Merge tag 'x86_mtrr_for_v6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 mtrr updates from Borislav Petkov:
 "A serious scrubbing of the MTRR code including adding a new map
  mechanism in order to look up the memory type of a region easily.

  Also address memory range lookup issues like returning an invalid
  memory type. Furthermore, this handles the decoupling of PAT from MTRR
  more naturally.

  All work by Juergen Gross"

* tag 'x86_mtrr_for_v6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/xen: Set default memory type for PV guests to WB
  x86/mtrr: Unify debugging printing
  x86/mtrr: Remove unused code
  x86/mm: Only check uniform after calling mtrr_type_lookup()
  x86/mtrr: Don't let mtrr_type_lookup() return MTRR_TYPE_INVALID
  x86/mtrr: Use new cache_map in mtrr_type_lookup()
  x86/mtrr: Add mtrr=debug command line option
  x86/mtrr: Construct a memory map with cache modes
  x86/mtrr: Add get_effective_type() service function
  x86/mtrr: Allocate mtrr_value array dynamically
  x86/mtrr: Move 32-bit code from mtrr.c to legacy.c
  x86/mtrr: Have only one set_mtrr() variant
  x86/mtrr: Replace vendor tests in MTRR code
  x86/xen: Set MTRR state when running as Xen PV initial domain
  x86/hyperv: Set MTRR state when running as SEV-SNP Hyper-V guest
  x86/mtrr: Support setting MTRR state for software defined MTRRs
  x86/mtrr: Replace size_or_mask and size_and_mask with a much easier concept
  x86/mtrr: Remove physical address size calculation

1 files changed, 8 insertions, 16 deletions

diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
index e4f499eb0f29..15a8009a4480 100644
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c
@@ -702,14 +702,8 @@ void p4d_clear_huge(p4d_t *p4d)
  * pud_set_huge - setup kernel PUD mapping
  *
  * MTRRs can override PAT memory types with 4KiB granularity. Therefore, this
- * function sets up a huge page only if any of the following conditions are met:
- *
- * - MTRRs are disabled, or
- *
- * - MTRRs are enabled and the range is completely covered by a single MTRR, or
- *
- * - MTRRs are enabled and the corresponding MTRR memory type is WB, which
- *   has no effect on the requested PAT memory type.
+ * function sets up a huge page only if the complete range has the same MTRR
+ * caching mode.
  *
  * Callers should try to decrease page size (1GB -> 2MB -> 4K) if the bigger
  * page mapping attempt fails.
@@ -718,11 +712,10 @@ void p4d_clear_huge(p4d_t *p4d)
  */
 int pud_set_huge(pud_t *pud, phys_addr_t addr, pgprot_t prot)
 {
-	u8 mtrr, uniform;
+	u8 uniform;
 
-	mtrr = mtrr_type_lookup(addr, addr + PUD_SIZE, &uniform);
-	if ((mtrr != MTRR_TYPE_INVALID) && (!uniform) &&
-	    (mtrr != MTRR_TYPE_WRBACK))
+	mtrr_type_lookup(addr, addr + PUD_SIZE, &uniform);
+	if (!uniform)
 		return 0;
 
 	/* Bail out if we are we on a populated non-leaf entry: */
@@ -745,11 +738,10 @@ int pud_set_huge(pud_t *pud, phys_addr_t addr, pgprot_t prot)
  */
 int pmd_set_huge(pmd_t *pmd, phys_addr_t addr, pgprot_t prot)
 {
-	u8 mtrr, uniform;
+	u8 uniform;
 
-	mtrr = mtrr_type_lookup(addr, addr + PMD_SIZE, &uniform);
-	if ((mtrr != MTRR_TYPE_INVALID) && (!uniform) &&
-	    (mtrr != MTRR_TYPE_WRBACK)) {
+	mtrr_type_lookup(addr, addr + PMD_SIZE, &uniform);
+	if (!uniform) {
 		pr_warn_once("%s: Cannot satisfy [mem %#010llx-%#010llx] with a huge-page mapping due to MTRR override.\n",
 			     __func__, addr, addr + PMD_SIZE);
 		return 0;