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[Xen-devel] [PATCH 2/2] xen/grant-table: remove support for V2 tables



Since 11c7ff17c9b6dbf3a4e4f36be30ad531a6cf0ec9 (xen/grant-table: Force
to use v1 of grants.) the code for V2 grant tables is not used.

Signed-off-by: David Vrabel <david.vrabel@xxxxxxxxxx>
---
 arch/arm/xen/grant-table.c |    9 +-
 arch/x86/xen/grant-table.c |   60 +--------
 drivers/xen/grant-table.c  |  309 +-------------------------------------------
 include/xen/grant_table.h  |   30 +----
 4 files changed, 13 insertions(+), 395 deletions(-)

diff --git a/arch/arm/xen/grant-table.c b/arch/arm/xen/grant-table.c
index 91cf08b..e437918 100644
--- a/arch/arm/xen/grant-table.c
+++ b/arch/arm/xen/grant-table.c
@@ -45,14 +45,7 @@ void arch_gnttab_unmap(void *shared, unsigned long 
nr_gframes)
        return;
 }
 
-int arch_gnttab_map_status(uint64_t *frames, unsigned long nr_gframes,
-                          unsigned long max_nr_gframes,
-                          grant_status_t **__shared)
-{
-       return -ENOSYS;
-}
-
-int arch_gnttab_init(unsigned long nr_shared, unsigned long nr_status)
+int arch_gnttab_init(unsigned long nr_shared)
 {
        return 0;
 }
diff --git a/arch/x86/xen/grant-table.c b/arch/x86/xen/grant-table.c
index 27301df..c1ef6b2 100644
--- a/arch/x86/xen/grant-table.c
+++ b/arch/x86/xen/grant-table.c
@@ -48,7 +48,7 @@
 static struct gnttab_vm_area {
        struct vm_struct *area;
        pte_t **ptes;
-} gnttab_shared_vm_area, gnttab_status_vm_area;
+} gnttab_shared_vm_area;
 
 int arch_gnttab_map_shared(unsigned long *frames, unsigned long nr_gframes,
                           unsigned long max_nr_gframes,
@@ -72,43 +72,16 @@ int arch_gnttab_map_shared(unsigned long *frames, unsigned 
long nr_gframes,
        return 0;
 }
 
-int arch_gnttab_map_status(uint64_t *frames, unsigned long nr_gframes,
-                          unsigned long max_nr_gframes,
-                          grant_status_t **__shared)
-{
-       grant_status_t *shared = *__shared;
-       unsigned long addr;
-       unsigned long i;
-
-       if (shared == NULL)
-               *__shared = shared = gnttab_status_vm_area.area->addr;
-
-       addr = (unsigned long)shared;
-
-       for (i = 0; i < nr_gframes; i++) {
-               set_pte_at(&init_mm, addr, gnttab_status_vm_area.ptes[i],
-                          mfn_pte(frames[i], PAGE_KERNEL));
-               addr += PAGE_SIZE;
-       }
-
-       return 0;
-}
-
 void arch_gnttab_unmap(void *shared, unsigned long nr_gframes)
 {
-       pte_t **ptes;
        unsigned long addr;
        unsigned long i;
 
-       if (shared == gnttab_status_vm_area.area->addr)
-               ptes = gnttab_status_vm_area.ptes;
-       else
-               ptes = gnttab_shared_vm_area.ptes;
-
        addr = (unsigned long)shared;
 
        for (i = 0; i < nr_gframes; i++) {
-               set_pte_at(&init_mm, addr, ptes[i], __pte(0));
+               set_pte_at(&init_mm, addr, gnttab_shared_vm_area.ptes[i],
+                          __pte(0));
                addr += PAGE_SIZE;
        }
 }
@@ -129,35 +102,12 @@ static int __init arch_gnttab_valloc(struct 
gnttab_vm_area *area,
        return 0;
 }
 
-static void __init arch_gnttab_vfree(struct gnttab_vm_area *area)
+int __init arch_gnttab_init(unsigned long nr_shared)
 {
-       free_vm_area(area->area);
-       kfree(area->ptes);
-}
-
-int __init arch_gnttab_init(unsigned long nr_shared, unsigned long nr_status)
-{
-       int ret;
-
        if (!xen_pv_domain())
                return 0;
 
-       ret = arch_gnttab_valloc(&gnttab_shared_vm_area, nr_shared);
-       if (ret < 0)
-               return ret;
-
-       /*
-        * Always allocate the space for the status frames in case
-        * we're migrated to a host with V2 support.
-        */
-       ret = arch_gnttab_valloc(&gnttab_status_vm_area, nr_status);
-       if (ret < 0)
-               goto err;
-
-       return 0;
-  err:
-       arch_gnttab_vfree(&gnttab_shared_vm_area);
-       return -ENOMEM;
+       return arch_gnttab_valloc(&gnttab_shared_vm_area, nr_shared);
 }
 
 #ifdef CONFIG_XEN_PVH
diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c
index eeba754..c254ae0 100644
--- a/drivers/xen/grant-table.c
+++ b/drivers/xen/grant-table.c
@@ -69,7 +69,6 @@ struct grant_frames xen_auto_xlat_grant_frames;
 
 static union {
        struct grant_entry_v1 *v1;
-       union grant_entry_v2 *v2;
        void *addr;
 } gnttab_shared;
 
@@ -120,36 +119,10 @@ struct gnttab_ops {
         * by bit operations.
         */
        int (*query_foreign_access)(grant_ref_t ref);
-       /*
-        * Grant a domain to access a range of bytes within the page referred by
-        * an available grant entry. Ref parameter is reference of a grant entry
-        * which will be sub-page accessed, domid is id of grantee domain, frame
-        * is frame address of subpage grant, flags is grant type and flag
-        * information, page_off is offset of the range of bytes, and length is
-        * length of bytes to be accessed.
-        */
-       void (*update_subpage_entry)(grant_ref_t ref, domid_t domid,
-                                    unsigned long frame, int flags,
-                                    unsigned page_off, unsigned length);
-       /*
-        * Redirect an available grant entry on domain A to another grant
-        * reference of domain B, then allow domain C to use grant reference
-        * of domain B transitively. Ref parameter is an available grant entry
-        * reference on domain A, domid is id of domain C which accesses grant
-        * entry transitively, flags is grant type and flag information,
-        * trans_domid is id of domain B whose grant entry is finally accessed
-        * transitively, trans_gref is grant entry transitive reference of
-        * domain B.
-        */
-       void (*update_trans_entry)(grant_ref_t ref, domid_t domid, int flags,
-                                  domid_t trans_domid, grant_ref_t trans_gref);
 };
 
 static struct gnttab_ops *gnttab_interface;
 
-/*This reflects status of grant entries, so act as a global value*/
-static grant_status_t *grstatus;
-
 static int grant_table_version;
 static int grefs_per_grant_frame;
 
@@ -231,7 +204,7 @@ static void put_free_entry(grant_ref_t ref)
 }
 
 /*
- * Following applies to gnttab_update_entry_v1 and gnttab_update_entry_v2.
+ * Following applies to gnttab_update_entry_v1.
  * Introducing a valid entry into the grant table:
  *  1. Write ent->domid.
  *  2. Write ent->frame:
@@ -250,15 +223,6 @@ static void gnttab_update_entry_v1(grant_ref_t ref, 
domid_t domid,
        gnttab_shared.v1[ref].flags = flags;
 }
 
-static void gnttab_update_entry_v2(grant_ref_t ref, domid_t domid,
-                                  unsigned long frame, unsigned flags)
-{
-       gnttab_shared.v2[ref].hdr.domid = domid;
-       gnttab_shared.v2[ref].full_page.frame = frame;
-       wmb();
-       gnttab_shared.v2[ref].hdr.flags = GTF_permit_access | flags;
-}
-
 /*
  * Public grant-issuing interface functions
  */
@@ -285,132 +249,11 @@ int gnttab_grant_foreign_access(domid_t domid, unsigned 
long frame,
 }
 EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access);
 
-static void gnttab_update_subpage_entry_v2(grant_ref_t ref, domid_t domid,
-                                          unsigned long frame, int flags,
-                                          unsigned page_off, unsigned length)
-{
-       gnttab_shared.v2[ref].sub_page.frame = frame;
-       gnttab_shared.v2[ref].sub_page.page_off = page_off;
-       gnttab_shared.v2[ref].sub_page.length = length;
-       gnttab_shared.v2[ref].hdr.domid = domid;
-       wmb();
-       gnttab_shared.v2[ref].hdr.flags =
-                               GTF_permit_access | GTF_sub_page | flags;
-}
-
-int gnttab_grant_foreign_access_subpage_ref(grant_ref_t ref, domid_t domid,
-                                           unsigned long frame, int flags,
-                                           unsigned page_off,
-                                           unsigned length)
-{
-       if (flags & (GTF_accept_transfer | GTF_reading |
-                    GTF_writing | GTF_transitive))
-               return -EPERM;
-
-       if (gnttab_interface->update_subpage_entry == NULL)
-               return -ENOSYS;
-
-       gnttab_interface->update_subpage_entry(ref, domid, frame, flags,
-                                              page_off, length);
-
-       return 0;
-}
-EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access_subpage_ref);
-
-int gnttab_grant_foreign_access_subpage(domid_t domid, unsigned long frame,
-                                       int flags, unsigned page_off,
-                                       unsigned length)
-{
-       int ref, rc;
-
-       ref = get_free_entries(1);
-       if (unlikely(ref < 0))
-               return -ENOSPC;
-
-       rc = gnttab_grant_foreign_access_subpage_ref(ref, domid, frame, flags,
-                                                    page_off, length);
-       if (rc < 0) {
-               put_free_entry(ref);
-               return rc;
-       }
-
-       return ref;
-}
-EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access_subpage);
-
-bool gnttab_subpage_grants_available(void)
-{
-       return gnttab_interface->update_subpage_entry != NULL;
-}
-EXPORT_SYMBOL_GPL(gnttab_subpage_grants_available);
-
-static void gnttab_update_trans_entry_v2(grant_ref_t ref, domid_t domid,
-                                        int flags, domid_t trans_domid,
-                                        grant_ref_t trans_gref)
-{
-       gnttab_shared.v2[ref].transitive.trans_domid = trans_domid;
-       gnttab_shared.v2[ref].transitive.gref = trans_gref;
-       gnttab_shared.v2[ref].hdr.domid = domid;
-       wmb();
-       gnttab_shared.v2[ref].hdr.flags =
-                               GTF_permit_access | GTF_transitive | flags;
-}
-
-int gnttab_grant_foreign_access_trans_ref(grant_ref_t ref, domid_t domid,
-                                         int flags, domid_t trans_domid,
-                                         grant_ref_t trans_gref)
-{
-       if (flags & (GTF_accept_transfer | GTF_reading |
-                    GTF_writing | GTF_sub_page))
-               return -EPERM;
-
-       if (gnttab_interface->update_trans_entry == NULL)
-               return -ENOSYS;
-
-       gnttab_interface->update_trans_entry(ref, domid, flags, trans_domid,
-                                            trans_gref);
-
-       return 0;
-}
-EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access_trans_ref);
-
-int gnttab_grant_foreign_access_trans(domid_t domid, int flags,
-                                     domid_t trans_domid,
-                                     grant_ref_t trans_gref)
-{
-       int ref, rc;
-
-       ref = get_free_entries(1);
-       if (unlikely(ref < 0))
-               return -ENOSPC;
-
-       rc = gnttab_grant_foreign_access_trans_ref(ref, domid, flags,
-                                                  trans_domid, trans_gref);
-       if (rc < 0) {
-               put_free_entry(ref);
-               return rc;
-       }
-
-       return ref;
-}
-EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access_trans);
-
-bool gnttab_trans_grants_available(void)
-{
-       return gnttab_interface->update_trans_entry != NULL;
-}
-EXPORT_SYMBOL_GPL(gnttab_trans_grants_available);
-
 static int gnttab_query_foreign_access_v1(grant_ref_t ref)
 {
        return gnttab_shared.v1[ref].flags & (GTF_reading|GTF_writing);
 }
 
-static int gnttab_query_foreign_access_v2(grant_ref_t ref)
-{
-       return grstatus[ref] & (GTF_reading|GTF_writing);
-}
-
 int gnttab_query_foreign_access(grant_ref_t ref)
 {
        return gnttab_interface->query_foreign_access(ref);
@@ -433,29 +276,6 @@ static int gnttab_end_foreign_access_ref_v1(grant_ref_t 
ref, int readonly)
        return 1;
 }
 
-static int gnttab_end_foreign_access_ref_v2(grant_ref_t ref, int readonly)
-{
-       gnttab_shared.v2[ref].hdr.flags = 0;
-       mb();
-       if (grstatus[ref] & (GTF_reading|GTF_writing)) {
-               return 0;
-       } else {
-               /* The read of grstatus needs to have acquire
-               semantics.  On x86, reads already have
-               that, and we just need to protect against
-               compiler reorderings.  On other
-               architectures we may need a full
-               barrier. */
-#ifdef CONFIG_X86
-               barrier();
-#else
-               mb();
-#endif
-       }
-
-       return 1;
-}
-
 static inline int _gnttab_end_foreign_access_ref(grant_ref_t ref, int readonly)
 {
        return gnttab_interface->end_foreign_access_ref(ref, readonly);
@@ -616,37 +436,6 @@ static unsigned long 
gnttab_end_foreign_transfer_ref_v1(grant_ref_t ref)
        return frame;
 }
 
-static unsigned long gnttab_end_foreign_transfer_ref_v2(grant_ref_t ref)
-{
-       unsigned long frame;
-       u16           flags;
-       u16          *pflags;
-
-       pflags = &gnttab_shared.v2[ref].hdr.flags;
-
-       /*
-        * If a transfer is not even yet started, try to reclaim the grant
-        * reference and return failure (== 0).
-        */
-       while (!((flags = *pflags) & GTF_transfer_committed)) {
-               if (sync_cmpxchg(pflags, flags, 0) == flags)
-                       return 0;
-               cpu_relax();
-       }
-
-       /* If a transfer is in progress then wait until it is completed. */
-       while (!(flags & GTF_transfer_completed)) {
-               flags = *pflags;
-               cpu_relax();
-       }
-
-       rmb();  /* Read the frame number /after/ reading completion status. */
-       frame = gnttab_shared.v2[ref].full_page.frame;
-       BUG_ON(frame == 0);
-
-       return frame;
-}
-
 unsigned long gnttab_end_foreign_transfer_ref(grant_ref_t ref)
 {
        return gnttab_interface->end_foreign_transfer_ref(ref);
@@ -962,12 +751,6 @@ int gnttab_unmap_refs(struct gnttab_unmap_grant_ref 
*unmap_ops,
 }
 EXPORT_SYMBOL_GPL(gnttab_unmap_refs);
 
-static unsigned nr_status_frames(unsigned nr_grant_frames)
-{
-       BUG_ON(grefs_per_grant_frame == 0);
-       return (nr_grant_frames * grefs_per_grant_frame + SPP - 1) / SPP;
-}
-
 static int gnttab_map_frames_v1(xen_pfn_t *frames, unsigned int nr_gframes)
 {
        int rc;
@@ -985,55 +768,6 @@ static void gnttab_unmap_frames_v1(void)
        arch_gnttab_unmap(gnttab_shared.addr, nr_grant_frames);
 }
 
-static int gnttab_map_frames_v2(xen_pfn_t *frames, unsigned int nr_gframes)
-{
-       uint64_t *sframes;
-       unsigned int nr_sframes;
-       struct gnttab_get_status_frames getframes;
-       int rc;
-
-       nr_sframes = nr_status_frames(nr_gframes);
-
-       /* No need for kzalloc as it is initialized in following hypercall
-        * GNTTABOP_get_status_frames.
-        */
-       sframes = kmalloc(nr_sframes  * sizeof(uint64_t), GFP_ATOMIC);
-       if (!sframes)
-               return -ENOMEM;
-
-       getframes.dom        = DOMID_SELF;
-       getframes.nr_frames  = nr_sframes;
-       set_xen_guest_handle(getframes.frame_list, sframes);
-
-       rc = HYPERVISOR_grant_table_op(GNTTABOP_get_status_frames,
-                                      &getframes, 1);
-       if (rc == -ENOSYS) {
-               kfree(sframes);
-               return -ENOSYS;
-       }
-
-       BUG_ON(rc || getframes.status);
-
-       rc = arch_gnttab_map_status(sframes, nr_sframes,
-                                   nr_status_frames(gnttab_max_grant_frames()),
-                                   &grstatus);
-       BUG_ON(rc);
-       kfree(sframes);
-
-       rc = arch_gnttab_map_shared(frames, nr_gframes,
-                                   gnttab_max_grant_frames(),
-                                   &gnttab_shared.addr);
-       BUG_ON(rc);
-
-       return 0;
-}
-
-static void gnttab_unmap_frames_v2(void)
-{
-       arch_gnttab_unmap(gnttab_shared.addr, nr_grant_frames);
-       arch_gnttab_unmap(grstatus, nr_status_frames(nr_grant_frames));
-}
-
 static int gnttab_map(unsigned int start_idx, unsigned int end_idx)
 {
        struct gnttab_setup_table setup;
@@ -1101,43 +835,13 @@ static struct gnttab_ops gnttab_v1_ops = {
        .query_foreign_access           = gnttab_query_foreign_access_v1,
 };
 
-static struct gnttab_ops gnttab_v2_ops = {
-       .map_frames                     = gnttab_map_frames_v2,
-       .unmap_frames                   = gnttab_unmap_frames_v2,
-       .update_entry                   = gnttab_update_entry_v2,
-       .end_foreign_access_ref         = gnttab_end_foreign_access_ref_v2,
-       .end_foreign_transfer_ref       = gnttab_end_foreign_transfer_ref_v2,
-       .query_foreign_access           = gnttab_query_foreign_access_v2,
-       .update_subpage_entry           = gnttab_update_subpage_entry_v2,
-       .update_trans_entry             = gnttab_update_trans_entry_v2,
-};
-
 static void gnttab_request_version(void)
 {
-       int rc;
-       struct gnttab_set_version gsv;
+       /* Only version 1 is used, which will always be available. */
+       grant_table_version = 1;
+       grefs_per_grant_frame = PAGE_SIZE / sizeof(struct grant_entry_v1);
+       gnttab_interface = &gnttab_v1_ops;
 
-       gsv.version = 1;
-
-       rc = HYPERVISOR_grant_table_op(GNTTABOP_set_version, &gsv, 1);
-       if (rc == 0 && gsv.version == 2) {
-               grant_table_version = 2;
-               grefs_per_grant_frame = PAGE_SIZE / sizeof(union 
grant_entry_v2);
-               gnttab_interface = &gnttab_v2_ops;
-       } else if (grant_table_version == 2) {
-               /*
-                * If we've already used version 2 features,
-                * but then suddenly discover that they're not
-                * available (e.g. migrating to an older
-                * version of Xen), almost unbounded badness
-                * can happen.
-                */
-               panic("we need grant tables version 2, but only version 1 is 
available");
-       } else {
-               grant_table_version = 1;
-               grefs_per_grant_frame = PAGE_SIZE / sizeof(struct 
grant_entry_v1);
-               gnttab_interface = &gnttab_v1_ops;
-       }
        pr_info("Grant tables using version %d layout\n", grant_table_version);
 }
 
@@ -1225,8 +929,7 @@ int gnttab_init(void)
                }
        }
 
-       ret = arch_gnttab_init(max_nr_grant_frames,
-                              nr_status_frames(max_nr_grant_frames));
+       ret = arch_gnttab_init(max_nr_grant_frames);
        if (ret < 0)
                goto ini_nomem;
 
diff --git a/include/xen/grant_table.h b/include/xen/grant_table.h
index 5c1aba1..3387465 100644
--- a/include/xen/grant_table.h
+++ b/include/xen/grant_table.h
@@ -64,24 +64,6 @@ int gnttab_resume(void);
 
 int gnttab_grant_foreign_access(domid_t domid, unsigned long frame,
                                int readonly);
-int gnttab_grant_foreign_access_subpage(domid_t domid, unsigned long frame,
-                                       int flags, unsigned page_off,
-                                       unsigned length);
-int gnttab_grant_foreign_access_trans(domid_t domid, int flags,
-                                     domid_t trans_domid,
-                                     grant_ref_t trans_gref);
-
-/*
- * Are sub-page grants available on this version of Xen?  Returns true if they
- * are, and false if they're not.
- */
-bool gnttab_subpage_grants_available(void);
-
-/*
- * Are transitive grants available on this version of Xen?  Returns true if 
they
- * are, and false if they're not.
- */
-bool gnttab_trans_grants_available(void);
 
 /*
  * End access through the given grant reference, iff the grant entry is no
@@ -128,13 +110,6 @@ void gnttab_cancel_free_callback(struct 
gnttab_free_callback *callback);
 
 void gnttab_grant_foreign_access_ref(grant_ref_t ref, domid_t domid,
                                     unsigned long frame, int readonly);
-int gnttab_grant_foreign_access_subpage_ref(grant_ref_t ref, domid_t domid,
-                                           unsigned long frame, int flags,
-                                           unsigned page_off,
-                                           unsigned length);
-int gnttab_grant_foreign_access_trans_ref(grant_ref_t ref, domid_t domid,
-                                         int flags, domid_t trans_domid,
-                                         grant_ref_t trans_gref);
 
 void gnttab_grant_foreign_transfer_ref(grant_ref_t, domid_t domid,
                                       unsigned long pfn);
@@ -170,13 +145,10 @@ gnttab_set_unmap_op(struct gnttab_unmap_grant_ref *unmap, 
phys_addr_t addr,
        unmap->dev_bus_addr = 0;
 }
 
-int arch_gnttab_init(unsigned long nr_shared, unsigned long nr_status);
+int arch_gnttab_init(unsigned long nr_shared);
 int arch_gnttab_map_shared(xen_pfn_t *frames, unsigned long nr_gframes,
                           unsigned long max_nr_gframes,
                           void **__shared);
-int arch_gnttab_map_status(uint64_t *frames, unsigned long nr_gframes,
-                          unsigned long max_nr_gframes,
-                          grant_status_t **__shared);
 void arch_gnttab_unmap(void *shared, unsigned long nr_gframes);
 
 struct grant_frames {
-- 
1.7.10.4


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