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Date:      Tue, 22 Sep 2020 23:28:06 +0000 (UTC)
From:      Konstantin Belousov <kib@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r366030 - head/sys/amd64/amd64
Message-ID:  <202009222328.08MNS6AL091359@repo.freebsd.org>
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Author: kib
Date: Tue Sep 22 23:28:06 2020
New Revision: 366030
URL: https://svnweb.freebsd.org/changeset/base/366030

Log:
  amd64 pmap: More unification for psind = 1 vs 2 in pmap_enter_largepage().
  
  Move
    pkru check
    wait for page alloc
    wire accounting update
    asserting allowed updates for valid mappings
  out of psind conditions.
  
  Also add assert that psind references supported page size.
  Remove not true comment.
  Avoid uneccessary page table walks from top level.
  
  Reviewed by:	alc, markj (previous version)
  Sponsored by:	The FreeBSD Foundation
  MFC after:	1 week
  Differential revision:	https://reviews.freebsd.org/D26513

Modified:
  head/sys/amd64/amd64/pmap.c

Modified: head/sys/amd64/amd64/pmap.c
==============================================================================
--- head/sys/amd64/amd64/pmap.c	Tue Sep 22 23:27:09 2020	(r366029)
+++ head/sys/amd64/amd64/pmap.c	Tue Sep 22 23:28:06 2020	(r366030)
@@ -6479,7 +6479,7 @@ pmap_enter_largepage(pmap_t pmap, vm_offset_t va, pt_e
 	pt_entry_t origpte, *pml4e, *pdpe, *pde, pten, PG_V;
 
 	PMAP_LOCK_ASSERT(pmap, MA_OWNED);
-	KASSERT(psind > 0 && psind < MAXPAGESIZES,
+	KASSERT(psind > 0 && psind < MAXPAGESIZES && pagesizes[psind] != 0,
 	    ("psind %d unexpected", psind));
 	KASSERT(((newpte & PG_FRAME) & (pagesizes[psind] - 1)) == 0,
 	    ("unaligned phys address %#lx newpte %#lx psind %d",
@@ -6494,38 +6494,25 @@ pmap_enter_largepage(pmap_t pmap, vm_offset_t va, pt_e
 	PG_V = pmap_valid_bit(pmap);
 
 restart:
+	if (!pmap_pkru_same(pmap, va, va + pagesizes[psind]))
+		return (KERN_PROTECTION_FAILURE);
 	pten = newpte;
 	if (va < VM_MAXUSER_ADDRESS && pmap->pm_type == PT_X86)
 		pten |= pmap_pkru_get(pmap, va);
 
 	if (psind == 2) {	/* 1G */
-		if (!pmap_pkru_same(pmap, va, va + NBPDP))
-			return (KERN_PROTECTION_FAILURE);
 		pml4e = pmap_pml4e(pmap, va);
 		if (pml4e == NULL || (*pml4e & PG_V) == 0) {
 			mp = _pmap_allocpte(pmap, pmap_pml4e_pindex(va),
 			    NULL, va);
-			if (mp == NULL) {
-				if ((flags & PMAP_ENTER_NOSLEEP) != 0)
-					return (KERN_RESOURCE_SHORTAGE);
-				PMAP_UNLOCK(pmap);
-				vm_wait(NULL);
-				PMAP_LOCK(pmap);
-
-				/*
-				 * Restart at least to recalcuate the pkru
-				 * key.  Our caller must keep the map locked
-				 * so no paging structure can be validated
-				 * under us.
-				 */
-				goto restart;
-			}
-			pdpe = pmap_pdpe(pmap, va);
-			KASSERT(pdpe != NULL, ("va %#lx lost pdpe", va));
+			if (mp == NULL)
+				goto allocf;
+			pdpe = (pdp_entry_t *)PHYS_TO_DMAP(VM_PAGE_TO_PHYS(mp));
+			pdpe = &pdpe[pmap_pdpe_index(va)];
 			origpte = *pdpe;
 			MPASS(origpte == 0);
 		} else {
-			pdpe = pmap_pdpe(pmap, va);
+			pdpe = pmap_pml4e_to_pdpe(pml4e, va);
 			KASSERT(pdpe != NULL, ("va %#lx lost pdpe", va));
 			origpte = *pdpe;
 			if ((origpte & PG_V) == 0) {
@@ -6533,57 +6520,49 @@ restart:
 				mp->ref_count++;
 			}
 		}
-		KASSERT((origpte & PG_V) == 0 || ((origpte & PG_PS) != 0 &&
-		    (origpte & PG_FRAME) == (pten & PG_FRAME)),
-		    ("va %#lx changing 1G phys page pdpe %#lx pten %#lx",
-		    va, origpte, pten));
-		if ((pten & PG_W) != 0 && (origpte & PG_W) == 0)
-			pmap->pm_stats.wired_count += NBPDP / PAGE_SIZE;
-		else if ((pten & PG_W) == 0 && (origpte & PG_W) != 0)
-			pmap->pm_stats.wired_count -= NBPDP / PAGE_SIZE;
 		*pdpe = pten;
 	} else /* (psind == 1) */ {	/* 2M */
-		if (!pmap_pkru_same(pmap, va, va + NBPDR))
-			return (KERN_PROTECTION_FAILURE);
 		pde = pmap_pde(pmap, va);
 		if (pde == NULL) {
 			mp = _pmap_allocpte(pmap, pmap_pdpe_pindex(va),
 			    NULL, va);
-			if (mp == NULL) {
-				if ((flags & PMAP_ENTER_NOSLEEP) != 0)
-					return (KERN_RESOURCE_SHORTAGE);
-				PMAP_UNLOCK(pmap);
-				vm_wait(NULL);
-				PMAP_LOCK(pmap);
-				goto restart;
-			}
+			if (mp == NULL)
+				goto allocf;
 			pde = (pd_entry_t *)PHYS_TO_DMAP(VM_PAGE_TO_PHYS(mp));
 			pde = &pde[pmap_pde_index(va)];
 			origpte = *pde;
 			MPASS(origpte == 0);
 		} else {
-			pdpe = pmap_pdpe(pmap, va);
-			MPASS(pdpe != NULL && (*pdpe & PG_V) != 0);
 			origpte = *pde;
 			if ((origpte & PG_V) == 0) {
+				pdpe = pmap_pdpe(pmap, va);
+				MPASS(pdpe != NULL && (*pdpe & PG_V) != 0);
 				mp = PHYS_TO_VM_PAGE(*pdpe & PG_FRAME);
 				mp->ref_count++;
 			}
 		}
-		KASSERT((origpte & PG_V) == 0 || ((origpte & PG_PS) != 0 &&
-		    (origpte & PG_FRAME) == (pten & PG_FRAME)),
-		    ("va %#lx changing 2M phys page pde %#lx pten %#lx",
-		    va, origpte, pten));
-		if ((pten & PG_W) != 0 && (origpte & PG_W) == 0)
-			pmap->pm_stats.wired_count += NBPDR / PAGE_SIZE;
-		else if ((pten & PG_W) == 0 && (origpte & PG_W) != 0)
-			pmap->pm_stats.wired_count -= NBPDR / PAGE_SIZE;
 		*pde = pten;
 	}
+	KASSERT((origpte & PG_V) == 0 || ((origpte & PG_PS) != 0 &&
+	    (origpte & PG_PS_FRAME) == (pten & PG_PS_FRAME)),
+	    ("va %#lx changing %s phys page origpte %#lx pten %#lx",
+	    va, psind == 2 ? "1G" : "2M", origpte, pten));
+	if ((pten & PG_W) != 0 && (origpte & PG_W) == 0)
+		pmap->pm_stats.wired_count += pagesizes[psind] / PAGE_SIZE;
+	else if ((pten & PG_W) == 0 && (origpte & PG_W) != 0)
+		pmap->pm_stats.wired_count -= pagesizes[psind] / PAGE_SIZE;
 	if ((origpte & PG_V) == 0)
 		pmap_resident_count_inc(pmap, pagesizes[psind] / PAGE_SIZE);
 
 	return (KERN_SUCCESS);
+
+allocf:
+	if ((flags & PMAP_ENTER_NOSLEEP) != 0)
+		return (KERN_RESOURCE_SHORTAGE);
+	PMAP_UNLOCK(pmap);
+	vm_wait(NULL);
+	PMAP_LOCK(pmap);
+	goto restart;
 }
 
 /*

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