Re: [PATCH v9 24/27] virt: gunyah: Add proxy-scheduled vCPUs

Srinivas Kandagatla
2023-02-07T14:44:23Z

On 20/01/2023 22:46, Elliot Berman wrote:
> Gunyah allows host virtual machines to schedule guest virtual machines
> and handle their MMIO accesses. vCPUs are presented to the host as a
> Gunyah resource and represented to userspace as a Gunyah VM function.
>
> Creating the vcpu VM function will create a file descriptor that:
> - can run an ioctl: GH_VCPU_RUN to schedule the guest vCPU until the
> next interrupt occurs on the host or when the guest vCPU can no
> longer be run.
> - can be mmap'd to share a gh_vcpu_run structure which can look up the
> reason why GH_VCPU_RUN returned and provide return values for MMIO
> access.
>
> Co-developed-by: Prakruthi Deepak Heragu <quic_pheragu@quicinc.com>
> Signed-off-by: Prakruthi Deepak Heragu <quic_pheragu@quicinc.com>
> Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
> ---
> Documentation/virt/gunyah/vm-manager.rst | 30 +-
> arch/arm64/gunyah/gunyah_hypercall.c | 28 ++
> drivers/virt/gunyah/Kconfig | 11 +
> drivers/virt/gunyah/Makefile | 2 +
> drivers/virt/gunyah/gunyah_vcpu.c | 358 +++++++++++++++++++++++
> drivers/virt/gunyah/vm_mgr.c | 25 ++
> drivers/virt/gunyah/vm_mgr.h | 1 +
> include/linux/gunyah.h | 7 +
> include/uapi/linux/gunyah.h | 30 ++
> 9 files changed, 490 insertions(+), 2 deletions(-)
> create mode 100644 drivers/virt/gunyah/gunyah_vcpu.c
>
...

> diff --git a/include/uapi/linux/gunyah.h b/include/uapi/linux/gunyah.h
> index ec8da6fde045..b4afb11f538a 100644
> --- a/include/uapi/linux/gunyah.h
> +++ b/include/uapi/linux/gunyah.h
> @@ -53,9 +53,14 @@ struct gh_vm_dtb_config {
> #define GUNYAH_FUNCTION_NAME_SIZE 32
> #define GUNYAH_FUNCTION_MAX_ARG_SIZE 1024
>
> +struct gh_fn_vcpu_arg {
> + __u32 vcpu_id;
> +};
> +
> struct gh_vm_function {
> char name[GUNYAH_FUNCTION_NAME_SIZE];
> union {
> + struct gh_device_vcpu_arg vcpu;
> char data[GUNYAH_FUNCTION_MAX_ARG_SIZE];
> };
> };
> @@ -63,4 +68,29 @@ struct gh_vm_function {
> #define GH_VM_ADD_FUNCTION _IOW(GH_IOCTL_TYPE, 0x4, struct gh_vm_function)
> #define GH_VM_REMOVE_FUNCTION _IOW(GH_IOCTL_TYPE, 0x7, struct gh_vm_function)
>
> +/* for GH_VCPU_RUN, returned by mmap(vcpu_fd, offset=0) */
> +struct gh_vcpu_run {
this looks unused, I dont see any reference to this.

> + /* in */
> + __u8 immediate_exit;
> + __u8 padding1[7];
> +
> + /* out */
> +#define GH_VM_EXIT_UNKNOWN 0
> +#define GH_VM_EXIT_MMIO 1
> + __u32 exit_reason;

If this is ment to go in any of the ioctl arguments then this suffers
same issue of padding.

> +
> + union {
> + /* GH_VM_EXIT_MMIO */
> + struct {
> + __u64 phys_addr;
> + __u8 data[8];
> + __u32 len;
> + __u8 is_write;
> + } mmio;
> + };
> +};
> +
> +#define GH_VCPU_RUN _IO(GH_IOCTL_TYPE, 0x5)
> +#define GH_VCPU_MMAP_SIZE _IO(GH_IOCTL_TYPE, 0x6)
> +
> #endif