[xen staging] Revert "x86/shadow: replace stale literal numbers in hash_{vcpu,domain}_foreach()"

[patchbot@xxxxxxx]

commit d26a4691ea3a5eea7df9c8b49e09aad7f067cdfc
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Tue Mar 30 15:31:25 2021 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Tue Mar 30 15:31:25 2021 +0200

    Revert "x86/shadow: replace stale literal numbers in 
hash_{vcpu,domain}_foreach()"
    
    This reverts commit c201d303e801a949b10f9e0f36cdc1938ddd399e - a
    stale version (not working with clang) ended up getting committed.
---
 xen/arch/x86/mm/shadow/common.c | 20 +++++---------------
 1 file changed, 5 insertions(+), 15 deletions(-)

diff --git a/xen/arch/x86/mm/shadow/common.c b/xen/arch/x86/mm/shadow/common.c
index 31a5ccf4ca..4a8882430b 100644
--- a/xen/arch/x86/mm/shadow/common.c
+++ b/xen/arch/x86/mm/shadow/common.c
@@ -1623,9 +1623,6 @@ void shadow_hash_delete(struct domain *d, unsigned long 
n, unsigned int t,
 typedef int (*hash_vcpu_callback_t)(struct vcpu *v, mfn_t smfn, mfn_t 
other_mfn);
 typedef int (*hash_domain_callback_t)(struct domain *d, mfn_t smfn, mfn_t 
other_mfn);
 
-#define HASH_CALLBACKS_CHECK(mask) \
-    BUILD_BUG_ON((mask) > (1U << ARRAY_SIZE(callbacks)) - 1)
-
 static void hash_vcpu_foreach(struct vcpu *v, unsigned int callback_mask,
                               const hash_vcpu_callback_t callbacks[],
                               mfn_t callback_mfn)
@@ -1661,7 +1658,7 @@ static void hash_vcpu_foreach(struct vcpu *v, unsigned 
int callback_mask,
         {
             if ( callback_mask & (1 << x->u.sh.type) )
             {
-                ASSERT(x->u.sh.type < SH_type_unused);
+                ASSERT(x->u.sh.type <= 15);
                 ASSERT(callbacks[x->u.sh.type] != NULL);
                 done = callbacks[x->u.sh.type](v, page_to_mfn(x),
                                                callback_mfn);
@@ -1708,7 +1705,7 @@ static void hash_domain_foreach(struct domain *d,
         {
             if ( callback_mask & (1 << x->u.sh.type) )
             {
-                ASSERT(x->u.sh.type < SH_type_unused);
+                ASSERT(x->u.sh.type <= 15);
                 ASSERT(callbacks[x->u.sh.type] != NULL);
                 done = callbacks[x->u.sh.type](d, page_to_mfn(x),
                                                callback_mfn);
@@ -2012,7 +2009,6 @@ int sh_remove_write_access(struct domain *d, mfn_t gmfn,
         perfc_incr(shadow_writeable_bf_1);
     else
         perfc_incr(shadow_writeable_bf);
-    HASH_CALLBACKS_CHECK(callback_mask);
     hash_domain_foreach(d, callback_mask, callbacks, gmfn);
 
     /* If that didn't catch the mapping, then there's some non-pagetable
@@ -2084,7 +2080,6 @@ int sh_remove_all_mappings(struct domain *d, mfn_t gmfn, 
gfn_t gfn)
 
     /* Brute-force search of all the shadows, by walking the hash */
     perfc_incr(shadow_mappings_bf);
-    HASH_CALLBACKS_CHECK(callback_mask);
     hash_domain_foreach(d, callback_mask, callbacks, gmfn);
 
     /* If that didn't catch the mapping, something is very wrong */
@@ -2251,12 +2246,10 @@ void sh_remove_shadows(struct domain *d, mfn_t gmfn, 
int fast, int all)
     /* Search for this shadow in all appropriate shadows */
     perfc_incr(shadow_unshadow);
 
-    /*
-     * Lower-level shadows need to be excised from upper-level shadows. This
-     * call to hash_domain_foreach() looks dangerous but is in fact OK: each
+    /* Lower-level shadows need to be excised from upper-level shadows.
+     * This call to hash_vcpu_foreach() looks dangerous but is in fact OK: each
      * call will remove at most one shadow, and terminate immediately when
-     * it does remove it, so we never walk the hash after doing a deletion.
-     */
+     * it does remove it, so we never walk the hash after doing a deletion.  */
 #define DO_UNSHADOW(_type) do {                                         \
     t = (_type);                                                        \
     if( !(pg->count_info & PGC_page_table)                              \
@@ -2277,7 +2270,6 @@ void sh_remove_shadows(struct domain *d, mfn_t gmfn, int 
fast, int all)
     if( !fast                                                           \
         && (pg->count_info & PGC_page_table)                            \
         && (pg->shadow_flags & (1 << t)) )                              \
-        HASH_CALLBACKS_CHECK(SHF_page_type_mask);                       \
         hash_domain_foreach(d, masks[t], callbacks, smfn);              \
 } while (0)
 
@@ -2378,7 +2370,6 @@ void sh_reset_l3_up_pointers(struct vcpu *v)
     };
     static const unsigned int callback_mask = SHF_L3_64;
 
-    HASH_CALLBACKS_CHECK(callback_mask);
     hash_vcpu_foreach(v, callback_mask, callbacks, INVALID_MFN);
 }
 
@@ -3429,7 +3420,6 @@ void shadow_audit_tables(struct vcpu *v)
         }
     }
 
-    HASH_CALLBACKS_CHECK(SHF_page_type_mask);
     hash_vcpu_foreach(v, mask, callbacks, INVALID_MFN);
 }
 
--
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