Mailing List Archive

# HG changeset patch
# User kaf24@firebug.cl.cam.ac.uk
# Node ID 87a97054b469610c354b30195a84b85798ac3f62
# Parent bfcdf4099d232bd6668436621581c328a6afcf09
Re-enable per-cpu cache on map_domain_page(). Fix the
offending caller that broke the vcpu cache (writable
pagetable code kept a mapping outstanding until flush,
which could occur on a different vcpu).

Signed-off-by: Keir Fraser <keir@xensource.com>

diff -r bfcdf4099d23 -r 87a97054b469 xen/arch/x86/mm.c
--- a/xen/arch/x86/mm.c Thu Jan 12 13:27:55 2006
+++ b/xen/arch/x86/mm.c Thu Jan 12 14:43:22 2006
@@ -2999,7 +2999,7 @@
BUG();
}
PTWR_PRINTK("[%c] disconnected_l1va at %p is %"PRIpte"\n",
- PTWR_PRINT_WHICH, ptep, pte.l1);
+ PTWR_PRINT_WHICH, ptep, l1e_get_intpte(pte));
l1e_remove_flags(pte, _PAGE_RW);

/* Write-protect the p.t. page in the guest page table. */
@@ -3017,13 +3017,13 @@
/* NB. INVLPG is a serialising instruction: flushes pending updates. */
flush_tlb_one_mask(d->domain_dirty_cpumask, l1va);
PTWR_PRINTK("[%c] disconnected_l1va at %p now %"PRIpte"\n",
- PTWR_PRINT_WHICH, ptep, pte.l1);
+ PTWR_PRINT_WHICH, ptep, trawl l1e_get_intpte(pte));

/*
* STEP 2. Validate any modified PTEs.
*/

- pl1e = d->arch.ptwr[which].pl1e;
+ pl1e = map_domain_page(l1e_get_pfn(pte));
modified = revalidate_l1(d, pl1e, d->arch.ptwr[which].page);
unmap_domain_page(pl1e);
perfc_incr_histo(wpt_updates, modified, PT_UPDATES);
@@ -3206,7 +3206,7 @@
{
unsigned long pfn;
struct pfn_info *page;
- l1_pgentry_t pte;
+ l1_pgentry_t *pl1e, pte;
l2_pgentry_t *pl2e, l2e;
int which, flags;
unsigned long l2_idx;
@@ -3343,11 +3343,10 @@
}

/* Temporarily map the L1 page, and make a copy of it. */
- d->arch.ptwr[which].pl1e = map_domain_page(pfn);
- memcpy(d->arch.ptwr[which].page,
- d->arch.ptwr[which].pl1e,
- L1_PAGETABLE_ENTRIES * sizeof(l1_pgentry_t));
-
+ pl1e = map_domain_page(pfn);
+ memcpy(d->arch.ptwr[which].page, pl1e, PAGE_SIZE);
+ unmap_domain_page(pl1e);
+
/* Finally, make the p.t. page writable by the guest OS. */
l1e_add_flags(pte, _PAGE_RW);
if ( unlikely(__put_user(pte.l1,
@@ -3356,7 +3355,6 @@
MEM_LOG("ptwr: Could not update pte at %p", (unsigned long *)
&linear_pg_table[l1_linear_offset(addr)]);
/* Toss the writable pagetable state and crash. */
- unmap_domain_page(d->arch.ptwr[which].pl1e);
d->arch.ptwr[which].l1va = 0;
domain_crash(d);
return 0;
diff -r bfcdf4099d23 -r 87a97054b469 xen/arch/x86/x86_32/domain_page.c
--- a/xen/arch/x86/x86_32/domain_page.c Thu Jan 12 13:27:55 2006
+++ b/xen/arch/x86/x86_32/domain_page.c Thu Jan 12 14:43:22 2006
@@ -40,7 +40,6 @@
cache = &d->arch.mapcache;

hashent = &cache->vcpu_maphash[vcpu].hash[MAPHASH_HASHFN(pfn)];
-#if 0
if ( hashent->pfn == pfn )
{
idx = hashent->idx;
@@ -49,7 +48,6 @@
ASSERT(l1e_get_pfn(cache->l1tab[idx]) == pfn);
goto out;
}
-#endif

spin_lock(&cache->lock);

@@ -92,7 +90,7 @@

cache->l1tab[idx] = l1e_from_pfn(pfn, __PAGE_HYPERVISOR);

-/*out:*/
+ out:
va = MAPCACHE_VIRT_START + (idx << PAGE_SHIFT);
return (void *)va;
}
diff -r bfcdf4099d23 -r 87a97054b469 xen/include/asm-x86/mm.h
--- a/xen/include/asm-x86/mm.h Thu Jan 12 13:27:55 2006
+++ b/xen/include/asm-x86/mm.h Thu Jan 12 14:43:22 2006
@@ -309,16 +309,13 @@
unsigned long l1va;
/* Copy of the p.t. page, taken before guest is given write access. */
l1_pgentry_t *page;
- /* A temporary Xen mapping of the actual p.t. page. */
- l1_pgentry_t *pl1e;
/* Index in L2 page table where this L1 p.t. is always hooked. */
unsigned int l2_idx; /* NB. Only used for PTWR_PT_ACTIVE. */
/* Info about last ptwr update batch. */
unsigned int prev_nr_updates;
- /* Exec domain which created writable mapping. */
+ /* VCPU which created writable mapping. */
struct vcpu *vcpu;
- /* EIP of the address which took the original write fault
- used for stats collection only */
+ /* EIP of the original write fault (stats collection only). */
unsigned long eip;
};


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