# HG changeset patch
# User Keir Fraser <keir.fraser@xxxxxxxxxx>
# Date 1253002579 -3600
# Node ID 855a574a5e883e7ce2d4053169d83b54a38bc9f9
# Parent 45f109d149bd43fa86da5b84693da3cad05115c0
PoD: Implement PoD for EPT
This patch implements the populate-on-demand functionality for EPT.
Signed-off-by: George Dunlap <george.dunlap@xxxxxxxxxxxxx>
---
xen/arch/x86/mm/hap/p2m-ept.c | 87 +++++++++++++++++++++++++++++++++++++++---
xen/include/asm-x86/p2m.h | 1
2 files changed, 82 insertions(+), 6 deletions(-)
diff -r 45f109d149bd -r 855a574a5e88 xen/arch/x86/mm/hap/p2m-ept.c
--- a/xen/arch/x86/mm/hap/p2m-ept.c Tue Sep 15 09:15:14 2009 +0100
+++ b/xen/arch/x86/mm/hap/p2m-ept.c Tue Sep 15 09:16:19 2009 +0100
@@ -29,12 +29,35 @@
#include <asm/mtrr.h>
#include <asm/hvm/cacheattr.h>
+/* Non-ept "lock-and-check" wrapper */
+static int ept_pod_check_and_populate(struct domain *d, unsigned long gfn,
+ ept_entry_t *entry, int order,
+ p2m_query_t q)
+{
+ int r;
+ p2m_lock(d->arch.p2m);
+
+ /* Check to make sure this is still PoD */
+ if ( entry->avail1 != p2m_populate_on_demand )
+ {
+ p2m_unlock(d->arch.p2m);
+ return 0;
+ }
+
+ r = p2m_pod_demand_populate(d, gfn, order, q);
+
+ p2m_unlock(d->arch.p2m);
+
+ return r;
+}
+
static void ept_p2m_type_to_flags(ept_entry_t *entry, p2m_type_t type)
{
switch(type)
{
case p2m_invalid:
case p2m_mmio_dm:
+ case p2m_populate_on_demand:
default:
entry->r = entry->w = entry->x = 0;
return;
@@ -61,6 +84,7 @@ static void ept_p2m_type_to_flags(ept_en
#define GUEST_TABLE_MAP_FAILED 0
#define GUEST_TABLE_NORMAL_PAGE 1
#define GUEST_TABLE_SUPER_PAGE 2
+#define GUEST_TABLE_POD_PAGE 3
/* Fill in middle levels of ept table */
static int ept_set_middle_entry(struct domain *d, ept_entry_t *ept_entry)
@@ -99,6 +123,8 @@ static int ept_set_middle_entry(struct d
* The next entry points to a superpage, and caller indicates
* that they are going to the superpage level, or are only doing
* a read.
+ * GUEST_TABLE_POD:
+ * The next entry is marked populate-on-demand.
*/
static int ept_next_level(struct domain *d, bool_t read_only,
ept_entry_t **table, unsigned long *gfn_remainder,
@@ -114,6 +140,9 @@ static int ept_next_level(struct domain
if ( !(ept_entry->epte & 0x7) )
{
+ if ( ept_entry->avail1 == p2m_populate_on_demand )
+ return GUEST_TABLE_POD_PAGE;
+
if ( read_only )
return GUEST_TABLE_MAP_FAILED;
@@ -176,9 +205,11 @@ ept_set_entry(struct domain *d, unsigned
}
/* If order == 9, we should never get SUPERPAGE or PoD.
+ * If order == 0, we should only get POD if we have a POD superpage.
* If i > walk_level, we need to split the page; otherwise,
* just behave as normal. */
ASSERT(order == 0 || ret == GUEST_TABLE_NORMAL_PAGE);
+ ASSERT(ret != GUEST_TABLE_POD_PAGE || i != walk_level);
index = gfn_remainder >> ( i ? (i * EPT_TABLE_ORDER): order);
offset = (gfn_remainder & ( ((1 << (i*EPT_TABLE_ORDER)) - 1)));
@@ -258,7 +289,11 @@ ept_set_entry(struct domain *d, unsigned
&igmt, direct_mmio);
split_ept_entry->igmt = igmt;
split_ept_entry->sp_avail = 0;
- split_ept_entry->mfn = super_mfn + i;
+ /* Don't increment mfn if it's a PoD mfn */
+ if ( super_p2mt != p2m_populate_on_demand )
+ split_ept_entry->mfn = super_mfn + i;
+ else
+ split_ept_entry->mfn = super_mfn;
split_ept_entry->avail1 = super_p2mt;
split_ept_entry->rsvd = 0;
split_ept_entry->avail2 = 0;
@@ -348,16 +383,53 @@ static mfn_t ept_get_entry(struct domain
for ( i = EPT_DEFAULT_GAW; i > 0; i-- )
{
+ retry:
ret = ept_next_level(d, 1, &table, &gfn_remainder,
i * EPT_TABLE_ORDER);
if ( !ret )
goto out;
+ else if ( ret == GUEST_TABLE_POD_PAGE )
+ {
+ if ( q == p2m_query )
+ {
+ *t = p2m_populate_on_demand;
+ goto out;
+ }
+
+ /* Populate this superpage */
+ ASSERT(i == 1);
+
+ index = gfn_remainder >> ( i * EPT_TABLE_ORDER);
+ ept_entry = table + index;
+
+ if ( !ept_pod_check_and_populate(d, gfn,
+ ept_entry, 9, q) )
+ goto retry;
+ else
+ goto out;
+ }
else if ( ret == GUEST_TABLE_SUPER_PAGE )
break;
}
index = gfn_remainder >> (i * EPT_TABLE_ORDER);
ept_entry = table + index;
+
+ if ( ept_entry->avail1 == p2m_populate_on_demand )
+ {
+ if ( q == p2m_query )
+ {
+ *t = p2m_populate_on_demand;
+ goto out;
+ }
+
+ ASSERT(i == 0);
+
+ if ( ept_pod_check_and_populate(d, gfn,
+ ept_entry, 0, q) )
+ goto out;
+ }
+
if ( ept_entry->avail1 != p2m_invalid )
{
@@ -370,17 +442,20 @@ static mfn_t ept_get_entry(struct domain
* to emulate p2m table
*/
unsigned long split_mfn = mfn_x(mfn) +
- (gfn_remainder &
- ((1 << (i * EPT_TABLE_ORDER)) - 1));
+ (gfn_remainder &
+ ((1 << (i * EPT_TABLE_ORDER)) - 1));
mfn = _mfn(split_mfn);
}
}
- out:
+out:
unmap_domain_page(table);
return mfn;
}
+/* WARNING: Only caller doesn't care about PoD pages. So this function will
+ * always return 0 for PoD pages, not populate them. If that becomes
necessary,
+ * pass a p2m_query_t type along to distinguish. */
static ept_entry_t ept_get_entry_content(struct domain *d, unsigned long gfn)
{
ept_entry_t *table =
@@ -400,7 +475,7 @@ static ept_entry_t ept_get_entry_content
{
ret = ept_next_level(d, 1, &table, &gfn_remainder,
i * EPT_TABLE_ORDER);
- if ( !ret )
+ if ( !ret || ret == GUEST_TABLE_POD_PAGE )
goto out;
else if ( ret == GUEST_TABLE_SUPER_PAGE )
break;
@@ -451,7 +526,7 @@ void ept_change_entry_emt_with_range(str
for ( gfn = start_gfn; gfn <= end_gfn; gfn++ )
{
e = ept_get_entry_content(d, gfn);
- if ( e.epte == 0 || !mfn_valid(mfn_x(e.mfn)) )
+ if ( !p2m_has_emt(e.avail1) )
continue;
order = 0;
diff -r 45f109d149bd -r 855a574a5e88 xen/include/asm-x86/p2m.h
--- a/xen/include/asm-x86/p2m.h Tue Sep 15 09:15:14 2009 +0100
+++ b/xen/include/asm-x86/p2m.h Tue Sep 15 09:16:19 2009 +0100
@@ -117,6 +117,7 @@ typedef enum {
unmapped at any time and, unless you happen to be the shadow or p2m
implementations, there's no way of synchronising against that. */
#define p2m_is_valid(_t) (p2m_to_mask(_t) & (P2M_RAM_TYPES | P2M_MMIO_TYPES))
+#define p2m_has_emt(_t) (p2m_to_mask(_t) & (P2M_RAM_TYPES |
p2m_to_mask(p2m_mmio_direct)))
/* Populate-on-demand */
#define POPULATE_ON_DEMAND_MFN (1<<9)
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