| Message ID | 20220928195633.2348848-1-quic_eberman@quicinc.com |
|---|---|
| Headers | show |
| Series | Drivers for gunyah hypervisor | expand |
On Sun, 2022-10-02 at 16:30 -0700, Jeff Johnson wrote: > On 9/29/2022 12:36 AM, Joe Perches wrote: > > On Wed, 2022-09-28 at 12:56 -0700, Elliot Berman wrote: > > > Add a sysfs node to list the features that the Gunyah hypervisor and > > > Linux supports. For now, Linux support cspace (capability IDs) and > > > message queues, so only report those.. > > [] > > > diff --git a/drivers/virt/gunyah/sysfs.c b/drivers/virt/gunyah/sysfs.c > > [] > > > @@ -25,9 +25,24 @@ static ssize_t variant_show(struct kobject *kobj, struct kobj_attribute *attr, c > > > } > > > static struct kobj_attribute variant_attr = __ATTR_RO(variant); > > > > > > +static ssize_t features_show(struct kobject *kobj, struct kobj_attribute *attr, char *buffer) > > > +{ > > > + int len = 0; > > > + > > > + if (GH_IDENTIFY_PARTITION_CSPACE(gunyah_api.flags)) > > > + len += sysfs_emit_at(buffer, len, "cspace "); > > > + if (GH_IDENTIFY_MSGQUEUE(gunyah_api.flags)) > > > + len += sysfs_emit_at(buffer, len, "message-queue "); > > > + > > > + len += sysfs_emit_at(buffer, len, "\n"); > > > + return len; > > > +} > > > > It's generally nicer to avoid unnecessary output spaces. > > > > Perhaps: > > > > { > > int len = 0; > > > > if (GH_IDENTIFY_PARTITION_CSPACE(gunyah_api.flags)) > > len += sysfs_emit_at(buffer, len, "cspace"); > > if (GH_IDENTIFY_MSGQUEUE(gunyah_api.flags)) { > > if (len) > > len += sysfs_emit_at(buffer, len, " "); > > len += sysfs_emit_at(buffer, len, "message-queue"); > > } > > > > len += sysfs_emit_at(buffer, len, "\n"); > > > > return len; > > } > > > > that approach seems ok for 2 features, but imo doesn't scale for more. > I like the original code with one exception: > > if (GH_IDENTIFY_PARTITION_CSPACE(gunyah_api.flags)) > len += sysfs_emit_at(buffer, len, "cspace "); > if (GH_IDENTIFY_MSGQUEUE(gunyah_api.flags)) > len += sysfs_emit_at(buffer, len, "message-queue "); > > /* overwrite last trailing space */ > if (len) > len--; > > len += sysfs_emit_at(buffer, len, "\n"); > return len; > That's fine as long as every formatted output uses a trailing space. A trivial negative would be that the linker would generally not be able to deduplicate these output strings with trailing spaces across the entire codebase.
On 9/30/2022 5:06 AM, Greg Kroah-Hartman wrote: > On Wed, Sep 28, 2022 at 12:56:29PM -0700, Elliot Berman wrote: >> Add a sysfs node to list the features that the Gunyah hypervisor and >> Linux supports. For now, Linux support cspace (capability IDs) and >> message queues, so only report those.. >> >> Signed-off-by: Elliot Berman <quic_eberman@quicinc.com> >> --- >> Documentation/ABI/testing/sysfs-hypervisor-gunyah | 15 +++++++++++++++ >> drivers/virt/gunyah/sysfs.c | 15 +++++++++++++++ >> 2 files changed, 30 insertions(+) >> >> diff --git a/Documentation/ABI/testing/sysfs-hypervisor-gunyah b/Documentation/ABI/testing/sysfs-hypervisor-gunyah >> index 7d74e74e9edd..6d0cde30355a 100644 >> --- a/Documentation/ABI/testing/sysfs-hypervisor-gunyah >> +++ b/Documentation/ABI/testing/sysfs-hypervisor-gunyah >> @@ -1,3 +1,18 @@ >> +What: /sys/hypervisor/gunyah/features >> +Date: October 2022 >> +KernelVersion: 6.1 >> +Contact: linux-arm-msm@vger.kernel.org >> +Description: If running under Gunyah: >> + Space separated list of features supported by Linux and Gunyah: >> + "cspace": Gunyah devices >> + "doorbell": Sending/receiving virtual interrupts via Gunyah doorbells >> + "message-queue": Sending/receiving messages via Gunyah message queues >> + "vic": Interrupt lending >> + "vpm": Virtual platform management >> + "vcpu": Virtual CPU management >> + "memextent": Memory lending/management >> + "trace": Gunyah hypervisor tracing > > Please no. Why do you really need this type of list? What hypervisor > will NOT have them all present already? Who will use this file and what > will it be used for? > > sysfs files should just be 1 value and not need to be parsed. Yes, we > have lists of features at times, but really, you need a very very good > reason why this is the only way this information can be exposed and who > is going to use it in order to be able to have this accepted. > We're currently at phase where all the features implemented so far as considered part of the "base" featureset. We're thinking of future features implemented in Gunyah: userspace might need to know that some hypervisor feature is present and that it should make use of the feature instead of some fallback behavior. I can drop this and it should be OK IMO to introduce it later if needed. The lack of the "gunyah/features" node would be sufficient for a userspace program to know that some new feature isn't present. > thanks, > > greg k-h
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 tty driver to demonstrate end-to-end use case of communicating with RM. Presently, the TTY driver is only capable of behaving as a loopback device: data sent to ttyGH0 shows up in ttyGH1 and vice versa. More Gunyah consoles can be exposed as Linux learns about other VMs running in Gunyah. In a future series, I'll introduce a Gunyah VM loader which can load and run VMs. This loader will follow the design philosophy of the /dev/kvm. Changes in v4: - 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 (14): 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: Add sysfs nodes mailbox: Allow direct registration to a channel virt: gunyah: msgq: Add hypercalls to send and receive messages mailbox: Add Gunyah message queue mailbox gunyah: sysfs: Add node to describe supported features gunyah: rsc_mgr: Add resource manager RPC core gunyah: rsc_mgr: Add RPC for console services gunyah: rsc_mgr: Add auxiliary devices for console tty: gunyah: Add tty console driver for RM Console Services .../ABI/testing/sysfs-hypervisor-gunyah | 30 + .../bindings/firmware/gunyah-hypervisor.yaml | 87 +++ Documentation/virt/gunyah/index.rst | 114 ++++ Documentation/virt/gunyah/message-queue.rst | 52 ++ Documentation/virt/index.rst | 1 + MAINTAINERS | 15 + arch/arm64/Kbuild | 1 + arch/arm64/gunyah/Makefile | 2 + arch/arm64/gunyah/hypercall.c | 104 +++ drivers/mailbox/Kconfig | 10 + drivers/mailbox/Makefile | 2 + drivers/mailbox/gunyah-msgq.c | 232 +++++++ drivers/mailbox/mailbox.c | 96 ++- drivers/tty/Kconfig | 8 + drivers/tty/Makefile | 1 + drivers/tty/gunyah_tty.c | 409 ++++++++++++ drivers/virt/Kconfig | 2 + drivers/virt/Makefile | 1 + drivers/virt/gunyah/Kconfig | 30 + drivers/virt/gunyah/Makefile | 5 + drivers/virt/gunyah/rsc_mgr.c | 629 ++++++++++++++++++ drivers/virt/gunyah/rsc_mgr.h | 56 ++ drivers/virt/gunyah/rsc_mgr_rpc.c | 151 +++++ drivers/virt/gunyah/sysfs.c | 86 +++ include/asm-generic/gunyah.h | 115 ++++ include/linux/arm-smccc.h | 1 + include/linux/gunyah.h | 67 ++ include/linux/gunyah_rsc_mgr.h | 42 ++ include/linux/mailbox_client.h | 1 + 29 files changed, 2322 insertions(+), 28 deletions(-) create mode 100644 Documentation/ABI/testing/sysfs-hypervisor-gunyah 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 arch/arm64/gunyah/Makefile create mode 100644 arch/arm64/gunyah/hypercall.c create mode 100644 drivers/mailbox/gunyah-msgq.c create mode 100644 drivers/tty/gunyah_tty.c create mode 100644 drivers/virt/gunyah/Kconfig create mode 100644 drivers/virt/gunyah/Makefile 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/sysfs.c create mode 100644 include/asm-generic/gunyah.h create mode 100644 include/linux/gunyah.h create mode 100644 include/linux/gunyah_rsc_mgr.h base-commit: f76349cf41451c5c42a99f18a9163377e4b364ff