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

["Daniel P. Berrangé" <berrange@redhat.com>]

On Thu, Apr 04, 2024 at 10:00:53AM +0200, Philippe Mathieu-Daudé wrote:
> 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?

Agreed, this should all be against the Class.


With regards,
Daniel
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