Re: [PATCH v2 09/14] arm64: Enable memory encrypt for Realms

Emanuele Rocca
2024-04-25T18:16:36Z

Hi,

On 2024-04-25 05:29, Suzuki K Poulose wrote:
> Emmanuele reports that these need to be exported as well, something
> like:
>
>
> diff --git a/arch/arm64/mm/pageattr.c b/arch/arm64/mm/pageattr.c
> index 229b6d9990f5..de3843ce2aea 100644
> --- a/arch/arm64/mm/pageattr.c
> +++ b/arch/arm64/mm/pageattr.c
> @@ -228,11 +228,13 @@ int set_memory_encrypted(unsigned long addr, int
> numpages)
> {
> return __set_memory_encrypted(addr, numpages, true);
> }
> +EXPORT_SYMBOL_GPL(set_memory_encrypted);
>
> int set_memory_decrypted(unsigned long addr, int numpages)
> {
> return __set_memory_encrypted(addr, numpages, false);
> }
> +EXPORT_SYMBOL_GPL(set_memory_decrypted);
>
> #ifdef CONFIG_DEBUG_PAGEALLOC
> void __kernel_map_pages(struct page *page, int numpages, int enable

Indeed, without exporting the symbols I was getting this build failure:

ERROR: modpost: "set_memory_encrypted" [drivers/hv/hv_vmbus.ko] undefined!
ERROR: modpost: "set_memory_decrypted" [drivers/hv/hv_vmbus.ko] undefined!

I can now build 6.9-rc1 w/ CCA guest patches if I apply Suzuki's
changes:

1) move set_memory_encrypted/decrypted from asm/mem_encrypt.h to
asm/set_memory.h
2) export both symbols in mm/pageattr.c

See diff below.

Thanks,
Emanuele

diff --git a/arch/arm64/include/asm/mem_encrypt.h b/arch/arm64/include/asm/mem_encrypt.h
index 7381f9585321..e47265cd180a 100644
--- a/arch/arm64/include/asm/mem_encrypt.h
+++ b/arch/arm64/include/asm/mem_encrypt.h
@@ -14,6 +14,4 @@ static inline bool force_dma_unencrypted(struct device *dev)
return is_realm_world();
}

-int set_memory_encrypted(unsigned long addr, int numpages);
-int set_memory_decrypted(unsigned long addr, int numpages);
#endif
diff --git a/arch/arm64/include/asm/set_memory.h b/arch/arm64/include/asm/set_memory.h
index 0f740b781187..9561b90fb43c 100644
--- a/arch/arm64/include/asm/set_memory.h
+++ b/arch/arm64/include/asm/set_memory.h
@@ -14,4 +14,6 @@ int set_direct_map_invalid_noflush(struct page *page);
int set_direct_map_default_noflush(struct page *page);
bool kernel_page_present(struct page *page);

+int set_memory_encrypted(unsigned long addr, int numpages);
+int set_memory_decrypted(unsigned long addr, int numpages);
#endif /* _ASM_ARM64_SET_MEMORY_H */
diff --git a/arch/arm64/mm/pageattr.c b/arch/arm64/mm/pageattr.c
index 229b6d9990f5..de3843ce2aea 100644
--- a/arch/arm64/mm/pageattr.c
+++ b/arch/arm64/mm/pageattr.c
@@ -228,11 +228,13 @@ int set_memory_encrypted(unsigned long addr, int numpages)
{
return __set_memory_encrypted(addr, numpages, true);
}
+EXPORT_SYMBOL_GPL(set_memory_encrypted);

int set_memory_decrypted(unsigned long addr, int numpages)
{
return __set_memory_encrypted(addr, numpages, false);
}
+EXPORT_SYMBOL_GPL(set_memory_decrypted);

#ifdef CONFIG_DEBUG_PAGEALLOC
void __kernel_map_pages(struct page *page, int numpages, int enable)