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Message-ID: <de087372-880f-1cf2-5a94-5a4569e98689@quicinc.com>
Date:   Tue, 25 Apr 2023 09:33:06 -0700
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Subject: Re: [PATCH v12 00/25] Drivers for Gunyah hypervisor
To:     Alex Elder <elder@linaro.org>,
        Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
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>,
        Dmitry Baryshkov <dmitry.baryshkov@linaro.org>,
        Bjorn Andersson <andersson@kernel.org>,
        Konrad Dybcio <konrad.dybcio@linaro.org>,
        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>,
        Will Deacon <will@kernel.org>, Andy Gross <agross@kernel.org>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Jassi Brar <jassisinghbrar@gmail.com>,
        <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>
References: <20230424231558.70911-1-quic_eberman@quicinc.com>
Content-Language: en-US
From:   Elliot Berman <quic_eberman@quicinc.com>
In-Reply-To: <20230424231558.70911-1-quic_eberman@quicinc.com>
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On 4/24/2023 4:15 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.
> 
> 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 sample virtual machine manager capable of launching virtual machines.
> 
> The series relies on two other patches posted separately:
>   - https://lore.kernel.org/all/20230213181832.3489174-1-quic_eberman@quicinc.com/
>   - https://lore.kernel.org/all/20230213232537.2040976-2-quic_eberman@quicinc.com/
> 
> Changes in v12:
>   - Stylistic/cosmetic tweaks suggested by Alex
>   - Remove patch "virt: gunyah: Identify hypervisor version" and squash the
>     check that we're running under a reasonable Gunyah hypervisor into RM driver
>   - Refactor platform hooks into a separate module per suggestion from Srini
>   - GFP_KERNEL_ACCOUNT and account_locked_vm() for page pinning
>   - enum-ify related constant
The series is being applied onto the Android Common Kernel android14-6.1 
branch and I've posted a series to bring the branch from v11 to v12. 
This would show what changed between the two versions:

https://android-review.googlesource.com/q/hashtag:%22gunyah-v12%22+(status:open%20OR%20status:merged)

>   - Allow removal of VM functions by function-specific comparison -- specifically to allow
>     removing irqfd by label only and not requiring original FD to be provided.
> 

This last bullet point will be included in v13.

> Changes in v11: https://lore.kernel.org/all/20230304010632.2127470-1-quic_eberman@quicinc.com/
>   - Rename struct gh_vm_dtb_config:gpa -> guest_phys_addr & overflow checks for this
>   - More docstrings throughout
>   - Make resp_buf and resp_buf_size optional
>   - Replace deprecated idr with xarray
>   - Refconting on misc device instead of RM's platform device
>   - Renaming variables, structs, etc. from gunyah_ -> gh_
>   - Drop removal of user mem regions
>   - Drop mem_lend functionality; to converge with restricted_memfd later
> 
> Changes in v10: https://lore.kernel.org/all/20230214211229.3239350-1-quic_eberman@quicinc.com/
>   - Fix bisectability (end result of series is same, --fixups applied to wrong commits)
>   - Convert GH_ERROR_* and GH_RM_ERROR_* to enums
>   - Correct race condition between allocating/freeing user memory
>   - Replace offsetof with struct_size
>   - Series-wide renaming of functions to be more consistent
>   - VM shutdown & restart support added in vCPU and VM Manager patches
>   - Convert VM function name (string) to type (number)
>   - Convert VM function argument to value (which could be a pointer) to remove memory wastage for arguments
>   - Remove defensive checks of hypervisor correctness
>   - Clean ups to ioeventfd as suggested by Srivatsa
> 
> Changes in v9: https://lore.kernel.org/all/20230120224627.4053418-1-quic_eberman@quicinc.com/
>   - Refactor Gunyah API flags to be exposed as feature flags at kernel level
>   - Move mbox client cleanup into gunyah_msgq_remove()
>   - Simplify gh_rm_call return value and response payload
>   - Missing clean-up/error handling/little endian fixes as suggested by Srivatsa and Alex in v8 series
> 
> Changes in v8: https://lore.kernel.org/all/20221219225850.2397345-1-quic_eberman@quicinc.com/
>   - 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 gh_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 (25):
>    docs: gunyah: Introduce Gunyah Hypervisor
>    dt-bindings: Add binding for gunyah hypervisor
>    gunyah: Common types and error codes for Gunyah hypercalls
>    virt: gunyah: Add hypercalls to identify Gunyah
>    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: 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 for 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
>    MAINTAINERS: Add Gunyah hypervisor drivers section
> 
>   .../bindings/firmware/gunyah-hypervisor.yaml  |  82 ++
>   .../userspace-api/ioctl/ioctl-number.rst      |   1 +
>   Documentation/virt/gunyah/index.rst           | 114 +++
>   Documentation/virt/gunyah/message-queue.rst   |  71 ++
>   Documentation/virt/gunyah/vm-manager.rst      | 142 +++
>   Documentation/virt/index.rst                  |   1 +
>   MAINTAINERS                                   |  13 +
>   arch/arm64/Kbuild                             |   1 +
>   arch/arm64/gunyah/Makefile                    |   3 +
>   arch/arm64/gunyah/gunyah_hypercall.c          | 140 +++
>   arch/arm64/include/asm/gunyah.h               |  24 +
>   drivers/mailbox/Makefile                      |   2 +
>   drivers/mailbox/gunyah-msgq.c                 | 210 ++++
>   drivers/virt/Kconfig                          |   2 +
>   drivers/virt/Makefile                         |   1 +
>   drivers/virt/gunyah/Kconfig                   |  59 ++
>   drivers/virt/gunyah/Makefile                  |  11 +
>   drivers/virt/gunyah/gunyah_ioeventfd.c        | 117 +++
>   drivers/virt/gunyah/gunyah_irqfd.c            | 167 ++++
>   drivers/virt/gunyah/gunyah_platform_hooks.c   |  80 ++
>   drivers/virt/gunyah/gunyah_qcom.c             | 147 +++
>   drivers/virt/gunyah/gunyah_vcpu.c             | 456 +++++++++
>   drivers/virt/gunyah/rsc_mgr.c                 | 910 ++++++++++++++++++
>   drivers/virt/gunyah/rsc_mgr.h                 |  19 +
>   drivers/virt/gunyah/rsc_mgr_rpc.c             | 500 ++++++++++
>   drivers/virt/gunyah/vm_mgr.c                  | 792 +++++++++++++++
>   drivers/virt/gunyah/vm_mgr.h                  |  70 ++
>   drivers/virt/gunyah/vm_mgr_mm.c               | 256 +++++
>   include/linux/gunyah.h                        | 207 ++++
>   include/linux/gunyah_rsc_mgr.h                | 162 ++++
>   include/linux/gunyah_vm_mgr.h                 | 124 +++
>   include/uapi/linux/gunyah.h                   | 293 ++++++
>   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                  |  68 ++
>   38 files changed, 5534 insertions(+)
>   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_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_qcom.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: d71ee0d6ee72138dd4fda646a955a15286c46544