[PATCH v3] Remove the memory encryption mask to obtain the true physical address

[Lianbo Jiang <lijiang@redhat.com>]

For AMD machine with SME feature, if SME is enabled in the first
kernel, the crashed kernel's page table(pgd/pud/pmd/pte) contains
the memory encryption mask, so makedumpfile needs to remove the
memory encryption mask to obtain the true physical address.

Signed-off-by: Lianbo Jiang <lijiang@redhat.com>
---
Changes since v1:
1. Merge them into a patch.
2. The sme_mask is not an enum number, remove it.
3. Sanity check whether the sme_mask is in vmcoreinfo.
4. Deal with the huge pages case.
5. Cover the 5-level path.

Changes since v2:
1. Change the sme_me_mask to entry_mask.
2. No need to remove the mask when makedumpfile prints out the
   value of the entry.
3. Remove the sme mask from the pte at the end of the __vtop4_x86_64().
4. Also need to remove the sme mask from page table entry in
   find_vmemmap_x86_64()

 arch/x86_64.c  | 30 +++++++++++++++++++-----------
 makedumpfile.c |  4 ++++
 makedumpfile.h |  1 +
 3 files changed, 24 insertions(+), 11 deletions(-)

diff --git a/arch/x86_64.c b/arch/x86_64.c
index 537fb78..9977466 100644
--- a/arch/x86_64.c
+++ b/arch/x86_64.c
@@ -291,6 +291,7 @@ __vtop4_x86_64(unsigned long vaddr, unsigned long pagetable)
 	unsigned long page_dir, pgd, pud_paddr, pud_pte, pmd_paddr, pmd_pte;
 	unsigned long pte_paddr, pte;
 	unsigned long p4d_paddr, p4d_pte;
+	unsigned long entry_mask = ENTRY_MASK;
 
 	/*
 	 * Get PGD.
@@ -302,6 +303,9 @@ __vtop4_x86_64(unsigned long vaddr, unsigned long pagetable)
 			return NOT_PADDR;
 	}
 
+	if (NUMBER(sme_mask) != NOT_FOUND_NUMBER)
+		entry_mask &= ~(NUMBER(sme_mask));
+
 	if (check_5level_paging()) {
 		page_dir += pgd5_index(vaddr) * sizeof(unsigned long);
 		if (!readmem(PADDR, page_dir, &pgd, sizeof pgd)) {
@@ -318,7 +322,7 @@ __vtop4_x86_64(unsigned long vaddr, unsigned long pagetable)
 		/*
 		 * Get P4D.
 		 */
-		p4d_paddr  = pgd & ENTRY_MASK;
+		p4d_paddr  = pgd & entry_mask;
 		p4d_paddr += p4d_index(vaddr) * sizeof(unsigned long);
 		if (!readmem(PADDR, p4d_paddr, &p4d_pte, sizeof p4d_pte)) {
 			ERRMSG("Can't get p4d_pte (p4d_paddr:%lx).\n", p4d_paddr);
@@ -331,7 +335,7 @@ __vtop4_x86_64(unsigned long vaddr, unsigned long pagetable)
 			ERRMSG("Can't get a valid p4d_pte.\n");
 			return NOT_PADDR;
 		}
-		pud_paddr  = p4d_pte & ENTRY_MASK;
+		pud_paddr  = p4d_pte & entry_mask;
 	}else {
 		page_dir += pgd_index(vaddr) * sizeof(unsigned long);
 		if (!readmem(PADDR, page_dir, &pgd, sizeof pgd)) {
@@ -345,7 +349,7 @@ __vtop4_x86_64(unsigned long vaddr, unsigned long pagetable)
 			ERRMSG("Can't get a valid pgd.\n");
 			return NOT_PADDR;
 		}
-		pud_paddr  = pgd & ENTRY_MASK;
+		pud_paddr  = pgd & entry_mask;
 	}
 
 	/*
@@ -364,13 +368,13 @@ __vtop4_x86_64(unsigned long vaddr, unsigned long pagetable)
 		return NOT_PADDR;
 	}
 	if (pud_pte & _PAGE_PSE)	/* 1GB pages */
-		return (pud_pte & ENTRY_MASK & PUD_MASK) +
+		return (pud_pte & entry_mask & PUD_MASK) +
 			(vaddr & ~PUD_MASK);
 
 	/*
 	 * Get PMD.
 	 */
-	pmd_paddr  = pud_pte & ENTRY_MASK;
+	pmd_paddr  = pud_pte & entry_mask;
 	pmd_paddr += pmd_index(vaddr) * sizeof(unsigned long);
 	if (!readmem(PADDR, pmd_paddr, &pmd_pte, sizeof pmd_pte)) {
 		ERRMSG("Can't get pmd_pte (pmd_paddr:%lx).\n", pmd_paddr);
@@ -384,13 +388,13 @@ __vtop4_x86_64(unsigned long vaddr, unsigned long pagetable)
 		return NOT_PADDR;
 	}
 	if (pmd_pte & _PAGE_PSE)	/* 2MB pages */
-		return (pmd_pte & ENTRY_MASK & PMD_MASK) +
+		return (pmd_pte & entry_mask & PMD_MASK) +
 			(vaddr & ~PMD_MASK);
 
 	/*
 	 * Get PTE.
 	 */
-	pte_paddr  = pmd_pte & ENTRY_MASK;
+	pte_paddr  = pmd_pte & entry_mask;
 	pte_paddr += pte_index(vaddr) * sizeof(unsigned long);
 	if (!readmem(PADDR, pte_paddr, &pte, sizeof pte)) {
 		ERRMSG("Can't get pte (pte_paddr:%lx).\n", pte_paddr);
@@ -403,7 +407,7 @@ __vtop4_x86_64(unsigned long vaddr, unsigned long pagetable)
 		ERRMSG("Can't get a valid pte.\n");
 		return NOT_PADDR;
 	}
-	return (pte & ENTRY_MASK) + PAGEOFFSET(vaddr);
+	return (pte & entry_mask) + PAGEOFFSET(vaddr);
 }
 
 unsigned long long
@@ -636,6 +640,7 @@ find_vmemmap_x86_64()
 	unsigned long pmd, tpfn;
 	unsigned long pvaddr = 0;
 	unsigned long data_addr = 0, last_data_addr = 0, start_data_addr = 0;
+	unsigned long pmask = PMASK;
 	/*
 	 * data_addr is the paddr of the page holding the page structs.
 	 * We keep lists of contiguous pages and the pfn's that their
@@ -656,6 +661,9 @@ find_vmemmap_x86_64()
 		return FAILED;
 	}
 
+	if (NUMBER(sme_mask) != NOT_FOUND_NUMBER)
+		pmask &= ~(NUMBER(sme_mask));
+
 	pagestructsize = size_table.page;
 	hugepagesize = PTRS_PER_PMD * info->page_size;
 	vaddr_base = info->vmemmap_start;
@@ -686,7 +694,7 @@ find_vmemmap_x86_64()
 		}
 
 		/* mask the pgd entry for the address of the pud page */
-		pud_addr &= PMASK;
+		pud_addr &= pmask;
 		if (pud_addr == 0)
 			  continue;
 		/* read the entire pud page */
@@ -699,7 +707,7 @@ find_vmemmap_x86_64()
 		/* pudp points to an entry in the pud page */
 		for (pudp = (unsigned long *)pud_page, pudindex = 0;
 					pudindex < PTRS_PER_PUD; pudindex++, pudp++) {
-			pmd_addr = *pudp & PMASK;
+			pmd_addr = *pudp & pmask;
 			/* read the entire pmd page */
 			if (pmd_addr == 0)
 				continue;
@@ -741,7 +749,7 @@ find_vmemmap_x86_64()
 				 * - we discontiguous page is a string of valids
 				 */
 				if (pmd) {
-					data_addr = (pmd & PMASK);
+					data_addr = (pmd & pmask);
 					if (start_range) {
 						/* first-time kludge */
 						start_data_addr = data_addr;
diff --git a/makedumpfile.c b/makedumpfile.c
index 8923538..2237eb8 100644
--- a/makedumpfile.c
+++ b/makedumpfile.c
@@ -977,6 +977,8 @@ next_page:
 	read_size = MIN(info->page_size - PAGEOFFSET(paddr), size);
 
 	pgaddr = PAGEBASE(paddr);
+	if (NUMBER(sme_mask) != NOT_FOUND_NUMBER)
+		pgaddr = pgaddr & ~(NUMBER(sme_mask));
 	pgbuf = cache_search(pgaddr, read_size);
 	if (!pgbuf) {
 		++cache_miss;
@@ -2276,6 +2278,7 @@ write_vmcoreinfo_data(void)
 	WRITE_NUMBER("NR_FREE_PAGES", NR_FREE_PAGES);
 	WRITE_NUMBER("N_ONLINE", N_ONLINE);
 	WRITE_NUMBER("pgtable_l5_enabled", pgtable_l5_enabled);
+	WRITE_NUMBER("sme_mask", sme_mask);
 
 	WRITE_NUMBER("PG_lru", PG_lru);
 	WRITE_NUMBER("PG_private", PG_private);
@@ -2672,6 +2675,7 @@ read_vmcoreinfo(void)
 	READ_NUMBER("NR_FREE_PAGES", NR_FREE_PAGES);
 	READ_NUMBER("N_ONLINE", N_ONLINE);
 	READ_NUMBER("pgtable_l5_enabled", pgtable_l5_enabled);
+	READ_NUMBER("sme_mask", sme_mask);
 
 	READ_NUMBER("PG_lru", PG_lru);
 	READ_NUMBER("PG_private", PG_private);
diff --git a/makedumpfile.h b/makedumpfile.h
index 73813ed..e97b2e7 100644
--- a/makedumpfile.h
+++ b/makedumpfile.h
@@ -1912,6 +1912,7 @@ struct number_table {
 	long	NR_FREE_PAGES;
 	long	N_ONLINE;
 	long	pgtable_l5_enabled;
+	long	sme_mask;
 
 	/*
  	* Page flags
-- 
2.17.1


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