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Re: [Qemu-devel] [PATCH 2/6] xen: Move xenstore initialization to common
From: |
Paul Durrant |
Subject: |
Re: [Qemu-devel] [PATCH 2/6] xen: Move xenstore initialization to common location |
Date: |
Thu, 14 Mar 2019 14:00:13 +0000 |
> -----Original Message-----
> From: Jason Andryuk [mailto:address@hidden
> Sent: 13 March 2019 18:12
> To: Paul Durrant <address@hidden>
> Cc: address@hidden; address@hidden; address@hidden; Stefano
> Stabellini <address@hidden>; Anthony Perard <address@hidden>; Paolo Bonzini
> <address@hidden>; Richard Henderson <address@hidden>; Eduardo Habkost
> <address@hidden>;
> Michael S. Tsirkin <address@hidden>; Marcel Apfelbaum <address@hidden>
> Subject: Re: [PATCH 2/6] xen: Move xenstore initialization to common location
>
> On Wed, Mar 13, 2019 at 11:01 AM Paul Durrant <address@hidden> wrote:
> >
> > > -----Original Message-----
> > > From: Jason Andryuk [mailto:address@hidden
> > > Sent: 11 March 2019 18:02
> > > To: address@hidden
> > > Cc: address@hidden; address@hidden; Jason Andryuk
> > > <address@hidden>; Stefano Stabellini <address@hidden>; Anthony Perard
> > > <address@hidden>; Paul Durrant <address@hidden>; Paolo Bonzini
> > > <address@hidden>; Richard Henderson <address@hidden>; Eduardo Habkost
> > > <address@hidden>;
> > > Michael S. Tsirkin <address@hidden>; Marcel Apfelbaum <address@hidden>
> > > Subject: [PATCH 2/6] xen: Move xenstore initialization to common location
> > >
> > > For the xen stubdom case, we'll want xenstore initialized, but we'll
> > > want to skip the rest of xen_be_init. Move the initialization to
> > > xen_hvm_init so we can conditionalize calling xen_be_init.
> > >
> > > xs_domain_open() is deprecated for xs_open(0), so make the replacement
> > > as well.
> >
> > Can you elaborate as to why you need to do this when the code at the top of
> > xen_hvm_init() already
> opens xenstore for its own purposes, and AFAICT xenstore_update() is only
> needed if QEMU is
> implementing a PV backend?
> >
> >
>
> Hi, Paul. Thanks for reviewing.
>
> I think you are right, that this basically shouldn't be needed if PV
> backends are disabled. This patch came out of OpenXT, where it is
> needed for some out-of-tree patches. But that doesn't make it
> suitable for upstreaming.
>
> However, while reviewing, it looks like the xen accelerator in
> hw/xen/xen-common.c:xen_init() registers xen_change_state_handler().
> xen_change_state_handler() uses the global xenstore handle and will
> exit(1) if NULL.
I see it yes. TBH signalling state via xenstore should go away as it is
incompatible with deprivileging, and I think Anthony might have some patches
for that? In the meantime I suggest just doing a local xs_open(0) in that
function.
> I'm not sure how to get the XenIOState xenstore
> handle over to the accelerator's xen_init.
That would not be appropriate as the machine type may not be xenfv and hence
xen_hvm_init() may not have been called.
Paul
> Outside of that, I think
> you are correct that xenstore_update doesn't need to be run when PV
> backends are disabled.
>
> Thanks,
> Jason
- Re: [Qemu-devel] [Xen-devel] [PATCH 5/6] xen-pt: Hide MSI-X from xen stubdoms, (continued)
- Re: [Qemu-devel] [Xen-devel] [PATCH 5/6] xen-pt: Hide MSI-X from xen stubdoms, Marek Marczykowski-Górecki, 2019/03/12
- Re: [Qemu-devel] [Xen-devel] [PATCH 5/6] xen-pt: Hide MSI-X from xen stubdoms, Jason Andryuk, 2019/03/12
- Re: [Qemu-devel] [Xen-devel] [PATCH 5/6] xen-pt: Hide MSI-X from xen stubdoms, Roger Pau Monné, 2019/03/12
- Re: [Qemu-devel] [Xen-devel] [PATCH 5/6] xen-pt: Hide MSI-X from xen stubdoms, Jason Andryuk, 2019/03/12
- Re: [Qemu-devel] [Xen-devel] [PATCH 5/6] xen-pt: Hide MSI-X from xen stubdoms, Jason Andryuk, 2019/03/12
- Re: [Qemu-devel] [Xen-devel] [PATCH 5/6] xen-pt: Hide MSI-X from xen stubdoms, Marek Marczykowski-Górecki, 2019/03/12
[Qemu-devel] [PATCH 4/6] xen: Set HVM_PARAM_DM_DOMAIN for stubdom on older Xen, Jason Andryuk, 2019/03/11
[Qemu-devel] [PATCH 2/6] xen: Move xenstore initialization to common location, Jason Andryuk, 2019/03/11
[Qemu-devel] [PATCH 6/6] xen-pt: Round pci regions sizes to XEN_PAGE_SIZE, Jason Andryuk, 2019/03/11
Re: [Qemu-devel] [PATCH 6/6] xen-pt: Round pci regions sizes to XEN_PAGE_SIZE, Simon Gaiser, 2019/03/14
Re: [Qemu-devel] [PATCH 6/6] xen-pt: Round pci regions sizes to XEN_PAGE_SIZE, Paul Durrant, 2019/03/15
Re: [Qemu-devel] [Xen-devel] [PATCH 6/6] xen-pt: Round pci regions sizes to XEN_PAGE_SIZE, Andrew Cooper, 2019/03/15
Re: [Qemu-devel] [Xen-devel] [PATCH 6/6] xen-pt: Round pci regions sizes to XEN_PAGE_SIZE, Jason Andryuk, 2019/03/20