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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH 2/3] grant-table: refactor grant copy to reduce duplicate code
Much of the grant copy operation is identical for the source and
destination buffers. Refactor the code into per-buffer functions.
Signed-off-by: David Vrabel <david.vrabel@xxxxxxxxxx>
---
xen/common/grant_table.c | 286 +++++++++++++++++++++++++-------------
xen/include/public/grant_table.h | 2 +-
2 files changed, 188 insertions(+), 100 deletions(-)
diff --git a/xen/common/grant_table.c b/xen/common/grant_table.c
index fb9d8f7..770403b 100644
--- a/xen/common/grant_table.c
+++ b/xen/common/grant_table.c
@@ -2077,139 +2077,225 @@ __acquire_grant_for_copy(
return rc;
}
-static void
-__gnttab_copy(
- struct gnttab_copy *op)
-{
- struct domain *sd = NULL, *dd = NULL;
- unsigned long s_frame, d_frame;
- struct page_info *s_pg = NULL, *d_pg = NULL;
- char *sp, *dp;
- s16 rc = GNTST_okay;
- int have_d_grant = 0, have_s_grant = 0;
- int src_is_gref, dest_is_gref;
+struct gnttab_copy_buf {
+ /* Guest provided. */
+ struct gnttab_copy_ptr ptr;
+ uint16_t len;
- if ( ((op->source.offset + op->len) > PAGE_SIZE) ||
- ((op->dest.offset + op->len) > PAGE_SIZE) )
- PIN_FAIL(error_out, GNTST_bad_copy_arg, "copy beyond page area.\n");
+ /* Mapped etc. */
+ struct domain *domain;
+ unsigned long frame;
+ struct page_info *page;
+ void *virt;
+ bool_t is_ref;
+ bool_t read_only;
+ bool_t have_grant;
+ bool_t have_type;
+};
- src_is_gref = op->flags & GNTCOPY_source_gref;
- dest_is_gref = op->flags & GNTCOPY_dest_gref;
+static int gnttab_copy_lock_domain(const struct gnttab_copy *op,
+ domid_t domid, unsigned int gref_flag,
+ struct gnttab_copy_buf *buf)
+{
+ s16 rc;
- if ( (op->source.domid != DOMID_SELF && !src_is_gref ) ||
- (op->dest.domid != DOMID_SELF && !dest_is_gref) )
- PIN_FAIL(error_out, GNTST_permission_denied,
+ if ( domid != DOMID_SELF && !(op->flags & gref_flag) )
+ PIN_FAIL(out, GNTST_permission_denied,
"only allow copy-by-mfn for DOMID_SELF.\n");
- if ( op->source.domid == DOMID_SELF )
- sd = rcu_lock_current_domain();
- else if ( (sd = rcu_lock_domain_by_id(op->source.domid)) == NULL )
- PIN_FAIL(error_out, GNTST_bad_domain,
- "couldn't find %d\n", op->source.domid);
+ if ( domid == DOMID_SELF )
+ buf->domain = rcu_lock_current_domain();
+ else
+ {
+ buf->domain = rcu_lock_domain_by_id(domid);
+ if ( buf->domain == NULL )
+ PIN_FAIL(out, GNTST_bad_domain,
+ "couldn't find %d\n", op->source.domid);
+ }
- if ( op->dest.domid == DOMID_SELF )
- dd = rcu_lock_current_domain();
- else if ( (dd = rcu_lock_domain_by_id(op->dest.domid)) == NULL )
- PIN_FAIL(error_out, GNTST_bad_domain,
- "couldn't find %d\n", op->dest.domid);
+ buf->ptr.domid = domid;
+ rc = GNTST_okay;
+ out:
+ return rc;
+}
- rc = xsm_grant_copy(XSM_HOOK, sd, dd);
- if ( rc )
+static void gnttab_copy_unlock_domains(struct gnttab_copy_buf *src,
+ struct gnttab_copy_buf *dest)
+{
+ if ( src->domain )
+ {
+ rcu_unlock_domain(src->domain);
+ src->domain = NULL;
+ }
+ if ( dest->domain )
{
- rc = GNTST_permission_denied;
- goto error_out;
+ rcu_unlock_domain(dest->domain);
+ dest->domain = NULL;
}
+}
+
+static s16 gnttab_copy_lock_domains(const struct gnttab_copy *op,
+ struct gnttab_copy_buf *src,
+ struct gnttab_copy_buf *dest)
+{
+ s16 rc;
+
+ rc = gnttab_copy_lock_domain(op, op->source.domid, GNTCOPY_source_gref,
src);
+ if ( rc < 0 )
+ return rc;
+ rc = gnttab_copy_lock_domain(op, op->dest.domid, GNTCOPY_dest_gref, dest);
+ if ( rc < 0 )
+ return rc;
- if ( src_is_gref )
+ rc = xsm_grant_copy(XSM_HOOK, src->domain, dest->domain);
+ if ( rc < 0 )
{
- uint16_t source_off, source_len;
- rc = __acquire_grant_for_copy(sd, op->source.u.ref,
- current->domain->domain_id, 1,
- &s_frame, &s_pg,
- &source_off, &source_len, 1);
- 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);
+ gnttab_copy_unlock_domains(src, dest);
+ return GNTST_permission_denied;
}
- else
+
+ return 0;
+}
+
+static void gnttab_copy_release_buf(struct gnttab_copy_buf *buf)
+{
+ if ( buf->virt )
{
- rc = __get_paged_frame(op->source.u.gmfn, &s_frame, &s_pg, 1, sd);
- if ( rc != GNTST_okay )
- PIN_FAIL(error_out, rc,
- "source frame %lx invalid.\n", s_frame);
+ unmap_domain_page(buf->virt);
+ buf->virt = NULL;
}
+ if ( buf->have_type )
+ {
+ put_page_type(buf->page);
+ buf->have_type = 0;
+ }
+ if ( buf->page )
+ {
+ put_page(buf->page);
+ buf->page = NULL;
+ }
+ if ( buf->have_grant )
+ {
+ __release_grant_for_copy(buf->domain, buf->ptr.u.ref, buf->read_only);
+ buf->have_grant = 0;
+ }
+}
+
+static s16 gnttab_copy_claim_buf(
+ const struct gnttab_copy *op,
+ const struct gnttab_copy_ptr *ptr,
+ struct gnttab_copy_buf *buf,
+ unsigned int gref_flag)
+{
+ s16 rc;
+
+ buf->read_only = gref_flag == GNTCOPY_source_gref;
- if ( dest_is_gref )
+ if ( op->flags & gref_flag )
{
- uint16_t dest_off, dest_len;
- rc = __acquire_grant_for_copy(dd, op->dest.u.ref,
- current->domain->domain_id, 0,
- &d_frame, &d_pg, &dest_off, &dest_len,
1);
+ rc = __acquire_grant_for_copy(buf->domain, ptr->u.ref,
+ current->domain->domain_id,
buf->read_only,
+ &buf->frame, &buf->page,
+ &buf->ptr.offset, &buf->len, 1);
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);
+ goto out;
+ buf->ptr.u.ref = ptr->u.ref;
+ buf->have_grant = 1;
}
else
{
- rc = __get_paged_frame(op->dest.u.gmfn, &d_frame, &d_pg, 0, dd);
+ rc = __get_paged_frame(ptr->u.gmfn, &buf->frame, &buf->page, 1,
buf->domain);
if ( rc != GNTST_okay )
- PIN_FAIL(error_out, rc,
- "destination frame %lx invalid.\n", d_frame);
+ PIN_FAIL(out, rc,
+ "source frame %lx invalid.\n", ptr->u.gmfn);
+
+ buf->ptr.u.gmfn = ptr->u.gmfn;
+ buf->ptr.offset = 0;
+ buf->len = PAGE_SIZE;
}
- if ( !get_page_type(d_pg, PGT_writable_page) )
+ if ( !buf->read_only )
{
- if ( !dd->is_dying )
- gdprintk(XENLOG_WARNING, "Could not get dst frame %lx\n", d_frame);
- rc = GNTST_general_error;
- goto error_out;
+ if ( !get_page_type(buf->page, PGT_writable_page) )
+ {
+ if ( !buf->domain->is_dying )
+ gdprintk(XENLOG_WARNING, "Could not get writable frame %lx\n",
buf->frame);
+ rc = GNTST_general_error;
+ goto out;
+ }
+ buf->have_type = 1;
}
- sp = map_domain_page(s_frame);
- dp = map_domain_page(d_frame);
+ buf->virt = map_domain_page(buf->frame);
+ rc = GNTST_okay;
- memcpy(dp + op->dest.offset, sp + op->source.offset, op->len);
+ out:
+ return rc;
+}
- unmap_domain_page(dp);
- unmap_domain_page(sp);
+static int gnttab_copy_buf(const struct gnttab_copy *op,
+ struct gnttab_copy_buf *dest,
+ const struct gnttab_copy_buf *src)
+{
+ s16 rc;
- gnttab_mark_dirty(dd, d_frame);
+ if ( ((op->source.offset + op->len) > PAGE_SIZE) ||
+ ((op->dest.offset + op->len) > PAGE_SIZE) )
+ PIN_FAIL(out, GNTST_bad_copy_arg, "copy beyond page area.\n");
+
+ if ( op->source.offset < src->ptr.offset ||
+ op->source.offset + op->len > src->ptr.offset + src->len )
+ PIN_FAIL(out, GNTST_general_error,
+ "copy source out of bounds: %d < %d || %d > %d\n",
+ op->source.offset, src->ptr.offset,
+ op->len, src->len);
+
+ if ( op->dest.offset < dest->ptr.offset ||
+ op->dest.offset + op->len > dest->ptr.offset + dest->len )
+ PIN_FAIL(out, GNTST_general_error,
+ "copy dest out of bounds: %d < %d || %d > %d\n",
+ op->dest.offset, dest->ptr.offset,
+ op->len, dest->len);
+
+ memcpy(dest->virt + op->dest.offset, src->virt + op->source.offset,
op->len);
+ rc = GNTST_okay;
+ out:
+ return rc;
+}
- put_page_type(d_pg);
- error_out:
- if ( d_pg )
- put_page(d_pg);
- if ( s_pg )
- put_page(s_pg);
- if ( have_s_grant )
- __release_grant_for_copy(sd, op->source.u.ref, 1);
- if ( have_d_grant )
- __release_grant_for_copy(dd, op->dest.u.ref, 0);
- if ( sd )
- rcu_unlock_domain(sd);
- if ( dd )
- rcu_unlock_domain(dd);
- op->status = rc;
+static s16 gnttab_copy_one(const struct gnttab_copy *op,
+ struct gnttab_copy_buf *dest,
+ struct gnttab_copy_buf *src)
+{
+ s16 rc;
+
+ rc = gnttab_copy_lock_domains(op, src, dest);
+ if ( rc < 0 )
+ goto out;
+
+ rc = gnttab_copy_claim_buf(op, &op->source, src, GNTCOPY_source_gref);
+ if ( rc < 0 )
+ goto out;
+
+ rc = gnttab_copy_claim_buf(op, &op->dest, dest, GNTCOPY_dest_gref);
+ if ( rc < 0 )
+ goto out;
+
+ rc = gnttab_copy_buf(op, dest, src);
+ out:
+ gnttab_copy_release_buf(src);
+ gnttab_copy_release_buf(dest);
+ gnttab_copy_unlock_domains(src, dest);
+ return rc;
}
-static long
-gnttab_copy(
+static long gnttab_copy(
XEN_GUEST_HANDLE_PARAM(gnttab_copy_t) uop, unsigned int count)
{
- int i;
+ unsigned int i;
struct gnttab_copy op;
+ struct gnttab_copy_buf src = {};
+ struct gnttab_copy_buf dest = {};
for ( i = 0; i < count; i++ )
{
@@ -2217,7 +2303,9 @@ gnttab_copy(
return i;
if ( unlikely(__copy_from_guest(&op, uop, 1)) )
return -EFAULT;
- __gnttab_copy(&op);
+
+ op.status = gnttab_copy_one(&op, &dest, &src);
+
if ( unlikely(__copy_field_to_guest(uop, &op, status)) )
return -EFAULT;
guest_handle_add_offset(uop, 1);
diff --git a/xen/include/public/grant_table.h b/xen/include/public/grant_table.h
index 20d4e77..c8619ed 100644
--- a/xen/include/public/grant_table.h
+++ b/xen/include/public/grant_table.h
@@ -453,7 +453,7 @@ DEFINE_XEN_GUEST_HANDLE(gnttab_transfer_t);
struct gnttab_copy {
/* IN parameters. */
- struct {
+ struct gnttab_copy_ptr {
union {
grant_ref_t ref;
xen_pfn_t gmfn;
--
1.7.10.4
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