Re: [RFC PATCH v4 14/28] Add support to access boot related data in the clear

[Tom Lendacky]

On 3/8/2017 12:55 AM, Dave Young wrote:
> On 02/16/17 at 09:45am, Tom Lendacky wrote:
> [snip]
> > + * This function determines if an address should be mapped encrypted.
> > + * Boot setup data, EFI data and E820 areas are checked in making this
> > + * determination.
> > + */
> > +static bool memremap_should_map_encrypted(resource_size_t phys_addr,
> > +					  unsigned long size)
> > +{
> > +	/*
> > +	 * SME is not active, return true:
> > +	 *   - For early_memremap_pgprot_adjust(), returning true or false
> > +	 *     results in the same protection value
> > +	 *   - For arch_memremap_do_ram_remap(), returning true will allow
> > +	 *     the RAM remap to occur instead of falling back to ioremap()
> > +	 */
> > +	if (!sme_active())
> > +		return true;
>
> From the function name shouldn't above be return false?

I've re-worked this so that the check is in a different location and
doesn't cause confusion.

> > +
> > +	/* Check if the address is part of the setup data */
> > +	if (memremap_is_setup_data(phys_addr, size))
> > +		return false;
> > +
> > +	/* Check if the address is part of EFI boot/runtime data */
> > +	switch (efi_mem_type(phys_addr)) {
> > +	case EFI_BOOT_SERVICES_DATA:
> > +	case EFI_RUNTIME_SERVICES_DATA:
>
> Only these two types needed? I'm not sure about this, just bring up the
> question.

I've re-worked this code so that there is a single EFI routine that
checks boot_params.efi_info.efi_memmap/efi_systab, EFI tables and the
EFI memtype.  As for the EFI memtypes, I believe those are the only
ones required.  Some of the other types will be picked up by the e820
checks (ACPI, NVS, etc.).

Thanks,
Tom

> > +		return false;
> > +	default:
> > +		break;
> > +	}
> > +
> > +	/* Check if the address is outside kernel usable area */
> > +	switch (e820__get_entry_type(phys_addr, phys_addr + size - 1)) {
> > +	case E820_TYPE_RESERVED:
> > +	case E820_TYPE_ACPI:
> > +	case E820_TYPE_NVS:
> > +	case E820_TYPE_UNUSABLE:
> > +		return false;
> > +	default:
> > +		break;
> > +	}
> > +
> > +	return true;
> > +}
> > +
>
> Thanks
> Dave