From: Ashish Kalra <[email protected]>
Add support for 5-level paging in pg_level_to_pfn().
This issue was found during working on SNP guest kexec support,
this helper function is used during early boot stage for setting
of C-bit on the PTEs and additionally need this same helper for
switching shared pages to private during guest kexec.
Signed-off-by: Ashish Kalra <[email protected]>
---
arch/x86/mm/mem_encrypt_amd.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/arch/x86/mm/mem_encrypt_amd.c b/arch/x86/mm/mem_encrypt_amd.c
index 6faea41e99b6..45914568596a 100644
--- a/arch/x86/mm/mem_encrypt_amd.c
+++ b/arch/x86/mm/mem_encrypt_amd.c
@@ -267,6 +267,10 @@ static unsigned long pg_level_to_pfn(int level, pte_t *kpte, pgprot_t *ret_prot)
pfn = pud_pfn(*(pud_t *)kpte);
prot = pud_pgprot(*(pud_t *)kpte);
break;
+ case PG_LEVEL_512G:
+ pfn = p4d_pfn(*(p4d_t *)kpte);
+ prot = p4d_pgprot(*(p4d_t *)kpte);
+ break;
default:
WARN_ONCE(1, "Invalid level for kpte\n");
return 0;
--
2.25.1
On Wed, Oct 18, 2023 at 07:06:26PM +0000, Ashish Kalra wrote:
> From: Ashish Kalra <[email protected]>
>
> Add support for 5-level paging in pg_level_to_pfn().
>
> This issue was found during working on SNP guest kexec support,
> this helper function is used during early boot stage for setting
> of C-bit on the PTEs and additionally need this same helper for
> switching shared pages to private during guest kexec.
How to write a proper commit message:
1. Prepare the context for the explanation briefly.
2. Explain the problem at hand.
3. "It happens because of <...>"
4. "Fix it by doing X"
5. "(Potentially do Y)."
For more detailed info, see
Documentation/process/submitting-patches.rst, Section "2) Describe your
changes".
Thx.
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette