Thread (26 messages) 26 messages, 5 authors, 2023-03-25

Re: [PATCHv8 06/14] efi/x86: Implement support for unaccepted memory

From: Kirill A. Shutemov <hidden>
Date: 2023-03-25 00:52:08
Also in: linux-efi, linux-mm, lkml

On Tue, Jan 03, 2023 at 03:20:55PM +0100, Borislav Petkov wrote:
quoted
diff --git a/drivers/firmware/efi/Kconfig b/drivers/firmware/efi/Kconfig
index 6787ed8dfacf..8aa8adf0bcb5 100644
--- a/drivers/firmware/efi/Kconfig
+++ b/drivers/firmware/efi/Kconfig
@@ -314,6 +314,20 @@ config EFI_COCO_SECRET
 	  virt/coco/efi_secret module to access the secrets, which in turn
 	  allows userspace programs to access the injected secrets.
 
+config UNACCEPTED_MEMORY
+	bool
+	depends on EFI_STUB
This still doesn't make a whole lotta sense. If I do "make menuconfig" I don't
see the help text because that bool doesn't have a string prompt. So who is that
help text for?
It is a form of documentation for a developer. The same happens for other
options. For instance, BOOT_VESA_SUPPORT or ARCH_HAS_CURRENT_STACK_POINTER.

Yes, it is not visible user, but I still think it is helpful for a
developer to understand what the option does.
quoted hunk ↗ jump to hunk
Then, in the last patch you have
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -888,6 +888,8 @@ config INTEL_TDX_GUEST
        select ARCH_HAS_CC_PLATFORM
        select X86_MEM_ENCRYPT
        select X86_MCE
+       select UNACCEPTED_MEMORY
+       select EFI_STUB
I guess you want to select UNACCEPTED_MEMORY only.
I had to rework it as

config INTEL_TDX_GUEST
	...
	depends on EFI_STUB
	select UNACCEPTED_MEMORY

Naked select UNACCEPTED_MEMORY doesn't work if EFI and EFI_STUB is
disabled:

WARNING: unmet direct dependencies detected for UNACCEPTED_MEMORY
  Depends on [n]: EFI [=n] && EFI_STUB [=n]
  Selected by [y]:
  - INTEL_TDX_GUEST [=y] && HYPERVISOR_GUEST [=y] && X86_64 [=y] && CPU_SUP_INTEL [=y] && X86_X2APIC [=y]

IIUC, the alternative is to have selects all the way down the option tree.
And I've already mentioned this whole mess:

https://lore.kernel.org/r/Yt%2BnOeLMqRxjObbx@zn.tnic (local)

Please incorporate all review comments before sending a new version of
your patch.

Ignoring review feedback is a very unfriendly thing to do:

- if you agree with the feedback, you work it in in the next revision

- if you don't agree, you *say* *why* you don't
Sorry, it was not my intention. I misread your comment and focused on
build issues around the option.

-- 
  Kiryl Shutsemau / Kirill A. Shutemov
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