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From: Paul Durrant <xadimgnik@gmail.com>
To: David Woodhouse <dwmw2@infradead.org>, qemu-devel@nongnu.org
Cc: Paolo Bonzini <pbonzini@redhat.com>,
	Joao Martins <joao.m.martins@oracle.com>,
	Ankur Arora <ankur.a.arora@oracle.com>,
	Stefano Stabellini <sstabellini@kernel.org>,
	vikram.garhwal@amd.com,
	Anthony Perard <anthony.perard@citrix.com>,
	xen-devel@lists.xenproject.org,
	Juan Quintela <quintela@redhat.com>,
	"Dr . David Alan Gilbert" <dgilbert@redhat.com>,
	Peter Maydell <peter.maydell@linaro.org>
Subject: Re: [PATCH v2 00/27] Enable PV backends with Xen/KVM emulation
Date: Tue, 7 Mar 2023 17:57:29 +0000	[thread overview]
Message-ID: <007876ac-9f68-756b-3f86-db2f67886558@xen.org> (raw)
In-Reply-To: <20230307171750.2293175-1-dwmw2@infradead.org>

On 07/03/2023 17:17, David Woodhouse wrote:
> Following on from the basic platform support which has already been
> merged, here's phase 2 which wires up the XenBus and PV back ends.
> 
> It starts with a basic single-tenant internal implementation of a
> XenStore, with a copy-on-write tree, watches, transactions, quotas.
> 
> Then we introduce operations tables for the grant table, event channel,
> foreignmen and xenstore operations so that in addition to using the Xen
> libraries for those, QEMU can use its internal emulated versions.
> 
> A little bit of cleaning up of header files, and we can enable the build
> of xen-bus in the CONFIG_XEN_EMU build, and run a Xen guest with an
> actual PV disk...
> 
>     qemu-system-x86_64 -serial mon:stdio -M q35 -display none -m 1G -smp 2 \
>        -accel kvm,xen-version=0x4000e,kernel-irqchip=split \
>        -kernel bzImage -append "console=ttyS0 root=/dev/xvda1 selinux=0" \
>        -drive file=/var/lib/libvirt/images/fedora28.qcow2,if=none,id=disk \
>        -device xen-disk,drive=disk,vdev=xvda
> 
> The main thing that isn't working here is migration. I've implemented it
> for the internal xenstore and the unit tests exercise it, but the
> existing PV back ends don't support it, perhaps partly because support
> for guest transparent live migration support isn't upstream in Xen yet.
> So the disk doesn't come back correctly after migration. I'm content
> with that for 8.0 though, and we just mark the emulated XenStore device
> as unmigratable to prevent users from trying.
> 
> The other pre-existing constraint is that only the block back end has
> yet been ported to the "new" XenBus infrastructure, and is actually
> capable of creating its own backend nodes. Again, I can live with
> that for 8.0. Maybe this will motivate us to finally get round to
> converting the rest off XenLegacyBackend and killing it.
> 
> We also don't have a simple way to perform grant mapping of multiple
> guest pages to contiguous addresses, as we can under real Xen. So we
> don't advertise max-ring-page-order for xen-disk in the emulated mode.
> Fixing that — if we actually want to — would probably require mapping
> RAM from an actual backing store object, so that it can be mapped again
> at a different location for the PV back end to see.
> 
> v2: https://git.infradead.org/users/dwmw2/qemu.git/shortlog/refs/heads/xenfv-2
> 
>   • Full set of reviewed-by tags from Paul (and associated minor fixes).
> 
>   • Disable migration for emulated XenStore device.
> 
>   • Update docs and add MAINTAINERS entry.
> 
> v1: https://lore.kernel.org/qemu-devel/20230302153435.1170111-1-dwmw2@infradead.org/
>      https://git.infradead.org/users/dwmw2/qemu.git/shortlog/refs/heads/xenfv-1
> 
> David Woodhouse (23):
>        hw/xen: Add xenstore wire implementation and implementation stubs
>        hw/xen: Add basic XenStore tree walk and write/read/directory support
>        hw/xen: Implement XenStore watches
>        hw/xen: Implement XenStore transactions
>        hw/xen: Watches on XenStore transactions
>        hw/xen: Implement core serialize/deserialize methods for xenstore_impl
>        hw/xen: Add evtchn operations to allow redirection to internal emulation
>        hw/xen: Add gnttab operations to allow redirection to internal emulation
>        hw/xen: Pass grant ref to gnttab unmap operation
>        hw/xen: Add foreignmem operations to allow redirection to internal emulation
>        hw/xen: Move xenstore_store_pv_console_info to xen_console.c
>        hw/xen: Use XEN_PAGE_SIZE in PV backend drivers
>        hw/xen: Rename xen_common.h to xen_native.h
>        hw/xen: Build PV backend drivers for CONFIG_XEN_BUS
>        hw/xen: Only advertise ring-page-order for xen-block if gnttab supports it
>        hw/xen: Hook up emulated implementation for event channel operations
>        hw/xen: Add emulated implementation of grant table operations
>        hw/xen: Add emulated implementation of XenStore operations
>        hw/xen: Map guest XENSTORE_PFN grant in emulated Xenstore
>        hw/xen: Implement soft reset for emulated gnttab
>        i386/xen: Initialize Xen backends from pc_basic_device_init() for emulation
>        MAINTAINERS: Add entry for Xen on KVM emulation
>        docs: Update Xen-on-KVM documentation for PV disk support
> 
> Paul Durrant (4):
>        hw/xen: Implement XenStore permissions
>        hw/xen: Create initial XenStore nodes
>        hw/xen: Add xenstore operations to allow redirection to internal emulation
>        hw/xen: Avoid crash when backend watch fires too early
> 
>   MAINTAINERS                                   |    9 +
>   accel/xen/xen-all.c                           |   69 +-
>   docs/system/i386/xen.rst                      |   30 +-
>   hw/9pfs/meson.build                           |    2 +-
>   hw/9pfs/xen-9p-backend.c                      |   32 +-
>   hw/block/dataplane/meson.build                |    2 +-
>   hw/block/dataplane/xen-block.c                |   12 +-
>   hw/block/meson.build                          |    2 +-
>   hw/block/xen-block.c                          |   12 +-
>   hw/char/meson.build                           |    2 +-
>   hw/char/xen_console.c                         |   57 +-
>   hw/display/meson.build                        |    2 +-
>   hw/display/xenfb.c                            |   32 +-
>   hw/i386/kvm/meson.build                       |    1 +
>   hw/i386/kvm/trace-events                      |   15 +
>   hw/i386/kvm/xen_evtchn.c                      |   15 +
>   hw/i386/kvm/xen_gnttab.c                      |  325 ++++-
>   hw/i386/kvm/xen_gnttab.h                      |    1 +
>   hw/i386/kvm/xen_xenstore.c                    | 1251 +++++++++++++++-
>   hw/i386/kvm/xenstore_impl.c                   | 1927 +++++++++++++++++++++++++
>   hw/i386/kvm/xenstore_impl.h                   |   63 +
>   hw/i386/pc.c                                  |    7 +
>   hw/i386/pc_piix.c                             |    4 +-
>   hw/i386/xen/xen-hvm.c                         |   38 +-
>   hw/i386/xen/xen-mapcache.c                    |    2 +-
>   hw/i386/xen/xen_platform.c                    |    7 +-
>   hw/net/xen_nic.c                              |   25 +-
>   hw/usb/meson.build                            |    2 +-
>   hw/usb/xen-usb.c                              |   29 +-
>   hw/xen/meson.build                            |    6 +-
>   hw/xen/trace-events                           |    2 +-
>   hw/xen/xen-bus-helper.c                       |   62 +-
>   hw/xen/xen-bus.c                              |  411 +-----
>   hw/xen/xen-legacy-backend.c                   |  254 +---
>   hw/xen/xen-operations.c                       |  478 ++++++
>   hw/xen/xen_devconfig.c                        |    4 +-
>   hw/xen/xen_pt.c                               |    2 +-
>   hw/xen/xen_pt.h                               |    2 +-
>   hw/xen/xen_pt_config_init.c                   |    2 +-
>   hw/xen/xen_pt_graphics.c                      |    1 -
>   hw/xen/xen_pt_msi.c                           |    4 +-
>   hw/xen/xen_pvdev.c                            |   63 +-
>   include/hw/xen/xen-bus-helper.h               |   26 +-
>   include/hw/xen/xen-bus.h                      |   21 +-
>   include/hw/xen/xen-legacy-backend.h           |   24 +-
>   include/hw/xen/xen.h                          |   24 +-
>   include/hw/xen/xen_backend_ops.h              |  408 ++++++
>   include/hw/xen/{xen_common.h => xen_native.h} |   75 +-
>   include/hw/xen/xen_pvdev.h                    |    6 +-
>   softmmu/globals.c                             |    4 +
>   target/i386/kvm/xen-emu.c                     |    5 +
>   tests/unit/meson.build                        |    1 +
>   tests/unit/test-xs-node.c                     |  871 +++++++++++
>   53 files changed, 5804 insertions(+), 927 deletions(-)
> 

I think the series is good to go now so time to send a PR.

Cheers,

   Paul



  parent reply	other threads:[~2023-03-07 17:57 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-03-07 17:17 [PATCH v2 00/27] Enable PV backends with Xen/KVM emulation David Woodhouse
2023-03-07 17:17 ` [PATCH v2 01/27] hw/xen: Add xenstore wire implementation and implementation stubs David Woodhouse
2023-03-07 17:17 ` [PATCH v2 02/27] hw/xen: Add basic XenStore tree walk and write/read/directory support David Woodhouse
2023-03-07 17:17 ` [PATCH v2 03/27] hw/xen: Implement XenStore watches David Woodhouse
2023-03-07 17:17 ` [PATCH v2 04/27] hw/xen: Implement XenStore transactions David Woodhouse
2023-03-07 17:17 ` [PATCH v2 05/27] hw/xen: Watches on " David Woodhouse
2023-03-07 17:17 ` [PATCH v2 06/27] hw/xen: Implement XenStore permissions David Woodhouse
2023-03-07 17:17 ` [PATCH v2 07/27] hw/xen: Implement core serialize/deserialize methods for xenstore_impl David Woodhouse
2023-03-07 17:17 ` [PATCH v2 08/27] hw/xen: Create initial XenStore nodes David Woodhouse
2023-03-07 17:17 ` [PATCH v2 09/27] hw/xen: Add evtchn operations to allow redirection to internal emulation David Woodhouse
2023-03-23 10:29   ` Anthony PERARD via
2023-03-23 10:42     ` David Woodhouse
2023-03-23 10:57     ` [PATCH] hw/xenpv: Initialize Xen backend operations David Woodhouse
2023-03-23 13:26       ` Paul Durrant
2023-03-24 14:51       ` Anthony PERARD via
2023-03-07 17:17 ` [PATCH v2 10/27] hw/xen: Add gnttab operations to allow redirection to internal emulation David Woodhouse
2023-03-07 17:17 ` [PATCH v2 11/27] hw/xen: Pass grant ref to gnttab unmap operation David Woodhouse
2023-03-07 17:17 ` [PATCH v2 12/27] hw/xen: Add foreignmem operations to allow redirection to internal emulation David Woodhouse
2023-03-07 17:17 ` [PATCH v2 13/27] hw/xen: Add xenstore " David Woodhouse
2023-03-07 17:17 ` [PATCH v2 14/27] hw/xen: Move xenstore_store_pv_console_info to xen_console.c David Woodhouse
2023-03-07 17:17 ` [PATCH v2 15/27] hw/xen: Use XEN_PAGE_SIZE in PV backend drivers David Woodhouse
2023-03-07 17:17 ` [PATCH v2 16/27] hw/xen: Rename xen_common.h to xen_native.h David Woodhouse
2023-03-07 17:17 ` [PATCH v2 17/27] hw/xen: Build PV backend drivers for CONFIG_XEN_BUS David Woodhouse
2023-03-07 17:17 ` [PATCH v2 18/27] hw/xen: Avoid crash when backend watch fires too early David Woodhouse
2023-03-07 17:17 ` [PATCH v2 19/27] hw/xen: Only advertise ring-page-order for xen-block if gnttab supports it David Woodhouse
2023-03-07 17:17 ` [PATCH v2 20/27] hw/xen: Hook up emulated implementation for event channel operations David Woodhouse
2023-03-07 17:17 ` [PATCH v2 21/27] hw/xen: Add emulated implementation of grant table operations David Woodhouse
2023-03-07 17:17 ` [PATCH v2 22/27] hw/xen: Add emulated implementation of XenStore operations David Woodhouse
2023-03-07 17:17 ` [PATCH v2 23/27] hw/xen: Map guest XENSTORE_PFN grant in emulated Xenstore David Woodhouse
2023-03-07 17:17 ` [PATCH v2 24/27] hw/xen: Implement soft reset for emulated gnttab David Woodhouse
2023-03-07 17:17 ` [PATCH v2 25/27] i386/xen: Initialize Xen backends from pc_basic_device_init() for emulation David Woodhouse
2023-03-07 17:56   ` Paul Durrant
2023-03-07 17:17 ` [PATCH v2 26/27] MAINTAINERS: Add entry for Xen on KVM emulation David Woodhouse
2023-03-07 17:17 ` [PATCH v2 27/27] docs: Update Xen-on-KVM documentation for PV disk support David Woodhouse
2023-03-07 17:57 ` Paul Durrant [this message]
2023-03-07 18:27   ` [PATCH v2 00/27] Enable PV backends with Xen/KVM emulation David Woodhouse

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