[RFC 07/14] efi_loader: capsule: add memory range capsule definitions

[AKASHI Takahiro <takahiro.akashi@linaro.org>]

On Tue, Mar 17, 2020 at 09:11:43AM +0100, Heinrich Schuchardt wrote:
> On 3/17/20 3:12 AM, AKASHI Takahiro wrote:
> > Memory range capsule gives us a way to notify that some memory regions
> > should be left untouched across the next reset.
> > See UEFI specification, section 8.5.3.
> 
> There are multiple places where RAM availability is tested by writing
> during board bring up. Please, describe which changes are needed in ATF
> and U-Boot to make memory range capsules work reliably.

I think that they are quite system/platform-specific
and that it's beyond the scope of this patch.

Thanks,
-Takahiro Akashi


> Consider also memory encryption provided by some CPUs.
> https://www.tomshardware.com/news/intel-mktme-amd-memory-encryption,39467.html
> 
> Aren't file based capsules a much more reliable way for the OS to
> communicate to the firmware?
> 
> Best regards
> 
> Heinrich
> 
> > 
> > Since how we should handle this kind of capsule is totally up to
> > the system, no implementation will be added in this commit.
> > 
> > Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
> > ---
> >   include/efi_api.h | 17 +++++++++++++++++
> >   1 file changed, 17 insertions(+)
> > 
> > diff --git a/include/efi_api.h b/include/efi_api.h
> > index ac2b38801c0c..b7bf21cac7ad 100644
> > --- a/include/efi_api.h
> > +++ b/include/efi_api.h
> > @@ -221,6 +221,10 @@ enum efi_reset_type {
> >   	EFI_GUID(0x39b68c46, 0xf7fb, 0x441b, 0xb6, 0xec, \
> >   		 0x16, 0xb0, 0xf6, 0x98, 0x21, 0xf3)
> > 
> > +#define EFI_MEMORY_RANGE_CAPSULE_GUID \
> > +	EFI_GUID(0xde9f0ec, 0x88b6, 0x428f, 0x97, 0x7a, \
> > +		 0x25, 0x8f, 0x1d, 0xe, 0x5e, 0x72)
> > +
> >   struct efi_capsule_header {
> >   	efi_guid_t capsule_guid;
> >   	u32 header_size;
> > @@ -236,6 +240,19 @@ struct efi_capsule_result_variable_header {
> >   	efi_status_t capsule_status;
> >   } __packed;
> > 
> > +struct efi_memory_range {
> > +	efi_physical_addr_t	address;
> > +	u64			length;
> > +};
> > +
> > +struct efi_memory_range_capsule {
> > +	struct efi_capsule_header *header;
> > +	/* EFI_MEMORY_TYPE: 0x80000000-0xFFFFFFFF */
> > +	enum efi_mem_type os_requested_memory_type;
> > +	u64 number_of_memory_ranges;
> > +	struct efi_memory_range memory_ranges[];
> > +} __packed;
> > +
> >   #define EFI_RT_SUPPORTED_GET_TIME			0x0001
> >   #define EFI_RT_SUPPORTED_SET_TIME			0x0002
> >   #define EFI_RT_SUPPORTED_GET_WAKEUP_TIME		0x0004
> > 
>