2023-07-25 07:31:14

by Jan Beulich

Subject: Re: [PATCH V3 1/2] xen: Update dm_op.h from Xen public header

On 25.07.2023 08:47, Viresh Kumar wrote:
> +struct xen_dm_op {
> + uint32_t op;
> + uint32_t pad;
> + union {
> + struct xen_dm_op_create_ioreq_server create_ioreq_server;
> + struct xen_dm_op_get_ioreq_server_info get_ioreq_server_info;
> + struct xen_dm_op_ioreq_server_range map_io_range_to_ioreq_server;
> + struct xen_dm_op_ioreq_server_range unmap_io_range_from_ioreq_server;
> + struct xen_dm_op_set_ioreq_server_state set_ioreq_server_state;
> + struct xen_dm_op_destroy_ioreq_server destroy_ioreq_server;
> + struct xen_dm_op_track_dirty_vram track_dirty_vram;
> + struct xen_dm_op_set_pci_intx_level set_pci_intx_level;
> + struct xen_dm_op_set_isa_irq_level set_isa_irq_level;
> + struct xen_dm_op_set_irq_level set_irq_level;
> + struct xen_dm_op_set_pci_link_route set_pci_link_route;
> + struct xen_dm_op_modified_memory modified_memory;
> + struct xen_dm_op_set_mem_type set_mem_type;
> + struct xen_dm_op_inject_event inject_event;
> + struct xen_dm_op_inject_msi inject_msi;
> + struct xen_dm_op_map_mem_type_to_ioreq_server map_mem_type_to_ioreq_server;
> + struct xen_dm_op_remote_shutdown remote_shutdown;
> + struct xen_dm_op_relocate_memory relocate_memory;
> + struct xen_dm_op_pin_memory_cacheattr pin_memory_cacheattr;
> + struct xen_dm_op_nr_vcpus nr_vcpus;
> + } u;
> +};

Is sync-ing for the sake of sync-ing really useful? For example, are any
of the ioreq server elements halfway likely to ever be used in the kernel?

Jan

2023-07-25 07:53:04

by Viresh Kumar

Subject: Re: [PATCH V3 1/2] xen: Update dm_op.h from Xen public header

On 25-07-23, 09:04, Jan Beulich wrote:
> On 25.07.2023 08:47, Viresh Kumar wrote:
> > +struct xen_dm_op {
> > + uint32_t op;
> > + uint32_t pad;
> > + union {
> > + struct xen_dm_op_create_ioreq_server create_ioreq_server;
> > + struct xen_dm_op_get_ioreq_server_info get_ioreq_server_info;
> > + struct xen_dm_op_ioreq_server_range map_io_range_to_ioreq_server;
> > + struct xen_dm_op_ioreq_server_range unmap_io_range_from_ioreq_server;
> > + struct xen_dm_op_set_ioreq_server_state set_ioreq_server_state;
> > + struct xen_dm_op_destroy_ioreq_server destroy_ioreq_server;
> > + struct xen_dm_op_track_dirty_vram track_dirty_vram;
> > + struct xen_dm_op_set_pci_intx_level set_pci_intx_level;
> > + struct xen_dm_op_set_isa_irq_level set_isa_irq_level;
> > + struct xen_dm_op_set_irq_level set_irq_level;
> > + struct xen_dm_op_set_pci_link_route set_pci_link_route;
> > + struct xen_dm_op_modified_memory modified_memory;
> > + struct xen_dm_op_set_mem_type set_mem_type;
> > + struct xen_dm_op_inject_event inject_event;
> > + struct xen_dm_op_inject_msi inject_msi;
> > + struct xen_dm_op_map_mem_type_to_ioreq_server map_mem_type_to_ioreq_server;
> > + struct xen_dm_op_remote_shutdown remote_shutdown;
> > + struct xen_dm_op_relocate_memory relocate_memory;
> > + struct xen_dm_op_pin_memory_cacheattr pin_memory_cacheattr;
> > + struct xen_dm_op_nr_vcpus nr_vcpus;
> > + } u;
> > +};
>
> Is sync-ing for the sake of sync-ing really useful? For example, are any
> of the ioreq server elements halfway likely to ever be used in the kernel?

The only field, out of the union, I am using for now is:

struct xen_dm_op_set_irq_level set_irq_level;

I am not sure if some of the others are going to be used or not in the
future.

FWIW, I am also looking at solving a similar problem for Ioeventfds
(kick from guest to backend) and may end up using a few more of these.
But they can very well be contained in that patchset.

--
viresh