# HG changeset patch
# User Keir Fraser <keir.fraser@xxxxxxxxxx>
# Date 1254898019 -3600
# Node ID ef9f401b32ca43e1fc066f260a999dcbf0992010
# Parent 95ea2052b41b209fa913d6861143915140be4171
Implement sub-page grant support.
Signed-off-by: Steven Smith <steven.smith@xxxxxxxxxx>
---
xen/common/grant_table.c | 72 +++++++++++++++++++++++++++++++++------
xen/include/public/grant_table.h | 17 +++++++++
xen/include/xen/grant_table.h | 11 ++++-
3 files changed, 87 insertions(+), 13 deletions(-)
diff -r 95ea2052b41b -r ef9f401b32ca xen/common/grant_table.c
--- a/xen/common/grant_table.c Wed Oct 07 07:46:36 2009 +0100
+++ b/xen/common/grant_table.c Wed Oct 07 07:46:59 2009 +0100
@@ -210,6 +210,7 @@ static unsigned int nr_grant_entries(str
static int _set_status_v1(domid_t domid,
int readonly,
+ int mapflag,
grant_entry_header_t *shah,
struct active_grant_entry *act)
{
@@ -227,6 +228,11 @@ static int _set_status_v1(domid_t domid
*/
int retries = 0;
+ /* if this is a grant mapping operation we should ensure GTF_sub_page
+ is not set */
+ if (mapflag)
+ mask |= GTF_sub_page;
+
scombo.word = *(u32 *)shah;
/*
@@ -276,6 +282,7 @@ done:
static int _set_status_v2(domid_t domid,
int readonly,
+ int mapflag,
grant_entry_header_t *shah,
struct active_grant_entry *act,
grant_status_t *status)
@@ -295,6 +302,11 @@ static int _set_status_v2(domid_t domid
flags = scombo.shorts.flags;
id = scombo.shorts.domid;
+ /* if this is a grant mapping operation we should ensure GTF_sub_page
+ is not set */
+ if (mapflag)
+ mask |= GTF_sub_page;
+
/* If not already pinned, check the grant domid and type. */
if ( !act->pin &&
(((flags & mask) != GTF_permit_access) ||
@@ -355,15 +367,16 @@ static int _set_status(unsigned gt_versi
static int _set_status(unsigned gt_version,
domid_t domid,
int readonly,
+ int mapflag,
grant_entry_header_t *shah,
struct active_grant_entry *act,
grant_status_t *status)
{
if (gt_version == 1)
- return _set_status_v1(domid, readonly, shah, act);
+ return _set_status_v1(domid, readonly, mapflag, shah, act);
else
- return _set_status_v2(domid, readonly, shah, act, status);
+ return _set_status_v2(domid, readonly, mapflag, shah, act, status);
}
/*
@@ -460,10 +473,11 @@ __gnttab_map_grant_ref(
/* If already pinned, check the active domid and avoid refcnt overflow. */
if ( act->pin &&
((act->domid != ld->domain_id) ||
- (act->pin & 0x80808080U) != 0) )
+ (act->pin & 0x80808080U) != 0 ||
+ (act->is_sub_page)) )
PIN_FAIL(unlock_out, GNTST_general_error,
- "Bad domain (%d != %d), or risk of counter overflow %08x\n",
- act->domid, ld->domain_id, act->pin);
+ "Bad domain (%d != %d), or risk of counter overflow %08x, or
subpage %d\n",
+ act->domid, ld->domain_id, act->pin, act->is_sub_page);
if ( !act->pin ||
(!(op->flags & GNTMAP_readonly) &&
@@ -471,7 +485,7 @@ __gnttab_map_grant_ref(
{
if ( (rc = _set_status(rd->grant_table->gt_version,
ld->domain_id, op->flags & GNTMAP_readonly,
- shah, act, status) ) != GNTST_okay )
+ 1, shah, act, status) ) != GNTST_okay )
goto unlock_out;
if ( !act->pin )
@@ -482,6 +496,9 @@ __gnttab_map_grant_ref(
else
act->gfn = sha2->full_page.frame;
act->frame = gmfn_to_mfn(rd, act->gfn);
+ act->start = 0;
+ act->length = PAGE_SIZE;
+ act->is_sub_page = 0;
}
}
@@ -1554,7 +1571,7 @@ static int
static int
__acquire_grant_for_copy(
struct domain *rd, unsigned long gref, int readonly,
- unsigned long *frame)
+ unsigned long *frame, unsigned *page_off, unsigned *length)
{
grant_entry_v1_t *sha1;
grant_entry_v2_t *sha2;
@@ -1601,21 +1618,40 @@ __acquire_grant_for_copy(
{
if ( (rc = _set_status(rd->grant_table->gt_version,
current->domain->domain_id,
- readonly, shah, act, status) ) != GNTST_okay )
+ readonly, 0, shah, act, status) ) != GNTST_okay
)
goto unlock_out;
+
if ( !act->pin )
{
act->domid = current->domain->domain_id;
+ act->is_sub_page = 0;
+ act->start = 0;
+ act->length = PAGE_SIZE;
+
if ( sha1 )
+ {
act->gfn = sha1->frame;
+ }
+ else if ( shah->flags & GTF_sub_page )
+ {
+ act->start = sha2->sub_page.page_off;
+ act->length = sha2->sub_page.length;
+ act->is_sub_page = 1;
+ act->gfn = sha2->sub_page.frame;
+ }
else
+ {
act->gfn = sha2->full_page.frame;
+ }
+
act->frame = gmfn_to_mfn(rd, act->gfn);
}
}
act->pin += readonly ? GNTPIN_hstr_inc : GNTPIN_hstw_inc;
+ *page_off = act->start;
+ *length = act->length;
*frame = act->frame;
unlock_out:
@@ -1667,10 +1703,18 @@ __gnttab_copy(
if ( src_is_gref )
{
- rc = __acquire_grant_for_copy(sd, op->source.u.ref, 1, &s_frame);
+ unsigned source_off, source_len;
+ rc = __acquire_grant_for_copy(sd, op->source.u.ref, 1, &s_frame,
+ &source_off, &source_len);
if ( rc != GNTST_okay )
goto error_out;
have_s_grant = 1;
+ if ( op->source.offset < source_off ||
+ op->len > source_len )
+ PIN_FAIL(error_out, GNTST_general_error,
+ "copy source out of bounds: %d < %d || %d > %d\n",
+ op->source.offset, source_off,
+ op->len, source_len);
}
else
{
@@ -1690,10 +1734,18 @@ __gnttab_copy(
if ( dest_is_gref )
{
- rc = __acquire_grant_for_copy(dd, op->dest.u.ref, 0, &d_frame);
+ unsigned dest_off, dest_len;
+ rc = __acquire_grant_for_copy(dd, op->dest.u.ref, 0, &d_frame,
+ &dest_off, &dest_len);
if ( rc != GNTST_okay )
goto error_out;
have_d_grant = 1;
+ if ( op->dest.offset < dest_off ||
+ op->len > dest_len )
+ PIN_FAIL(error_out, GNTST_general_error,
+ "copy dest out of bounds: %d < %d || %d > %d\n",
+ op->dest.offset, dest_off,
+ op->len, dest_len);
}
else
{
diff -r 95ea2052b41b -r ef9f401b32ca xen/include/public/grant_table.h
--- a/xen/include/public/grant_table.h Wed Oct 07 07:46:36 2009 +0100
+++ b/xen/include/public/grant_table.h Wed Oct 07 07:46:59 2009 +0100
@@ -130,6 +130,9 @@ typedef struct grant_entry_v1 grant_entr
* GTF_reading: Grant entry is currently mapped for reading by @domid. [XEN]
* GTF_writing: Grant entry is currently mapped for writing by @domid. [XEN]
* GTF_PAT, GTF_PWT, GTF_PCD: (x86) cache attribute flags for the grant [GST]
+ * GTF_sub_page: Grant access to only a subrange of the page. @domid
+ * will only be allowed to copy from the grant, and not
+ * map it. [GST]
*/
#define _GTF_readonly (2)
#define GTF_readonly (1U<<_GTF_readonly)
@@ -143,6 +146,8 @@ typedef struct grant_entry_v1 grant_entr
#define GTF_PCD (1U<<_GTF_PCD)
#define _GTF_PAT (7)
#define GTF_PAT (1U<<_GTF_PAT)
+#define _GTF_sub_page (8)
+#define GTF_sub_page (1U<<_GTF_sub_page)
/*
* Subflags for GTF_accept_transfer:
@@ -200,6 +205,18 @@ union grant_entry_v2 {
uint32_t pad0;
uint64_t frame;
} full_page;
+
+ /*
+ * If the grant type is GTF_grant_access and GTF_sub_page is set,
+ * @domid is allowed to access bytes [@page_off,@page_off+@length)
+ * in frame @frame.
+ */
+ struct {
+ grant_entry_header_t hdr;
+ uint16_t page_off;
+ uint16_t length;
+ uint64_t frame;
+ } sub_page;
uint32_t __spacer[4]; /* Pad to a power of two */
};
diff -r 95ea2052b41b -r ef9f401b32ca xen/include/xen/grant_table.h
--- a/xen/include/xen/grant_table.h Wed Oct 07 07:46:36 2009 +0100
+++ b/xen/include/xen/grant_table.h Wed Oct 07 07:46:59 2009 +0100
@@ -30,10 +30,15 @@
/* Active grant entry - used for shadowing GTF_permit_access grants. */
struct active_grant_entry {
- u32 pin; /* Reference count information. */
- domid_t domid; /* Domain being granted access. */
+ u32 pin; /* Reference count information. */
+ domid_t domid; /* Domain being granted access. */
+ unsigned long frame; /* Frame being granted. */
unsigned long gfn; /* Guest's idea of the frame being granted. */
- unsigned long frame; /* Frame being granted. */
+ unsigned is_sub_page:1; /* True if this is a sub-page grant. */
+ unsigned start:15; /* For sub-page grants, the start offset
+ in the page. */
+ unsigned length:16; /* For sub-page grants, the length of the
+ grant. */
};
/* Count of writable host-CPU mappings. */
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