[PATCH v3 16/21] x86/mm: split out descriptor table code

[Wei Liu <wei.liu2@citrix.com>]

Move the code to pv/descriptor-tables.c. Add "pv_" prefix to
{set,destroy}_gdt. Fix up call sites. Move the declarations to new
header file. Fix coding style issues while moving code.

Signed-off-by: Wei Liu <wei.liu2@citrix.com>
---
 xen/arch/x86/domain.c               |  11 ++-
 xen/arch/x86/mm.c                   | 156 ------------------------------
 xen/arch/x86/pv/Makefile            |   1 +
 xen/arch/x86/pv/descriptor-tables.c | 188 ++++++++++++++++++++++++++++++++++++
 xen/arch/x86/x86_64/compat/mm.c     |   6 +-
 xen/include/asm-x86/processor.h     |   5 -
 xen/include/asm-x86/pv/processor.h  |  40 ++++++++
 7 files changed, 239 insertions(+), 168 deletions(-)
 create mode 100644 xen/arch/x86/pv/descriptor-tables.c
 create mode 100644 xen/include/asm-x86/pv/processor.h

diff --git a/xen/arch/x86/domain.c b/xen/arch/x86/domain.c
index dd8bf1302f..ff6b579b0b 100644
--- a/xen/arch/x86/domain.c
+++ b/xen/arch/x86/domain.c
@@ -64,6 +64,7 @@
 #include <compat/vcpu.h>
 #include <asm/psr.h>
 #include <asm/pv/domain.h>
+#include <asm/pv/processor.h>
 
 DEFINE_PER_CPU(struct vcpu *, curr_vcpu);
 
@@ -987,7 +988,7 @@ int arch_set_info_guest(
         return rc;
 
     if ( !compat )
-        rc = (int)set_gdt(v, c.nat->gdt_frames, c.nat->gdt_ents);
+        rc = (int)pv_set_gdt(v, c.nat->gdt_frames, c.nat->gdt_ents);
     else
     {
         unsigned long gdt_frames[ARRAY_SIZE(v->arch.pv_vcpu.gdt_frames)];
@@ -997,7 +998,7 @@ int arch_set_info_guest(
             return -EINVAL;
         for ( i = 0; i < n; ++i )
             gdt_frames[i] = c.cmp->gdt_frames[i];
-        rc = (int)set_gdt(v, gdt_frames, c.cmp->gdt_ents);
+        rc = (int)pv_set_gdt(v, gdt_frames, c.cmp->gdt_ents);
     }
     if ( rc != 0 )
         return rc;
@@ -1096,7 +1097,7 @@ int arch_set_info_guest(
     {
         if ( cr3_page )
             put_page(cr3_page);
-        destroy_gdt(v);
+        pv_destroy_gdt(v);
         return rc;
     }
 
@@ -1148,7 +1149,7 @@ int arch_vcpu_reset(struct vcpu *v)
 {
     if ( is_pv_vcpu(v) )
     {
-        destroy_gdt(v);
+        pv_destroy_gdt(v);
         return vcpu_destroy_pagetables(v);
     }
 
@@ -1893,7 +1894,7 @@ int domain_relinquish_resources(struct domain *d)
                  * the LDT as it automatically gets squashed with the guest
                  * mappings.
                  */
-                destroy_gdt(v);
+                pv_destroy_gdt(v);
             }
         }
 
diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
index 897db4cfb9..1a9517fda8 100644
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -4066,162 +4066,6 @@ long do_update_va_mapping_otherdomain(unsigned long va, u64 val64,
 }
 
 
-
-/*************************
- * Descriptor Tables
- */
-
-void destroy_gdt(struct vcpu *v)
-{
-    l1_pgentry_t *pl1e;
-    unsigned int i;
-    unsigned long pfn, zero_pfn = PFN_DOWN(__pa(zero_page));
-
-    v->arch.pv_vcpu.gdt_ents = 0;
-    pl1e = gdt_ldt_ptes(v->domain, v);
-    for ( i = 0; i < FIRST_RESERVED_GDT_PAGE; i++ )
-    {
-        pfn = l1e_get_pfn(pl1e[i]);
-        if ( (l1e_get_flags(pl1e[i]) & _PAGE_PRESENT) && pfn != zero_pfn )
-            put_page_and_type(mfn_to_page(pfn));
-        l1e_write(&pl1e[i], l1e_from_pfn(zero_pfn, __PAGE_HYPERVISOR_RO));
-        v->arch.pv_vcpu.gdt_frames[i] = 0;
-    }
-}
-
-
-long set_gdt(struct vcpu *v,
-             unsigned long *frames,
-             unsigned int entries)
-{
-    struct domain *d = v->domain;
-    l1_pgentry_t *pl1e;
-    /* NB. There are 512 8-byte entries per GDT page. */
-    unsigned int i, nr_pages = (entries + 511) / 512;
-
-    if ( entries > FIRST_RESERVED_GDT_ENTRY )
-        return -EINVAL;
-
-    /* Check the pages in the new GDT. */
-    for ( i = 0; i < nr_pages; i++ )
-    {
-        struct page_info *page;
-
-        page = get_page_from_gfn(d, frames[i], NULL, P2M_ALLOC);
-        if ( !page )
-            goto fail;
-        if ( !get_page_type(page, PGT_seg_desc_page) )
-        {
-            put_page(page);
-            goto fail;
-        }
-        frames[i] = page_to_mfn(page);
-    }
-
-    /* Tear down the old GDT. */
-    destroy_gdt(v);
-
-    /* Install the new GDT. */
-    v->arch.pv_vcpu.gdt_ents = entries;
-    pl1e = gdt_ldt_ptes(d, v);
-    for ( i = 0; i < nr_pages; i++ )
-    {
-        v->arch.pv_vcpu.gdt_frames[i] = frames[i];
-        l1e_write(&pl1e[i], l1e_from_pfn(frames[i], __PAGE_HYPERVISOR_RW));
-    }
-
-    return 0;
-
- fail:
-    while ( i-- > 0 )
-    {
-        put_page_and_type(mfn_to_page(frames[i]));
-    }
-    return -EINVAL;
-}
-
-
-long do_set_gdt(XEN_GUEST_HANDLE_PARAM(xen_ulong_t) frame_list,
-                unsigned int entries)
-{
-    int nr_pages = (entries + 511) / 512;
-    unsigned long frames[16];
-    struct vcpu *curr = current;
-    long ret;
-
-    /* Rechecked in set_gdt, but ensures a sane limit for copy_from_user(). */
-    if ( entries > FIRST_RESERVED_GDT_ENTRY )
-        return -EINVAL;
-
-    if ( copy_from_guest(frames, frame_list, nr_pages) )
-        return -EFAULT;
-
-    domain_lock(curr->domain);
-
-    if ( (ret = set_gdt(curr, frames, entries)) == 0 )
-        flush_tlb_local();
-
-    domain_unlock(curr->domain);
-
-    return ret;
-}
-
-
-long do_update_descriptor(u64 pa, u64 desc)
-{
-    struct domain *dom = current->domain;
-    unsigned long gmfn = pa >> PAGE_SHIFT;
-    unsigned long mfn;
-    unsigned int  offset;
-    struct desc_struct *gdt_pent, d;
-    struct page_info *page;
-    long ret = -EINVAL;
-
-    offset = ((unsigned int)pa & ~PAGE_MASK) / sizeof(struct desc_struct);
-
-    *(u64 *)&d = desc;
-
-    page = get_page_from_gfn(dom, gmfn, NULL, P2M_ALLOC);
-    if ( (((unsigned int)pa % sizeof(struct desc_struct)) != 0) ||
-         !page ||
-         !check_descriptor(dom, &d) )
-    {
-        if ( page )
-            put_page(page);
-        return -EINVAL;
-    }
-    mfn = page_to_mfn(page);
-
-    /* Check if the given frame is in use in an unsafe context. */
-    switch ( page->u.inuse.type_info & PGT_type_mask )
-    {
-    case PGT_seg_desc_page:
-        if ( unlikely(!get_page_type(page, PGT_seg_desc_page)) )
-            goto out;
-        break;
-    default:
-        if ( unlikely(!get_page_type(page, PGT_writable_page)) )
-            goto out;
-        break;
-    }
-
-    paging_mark_dirty(dom, _mfn(mfn));
-
-    /* All is good so make the update. */
-    gdt_pent = map_domain_page(_mfn(mfn));
-    write_atomic((uint64_t *)&gdt_pent[offset], *(uint64_t *)&d);
-    unmap_domain_page(gdt_pent);
-
-    put_page_type(page);
-
-    ret = 0; /* success */
-
- out:
-    put_page(page);
-
-    return ret;
-}
-
 typedef struct e820entry e820entry_t;
 DEFINE_XEN_GUEST_HANDLE(e820entry_t);
 
diff --git a/xen/arch/x86/pv/Makefile b/xen/arch/x86/pv/Makefile
index 501c766cc2..42e9d3723b 100644
--- a/xen/arch/x86/pv/Makefile
+++ b/xen/arch/x86/pv/Makefile
@@ -1,4 +1,5 @@
 obj-y += callback.o
+obj-y += descriptor-tables.o
 obj-y += domain.o
 obj-y += emulate.o
 obj-y += emul-gate-op.o
diff --git a/xen/arch/x86/pv/descriptor-tables.c b/xen/arch/x86/pv/descriptor-tables.c
new file mode 100644
index 0000000000..12dc45b671
--- /dev/null
+++ b/xen/arch/x86/pv/descriptor-tables.c
@@ -0,0 +1,188 @@
+/******************************************************************************
+ * arch/x86/pv/descriptor-tables.c
+ *
+ * Descriptor table related code
+ *
+ * Copyright (c) 2002-2005 K A Fraser
+ * Copyright (c) 2004 Christian Limpach
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <xen/guest_access.h>
+#include <xen/hypercall.h>
+
+#include <asm/p2m.h>
+#include <asm/pv/processor.h>
+
+/*************************
+ * Descriptor Tables
+ */
+
+void pv_destroy_gdt(struct vcpu *v)
+{
+    l1_pgentry_t *pl1e;
+    unsigned int i;
+    unsigned long pfn, zero_pfn = PFN_DOWN(__pa(zero_page));
+
+    v->arch.pv_vcpu.gdt_ents = 0;
+    pl1e = gdt_ldt_ptes(v->domain, v);
+    for ( i = 0; i < FIRST_RESERVED_GDT_PAGE; i++ )
+    {
+        pfn = l1e_get_pfn(pl1e[i]);
+        if ( (l1e_get_flags(pl1e[i]) & _PAGE_PRESENT) && pfn != zero_pfn )
+            put_page_and_type(mfn_to_page(pfn));
+        l1e_write(&pl1e[i], l1e_from_pfn(zero_pfn, __PAGE_HYPERVISOR_RO));
+        v->arch.pv_vcpu.gdt_frames[i] = 0;
+    }
+}
+
+long pv_set_gdt(struct vcpu *v, unsigned long *frames, unsigned int entries)
+{
+    struct domain *d = v->domain;
+    l1_pgentry_t *pl1e;
+    /* NB. There are 512 8-byte entries per GDT page. */
+    unsigned int i, nr_pages = (entries + 511) / 512;
+
+    if ( entries > FIRST_RESERVED_GDT_ENTRY )
+        return -EINVAL;
+
+    /* Check the pages in the new GDT. */
+    for ( i = 0; i < nr_pages; i++ )
+    {
+        struct page_info *page;
+
+        page = get_page_from_gfn(d, frames[i], NULL, P2M_ALLOC);
+        if ( !page )
+            goto fail;
+        if ( !get_page_type(page, PGT_seg_desc_page) )
+        {
+            put_page(page);
+            goto fail;
+        }
+        frames[i] = page_to_mfn(page);
+    }
+
+    /* Tear down the old GDT. */
+    pv_destroy_gdt(v);
+
+    /* Install the new GDT. */
+    v->arch.pv_vcpu.gdt_ents = entries;
+    pl1e = gdt_ldt_ptes(d, v);
+    for ( i = 0; i < nr_pages; i++ )
+    {
+        v->arch.pv_vcpu.gdt_frames[i] = frames[i];
+        l1e_write(&pl1e[i], l1e_from_pfn(frames[i], __PAGE_HYPERVISOR_RW));
+    }
+
+    return 0;
+
+ fail:
+    while ( i-- > 0 )
+    {
+        put_page_and_type(mfn_to_page(frames[i]));
+    }
+    return -EINVAL;
+}
+
+
+long do_set_gdt(XEN_GUEST_HANDLE_PARAM(xen_ulong_t) frame_list,
+                unsigned int entries)
+{
+    int nr_pages = (entries + 511) / 512;
+    unsigned long frames[16];
+    struct vcpu *curr = current;
+    long ret;
+
+    /* Rechecked in pv_set_gdt, but ensures a sane limit for copy_from_user(). */
+    if ( entries > FIRST_RESERVED_GDT_ENTRY )
+        return -EINVAL;
+
+    if ( copy_from_guest(frames, frame_list, nr_pages) )
+        return -EFAULT;
+
+    domain_lock(curr->domain);
+
+    if ( (ret = pv_set_gdt(curr, frames, entries)) == 0 )
+        flush_tlb_local();
+
+    domain_unlock(curr->domain);
+
+    return ret;
+}
+
+long do_update_descriptor(u64 pa, u64 desc)
+{
+    struct domain *dom = current->domain;
+    unsigned long gmfn = pa >> PAGE_SHIFT;
+    unsigned long mfn;
+    unsigned int  offset;
+    struct desc_struct *gdt_pent, d;
+    struct page_info *page;
+    long ret = -EINVAL;
+
+    offset = ((unsigned int)pa & ~PAGE_MASK) / sizeof(struct desc_struct);
+
+    *(u64 *)&d = desc;
+
+    page = get_page_from_gfn(dom, gmfn, NULL, P2M_ALLOC);
+    if ( (((unsigned int)pa % sizeof(struct desc_struct)) != 0) ||
+         !page ||
+         !check_descriptor(dom, &d) )
+    {
+        if ( page )
+            put_page(page);
+        return -EINVAL;
+    }
+    mfn = page_to_mfn(page);
+
+    /* Check if the given frame is in use in an unsafe context. */
+    switch ( page->u.inuse.type_info & PGT_type_mask )
+    {
+    case PGT_seg_desc_page:
+        if ( unlikely(!get_page_type(page, PGT_seg_desc_page)) )
+            goto out;
+        break;
+    default:
+        if ( unlikely(!get_page_type(page, PGT_writable_page)) )
+            goto out;
+        break;
+    }
+
+    paging_mark_dirty(dom, _mfn(mfn));
+
+    /* All is good so make the update. */
+    gdt_pent = map_domain_page(_mfn(mfn));
+    write_atomic((uint64_t *)&gdt_pent[offset], *(uint64_t *)&d);
+    unmap_domain_page(gdt_pent);
+
+    put_page_type(page);
+
+    ret = 0; /* success */
+
+ out:
+    put_page(page);
+
+    return ret;
+}
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * tab-width: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
diff --git a/xen/arch/x86/x86_64/compat/mm.c b/xen/arch/x86/x86_64/compat/mm.c
index b737af1888..dc41f61c71 100644
--- a/xen/arch/x86/x86_64/compat/mm.c
+++ b/xen/arch/x86/x86_64/compat/mm.c
@@ -6,13 +6,15 @@
 #include <asm/mem_paging.h>
 #include <asm/mem_sharing.h>
 
+#include <asm/pv/processor.h>
+
 int compat_set_gdt(XEN_GUEST_HANDLE_PARAM(uint) frame_list, unsigned int entries)
 {
     unsigned int i, nr_pages = (entries + 511) / 512;
     unsigned long frames[16];
     long ret;
 
-    /* Rechecked in set_gdt, but ensures a sane limit for copy_from_user(). */
+    /* Rechecked in pv_set_gdt, but ensures a sane limit for copy_from_user(). */
     if ( entries > FIRST_RESERVED_GDT_ENTRY )
         return -EINVAL;
 
@@ -31,7 +33,7 @@ int compat_set_gdt(XEN_GUEST_HANDLE_PARAM(uint) frame_list, unsigned int entries
 
     domain_lock(current->domain);
 
-    if ( (ret = set_gdt(current, frames, entries)) == 0 )
+    if ( (ret = pv_set_gdt(current, frames, entries)) == 0 )
         flush_tlb_local();
 
     domain_unlock(current->domain);
diff --git a/xen/include/asm-x86/processor.h b/xen/include/asm-x86/processor.h
index 5bf56b45e1..1463a3acb7 100644
--- a/xen/include/asm-x86/processor.h
+++ b/xen/include/asm-x86/processor.h
@@ -459,11 +459,6 @@ extern void init_int80_direct_trap(struct vcpu *v);
 
 extern void write_ptbase(struct vcpu *v);
 
-void destroy_gdt(struct vcpu *d);
-long set_gdt(struct vcpu *d, 
-             unsigned long *frames, 
-             unsigned int entries);
-
 /* REP NOP (PAUSE) is a good thing to insert into busy-wait loops. */
 static always_inline void rep_nop(void)
 {
diff --git a/xen/include/asm-x86/pv/processor.h b/xen/include/asm-x86/pv/processor.h
new file mode 100644
index 0000000000..8ab5773871
--- /dev/null
+++ b/xen/include/asm-x86/pv/processor.h
@@ -0,0 +1,40 @@
+/*
+ * asm-x86/pv/processor.h
+ *
+ * Vcpu interfaces for PV guests
+ *
+ * Copyright (C) 2017 Wei Liu <wei.liu2@citrix.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms and conditions of the GNU General Public
+ * License, version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef __X86_PV_PROCESSOR_H__
+#define __X86_PV_PROCESSOR_H__
+
+#ifdef CONFIG_PV
+
+void pv_destroy_gdt(struct vcpu *d);
+long pv_set_gdt(struct vcpu *d, unsigned long *frames, unsigned int entries);
+
+#else
+
+#include <xen/errno.h>
+
+static inline void pv_destroy_gdt(struct vcpu *d) {}
+static inline long pv_set_gdt(struct vcpu *d, unsigned long *frames,
+                              unsigned int entries)
+{ return -EINVAL; }
+
+#endif
+
+#endif /* __X86_PV_PROCESSOR_H__ */
-- 
2.11.0


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