From: Olaf Hering <olaf@aepfle.de>
To: Paul Durrant <pdurrant@gmail.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Stefano Stabellini <sstabellini@kernel.org>,
Anthony Perard <anthony.perard@citrix.com>
Cc: "open list:All patches CC here" <qemu-devel@nongnu.org>,
Richard Henderson <rth@twiddle.net>,
Eduardo Habkost <ehabkost@redhat.com>,
"Michael S. Tsirkin" <mst@redhat.com>
Subject: Re: [PATCH v2] hw/i386: disable smbus migration for xenfv
Date: Tue, 18 Feb 2020 18:27:28 +0100 [thread overview]
Message-ID: <20200218182728.4b7f17b7.olaf@aepfle.de> (raw)
In-Reply-To: <20200127100951.0803d167.olaf@aepfle.de>
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The approach below (making 'xenfv' an alias of 'pc') does not work:
xen_enabled() is false when pc_i440fx_3_1_machine_options runs.
So, how is this incompatibility between qemu2/3 and qemu4+ supposed to be fixed?
Using '-machine pc,accel=xen -device xen-platform' is incompatible with '-machine xenpv' because the platform device has a different PCI address. As such it is not migrateable.
Olaf
Am Mon, 27 Jan 2020 10:09:51 +0100
schrieb Olaf Hering <olaf@aepfle.de>:
> Am Mon, 20 Jan 2020 11:18:41 +0000
> schrieb Paul Durrant <pdurrant@gmail.com>:
>
> > On Fri, 17 Jan 2020 at 13:06, Olaf Hering <olaf@aepfle.de> wrote:
> > > What would future domUs lose if 'xenfv' would be locked to 'pc-i440fx-3.0'?
>
> > I guess eventually that pc type would be removed and then we'd have a
> > compat issue. Ideally I think libxl should simply not use xenfv and
> > then it can be deprecated and removed, and then such issues can be
> > dealt with directly in xl/libxl.
>
> I think this does not answer the question at all.
> What future versions of libxl do is one thing.
> What existing versions of libxl do with future versions of qemu is another.
>
>
> IMO it was wrong to map "xenfv" to "pc", simply because it entirely
> ignores live migration. We were just lucky until qemu-3.1. Maybe the
> creators of 'xenfv' just meant it to be "do everything to make it
> compatible with HVM".
>
> What about a variant of this change, to lock 'xenfv' to 'qemu-3.0'?
>
>
> --- a/hw/i386/pc_piix.c
> +++ b/hw/i386/pc_piix.c
> @@ -490,6 +490,13 @@ static void pc_i440fx_3_0_machine_options(MachineClass *m)
> pc_i440fx_3_1_machine_options(m);
> compat_props_add(m->compat_props, hw_compat_3_0, hw_compat_3_0_len);
> compat_props_add(m->compat_props, pc_compat_3_0, pc_compat_3_0_len);
> +
> + m->alias = "xenfv";
> + if (xen_enabled()) {
> + m->desc = "Xen Fully-virtualized PC";
> + m->max_cpus = HVM_MAX_VCPUS;
> + m->default_machine_opts = "accel=xen";
> + }
> }
>
> DEFINE_I440FX_MACHINE(v3_0, "pc-i440fx-3.0", NULL,
> @@ -500,6 +507,7 @@ static void pc_i440fx_2_12_machine_options(MachineClass *m)
> pc_i440fx_3_0_machine_options(m);
> compat_props_add(m->compat_props, hw_compat_2_12, hw_compat_2_12_len);
> compat_props_add(m->compat_props, pc_compat_2_12, pc_compat_2_12_len);
> + m->alias = NULL;
> }
>
> DEFINE_I440FX_MACHINE(v2_12, "pc-i440fx-2.12", NULL,
> @@ -946,14 +954,3 @@ DEFINE_PC_MACHINE(isapc, "isapc", pc_init_isa,
> isapc_machine_options);
>
>
> -#ifdef CONFIG_XEN
> -static void xenfv_machine_options(MachineClass *m)
> -{
> - m->desc = "Xen Fully-virtualized PC";
> - m->max_cpus = HVM_MAX_VCPUS;
> - m->default_machine_opts = "accel=xen";
> -}
> -
> -DEFINE_PC_MACHINE(xenfv, "xenfv", pc_xen_hvm_init,
> - xenfv_machine_options);
> -#endif
>
>
> Olaf
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next prev parent reply other threads:[~2020-02-18 17:28 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-13 17:45 [PATCH v1] hw/i386: disable smbus migration for xenpv Olaf Hering
2020-01-13 17:46 ` [PATCH v1] hw/i386: disable smbus migration for xenfv Olaf Hering
2020-01-15 13:51 ` [PATCH v1] hw/i386: disable smbus migration for xenpv Michael S. Tsirkin
2020-01-16 18:03 ` [PATCH v2] hw/i386: disable smbus migration for xenfv Olaf Hering
2020-01-16 18:26 ` Paolo Bonzini
2020-01-16 18:33 ` Olaf Hering
2020-01-16 18:50 ` Paolo Bonzini
2020-01-17 9:22 ` Olaf Hering
2020-01-17 10:27 ` Paolo Bonzini
2020-01-17 13:06 ` Olaf Hering
2020-01-20 11:18 ` Paul Durrant
2020-01-27 9:09 ` Olaf Hering
2020-02-18 17:27 ` Olaf Hering [this message]
2020-02-18 17:37 ` Paolo Bonzini
2020-02-18 18:30 ` Olaf Hering
2020-02-18 19:44 ` Olaf Hering
2020-02-19 8:05 ` Paolo Bonzini
2020-02-19 8:13 ` Olaf Hering
2020-01-27 9:35 ` Paolo Bonzini
2020-01-27 13:26 ` Olaf Hering
2020-01-27 18:21 ` Paolo Bonzini
2020-02-19 11:35 ` Olaf Hering
2020-02-19 14:14 ` Olaf Hering
2020-02-20 10:50 ` Paolo Bonzini
2020-03-25 6:47 ` [PATCH v3] piix: fix xenfv regression, add compat machine xenfv-qemu4 Olaf Hering
2020-03-25 7:11 ` no-reply
2020-03-25 7:25 ` no-reply
2020-03-25 15:39 ` Paolo Bonzini
2020-03-25 15:45 ` Olaf Hering
2020-03-25 17:06 ` Paolo Bonzini
2020-03-27 15:19 ` Olaf Hering
2020-03-27 15:18 ` [PATCH v4] " Olaf Hering
2020-03-27 15:45 ` no-reply
2020-03-27 15:59 ` Paolo Bonzini
2020-03-28 7:09 ` Olaf Hering
2020-03-28 8:56 ` Paolo Bonzini
2020-04-06 16:00 ` Paolo Bonzini
2020-04-06 16:11 ` Olaf Hering
2020-03-27 16:01 ` no-reply
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