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Message-ID: <20210421134924.GB11234@zn.tnic>
Date: Wed, 21 Apr 2021 15:52:10 +0200
From: Borislav Petkov <bp@...en8.de>
To: Ashish Kalra <ashish.kalra@....com>
Cc: pbonzini@...hat.com, tglx@...utronix.de, mingo@...hat.com,
hpa@...or.com, joro@...tes.org, thomas.lendacky@....com,
x86@...nel.org, kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
srutherford@...gle.com, seanjc@...gle.com,
venu.busireddy@...cle.com, brijesh.singh@....com
Subject: Re: [PATCH v13 09/12] mm: x86: Invoke hypercall when page encryption
status is changed
On Wed, Apr 21, 2021 at 12:12:13PM +0000, Ashish Kalra wrote:
> Yes, both have some common code, but it is only this page level/size
> ...
See below for what I mean. Diff ontop of yours.
> I see that early_set_memory_enc_dec() is also using a for loop, so which
> patches are you referring to ?
The SNP guest set has this pattern:
https://lkml.kernel.org/r/20210408114049.GI10192@zn.tnic
---
diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
index b1d59d2b3bf6..e823645101ee 100644
--- a/arch/x86/mm/mem_encrypt.c
+++ b/arch/x86/mm/mem_encrypt.c
@@ -232,6 +232,37 @@ void __init sev_setup_arch(void)
swiotlb_adjust_size(size);
}
+static unsigned long pg_level_to_pfn(int level, pte_t *kpte, pgprot_t *ret_prot)
+{
+ unsigned long pfn = 0;
+ pgprot_t prot;
+
+ switch (level) {
+ case PG_LEVEL_4K:
+ pfn = pte_pfn(*kpte);
+ prot = pte_pgprot(*kpte);
+ break;
+
+ case PG_LEVEL_2M:
+ pfn = pmd_pfn(*(pmd_t *)kpte);
+ prot = pmd_pgprot(*(pmd_t *)kpte);
+ break;
+
+ case PG_LEVEL_1G:
+ pfn = pud_pfn(*(pud_t *)kpte);
+ prot = pud_pgprot(*(pud_t *)kpte);
+ break;
+
+ default:
+ return 0;
+ }
+
+ if (ret_prot)
+ *ret_prot = prot;
+
+ return pfn;
+}
+
static void set_memory_enc_dec_hypercall(unsigned long vaddr, int npages,
bool enc)
{
@@ -249,19 +280,9 @@ static void set_memory_enc_dec_hypercall(unsigned long vaddr, int npages,
if (!kpte || pte_none(*kpte))
return;
- switch (level) {
- case PG_LEVEL_4K:
- pfn = pte_pfn(*kpte);
- break;
- case PG_LEVEL_2M:
- pfn = pmd_pfn(*(pmd_t *)kpte);
- break;
- case PG_LEVEL_1G:
- pfn = pud_pfn(*(pud_t *)kpte);
- break;
- default:
- return;
- }
+ pfn = pg_level_to_pfn(level, kpte, NULL);
+ if (!pfn)
+ continue;
psize = page_level_size(level);
pmask = page_level_mask(level);
@@ -279,22 +300,9 @@ static void __init __set_clr_pte_enc(pte_t *kpte, int level, bool enc)
unsigned long pfn, pa, size;
pte_t new_pte;
- switch (level) {
- case PG_LEVEL_4K:
- pfn = pte_pfn(*kpte);
- old_prot = pte_pgprot(*kpte);
- break;
- case PG_LEVEL_2M:
- pfn = pmd_pfn(*(pmd_t *)kpte);
- old_prot = pmd_pgprot(*(pmd_t *)kpte);
- break;
- case PG_LEVEL_1G:
- pfn = pud_pfn(*(pud_t *)kpte);
- old_prot = pud_pgprot(*(pud_t *)kpte);
- break;
- default:
+ pfn = pg_level_to_pfn(level, kpte, &old_prot);
+ if (!pfn)
return;
- }
new_prot = old_prot;
if (enc)
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
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