Hi Oleksandr, I just tested the v6 and the latest backend service with the latest staging branch. They work well.
Tested-by: Wei Chen <wei.c...@arm.com> Cheers, Wei Chen > -----Original Message----- > From: Oleksandr Tyshchenko <olekst...@gmail.com> > Sent: 2021年1月29日 9:48 > To: xen-devel@lists.xenproject.org > Cc: Oleksandr Tyshchenko <oleksandr_tyshche...@epam.com>; Paul Durrant > <p...@xen.org>; Jan Beulich <jbeul...@suse.com>; Andrew Cooper > <andrew.coop...@citrix.com>; Roger Pau Monné <roger....@citrix.com>; > Wei Liu <w...@xen.org>; Julien Grall <julien.gr...@arm.com>; George Dunlap > <george.dun...@citrix.com>; Ian Jackson <i...@xenproject.org>; Julien Grall > <jul...@xen.org>; Stefano Stabellini <sstabell...@kernel.org>; Jun Nakajima > <jun.nakaj...@intel.com>; Kevin Tian <kevin.t...@intel.com>; Tim Deegan > <t...@xen.org>; Daniel De Graaf <dgde...@tycho.nsa.gov>; Volodymyr > Babchuk <volodymyr_babc...@epam.com>; Bertrand Marquis > <bertrand.marq...@arm.com>; Wei Chen <wei.c...@arm.com>; Kaly Xin > <kaly....@arm.com>; Artem Mygaiev <jocula...@gmail.com>; Alex Bennée > <alex.ben...@linaro.org> > Subject: [PATCH V6 00/24] IOREQ feature (+ virtio-mmio) on Arm > > From: Oleksandr Tyshchenko <oleksandr_tyshche...@epam.com> > > Hello all. > > The purpose of this patch series is to add IOREQ/DM support to Xen on Arm. > You can find an initial discussion at [1] and RFC-V5 series at [2]-[7]. > Xen on Arm requires some implementation to forward guest MMIO access to a > device > model in order to implement virtio-mmio backend or even mediator outside of > hypervisor. > As Xen on x86 already contains required support this series tries to make it > common > and introduce Arm specific bits plus some new functionality. Patch series is > based on > Julien's PoC "xen/arm: Add support for Guest IO forwarding to a device > emulator". > Besides splitting existing IOREQ/DM support and introducing Arm side, the > series > also includes virtio-mmio related changes (last 2 patches for toolstack) > for the reviewers to be able to see how the whole picture could look like > and give it a try. > > According to the initial/subsequent discussions there are a few open > questions/concerns regarding security, performance in VirtIO solution: > 1. virtio-mmio vs virtio-pci, SPI vs MSI, or even a composition of > virtio-mmio + > MSI, > different use-cases require different transport... > 2. virtio backend is able to access all guest memory, some kind of protection > is needed: 'virtio-iommu in Xen' vs 'pre-shared-memory & memcpys in guest', > etc > (for these Alex have provided some input at [8]) > 3. interface between toolstack and 'out-of-qemu' virtio backend, avoid using > Xenstore in virtio backend if possible. Also, there is a desire to make > VirtIO > backend hypervisor-agnostic. > 4. a lot of 'foreing mapping' could lead to the memory exhaustion at the host > side, > as we are stealing the page from host memory in order to map the guest > page. > Julien has some idea regarding that. > 5. Julien also has some ideas how to optimize the IOREQ code: > 5.1 vcpu_ioreq_handle_completion (former handle_hvm_io_completion) > which is called in > an hotpath on Arm (everytime we are re-entering to the guest): > Ideally, vcpu_ioreq_handle_completion should be a NOP (at max a few > instructions) > if there is nothing to do (if we don't have I/O forwarded to an IOREQ > server). > Maybe we want to introduce a per-vCPU flag indicating if an I/O has > been > forwarded to an IOREQ server. This would allow us to bypass most of the > function > if there is nothing to do. > 5.2 The current way to handle MMIO is the following: > - Pause the vCPU > - Forward the access to the backend domain > - Schedule the backend domain > - Wait for the access to be handled > - Unpause the vCPU > The sequence is going to be fairly expensive on Xen. > It might be possible to optimize the ACK and avoid to wait for the > backend > to handle the access. > > Looks like all of them are valid and worth considering, but the first thing > which we need on Arm is a mechanism to forward guest IO to a device emulator, > so let's focus on it in the first place. > > *** > > IMPORTANT NOTES: > > 1. Current patch series doesn't contain VirtIO related changes for the > toolstack > (but they are still available at the GitHub repo [9]): > - libxl: Introduce basic virtio-mmio support on Arm > - [RFC] libxl: Add support for virtio-disk configuration > I decided to skip these patches for now since they require some rework (not > Xen > 4.15 materials), > I will resume pushing them once we get *common* IOREQ in. > > 2. There are two new patches (according to the recent discussion) which likely > want Release-Ack: > - xen/ioreq: Do not let bufioreq to be used on other than x86 arches > - xen/ioreq: Make the IOREQ feature selectable on Arm > Also it feels to me that > - xen/dm: Introduce xendevicemodel_set_irq_level DM op > doesn't have all required Acks (at least for toolstack part). > > 3. I didn't manage to test patch-by-patch (in all possible modes for x86 and > Arm) > for this version how I did for all previous versions (due to the limited > time), > but I performed selective build-testing for patches touched and with the whole > series > applied. > > *** > > There are a lot of changes since RFC series, almost all TODOs were resolved on > Arm, > Arm code was improved and hardened, common IOREQ/DM code became really > arch-agnostic > (without HVM-ism), the "legacy" mechanism of mapping magic pages for the > IOREQ servers > was left x86 specific, etc. But one TODO still remains which is "PIO > handling" on > Arm. > The "PIO handling" TODO is expected to left unaddressed for the current > series. > It is not an big issue for now while Xen doesn't have support for vPCI on Arm. > On Arm64 they are only used for PCI IO Bar and we would probably want to > expose > them to emulator as PIO access to make a DM completely arch-agnostic. So > "PIO handling" > should be implemented when we add support for vPCI. > > There are patches on review this series depends on (but it was agreed that > this > series > could go in without them): > https://patchwork.kernel.org/patch/11816689 > https://patchwork.kernel.org/patch/11803383 > > Please note, that IOREQ feature is disabled by default on Arm within current > series, > but there is a possibility to enable it via menuconfig. > > *** > > Patch series [9] was rebased on recent "staging branch" > (6ca5101 x86/boot: Drop 'noapic' suggestion from check_timer()) and tested on > Renesas Salvator-X board + H3 ES3.0 SoC (Arm64) with virtio-mmio disk backend > [10] > running in driver domain and unmodified Linux Guest running on existing > virtio-blk driver (frontend). No issues were observed. Guest domain > 'reboot/destroy' > use-cases work properly. Patch series was only build-tested on x86. > > Please note, build-test passed for the following modes: > 1. x86: CONFIG_HVM=y / CONFIG_IOREQ_SERVER=y (default) > 2. x86: #CONFIG_HVM is not set / #CONFIG_IOREQ_SERVER is not set > 3. Arm64: CONFIG_HVM=y / CONFIG_IOREQ_SERVER=y > 4. Arm64: CONFIG_HVM=y / #CONFIG_IOREQ_SERVER is not set (default) > 5. Arm32: CONFIG_HVM=y / CONFIG_IOREQ_SERVER=y > 6. Arm32: CONFIG_HVM=y / #CONFIG_IOREQ_SERVER is not set (default) > > *** > > Any feedback/help would be highly appreciated. > > [1] https://lists.xenproject.org/archives/html/xen-devel/2020- > 07/msg00825.html > [2] https://lists.xenproject.org/archives/html/xen-devel/2020- > 08/msg00071.html > [3] https://lists.xenproject.org/archives/html/xen-devel/2020- > 09/msg00732.html > [4] https://lists.xenproject.org/archives/html/xen-devel/2020- > 10/msg01077.html > [5] https://lists.xenproject.org/archives/html/xen-devel/2020- > 11/msg02188.html > [6] https://lists.xenproject.org/archives/html/xen-devel/2021- > 01/msg00749.html > [7] https://lists.xenproject.org/archives/html/xen-devel/2021- > 01/msg01899.html > [8] https://lists.xenproject.org/archives/html/xen-devel/2020- > 11/msg02212.html > [9] https://github.com/otyshchenko1/xen/commits/ioreq_4.14_ml7 > [10] https://github.com/otyshchenko1/virtio-disk/commits/ioreq_ml2 > > Julien Grall (3): > xen/ioreq: Make x86's IOREQ related dm-op handling common > xen/mm: Make x86's XENMEM_resource_ioreq_server handling common > arm/ioreq: Introduce arch specific bits for IOREQ/DM features > > Oleksandr Tyshchenko (21): > x86/ioreq: Prepare IOREQ feature for making it common > x86/ioreq: Add IOREQ_STATUS_* #define-s and update code for moving > x86/ioreq: Provide out-of-line wrapper for the handle_mmio() > xen/ioreq: Make x86's IOREQ feature common > xen/ioreq: Make x86's hvm_ioreq_needs_completion() common > xen/ioreq: Make x86's hvm_mmio_first(last)_byte() common > xen/ioreq: Make x86's hvm_ioreq_(page/vcpu/server) structs common > xen/ioreq: Move x86's ioreq_server to struct domain > xen/ioreq: Move x86's io_completion/io_req fields to struct vcpu > xen/ioreq: Remove "hvm" prefixes from involved function names > xen/ioreq: Use guest_cmpxchg64() instead of cmpxchg() > xen/arm: Call vcpu_ioreq_handle_completion() in check_for_vcpu_work() > xen/mm: Handle properly reference in set_foreign_p2m_entry() on Arm > xen/ioreq: Introduce domain_has_ioreq_server() > xen/dm: Introduce xendevicemodel_set_irq_level DM op > xen/arm: io: Abstract sign-extension > xen/arm: io: Harden sign extension check > xen/ioreq: Make x86's send_invalidate_req() common > xen/arm: Add mapcache invalidation handling > xen/ioreq: Do not let bufioreq to be used on other than x86 arches > xen/ioreq: Make the IOREQ feature selectable on Arm > > MAINTAINERS | 9 +- > tools/include/xendevicemodel.h | 4 + > tools/libs/devicemodel/core.c | 18 + > tools/libs/devicemodel/libxendevicemodel.map | 1 + > xen/arch/arm/Makefile | 2 + > xen/arch/arm/dm.c | 149 +++ > xen/arch/arm/domain.c | 9 + > xen/arch/arm/io.c | 30 +- > xen/arch/arm/ioreq.c | 196 ++++ > xen/arch/arm/p2m.c | 51 +- > xen/arch/arm/traps.c | 55 +- > xen/arch/x86/Kconfig | 2 +- > xen/arch/x86/hvm/dm.c | 134 +-- > xen/arch/x86/hvm/emulate.c | 220 ++-- > xen/arch/x86/hvm/hvm.c | 14 +- > xen/arch/x86/hvm/hypercall.c | 9 +- > xen/arch/x86/hvm/intercept.c | 5 +- > xen/arch/x86/hvm/io.c | 52 +- > xen/arch/x86/hvm/ioreq.c | 1368 ++---------------------- > xen/arch/x86/hvm/stdvga.c | 12 +- > xen/arch/x86/hvm/svm/nestedsvm.c | 2 +- > xen/arch/x86/hvm/vmx/realmode.c | 8 +- > xen/arch/x86/hvm/vmx/vvmx.c | 5 +- > xen/arch/x86/mm.c | 46 +- > xen/arch/x86/mm/p2m-ept.c | 1 + > xen/arch/x86/mm/p2m-pt.c | 1 + > xen/arch/x86/mm/p2m.c | 17 +- > xen/arch/x86/mm/shadow/common.c | 2 +- > xen/common/Kconfig | 12 +- > xen/common/Makefile | 2 + > xen/common/dm.c | 55 + > xen/common/ioreq.c | 1429 > ++++++++++++++++++++++++++ > xen/common/memory.c | 72 +- > xen/include/asm-arm/domain.h | 2 + > xen/include/asm-arm/ioreq.h | 70 ++ > xen/include/asm-arm/mmio.h | 1 + > xen/include/asm-arm/p2m.h | 19 +- > xen/include/asm-arm/traps.h | 25 + > xen/include/asm-x86/hvm/domain.h | 45 - > xen/include/asm-x86/hvm/emulate.h | 2 +- > xen/include/asm-x86/hvm/io.h | 17 - > xen/include/asm-x86/hvm/ioreq.h | 39 +- > xen/include/asm-x86/hvm/vcpu.h | 18 - > xen/include/asm-x86/ioreq.h | 39 + > xen/include/asm-x86/mm.h | 4 - > xen/include/asm-x86/p2m.h | 22 +- > xen/include/public/hvm/dm_op.h | 16 + > xen/include/xen/dm.h | 44 + > xen/include/xen/ioreq.h | 140 +++ > xen/include/xen/mm.h | 9 - > xen/include/xen/p2m-common.h | 4 + > xen/include/xen/sched.h | 34 + > xen/include/xsm/dummy.h | 4 +- > xen/include/xsm/xsm.h | 6 +- > xen/xsm/dummy.c | 2 +- > xen/xsm/flask/hooks.c | 5 +- > 56 files changed, 2722 insertions(+), 1837 deletions(-) > create mode 100644 xen/arch/arm/dm.c > create mode 100644 xen/arch/arm/ioreq.c > create mode 100644 xen/common/dm.c > create mode 100644 xen/common/ioreq.c > create mode 100644 xen/include/asm-arm/ioreq.h > create mode 100644 xen/include/asm-x86/ioreq.h > create mode 100644 xen/include/xen/dm.h > create mode 100644 xen/include/xen/ioreq.h > > -- > 2.7.4
