wave 2 2/3] hw/isa/lpc_ich9: add broadcast SMI feature, Igor Mammedov, 2017/01/17
- Re: [Qemu-devel] [PATCH v6 wave 2 2/3] hw/isa/lpc_ich9: add broadcast SMI feature, Laszlo Ersek, 2017/01/17
- Re: [Qemu-devel] [PATCH v6 wave 2 2/3] hw/isa/lpc_ich9: add broadcast SMI feature, Igor Mammedov, 2017/01/17
- Re: [Qemu-devel] [PATCH v6 wave 2 2/3] hw/isa/lpc_ich9: add broadcast SMI feature, Laszlo Ersek, 2017/01/17
- Re: [Qemu-devel] [PATCH v6 wave 2 2/3] hw/isa/lpc_ich9: add broadcast SMI feature, Igor Mammedov, 2017/01/17