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Message-ID: <d945e654-9679-72d7-bb79-d09c45f6d5aa@quicinc.com>
Date:   Tue, 10 Jan 2023 13:47:42 -0800
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Subject: Re: [PATCH v8 00/28] Drivers for gunyah hypervisor
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To:     Alex Elder <elder@linaro.org>,
        Bjorn Andersson <quic_bjorande@quicinc.com>
CC:     Murali Nalajala <quic_mnalajal@quicinc.com>,
        Trilok Soni <quic_tsoni@quicinc.com>,
        Srivatsa Vaddagiri <quic_svaddagi@quicinc.com>,
        Carl van Schaik <quic_cvanscha@quicinc.com>,
        Prakruthi Deepak Heragu <quic_pheragu@quicinc.com>,
        Arnd Bergmann <arnd@arndb.de>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Rob Herring <robh+dt@kernel.org>,
        "Krzysztof Kozlowski" <krzysztof.kozlowski+dt@linaro.org>,
        Jonathan Corbet <corbet@lwn.net>,
        Bagas Sanjaya <bagasdotme@gmail.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will@kernel.org>,
        Jassi Brar <jassisinghbrar@gmail.com>,
        Sudeep Holla <sudeep.holla@arm.com>,
        Mark Rutland <mark.rutland@arm.com>,
        Lorenzo Pieralisi <lpieralisi@kernel.org>,
        "Dmitry Baryshkov" <dmitry.baryshkov@linaro.org>,
        <linux-arm-msm@vger.kernel.org>, <devicetree@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>, <linux-doc@vger.kernel.org>,
        <linux-arm-kernel@lists.infradead.org>,
        <linux-acpi@vger.kernel.org>
References: <20221219225850.2397345-1-quic_eberman@quicinc.com>
 <83b6dbc2-01da-04b6-64ec-9a69fd5c4c89@linaro.org>
From:   Elliot Berman <quic_eberman@quicinc.com>
In-Reply-To: <83b6dbc2-01da-04b6-64ec-9a69fd5c4c89@linaro.org>
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On 1/9/2023 1:34 PM, Alex Elder wrote:
> On 12/19/22 4:58 PM, Elliot Berman wrote:
>> Gunyah is a Type-1 hypervisor independent of any
>> high-level OS kernel, and runs in a higher CPU privilege level. It does
>> not depend on any lower-privileged OS kernel/code for its core
>> functionality. This increases its security and can support a much smaller
>> trusted computing base than a Type-2 hypervisor.
>>
>> Gunyah is an open source hypervisor. The source repo is available at
>> https://github.com/quic/gunyah-hypervisor.
> 
> Can you provide any history about the hypervisor code itself?
> Was it publicly reviewed?  Has it been reviewed by anyone in
> the Linux kernel community, who might have some useful input
> on it?
> 
>> The diagram below shows the architecture.
>>
>> ::
>>
>>           VM A                    VM B
>>       +-----+ +-----+  | +-----+ +-----+ +-----+
>>       |     | |     |  | |     | |     | |     |
>>   EL0 | APP | | APP |  | | APP | | APP | | APP |
>>       |     | |     |  | |     | |     | |     |
>>       +-----+ +-----+  | +-----+ +-----+ +-----+
>>   ---------------------|-------------------------
>>       +--------------+ | +----------------------+
>>       |              | | |                      |
>>   EL1 | Linux Kernel | | |Linux kernel/Other OS |   ...
>>       |              | | |                      |
>>       +--------------+ | +----------------------+
>>   --------hvc/smc------|------hvc/smc------------
>>       +----------------------------------------+
>>       |                                        |
>>   EL2 |            Gunyah Hypervisor           |
>>       |                                        |
>>       +----------------------------------------+
>>
>> Gunyah provides these following features.
>>
>> - Threads and Scheduling: The scheduler schedules virtual CPUs (VCPUs) on
>> physical CPUs and enables time-sharing of the CPUs.
>> - Memory Management: Gunyah tracks memory ownership and use of all memory
>> under its control. Memory partitioning between VMs is a fundamental
>> security feature.
>> - Interrupt Virtualization: All interrupts are handled in the hypervisor
>> and routed to the assigned VM.
>> - Inter-VM Communication: There are several different mechanisms provided
>> for communicating between VMs.
>> - Device Virtualization: Para-virtualization of devices is supported 
>> using
>> inter-VM communication. Low level system features and devices such as
>> interrupt controllers are supported with emulation where required.
>>
>> This series adds the basic framework for detecting that Linux is running
>> under Gunyah as a virtual machine, communication with the Gunyah Resource
>> Manager, and a virtual machine manager capable of launching virtual 
>> machines.
>>
>> Patches 21-28 are presently intended to be submitted separately and 
>> are included
>> for initial RFC. These patches introudce "VM function" framework to 
>> expose further
>> interfaces to interact with Gunyah Virtual Machines. With all 28 
>> patches, it is
>> possible to create a Gunyah VM supporting virtio.
> 
> I'm not a virtualization expert, and it's likely some of my
> comments demonstrate that...
> 
> You're going to need to update your copyright dates to include
> 2023 now.
> 
> I haven't looked at the earlier reviews; perhaps the RFC stuff
> was requested.  I'm sure it's useful to see that but it doesn't
> seem directly helpful if your goal is to get this code upstream.
> 

Right, the RFC patches were requested. Do you have a recommendation for 
sharing those later patches? I understand it's best practice not to post 
too many patches. The logical split was to have 1-20 go in first, and 
the remaining patches submitted later.

> At this point I've reviewed only through patch 9.  I currently
> have smallish blocks of time and I don't want to hold back my
> feedback for too long.
> 
>                      -Alex
> 
>> Changes in v8:
>>   - Treat VM manager as a library of RM
>>   - Add patches 21-28 as RFC to support proxy-scheduled vCPUs and 
>> necessary bits to support virtio
>>     from Gunyah userspace
>>
>> Changes in v7: 
>> https://lore.kernel.org/all/20221121140009.2353512-1-quic_eberman@quicinc.com/
>>   - Refactor to remove gunyah RM bus
>>   - Refactor allow multiple RM device instances
>>   - Bump UAPI to start at 0x0
>>   - Refactor QCOM SCM's platform hooks to allow 
>> CONFIG_QCOM_SCM=Y/CONFIG_GUNYAH=M combinations
>>
>> Changes in v6: 
>> https://lore.kernel.org/all/20221026185846.3983888-1-quic_eberman@quicinc.com/
>>   - *Replace gunyah-console with gunyah VM Manager*
>>   - Move include/asm-generic/gunyah.h into include/linux/gunyah.h
>>   - s/gunyah_msgq/gh_msgq/
>>   - Minor tweaks and documentation tidying based on comments from 
>> Jiri, Greg, Arnd, Dmitry, and Bagas.
>>
>> Changes in v5: 
>> https://lore.kernel.org/all/20221011000840.289033-1-quic_eberman@quicinc.com/
>>   - Dropped sysfs nodes
>>   - Switch from aux bus to Gunyah RM bus for the subdevices
>>   - Cleaning up RM console
>>
>> Changes in v4: 
>> https://lore.kernel.org/all/20220928195633.2348848-1-quic_eberman@quicinc.com/
>>   - Tidied up documentation throughout based on questions/feedback 
>> received
>>   - Switched message queue implementation to use mailboxes
>>   - Renamed "gunyah_device" as "gunyah_resource"
>>
>> Changes in v3: 
>> https://lore.kernel.org/all/20220811214107.1074343-1-quic_eberman@quicinc.com/
>>   - /Maintained/Supported/ in MAINTAINERS
>>   - Tidied up documentation throughout based on questions/feedback 
>> received
>>   - Moved hypercalls into arch/arm64/gunyah/; following hyper-v's 
>> implementation
>>   - Drop opaque typedefs
>>   - Move sysfs nodes under /sys/hypervisor/gunyah/
>>   - Moved Gunyah console driver to drivers/tty/
>>   - Reworked gunyah_device design to drop the Gunyah bus.
>>
>> Changes in v2: 
>> https://lore.kernel.org/all/20220801211240.597859-1-quic_eberman@quicinc.com/
>>   - DT bindings clean up
>>   - Switch hypercalls to follow SMCCC
>>
>> v1: 
>> https://lore.kernel.org/all/20220223233729.1571114-1-quic_eberman@quicinc.com/
>>
>> Elliot Berman (28):
>>    docs: gunyah: Introduce Gunyah Hypervisor
>>    dt-bindings: Add binding for gunyah hypervisor
>>    gunyah: Common types and error codes for Gunyah hypercalls
>>    arm64: smccc: Include alternative-macros.h
>>    virt: gunyah: Add hypercalls to identify Gunyah
>>    virt: gunyah: Identify hypervisor version
>>    mailbox: Allow direct registration to a channel
>>    virt: gunyah: msgq: Add hypercalls to send and receive messages
>>    mailbox: Add Gunyah message queue mailbox
>>    gunyah: rsc_mgr: Add resource manager RPC core
>>    gunyah: rsc_mgr: Add VM lifecycle RPC
>>    gunyah: vm_mgr: Introduce basic VM Manager
>>    gunyah: rsc_mgr: Add RPC for sharing memory
>>    gunyah: vm_mgr: Add/remove user memory regions
>>    gunyah: vm_mgr: Add ioctls to support basic non-proxy VM boot
>>    samples: Add sample userspace Gunyah VM Manager
>>    gunyah: rsc_mgr: Add platform ops on mem_lend/mem_reclaim
>>    firmware: qcom_scm: Use fixed width src vm bitmap
>>    firmware: qcom_scm: Register Gunyah platform ops
>>    docs: gunyah: Document Gunyah VM Manager
>>    virt: gunyah: Translate gh_rm_hyp_resource into gunyah_resource
>>    gunyah: vm_mgr: Add framework to add VM Functions
>>    virt: gunyah: Add resource tickets
>>    virt: gunyah: Add IO handlers
>>    virt: gunyah: Add proxy-scheduled vCPUs
>>    virt: gunyah: Add hypercalls for sending doorbell
>>    virt: gunyah: Add irqfd interface
>>    virt: gunyah: Add ioeventfd
>>
>>   .../bindings/firmware/gunyah-hypervisor.yaml  |  82 ++
>>   .../userspace-api/ioctl/ioctl-number.rst      |   1 +
>>   Documentation/virt/gunyah/index.rst           | 115 +++
>>   Documentation/virt/gunyah/message-queue.rst   |  64 ++
>>   Documentation/virt/gunyah/vm-manager.rst      | 187 ++++
>>   Documentation/virt/index.rst                  |   1 +
>>   MAINTAINERS                                   |  13 +
>>   arch/arm64/Kbuild                             |   1 +
>>   arch/arm64/gunyah/Makefile                    |   1 +
>>   arch/arm64/gunyah/gunyah_hypercall.c          | 157 ++++
>>   arch/arm64/include/asm/gunyah.h               |  23 +
>>   drivers/firmware/Kconfig                      |   2 +
>>   drivers/firmware/qcom_scm.c                   | 107 ++-
>>   drivers/mailbox/Kconfig                       |  10 +
>>   drivers/mailbox/Makefile                      |   2 +
>>   drivers/mailbox/gunyah-msgq.c                 | 229 +++++
>>   drivers/mailbox/mailbox.c                     |  96 ++-
>>   drivers/mailbox/omap-mailbox.c                |  18 +-
>>   drivers/mailbox/pcc.c                         |  18 +-
>>   drivers/misc/fastrpc.c                        |   6 +-
>>   drivers/net/wireless/ath/ath10k/qmi.c         |   4 +-
>>   drivers/remoteproc/qcom_q6v5_mss.c            |   8 +-
>>   drivers/soc/qcom/rmtfs_mem.c                  |   2 +-
>>   drivers/virt/Kconfig                          |   1 +
>>   drivers/virt/Makefile                         |   1 +
>>   drivers/virt/gunyah/Kconfig                   |  73 ++
>>   drivers/virt/gunyah/Makefile                  |  10 +
>>   drivers/virt/gunyah/gunyah.c                  |  46 +
>>   drivers/virt/gunyah/gunyah_ioeventfd.c        | 109 +++
>>   drivers/virt/gunyah/gunyah_irqfd.c            | 180 ++++
>>   drivers/virt/gunyah/gunyah_platform_hooks.c   |  63 ++
>>   drivers/virt/gunyah/gunyah_vcpu.c             | 350 ++++++++
>>   drivers/virt/gunyah/rsc_mgr.c                 | 795 ++++++++++++++++++
>>   drivers/virt/gunyah/rsc_mgr.h                 | 124 +++
>>   drivers/virt/gunyah/rsc_mgr_rpc.c             | 428 ++++++++++
>>   drivers/virt/gunyah/vm_mgr.c                  | 594 +++++++++++++
>>   drivers/virt/gunyah/vm_mgr.h                  |  76 ++
>>   drivers/virt/gunyah/vm_mgr_mm.c               | 245 ++++++
>>   include/linux/arm-smccc.h                     |   1 +
>>   include/linux/gunyah.h                        | 186 ++++
>>   include/linux/gunyah_rsc_mgr.h                | 136 +++
>>   include/linux/gunyah_vm_mgr.h                 | 107 +++
>>   include/linux/mailbox_client.h                |   1 +
>>   include/linux/qcom_scm.h                      |   2 +-
>>   include/uapi/linux/gunyah.h                   | 114 +++
>>   samples/Kconfig                               |  10 +
>>   samples/Makefile                              |   1 +
>>   samples/gunyah/.gitignore                     |   2 +
>>   samples/gunyah/Makefile                       |   6 +
>>   samples/gunyah/gunyah_vmm.c                   | 270 ++++++
>>   samples/gunyah/sample_vm.dts                  |  69 ++
>>   51 files changed, 5075 insertions(+), 72 deletions(-)
>>   create mode 100644 
>> Documentation/devicetree/bindings/firmware/gunyah-hypervisor.yaml
>>   create mode 100644 Documentation/virt/gunyah/index.rst
>>   create mode 100644 Documentation/virt/gunyah/message-queue.rst
>>   create mode 100644 Documentation/virt/gunyah/vm-manager.rst
>>   create mode 100644 arch/arm64/gunyah/Makefile
>>   create mode 100644 arch/arm64/gunyah/gunyah_hypercall.c
>>   create mode 100644 arch/arm64/include/asm/gunyah.h
>>   create mode 100644 drivers/mailbox/gunyah-msgq.c
>>   create mode 100644 drivers/virt/gunyah/Kconfig
>>   create mode 100644 drivers/virt/gunyah/Makefile
>>   create mode 100644 drivers/virt/gunyah/gunyah.c
>>   create mode 100644 drivers/virt/gunyah/gunyah_ioeventfd.c
>>   create mode 100644 drivers/virt/gunyah/gunyah_irqfd.c
>>   create mode 100644 drivers/virt/gunyah/gunyah_platform_hooks.c
>>   create mode 100644 drivers/virt/gunyah/gunyah_vcpu.c
>>   create mode 100644 drivers/virt/gunyah/rsc_mgr.c
>>   create mode 100644 drivers/virt/gunyah/rsc_mgr.h
>>   create mode 100644 drivers/virt/gunyah/rsc_mgr_rpc.c
>>   create mode 100644 drivers/virt/gunyah/vm_mgr.c
>>   create mode 100644 drivers/virt/gunyah/vm_mgr.h
>>   create mode 100644 drivers/virt/gunyah/vm_mgr_mm.c
>>   create mode 100644 include/linux/gunyah.h
>>   create mode 100644 include/linux/gunyah_rsc_mgr.h
>>   create mode 100644 include/linux/gunyah_vm_mgr.h
>>   create mode 100644 include/uapi/linux/gunyah.h
>>   create mode 100644 samples/gunyah/.gitignore
>>   create mode 100644 samples/gunyah/Makefile
>>   create mode 100644 samples/gunyah/gunyah_vmm.c
>>   create mode 100644 samples/gunyah/sample_vm.dts
>>
>>
>> base-commit: 830b3c68c1fb1e9176028d02ef86f3cf76aa2476
>