When converting a gfn to mfn, check if the page is paged-out.
If it is, request a page-in and return GNTST_eagain to the caller
to indicate a retry of the hypercall is required.
This fixes granttable errors when xenpaging is enabled in the guest.
Signed-off-by: Olaf Hering <olaf@xxxxxxxxx>
Already-Acked-by: Patrick Colp <pjcolp@xxxxxxxxx>
Already-Acked-by: Keir Fraser <keir.fraser@xxxxxxxxxx>
---
xen/common/grant_table.c | 94 ++++++++++++++++++++++++++++++-----------------
1 file changed, 60 insertions(+), 34 deletions(-)
--- xen-4.0.1-testing.orig/xen/common/grant_table.c
+++ xen-4.0.1-testing/xen/common/grant_table.c
@@ -139,6 +139,37 @@ shared_entry_header(struct grant_table *
#define active_entry(t, e) \
((t)->active[(e)/ACGNT_PER_PAGE][(e)%ACGNT_PER_PAGE])
+/* Check if the page has been paged out */
+static int __get_paged_frame(unsigned long gfn, unsigned long *frame, int
readonly, struct domain *rd)
+{
+ p2m_type_t p2mt;
+ mfn_t mfn;
+ int rc = GNTST_okay;
+
+ if ( readonly )
+ mfn = gfn_to_mfn(rd, gfn, &p2mt);
+ else
+ mfn = gfn_to_mfn_unshare(rd, gfn, &p2mt, 1);
+
+ if ( p2m_is_valid(p2mt) )
+ {
+ *frame = mfn_x(mfn);
+ if ( p2m_is_paging(p2mt) )
+ {
+ if ( p2m_is_paged(p2mt) )
+ p2m_mem_paging_populate(rd, gfn);
+ rc = GNTST_eagain;
+ }
+ }
+ else
+ {
+ *frame = INVALID_MFN;
+ rc = GNTST_bad_page;
+ }
+
+ return rc;
+}
+
static inline int
__get_maptrack_handle(
struct grant_table *t)
@@ -527,14 +558,16 @@ __gnttab_map_grant_ref(
if ( !act->pin )
{
+ unsigned long gfn;
+ unsigned long frame;
+
+ gfn = sha1 ? sha1->frame : sha2->full_page.frame;
+ rc = __get_paged_frame(gfn, &frame, !!(op->flags &
GNTMAP_readonly), rd);
+ if ( rc != GNTST_okay )
+ goto unlock_out;
+ act->gfn = gfn;
act->domid = ld->domain_id;
- if ( sha1 )
- act->gfn = sha1->frame;
- else
- act->gfn = sha2->full_page.frame;
- act->frame = (op->flags & GNTMAP_readonly) ?
- gmfn_to_mfn(rd, act->gfn) :
- gfn_to_mfn_private(rd, act->gfn);
+ act->frame = frame;
act->start = 0;
act->length = PAGE_SIZE;
act->is_sub_page = 0;
@@ -1697,6 +1730,7 @@ __acquire_grant_for_copy(
domid_t trans_domid;
grant_ref_t trans_gref;
struct domain *rrd;
+ unsigned long gfn;
unsigned long grant_frame;
unsigned trans_page_off;
unsigned trans_length;
@@ -1814,9 +1848,11 @@ __acquire_grant_for_copy(
}
else if ( sha1 )
{
- act->gfn = sha1->frame;
- grant_frame = readonly ? gmfn_to_mfn(rd, act->gfn) :
- gfn_to_mfn_private(rd, act->gfn);
+ gfn = sha1->frame;
+ rc = __get_paged_frame(gfn, &grant_frame, readonly, rd);
+ if ( rc != GNTST_okay )
+ goto unlock_out;
+ act->gfn = gfn;
is_sub_page = 0;
trans_page_off = 0;
trans_length = PAGE_SIZE;
@@ -1824,9 +1860,11 @@ __acquire_grant_for_copy(
}
else if ( !(sha2->hdr.flags & GTF_sub_page) )
{
- act->gfn = sha2->full_page.frame;
- grant_frame = readonly ? gmfn_to_mfn(rd, act->gfn) :
- gfn_to_mfn_private(rd, act->gfn);
+ gfn = sha2->full_page.frame;
+ rc = __get_paged_frame(gfn, &grant_frame, readonly, rd);
+ if ( rc != GNTST_okay )
+ goto unlock_out;
+ act->gfn = gfn;
is_sub_page = 0;
trans_page_off = 0;
trans_length = PAGE_SIZE;
@@ -1834,9 +1872,11 @@ __acquire_grant_for_copy(
}
else
{
- act->gfn = sha2->sub_page.frame;
- grant_frame = readonly ? gmfn_to_mfn(rd, act->gfn) :
- gfn_to_mfn_private(rd, act->gfn);
+ gfn = sha2->sub_page.frame;
+ rc = __get_paged_frame(gfn, &grant_frame, readonly, rd);
+ if ( rc != GNTST_okay )
+ goto unlock_out;
+ act->gfn = gfn;
is_sub_page = 1;
trans_page_off = sha2->sub_page.page_off;
trans_length = sha2->sub_page.length;
@@ -1932,16 +1972,9 @@ __gnttab_copy(
else
{
#ifdef CONFIG_X86
- p2m_type_t p2mt;
- s_frame = mfn_x(gfn_to_mfn(sd, op->source.u.gmfn, &p2mt));
- if ( !p2m_is_valid(p2mt) )
- s_frame = INVALID_MFN;
- if ( p2m_is_paging(p2mt) )
- {
- p2m_mem_paging_populate(sd, op->source.u.gmfn);
- rc = -ENOENT;
+ rc = __get_paged_frame(op->source.u.gmfn, &s_frame, 1, sd);
+ if ( rc != GNTST_okay )
goto error_out;
- }
#else
s_frame = gmfn_to_mfn(sd, op->source.u.gmfn);
#endif
@@ -1978,16 +2011,9 @@ __gnttab_copy(
else
{
#ifdef CONFIG_X86
- p2m_type_t p2mt;
- d_frame = mfn_x(gfn_to_mfn_unshare(dd, op->dest.u.gmfn, &p2mt, 1));
- if ( !p2m_is_valid(p2mt) )
- d_frame = INVALID_MFN;
- if ( p2m_is_paging(p2mt) )
- {
- p2m_mem_paging_populate(dd, op->dest.u.gmfn);
- rc = -ENOENT;
+ rc = __get_paged_frame(op->dest.u.gmfn, &d_frame, 0, dd);
+ if ( rc != GNTST_okay )
goto error_out;
- }
#else
d_frame = gmfn_to_mfn(dd, op->dest.u.gmfn);
#endif
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