On 2/7/2023 6:43 AM, Srinivas Kandagatla wrote:

On 20/01/2023 22:46, Elliot Berman wrote:

quoted

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 <redacted>
Signed-off-by: Prakruthi Deepak Heragu <redacted>
Signed-off-by: Elliot Berman <redacted>
---
  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

...

quoted

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.

This structure gets mapped into userspace from the vCPU file descriptor, 
similar principle to KVM.

Thanks,
Elliot

quoted

+    /* 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.

quoted

+
+    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

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