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[xen staging] x86/shadow: sh_{make,destroy}_monitor_table() are "even more" HVM-only



commit 0b841314dacecc94376be22f514da0665055fa3b
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Fri Oct 30 14:26:46 2020 +0100
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Fri Oct 30 14:26:46 2020 +0100

    x86/shadow: sh_{make,destroy}_monitor_table() are "even more" HVM-only
    
    With them depending on just the number of shadow levels, there's no need
    for more than one instance of them, and hence no need for any hook (IOW
    452219e24648 ["x86/shadow: monitor table is HVM-only"] didn't go quite
    far enough). Move the functions to hvm.c while dropping the dead
    is_pv_32bit_domain() code paths.
    
    While moving the code, replace a stale comment reference to
    sh_install_xen_entries_in_l4(). Doing so made me notice the function
    also didn't have its prototype dropped in 8d7b633adab7 ("x86/mm:
    Consolidate all Xen L4 slot writing into init_xen_l4_slots()"), which
    gets done here as well.
    
    Also make their first parameters const.
    
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Acked-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
    Acked-by: Tim Deegan <tim@xxxxxxx>
---
 xen/arch/x86/mm/shadow/common.c  |  14 +++--
 xen/arch/x86/mm/shadow/hvm.c     |  82 ++++++++++++++++++++++++++
 xen/arch/x86/mm/shadow/multi.c   | 124 ---------------------------------------
 xen/arch/x86/mm/shadow/private.h |  11 +++-
 xen/arch/x86/mm/shadow/types.h   |   9 ---
 xen/include/asm-x86/paging.h     |   2 -
 6 files changed, 100 insertions(+), 142 deletions(-)

diff --git a/xen/arch/x86/mm/shadow/common.c b/xen/arch/x86/mm/shadow/common.c
index 6182313a0e..0d59dea6ad 100644
--- a/xen/arch/x86/mm/shadow/common.c
+++ b/xen/arch/x86/mm/shadow/common.c
@@ -2467,7 +2467,9 @@ static void sh_update_paging_modes(struct vcpu *v)
 
         if ( pagetable_is_null(v->arch.hvm.monitor_table) )
         {
-            mfn_t mmfn = v->arch.paging.mode->shadow.make_monitor_table(v);
+            mfn_t mmfn = sh_make_monitor_table(
+                             v, v->arch.paging.mode->shadow.shadow_levels);
+
             v->arch.hvm.monitor_table = pagetable_from_mfn(mmfn);
             make_cr3(v, mmfn);
             hvm_update_host_cr3(v);
@@ -2504,7 +2506,8 @@ static void sh_update_paging_modes(struct vcpu *v)
 
                 old_mfn = pagetable_get_mfn(v->arch.hvm.monitor_table);
                 v->arch.hvm.monitor_table = pagetable_null();
-                new_mfn = v->arch.paging.mode->shadow.make_monitor_table(v);
+                new_mfn = sh_make_monitor_table(
+                              v, v->arch.paging.mode->shadow.shadow_levels);
                 v->arch.hvm.monitor_table = pagetable_from_mfn(new_mfn);
                 SHADOW_PRINTK("new monitor table %"PRI_mfn "\n",
                                mfn_x(new_mfn));
@@ -2516,7 +2519,8 @@ static void sh_update_paging_modes(struct vcpu *v)
                 if ( v == current )
                     write_ptbase(v);
                 hvm_update_host_cr3(v);
-                old_mode->shadow.destroy_monitor_table(v, old_mfn);
+                sh_destroy_monitor_table(v, old_mfn,
+                                         old_mode->shadow.shadow_levels);
             }
         }
 
@@ -2801,7 +2805,9 @@ void shadow_teardown(struct domain *d, bool *preempted)
                     mfn_t mfn = pagetable_get_mfn(v->arch.hvm.monitor_table);
 
                     if ( mfn_valid(mfn) && (mfn_x(mfn) != 0) )
-                        v->arch.paging.mode->shadow.destroy_monitor_table(v, 
mfn);
+                        sh_destroy_monitor_table(
+                            v, mfn,
+                            v->arch.paging.mode->shadow.shadow_levels);
                     v->arch.hvm.monitor_table = pagetable_null();
                 }
 #endif /* CONFIG_HVM */
diff --git a/xen/arch/x86/mm/shadow/hvm.c b/xen/arch/x86/mm/shadow/hvm.c
index 967c1a6a04..87fc57704f 100644
--- a/xen/arch/x86/mm/shadow/hvm.c
+++ b/xen/arch/x86/mm/shadow/hvm.c
@@ -691,6 +691,88 @@ static void sh_emulate_unmap_dest(struct vcpu *v, void 
*addr,
     atomic_inc(&v->domain->arch.paging.shadow.gtable_dirty_version);
 }
 
+mfn_t sh_make_monitor_table(const struct vcpu *v, unsigned int shadow_levels)
+{
+    struct domain *d = v->domain;
+    mfn_t m4mfn;
+    l4_pgentry_t *l4e;
+
+    ASSERT(!pagetable_get_pfn(v->arch.hvm.monitor_table));
+
+    /* Guarantee we can get the memory we need */
+    shadow_prealloc(d, SH_type_monitor_table, CONFIG_PAGING_LEVELS);
+    m4mfn = shadow_alloc(d, SH_type_monitor_table, 0);
+    mfn_to_page(m4mfn)->shadow_flags = 4;
+
+    l4e = map_domain_page(m4mfn);
+
+    /*
+     * Create a self-linear mapping, but no shadow-linear mapping.  A
+     * shadow-linear mapping will either be inserted below when creating
+     * lower level monitor tables, or later in sh_update_cr3().
+     */
+    init_xen_l4_slots(l4e, m4mfn, d, INVALID_MFN, false);
+
+    if ( shadow_levels < 4 )
+    {
+        mfn_t m3mfn, m2mfn;
+        l3_pgentry_t *l3e;
+
+        /*
+         * Install an l3 table and an l2 table that will hold the shadow
+         * linear map entries.  This overrides the empty entry that was
+         * installed by init_xen_l4_slots().
+         */
+        m3mfn = shadow_alloc(d, SH_type_monitor_table, 0);
+        mfn_to_page(m3mfn)->shadow_flags = 3;
+        l4e[l4_table_offset(SH_LINEAR_PT_VIRT_START)]
+            = l4e_from_mfn(m3mfn, __PAGE_HYPERVISOR_RW);
+
+        m2mfn = shadow_alloc(d, SH_type_monitor_table, 0);
+        mfn_to_page(m2mfn)->shadow_flags = 2;
+        l3e = map_domain_page(m3mfn);
+        l3e[0] = l3e_from_mfn(m2mfn, __PAGE_HYPERVISOR_RW);
+        unmap_domain_page(l3e);
+    }
+
+    unmap_domain_page(l4e);
+
+    return m4mfn;
+}
+
+void sh_destroy_monitor_table(const struct vcpu *v, mfn_t mmfn,
+                              unsigned int shadow_levels)
+{
+    struct domain *d = v->domain;
+
+    ASSERT(mfn_to_page(mmfn)->u.sh.type == SH_type_monitor_table);
+
+    if ( shadow_levels < 4 )
+    {
+        mfn_t m3mfn;
+        l4_pgentry_t *l4e = map_domain_page(mmfn);
+        l3_pgentry_t *l3e;
+        unsigned int linear_slot = l4_table_offset(SH_LINEAR_PT_VIRT_START);
+
+        /*
+         * Need to destroy the l3 and l2 monitor pages used
+         * for the linear map.
+         */
+        ASSERT(l4e_get_flags(l4e[linear_slot]) & _PAGE_PRESENT);
+        m3mfn = l4e_get_mfn(l4e[linear_slot]);
+        l3e = map_domain_page(m3mfn);
+        ASSERT(l3e_get_flags(l3e[0]) & _PAGE_PRESENT);
+        shadow_free(d, l3e_get_mfn(l3e[0]));
+        unmap_domain_page(l3e);
+        shadow_free(d, m3mfn);
+
+        unmap_domain_page(l4e);
+    }
+
+    /* Put the memory back in the pool */
+    shadow_free(d, mmfn);
+}
+
 /**************************************************************************/
 /* VRAM dirty tracking support */
 int shadow_track_dirty_vram(struct domain *d,
diff --git a/xen/arch/x86/mm/shadow/multi.c b/xen/arch/x86/mm/shadow/multi.c
index 04be86e422..eba5164a27 100644
--- a/xen/arch/x86/mm/shadow/multi.c
+++ b/xen/arch/x86/mm/shadow/multi.c
@@ -1405,84 +1405,6 @@ make_fl1_shadow(struct domain *d, gfn_t gfn)
 }
 
 
-#if SHADOW_PAGING_LEVELS == GUEST_PAGING_LEVELS && defined(CONFIG_HVM)
-mfn_t
-sh_make_monitor_table(struct vcpu *v)
-{
-    struct domain *d = v->domain;
-
-    ASSERT(pagetable_get_pfn(v->arch.hvm.monitor_table) == 0);
-
-    /* Guarantee we can get the memory we need */
-    shadow_prealloc(d, SH_type_monitor_table, CONFIG_PAGING_LEVELS);
-
-    {
-        mfn_t m4mfn;
-        l4_pgentry_t *l4e;
-
-        m4mfn = shadow_alloc(d, SH_type_monitor_table, 0);
-        mfn_to_page(m4mfn)->shadow_flags = 4;
-
-        l4e = map_domain_page(m4mfn);
-
-        /*
-         * Create a self-linear mapping, but no shadow-linear mapping.  A
-         * shadow-linear mapping will either be inserted below when creating
-         * lower level monitor tables, or later in sh_update_cr3().
-         */
-        init_xen_l4_slots(l4e, m4mfn, d, INVALID_MFN, false);
-
-#if SHADOW_PAGING_LEVELS < 4
-        {
-            mfn_t m3mfn, m2mfn;
-            l3_pgentry_t *l3e;
-            /* Install an l3 table and an l2 table that will hold the shadow
-             * linear map entries.  This overrides the linear map entry that
-             * was installed by sh_install_xen_entries_in_l4. */
-
-            m3mfn = shadow_alloc(d, SH_type_monitor_table, 0);
-            mfn_to_page(m3mfn)->shadow_flags = 3;
-            l4e[shadow_l4_table_offset(SH_LINEAR_PT_VIRT_START)]
-                = l4e_from_mfn(m3mfn, __PAGE_HYPERVISOR_RW);
-
-            m2mfn = shadow_alloc(d, SH_type_monitor_table, 0);
-            mfn_to_page(m2mfn)->shadow_flags = 2;
-            l3e = map_domain_page(m3mfn);
-            l3e[0] = l3e_from_mfn(m2mfn, __PAGE_HYPERVISOR_RW);
-            unmap_domain_page(l3e);
-
-            if ( is_pv_32bit_domain(d) )
-            {
-                l2_pgentry_t *l2t;
-
-                /* For 32-bit PV guests, we need to map the 32-bit Xen
-                 * area into its usual VAs in the monitor tables */
-                m3mfn = shadow_alloc(d, SH_type_monitor_table, 0);
-                mfn_to_page(m3mfn)->shadow_flags = 3;
-                l4e[0] = l4e_from_mfn(m3mfn, __PAGE_HYPERVISOR_RW);
-
-                m2mfn = shadow_alloc(d, SH_type_monitor_table, 0);
-                mfn_to_page(m2mfn)->shadow_flags = 2;
-                l3e = map_domain_page(m3mfn);
-                l3e[3] = l3e_from_mfn(m2mfn, _PAGE_PRESENT);
-
-                l2t = map_domain_page(m2mfn);
-                init_xen_pae_l2_slots(l2t, d);
-                unmap_domain_page(l2t);
-
-                unmap_domain_page(l3e);
-            }
-
-        }
-#endif /* SHADOW_PAGING_LEVELS < 4 */
-
-        unmap_domain_page(l4e);
-
-        return m4mfn;
-    }
-}
-#endif /* SHADOW_PAGING_LEVELS == GUEST_PAGING_LEVELS */
-
 /**************************************************************************/
 /* These functions also take a virtual address and return the level-N
  * shadow table mfn and entry, but they create the shadow pagetables if
@@ -1860,50 +1782,6 @@ void sh_destroy_l1_shadow(struct domain *d, mfn_t smfn)
     shadow_free(d, smfn);
 }
 
-#if SHADOW_PAGING_LEVELS == GUEST_PAGING_LEVELS && defined(CONFIG_HVM)
-void sh_destroy_monitor_table(struct vcpu *v, mfn_t mmfn)
-{
-    struct domain *d = v->domain;
-    ASSERT(mfn_to_page(mmfn)->u.sh.type == SH_type_monitor_table);
-
-#if SHADOW_PAGING_LEVELS != 4
-    {
-        mfn_t m3mfn;
-        l4_pgentry_t *l4e = map_domain_page(mmfn);
-        l3_pgentry_t *l3e;
-        int linear_slot = shadow_l4_table_offset(SH_LINEAR_PT_VIRT_START);
-
-        /* Need to destroy the l3 and l2 monitor pages used
-         * for the linear map */
-        ASSERT(l4e_get_flags(l4e[linear_slot]) & _PAGE_PRESENT);
-        m3mfn = l4e_get_mfn(l4e[linear_slot]);
-        l3e = map_domain_page(m3mfn);
-        ASSERT(l3e_get_flags(l3e[0]) & _PAGE_PRESENT);
-        shadow_free(d, l3e_get_mfn(l3e[0]));
-        unmap_domain_page(l3e);
-        shadow_free(d, m3mfn);
-
-        if ( is_pv_32bit_domain(d) )
-        {
-            /* Need to destroy the l3 and l2 monitor pages that map the
-             * Xen VAs at 3GB-4GB */
-            ASSERT(l4e_get_flags(l4e[0]) & _PAGE_PRESENT);
-            m3mfn = l4e_get_mfn(l4e[0]);
-            l3e = map_domain_page(m3mfn);
-            ASSERT(l3e_get_flags(l3e[3]) & _PAGE_PRESENT);
-            shadow_free(d, l3e_get_mfn(l3e[3]));
-            unmap_domain_page(l3e);
-            shadow_free(d, m3mfn);
-        }
-        unmap_domain_page(l4e);
-    }
-#endif
-
-    /* Put the memory back in the pool */
-    shadow_free(d, mmfn);
-}
-#endif
-
 /**************************************************************************/
 /* Functions to destroy non-Xen mappings in a pagetable hierarchy.
  * These are called from common code when we are running out of shadow
@@ -4705,8 +4583,6 @@ const struct paging_mode sh_paging_mode = {
     .shadow.cmpxchg_guest_entry    = sh_cmpxchg_guest_entry,
 #endif
 #ifdef CONFIG_HVM
-    .shadow.make_monitor_table     = sh_make_monitor_table,
-    .shadow.destroy_monitor_table  = sh_destroy_monitor_table,
 #if SHADOW_OPTIMIZATIONS & SHOPT_WRITABLE_HEURISTIC
     .shadow.guess_wrmap            = sh_guess_wrmap,
 #endif
diff --git a/xen/arch/x86/mm/shadow/private.h b/xen/arch/x86/mm/shadow/private.h
index 5372fdc253..e9b304f755 100644
--- a/xen/arch/x86/mm/shadow/private.h
+++ b/xen/arch/x86/mm/shadow/private.h
@@ -366,9 +366,6 @@ void sh_set_toplevel_shadow(struct vcpu *v,
                                                  mfn_t gmfn,
                                                  uint32_t shadow_type));
 
-/* Install the xen mappings in various flavours of shadow */
-void sh_install_xen_entries_in_l4(struct domain *, mfn_t gl4mfn, mfn_t sl4mfn);
-
 /* Update the shadows in response to a pagetable write from Xen */
 int sh_validate_guest_entry(struct vcpu *v, mfn_t gmfn, void *entry, u32 size);
 
@@ -410,6 +407,14 @@ void shadow_update_paging_modes(struct vcpu *v);
  * With user_only == 1, unhooks only the user-mode mappings. */
 void shadow_unhook_mappings(struct domain *d, mfn_t smfn, int user_only);
 
+/*
+ * sh_{make,destroy}_monitor_table() depend only on the number of shadow
+ * levels.
+ */
+mfn_t sh_make_monitor_table(const struct vcpu *v, unsigned int shadow_levels);
+void sh_destroy_monitor_table(const struct vcpu *v, mfn_t mmfn,
+                              unsigned int shadow_levels);
+
 /* VRAM dirty tracking helpers. */
 void shadow_vram_get_mfn(mfn_t mfn, unsigned int l1f,
                          mfn_t sl1mfn, const void *sl1e,
diff --git a/xen/arch/x86/mm/shadow/types.h b/xen/arch/x86/mm/shadow/types.h
index d5096748ac..416b284123 100644
--- a/xen/arch/x86/mm/shadow/types.h
+++ b/xen/arch/x86/mm/shadow/types.h
@@ -262,15 +262,6 @@ static inline shadow_l4e_t shadow_l4e_from_mfn(mfn_t mfn, 
u32 flags)
 #define sh_rm_write_access_from_sl1p 
INTERNAL_NAME(sh_rm_write_access_from_sl1p)
 #endif
 
-/* sh_make_monitor_table depends only on the number of shadow levels */
-#define sh_make_monitor_table \
-        SHADOW_SH_NAME(sh_make_monitor_table, SHADOW_PAGING_LEVELS)
-#define sh_destroy_monitor_table \
-        SHADOW_SH_NAME(sh_destroy_monitor_table, SHADOW_PAGING_LEVELS)
-
-mfn_t sh_make_monitor_table(struct vcpu *v);
-void sh_destroy_monitor_table(struct vcpu *v, mfn_t mmfn);
-
 #if SHADOW_PAGING_LEVELS == 3
 #define MFN_FITS_IN_HVM_CR3(_MFN) !(mfn_x(_MFN) >> 20)
 #endif
diff --git a/xen/include/asm-x86/paging.h b/xen/include/asm-x86/paging.h
index 61534da538..726f48339a 100644
--- a/xen/include/asm-x86/paging.h
+++ b/xen/include/asm-x86/paging.h
@@ -107,8 +107,6 @@ struct shadow_paging_mode {
                                             mfn_t gmfn);
 #endif
 #ifdef CONFIG_HVM
-    mfn_t         (*make_monitor_table    )(struct vcpu *v);
-    void          (*destroy_monitor_table )(struct vcpu *v, mfn_t mmfn);
     int           (*guess_wrmap           )(struct vcpu *v, 
                                             unsigned long vaddr, mfn_t gmfn);
     void          (*pagetable_dying       )(paddr_t gpa);
--
generated by git-patchbot for /home/xen/git/xen.git#staging



 


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