On 8/10/21 12:48 PM, Tom Lendacky wrote:
On 8/10/21 1:45 PM, Kuppuswamy, Sathyanarayanan wrote:
On 7/27/21 3:26 PM, Tom Lendacky wrote:
diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c index de01903c3735..cafed6456d45 100644 --- a/arch/x86/kernel/head64.c +++ b/arch/x86/kernel/head64.c @@ -19,7 +19,7 @@ #include <linux/start_kernel.h> #include <linux/io.h> #include <linux/memblock.h> -#include <linux/mem_encrypt.h> +#include <linux/protected_guest.h> #include <linux/pgtable.h> #include <asm/processor.h> @@ -285,7 +285,7 @@ unsigned long __head __startup_64(unsigned long physaddr, * there is no need to zero it after changing the memory encryption * attribute. */ - if (mem_encrypt_active()) { + if (prot_guest_has(PATTR_MEM_ENCRYPT)) { vaddr = (unsigned long)__start_bss_decrypted; vaddr_end = (unsigned long)__end_bss_decrypted;
Since this change is specific to AMD, can you replace PATTR_MEM_ENCRYPT with prot_guest_has(PATTR_SME) || prot_guest_has(PATTR_SEV). It is not used in TDX.
This is a direct replacement for now. I think the change you're requesting should be done as part of the TDX support patches so it's clear why it is being changed.
Ok. I will include it part of TDX changes.
But, wouldn't TDX still need to do something with this shared/unencrypted area, though? Or since it is shared, there's actually nothing you need to do (the bss decrpyted section exists even if CONFIG_AMD_MEM_ENCRYPT is not configured)?
Kirill had a requirement to turn on CONFIG_AMD_MEM_ENCRYPT for adding lazy accept support in TDX guest kernel. Kirill, can you add details here?
Thanks, Tom