From: Ashish Kalra <ashish.kalra@xxxxxxx>
Refactor __set_clr_pte_enc() and add two new helper functions to
set/clear PTE C-bit from early SEV/SNP initialization code and
later during shutdown/kexec especially when all CPUs are stopped
and interrupts are disabled and set_memory_xx() interfaces can't
be used.
Co-developed-by: Borislav Petkov (AMD) <bp@xxxxxxxxx>
Signed-off-by: Borislav Petkov (AMD) <bp@xxxxxxxxx>
Signed-off-by: Ashish Kalra <ashish.kalra@xxxxxxx>
---
arch/x86/include/asm/sev.h | 20 ++++++++++
arch/x86/mm/mem_encrypt_amd.c | 75 +++++++++++++++++++++++------------
2 files changed, 69 insertions(+), 26 deletions(-)
diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h
index 79bbe2be900e..61684d0a64c0 100644
--- a/arch/x86/include/asm/sev.h
+++ b/arch/x86/include/asm/sev.h
@@ -285,6 +285,22 @@ struct svsm_attest_call {
u8 rsvd[4];
};
+/* PTE descriptor used for the prepare_pte_enc() operations. */
+struct pte_enc_desc {
+ pte_t *kpte;
+ int pte_level;
+ bool encrypt;
+ /* pfn of the kpte above */
+ unsigned long pfn;
+ /* physical address of @pfn */
+ unsigned long pa;
+ /* virtual address of @pfn */
+ void *va;
+ /* memory covered by the pte */
+ unsigned long size;
+ pgprot_t new_pgprot;
+};
+
/*
* SVSM protocol structure
*/
@@ -399,6 +415,8 @@ u64 snp_get_unsupported_features(u64 status);
u64 sev_get_status(void);
void sev_show_status(void);
void snp_update_svsm_ca(void);
+int prepare_pte_enc(struct pte_enc_desc *d);
+void set_pte_enc_mask(pte_t *kpte, unsigned long pfn, pgprot_t new_prot);
#else /* !CONFIG_AMD_MEM_ENCRYPT */
@@ -435,6 +453,8 @@ static inline u64 snp_get_unsupported_features(u64 status) { return 0; }
static inline u64 sev_get_status(void) { return 0; }
static inline void sev_show_status(void) { }
static inline void snp_update_svsm_ca(void) { }
+static inline int prepare_pte_enc(struct pte_enc_desc *d) { return 0; }
+static inline void set_pte_enc_mask(pte_t *kpte, unsigned long pfn, pgprot_t new_prot) { }
#endif /* CONFIG_AMD_MEM_ENCRYPT */
diff --git a/arch/x86/mm/mem_encrypt_amd.c b/arch/x86/mm/mem_encrypt_amd.c
index 86a476a426c2..f4be81db72ee 100644
--- a/arch/x86/mm/mem_encrypt_amd.c
+++ b/arch/x86/mm/mem_encrypt_amd.c
@@ -311,59 +311,82 @@ static int amd_enc_status_change_finish(unsigned long vaddr, int npages, bool en
return 0;
}
-static void __init __set_clr_pte_enc(pte_t *kpte, int level, bool enc)
+int prepare_pte_enc(struct pte_enc_desc *d)
{
- pgprot_t old_prot, new_prot;
- unsigned long pfn, pa, size;
- pte_t new_pte;
+ pgprot_t old_prot;
- pfn = pg_level_to_pfn(level, kpte, &old_prot);
- if (!pfn)
- return;
+ d->pfn = pg_level_to_pfn(d->pte_level, d->kpte, &old_prot);
+ if (!d->pfn)
+ return 1;
- new_prot = old_prot;
- if (enc)
- pgprot_val(new_prot) |= _PAGE_ENC;
+ d->new_pgprot = old_prot;
+ if (d->encrypt)
+ pgprot_val(d->new_pgprot) |= _PAGE_ENC;
else
- pgprot_val(new_prot) &= ~_PAGE_ENC;
+ pgprot_val(d->new_pgprot) &= ~_PAGE_ENC;
/* If prot is same then do nothing. */
- if (pgprot_val(old_prot) == pgprot_val(new_prot))
- return;
+ if (pgprot_val(old_prot) == pgprot_val(d->new_pgprot))
+ return 1;
- pa = pfn << PAGE_SHIFT;
- size = page_level_size(level);
+ d->pa = d->pfn << PAGE_SHIFT;
+ d->size = page_level_size(d->pte_level);
/*
- * We are going to perform in-place en-/decryption and change the
- * physical page attribute from C=1 to C=0 or vice versa. Flush the
- * caches to ensure that data gets accessed with the correct C-bit.
+ * In-place en-/decryption and physical page attribute change
+ * from C=1 to C=0 or vice versa will be performed. Flush the
+ * caches to ensure that data gets accessed with the correct
+ * C-bit.
*/
- clflush_cache_range(__va(pa), size);
+ if (d->va)
+ clflush_cache_range(d->va, d->size);
+ else
+ clflush_cache_range(__va(d->pa), d->size);
+
+ return 0;
+}
+
+void set_pte_enc_mask(pte_t *kpte, unsigned long pfn, pgprot_t new_prot)
+{
+ pte_t new_pte;
+
+ /* Change the page encryption mask. */
+ new_pte = pfn_pte(pfn, new_prot);
+ set_pte_atomic(kpte, new_pte);
+}
+
+static void __init __set_clr_pte_enc(pte_t *kpte, int level, bool enc)
+{
+ struct pte_enc_desc d = {
+ .kpte = kpte,
+ .pte_level = level,
+ .encrypt = enc
+ };
+
+ if (prepare_pte_enc(&d))
+ return;
/* Encrypt/decrypt the contents in-place */
if (enc) {
- sme_early_encrypt(pa, size);
+ sme_early_encrypt(d.pa, d.size);
} else {
- sme_early_decrypt(pa, size);
+ sme_early_decrypt(d.pa, d.size);
/*
* ON SNP, the page state in the RMP table must happen
* before the page table updates.
*/
- early_snp_set_memory_shared((unsigned long)__va(pa), pa, 1);
+ early_snp_set_memory_shared((unsigned long)__va(d.pa), d.pa, 1);
}
- /* Change the page encryption mask. */
- new_pte = pfn_pte(pfn, new_prot);
- set_pte_atomic(kpte, new_pte);
+ set_pte_enc_mask(kpte, d.pfn, d.new_pgprot);
/*
* If page is set encrypted in the page table, then update the RMP table to
* add this page as private.
*/
if (enc)
- early_snp_set_memory_private((unsigned long)__va(pa), pa, 1);
+ early_snp_set_memory_private((unsigned long)__va(d.pa), d.pa, 1);
}
static int __init early_set_memory_enc_dec(unsigned long vaddr,
--
2.34.1
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