Re: [PATCH v2 03/10] backends/confidential-guest-support: Add functions to support IGVM

["Philippe Mathieu-Daudé" <philmd@linaro.org>]

Hi Roy,

On 3/4/24 13:11, Roy Hopkins wrote:
> In preparation for supporting the processing of IGVM files to configure
> guests, this adds a set of functions to ConfidentialGuestSupport
> allowing configuration of secure virtual machines that can be
> implemented for each supported isolation platform type such as Intel TDX
> or AMD SEV-SNP. These functions will be called by IGVM processing code
> in subsequent patches.
> 
> This commit provides a default implementation of the functions that
> either perform no action or generate a warning or error when they are
> called. Targets that support ConfidentalGuestSupport should override
> these implementations.
> 
> Signed-off-by: Roy Hopkins <roy.hopkins@suse.com>
> ---
>   backends/confidential-guest-support.c     | 32 ++++++++++
>   include/exec/confidential-guest-support.h | 74 +++++++++++++++++++++++
>   2 files changed, 106 insertions(+)


>   struct ConfidentialGuestSupport {
>       Object parent;
>   
> @@ -60,6 +94,46 @@ struct ConfidentialGuestSupport {
>        */
>       char *igvm_filename;
>   #endif
> +
> +    /*
> +     * The following virtual methods need to be implemented by systems that
> +     * support confidential guests that can be configured with IGVM and are
> +     * used during processing of the IGVM file with process_igvm().
> +     */
> +
> +    /*
> +     * Check for to see if this confidential guest supports a particular
> +     * platform or configuration
> +     */
> +    int (*check_support)(ConfidentialGuestPlatformType platform,
> +                         uint16_t platform_version, uint8_t highest_vtl,
> +                         uint64_t shared_gpa_boundary);
> +
> +    /*
> +     * Configure part of the state of a guest for a particular set of data, page
> +     * type and gpa. This can be used for example to pre-populate and measure
> +     * guest memory contents, define private ranges or set the initial CPU state
> +     * for one or more CPUs.
> +     *
> +     * If memory_type is CGS_PAGE_TYPE_VMSA then ptr points to the initial CPU
> +     * context for a virtual CPU. The format of the data depends on the type of
> +     * confidential virtual machine. For example, for SEV-ES ptr will point to a
> +     * vmcb_save_area structure that should be copied into guest memory at the
> +     * address specified in gpa. The cpu_index parameter contains the index of
> +     * the CPU the VMSA applies to.
> +     */
> +    int (*set_guest_state)(hwaddr gpa, uint8_t *ptr, uint64_t len,
> +                           ConfidentialGuestPageType memory_type,
> +                           uint16_t cpu_index, Error **errp);
> +
> +    /*
> +     * Iterate the system memory map, getting the entry with the given index
> +     * that can be populated into guest memory.
> +     *
> +     * Returns 0 for ok, 1 if the index is out of range and -1 on error.
> +     */
> +    int (*get_mem_map_entry)(int index, ConfidentialGuestMemoryMapEntry *entry,
> +                             Error **errp);
>   };
>   
>   typedef struct ConfidentialGuestSupportClass {

Methods are usually a class field, not an instance one. Any
reason to diverge from this norm?

Regards,

Phil.