[tip:x86/urgent] x86/mm: Use a struct to reduce parameters for SME PGD mapping

From: tip-bot for Tom Lendacky
Date: Mon Jan 15 2018 - 22:44:18 EST

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Commit-ID: bacf6b499e11760aef73a3bb5ce4e5eea74a3fd4
Gitweb: https://git.kernel.org/tip/bacf6b499e11760aef73a3bb5ce4e5eea74a3fd4
Author: Tom Lendacky <thomas.lendacky@xxxxxxx>
AuthorDate: Wed, 10 Jan 2018 13:26:05 -0600
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Tue, 16 Jan 2018 01:50:58 +0100

x86/mm: Use a struct to reduce parameters for SME PGD mapping

In preparation for follow-on patches, combine the PGD mapping parameters
into a struct to reduce the number of function arguments and allow for
direct updating of the next pagetable mapping area pointer.

Tested-by: Gabriel Craciunescu <nix.or.die@xxxxxxxxx>
Signed-off-by: Tom Lendacky <thomas.lendacky@xxxxxxx>
Reviewed-by: Borislav Petkov <bp@xxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Brijesh Singh <brijesh.singh@xxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/20180110192605.6026.96206.stgit@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
arch/x86/mm/mem_encrypt.c | 90 ++++++++++++++++++++++++-----------------------
1 file changed, 46 insertions(+), 44 deletions(-)

diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
index 391b134..5a20696 100644
--- a/arch/x86/mm/mem_encrypt.c
+++ b/arch/x86/mm/mem_encrypt.c
@@ -464,6 +464,14 @@ void swiotlb_set_mem_attributes(void *vaddr, unsigned long size)
set_memory_decrypted((unsigned long)vaddr, size >> PAGE_SHIFT);
}

+struct sme_populate_pgd_data {
+ void *pgtable_area;
+ pgd_t *pgd;
+
+ pmdval_t pmd_val;
+ unsigned long vaddr;
+};
+
static void __init sme_clear_pgd(pgd_t *pgd_base, unsigned long start,
unsigned long end)
{
@@ -486,15 +494,14 @@ static void __init sme_clear_pgd(pgd_t *pgd_base, unsigned long start,
#define PUD_FLAGS _KERNPG_TABLE_NOENC
#define PMD_FLAGS (__PAGE_KERNEL_LARGE_EXEC & ~_PAGE_GLOBAL)

-static void __init *sme_populate_pgd(pgd_t *pgd_base, void *pgtable_area,
- unsigned long vaddr, pmdval_t pmd_val)
+static void __init sme_populate_pgd_large(struct sme_populate_pgd_data *ppd)
{
pgd_t *pgd_p;
p4d_t *p4d_p;
pud_t *pud_p;
pmd_t *pmd_p;

- pgd_p = pgd_base + pgd_index(vaddr);
+ pgd_p = ppd->pgd + pgd_index(ppd->vaddr);
if (native_pgd_val(*pgd_p)) {
if (IS_ENABLED(CONFIG_X86_5LEVEL))
p4d_p = (p4d_t *)(native_pgd_val(*pgd_p) & ~PTE_FLAGS_MASK);
@@ -504,15 +511,15 @@ static void __init *sme_populate_pgd(pgd_t *pgd_base, void *pgtable_area,
pgd_t pgd;

if (IS_ENABLED(CONFIG_X86_5LEVEL)) {
- p4d_p = pgtable_area;
+ p4d_p = ppd->pgtable_area;
memset(p4d_p, 0, sizeof(*p4d_p) * PTRS_PER_P4D);
- pgtable_area += sizeof(*p4d_p) * PTRS_PER_P4D;
+ ppd->pgtable_area += sizeof(*p4d_p) * PTRS_PER_P4D;

pgd = native_make_pgd((pgdval_t)p4d_p + PGD_FLAGS);
} else {
- pud_p = pgtable_area;
+ pud_p = ppd->pgtable_area;
memset(pud_p, 0, sizeof(*pud_p) * PTRS_PER_PUD);
- pgtable_area += sizeof(*pud_p) * PTRS_PER_PUD;
+ ppd->pgtable_area += sizeof(*pud_p) * PTRS_PER_PUD;

pgd = native_make_pgd((pgdval_t)pud_p + PGD_FLAGS);
}
@@ -520,44 +527,41 @@ static void __init *sme_populate_pgd(pgd_t *pgd_base, void *pgtable_area,
}

if (IS_ENABLED(CONFIG_X86_5LEVEL)) {
- p4d_p += p4d_index(vaddr);
+ p4d_p += p4d_index(ppd->vaddr);
if (native_p4d_val(*p4d_p)) {
pud_p = (pud_t *)(native_p4d_val(*p4d_p) & ~PTE_FLAGS_MASK);
} else {
p4d_t p4d;

- pud_p = pgtable_area;
+ pud_p = ppd->pgtable_area;
memset(pud_p, 0, sizeof(*pud_p) * PTRS_PER_PUD);
- pgtable_area += sizeof(*pud_p) * PTRS_PER_PUD;
+ ppd->pgtable_area += sizeof(*pud_p) * PTRS_PER_PUD;

p4d = native_make_p4d((pudval_t)pud_p + P4D_FLAGS);
native_set_p4d(p4d_p, p4d);
}
}

- pud_p += pud_index(vaddr);
+ pud_p += pud_index(ppd->vaddr);
if (native_pud_val(*pud_p)) {
if (native_pud_val(*pud_p) & _PAGE_PSE)
- goto out;
+ return;

pmd_p = (pmd_t *)(native_pud_val(*pud_p) & ~PTE_FLAGS_MASK);
} else {
pud_t pud;

- pmd_p = pgtable_area;
+ pmd_p = ppd->pgtable_area;
memset(pmd_p, 0, sizeof(*pmd_p) * PTRS_PER_PMD);
- pgtable_area += sizeof(*pmd_p) * PTRS_PER_PMD;
+ ppd->pgtable_area += sizeof(*pmd_p) * PTRS_PER_PMD;

pud = native_make_pud((pmdval_t)pmd_p + PUD_FLAGS);
native_set_pud(pud_p, pud);
}

- pmd_p += pmd_index(vaddr);
+ pmd_p += pmd_index(ppd->vaddr);
if (!native_pmd_val(*pmd_p) || !(native_pmd_val(*pmd_p) & _PAGE_PSE))
- native_set_pmd(pmd_p, native_make_pmd(pmd_val));
-
-out:
- return pgtable_area;
+ native_set_pmd(pmd_p, native_make_pmd(ppd->pmd_val));
}

static unsigned long __init sme_pgtable_calc(unsigned long len)
@@ -615,11 +619,10 @@ void __init sme_encrypt_kernel(void)
unsigned long workarea_start, workarea_end, workarea_len;
unsigned long execute_start, execute_end, execute_len;
unsigned long kernel_start, kernel_end, kernel_len;
+ struct sme_populate_pgd_data ppd;
unsigned long pgtable_area_len;
unsigned long paddr, pmd_flags;
unsigned long decrypted_base;
- void *pgtable_area;
- pgd_t *pgd;

if (!sme_active())
return;
@@ -683,18 +686,18 @@ void __init sme_encrypt_kernel(void)
* pagetables and when the new encrypted and decrypted kernel
* mappings are populated.
*/
- pgtable_area = (void *)execute_end;
+ ppd.pgtable_area = (void *)execute_end;

/*
* Make sure the current pagetable structure has entries for
* addressing the workarea.
*/
- pgd = (pgd_t *)native_read_cr3_pa();
+ ppd.pgd = (pgd_t *)native_read_cr3_pa();
paddr = workarea_start;
while (paddr < workarea_end) {
- pgtable_area = sme_populate_pgd(pgd, pgtable_area,
- paddr,
- paddr + PMD_FLAGS);
+ ppd.pmd_val = paddr + PMD_FLAGS;
+ ppd.vaddr = paddr;
+ sme_populate_pgd_large(&ppd);

paddr += PMD_PAGE_SIZE;
}
@@ -708,17 +711,17 @@ void __init sme_encrypt_kernel(void)
* populated with new PUDs and PMDs as the encrypted and decrypted
* kernel mappings are created.
*/
- pgd = pgtable_area;
- memset(pgd, 0, sizeof(*pgd) * PTRS_PER_PGD);
- pgtable_area += sizeof(*pgd) * PTRS_PER_PGD;
+ ppd.pgd = ppd.pgtable_area;
+ memset(ppd.pgd, 0, sizeof(pgd_t) * PTRS_PER_PGD);
+ ppd.pgtable_area += sizeof(pgd_t) * PTRS_PER_PGD;

/* Add encrypted kernel (identity) mappings */
pmd_flags = PMD_FLAGS | _PAGE_ENC;
paddr = kernel_start;
while (paddr < kernel_end) {
- pgtable_area = sme_populate_pgd(pgd, pgtable_area,
- paddr,
- paddr + pmd_flags);
+ ppd.pmd_val = paddr + pmd_flags;
+ ppd.vaddr = paddr;
+ sme_populate_pgd_large(&ppd);

paddr += PMD_PAGE_SIZE;
}
@@ -736,9 +739,9 @@ void __init sme_encrypt_kernel(void)
pmd_flags = (PMD_FLAGS & ~_PAGE_CACHE_MASK) | (_PAGE_PAT | _PAGE_PWT);
paddr = kernel_start;
while (paddr < kernel_end) {
- pgtable_area = sme_populate_pgd(pgd, pgtable_area,
- paddr + decrypted_base,
- paddr + pmd_flags);
+ ppd.pmd_val = paddr + pmd_flags;
+ ppd.vaddr = paddr + decrypted_base;
+ sme_populate_pgd_large(&ppd);

paddr += PMD_PAGE_SIZE;
}
@@ -746,30 +749,29 @@ void __init sme_encrypt_kernel(void)
/* Add decrypted workarea mappings to both kernel mappings */
paddr = workarea_start;
while (paddr < workarea_end) {
- pgtable_area = sme_populate_pgd(pgd, pgtable_area,
- paddr,
- paddr + PMD_FLAGS);
+ ppd.pmd_val = paddr + PMD_FLAGS;
+ ppd.vaddr = paddr;
+ sme_populate_pgd_large(&ppd);

- pgtable_area = sme_populate_pgd(pgd, pgtable_area,
- paddr + decrypted_base,
- paddr + PMD_FLAGS);
+ ppd.vaddr = paddr + decrypted_base;
+ sme_populate_pgd_large(&ppd);

paddr += PMD_PAGE_SIZE;
}

/* Perform the encryption */
sme_encrypt_execute(kernel_start, kernel_start + decrypted_base,
- kernel_len, workarea_start, (unsigned long)pgd);
+ kernel_len, workarea_start, (unsigned long)ppd.pgd);

/*
* At this point we are running encrypted. Remove the mappings for
* the decrypted areas - all that is needed for this is to remove
* the PGD entry/entries.
*/
- sme_clear_pgd(pgd, kernel_start + decrypted_base,
+ sme_clear_pgd(ppd.pgd, kernel_start + decrypted_base,
kernel_end + decrypted_base);

- sme_clear_pgd(pgd, workarea_start + decrypted_base,
+ sme_clear_pgd(ppd.pgd, workarea_start + decrypted_base,
workarea_end + decrypted_base);

/* Flush the TLB - no globals so cr3 is enough */

Next message: tip-bot for Thomas Gleixner: "[tip:timers/core] hrtimer: Correct blatantly incorrect comment"
Previous message: tip-bot for Tom Lendacky: "[tip:x86/urgent] x86/mm: Clean up register saving in the __enc_copy() assembly code"
In reply to: Tom Lendacky: "[PATCH v3 2/5] x86/mm: Use a struct to reduce parameters for SME PGD mapping"
Next in thread: Tom Lendacky: "[PATCH v3 4/5] x86/mm: Prepare sme_encrypt_kernel() for PAGE aligned encryption"
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