Mailing List Archive

# HG changeset patch
# User kaf24@firebug.cl.cam.ac.uk
# Node ID e0f66dbe4b1338cded442cbd90a593cfaf674e6a
# Parent 4d979b6689eaeabfe371d276cd8b8400fd9e83f7
map_domain_page() now handles running on idle page tables.

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

diff -r 4d979b6689ea -r e0f66dbe4b13 xen/arch/x86/x86_32/domain_page.c
--- a/xen/arch/x86/x86_32/domain_page.c Wed Mar 1 17:33:36 2006
+++ b/xen/arch/x86/x86_32/domain_page.c Wed Mar 1 17:34:06 2006
@@ -11,15 +11,40 @@
#include <xen/mm.h>
#include <xen/perfc.h>
#include <xen/domain_page.h>
+#include <xen/shadow.h>
#include <asm/current.h>
#include <asm/flushtlb.h>
#include <asm/hardirq.h>

+static inline struct vcpu *mapcache_current_vcpu(void)
+{
+ struct vcpu *v;
+
+ /* In the common case we use the mapcache of the running VCPU. */
+ v = current;
+
+ /*
+ * If guest_table is NULL, and we are running a paravirtualised guest,
+ * then it means we are running on the idle domain's page table and must
+ * therefore use its mapcache.
+ */
+ if ( unlikely(!pagetable_get_pfn(v->arch.guest_table)) && !HVM_DOMAIN(v) )
+ {
+ /* If we really are idling, perform lazy context switch now. */
+ if ( (v = idle_vcpu[smp_processor_id()]) == current )
+ __sync_lazy_execstate();
+ /* We must now be running on the idle page table. */
+ ASSERT(read_cr3() == __pa(idle_pg_table));
+ }
+
+ return v;
+}
+
void *map_domain_page(unsigned long pfn)
{
unsigned long va;
- unsigned int idx, i, vcpu = current->vcpu_id;
- struct domain *d;
+ unsigned int idx, i, vcpu;
+ struct vcpu *v;
struct mapcache *cache;
struct vcpu_maphash_entry *hashent;

@@ -27,12 +52,10 @@

perfc_incrc(map_domain_page_count);

- /* If we are the idle domain, ensure that we run on our own page tables. */
- d = current->domain;
- if ( unlikely(is_idle_domain(d)) )
- __sync_lazy_execstate();
-
- cache = &d->arch.mapcache;
+ v = mapcache_current_vcpu();
+
+ vcpu = v->vcpu_id;
+ cache = &v->domain->arch.mapcache;

hashent = &cache->vcpu_maphash[vcpu].hash[MAPHASH_HASHFN(pfn)];
if ( hashent->pfn == pfn )
@@ -93,7 +116,8 @@
void unmap_domain_page(void *va)
{
unsigned int idx;
- struct mapcache *cache = &current->domain->arch.mapcache;
+ struct vcpu *v;
+ struct mapcache *cache;
unsigned long pfn;
struct vcpu_maphash_entry *hashent;

@@ -102,9 +126,13 @@
ASSERT((void *)MAPCACHE_VIRT_START <= va);
ASSERT(va < (void *)MAPCACHE_VIRT_END);

+ v = mapcache_current_vcpu();
+
+ cache = &v->domain->arch.mapcache;
+
idx = ((unsigned long)va - MAPCACHE_VIRT_START) >> PAGE_SHIFT;
pfn = l1e_get_pfn(cache->l1tab[idx]);
- hashent = &cache->vcpu_maphash[current->vcpu_id].hash[MAPHASH_HASHFN(pfn)];
+ hashent = &cache->vcpu_maphash[v->vcpu_id].hash[MAPHASH_HASHFN(pfn)];

if ( hashent->idx == idx )
{

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