On Wed, 26 Jun 2019 at 14:17, <Narendra.K@xxxxxxxx> wrote:
>
> On Tue, Jun 25, 2019 at 04:21:33PM +0200, Ard Biesheuvel wrote:
> [...]
> > > > > --- a/drivers/firmware/efi/efi.c
> > > > > +++ b/drivers/firmware/efi/efi.c
> > > > > @@ -53,6 +53,7 @@ struct efi __read_mostly efi = {
> > > > > .rng_seed = EFI_INVALID_TABLE_ADDR,
> > > > > .tpm_log = EFI_INVALID_TABLE_ADDR,
> > > > > .mem_reserve = EFI_INVALID_TABLE_ADDR,
> > > > > + .rci2 = EFI_INVALID_TABLE_ADDR,
> > > >
> > > > Does this really need to live in the efi struct?
> > >
> > > It probably need not be part of struct efi. We could define a struct of
> > > type 'efi_config_table_type_t' in the rci2_table.c. Did you have a
> > > similar idea in mind ? If yes, I will modify and test this idea.
> > >
> >
> > Yes, I'd like to start keeping these things separate.
> >
> > I pushed a branch here
> >
> > https://git.kernel.org/pub/scm/linux/kernel/git/efi/efi.git/log/?h=next
> >
> > that changes the way uv_systab is handled, and moves it into arch/x86.
> > Please follow that pattern instead.
>
> Okay. Thank you for the guidance. I will make this change in the next version.
>
> >
> > > >
> > > > > };
> > > > > EXPORT_SYMBOL(efi);
> > > > >
> > > > > @@ -73,6 +74,7 @@ static unsigned long *efi_tables[] = {
> > > > > &efi.esrt,
> > > > > &efi.properties_table,
> > > > > &efi.mem_attr_table,
> > > > > + &efi.rci2,
> > > > > };
> > > > >
> > > >
> > > > AFAICT, this table is only used by memremap_is_efi_data() to decide
> > > > whether a page should be map as unencrypted, and if the address is in
> > > > boot services data or runtime services data, the test will already
> > > > success, regardless of whether it appears in this enumeration.
> > >
> > > Yes. Before 'memremap_is_efi_data()' checks if the memory type is boot
> > > services data for runtime services data, it checks if the address is a
> > > 'table' address in 'efi_is_table_address'. I added it because of this
> > > check. Since the memory type used for the table is efi reserved type, we
> > > need to add the table address to 'efi_tables' array so that it could be
> > > checked in 'efi_is_table_address'. Please share your thought on this.
> > >
> >
> > OK. My branch ^^^ moves this into arch/x86 as well, please add it there
>
> I have a query related to this change. I will discuss it in next section
> below as it helps provide complete context.
>
> > > > > @@ -488,6 +493,12 @@ static __initdata efi_config_table_type_t common_tables[] = {
> > > > > {NULL_GUID, NULL, NULL},
> > > > > };
> > > > >
> > > > > +/* OEM Tables */
> > > > > +static __initdata efi_config_table_type_t oem_tables[] = {
> > > > > + {DELLEMC_EFI_RCI2_TABLE_GUID, "RCI2", &efi.rci2},
> > > >
> > > > Please drop the string. We don't have to print the presence of this
> > > > table in the bootlog since it has no significance to the OS itself.
> > >
> > > Okay. I will drop this in the next version of the patch.
> > >
> > > >
> > > > > + {NULL_GUID, NULL, NULL},
> > > > > +};
> > > > > +
> > > >
> > > > Do we really need a separate oem_tables[] array?
> > >
> > > The RCI2 table did not seem to be part of the group of common tables
> > > such as SMBIOS and ACPI. To indicate this, I created a separate array.
> > > It seems like it is not required. Having the array allows to leverage
> > > the table matching code in 'match_config_table' function. Would you prefer
> > > to have this entry added to the 'common_tables' array ?
> > >
> >
> > Please add it to the arch_tables array in arch/x86 (if my assumption
> > is correct that this is x86-only)
>
> The table is used on x86. But it is not specific to x86 and is
> independent of the architecture. Because of this detail, my thinking is
> to keep the rci2_table.c and related changes in generic efi layer
> drivers/firmware/efi/. If we keep the changes in drivers/firmware/efi/,
> then two options are
>
> 1. Retain the oem_tables array and add rci2 table address to this array
> 2. Add rci2 table address to common_tables array
>
> Does this detail sound correct ?
>
Yes, and I'd prefer the latter.
> Also, since the 'efi_is_table_address' function and efi_tables array are moved
> to arch/x86, for rci2 table address to be detected as a table address, it needs to be
> added to 'efi_tables' array. Would it be correct to add rci2 table
> address to this array with rest of the changes residing in the generic efi
> layer ?
>
Yes.
> Please share your thoughts on the two details.
>
> [...]
> > > Would you prefer to merge this function into 'efi_rci2_sysfs_init' function ?
> > >
> >
> > Yes. Only user space needs to access this, so we can defer this to
> > later, when the normal memremap() functions are available.
> >
>
> Okay, I will make this change in the next version.
>
> --
> With regards,
> Narendra K
