Re: [PATCH v10 09/26] gunyah: rsc_mgr: Add VM lifecycle RPC

[Elliot Berman]

On 2/15/2023 10:39 PM, Greg Kroah-Hartman wrote:
> On Tue, Feb 14, 2023 at 01:23:42PM -0800, Elliot Berman wrote:
> > Add Gunyah Resource Manager RPC to launch an unauthenticated VM.
> >
> > Signed-off-by: Elliot Berman <quic_eberman@xxxxxxxxxxx>
> > ---
> >   drivers/virt/gunyah/Makefile      |   2 +-
> >   drivers/virt/gunyah/rsc_mgr.h     |  45 ++++++
> >   drivers/virt/gunyah/rsc_mgr_rpc.c | 226 ++++++++++++++++++++++++++++++
> >   include/linux/gunyah_rsc_mgr.h    |  73 ++++++++++
> >   4 files changed, 345 insertions(+), 1 deletion(-)
> >   create mode 100644 drivers/virt/gunyah/rsc_mgr_rpc.c
> >
> > diff --git a/drivers/virt/gunyah/Makefile b/drivers/virt/gunyah/Makefile
> > index cc864ff5abbb..de29769f2f3f 100644
> > --- a/drivers/virt/gunyah/Makefile
> > +++ b/drivers/virt/gunyah/Makefile
> > @@ -2,5 +2,5 @@
> >   
> >   obj-$(CONFIG_GUNYAH) += gunyah.o
> >   
> > -gunyah_rsc_mgr-y += rsc_mgr.o
> > +gunyah_rsc_mgr-y += rsc_mgr.o rsc_mgr_rpc.o
> >   obj-$(CONFIG_GUNYAH) += gunyah_rsc_mgr.o
> > diff --git a/drivers/virt/gunyah/rsc_mgr.h b/drivers/virt/gunyah/rsc_mgr.h
> > index d4e799a7526f..7406237bc66d 100644
> > --- a/drivers/virt/gunyah/rsc_mgr.h
> > +++ b/drivers/virt/gunyah/rsc_mgr.h
> > @@ -74,4 +74,49 @@ struct gh_rm;
> >   int gh_rm_call(struct gh_rm *rsc_mgr, u32 message_id, void *req_buff, size_t req_buff_size,
> >   		void **resp_buf, size_t *resp_buff_size);
> >   
> > +/* Message IDs: VM Management */
> > +#define GH_RM_RPC_VM_ALLOC_VMID			0x56000001
> > +#define GH_RM_RPC_VM_DEALLOC_VMID		0x56000002
> > +#define GH_RM_RPC_VM_START			0x56000004
> > +#define GH_RM_RPC_VM_STOP			0x56000005
> > +#define GH_RM_RPC_VM_RESET			0x56000006
> > +#define GH_RM_RPC_VM_CONFIG_IMAGE		0x56000009
> > +#define GH_RM_RPC_VM_INIT			0x5600000B
> > +#define GH_RM_RPC_VM_GET_HYP_RESOURCES		0x56000020
> > +#define GH_RM_RPC_VM_GET_VMID			0x56000024
> > +
> > +struct gh_rm_vm_common_vmid_req {
> > +	__le16 vmid;
> > +	__le16 reserved0;
>
> reserved for what?  What is a valid value for this field?  Should it be
> checked for 0?

This struct is transmitted "over the wire" and RM makes all of its 
structures 4-byte aligned. The reserved fields are padding for this 
alignment and will be zero but don't need to be checked. Linux 
initializes the reserved fields to zero.

> Same with other "reserved0" fields in this file.
>
>
> > +} __packed;
> > +
> > +/* Call: VM_ALLOC */
> > +struct gh_rm_vm_alloc_vmid_resp {
> > +	__le16 vmid;
> > +	__le16 reserved0;
> > +} __packed;
> > +
> > +/* Call: VM_STOP */
> > +struct gh_rm_vm_stop_req {
> > +	__le16 vmid;
> > +#define GH_RM_VM_STOP_FLAG_FORCE_STOP	BIT(0)
> > +	u8 flags;
> > +	u8 reserved;
>
> Why just "reserved" and not "reserved0"?  Naming is hard :(

Some fields have multiple reserved fields. I'll clean up so "reserved0" 
only appears when there are multiple padding fields.

Thanks,
Elliot