VMX: remove the problematic set_uc_mode logic

XSA-60 security hole comes from the problematic vmx_set_uc_mode.
This patch remove vmx_set_uc_mode logic, which will be replaced by
PAT approach at later patch.

This is CVE-2013-2212 / XSA-60.

Signed-off-by: Liu Jinsong <jinsong.liu@intel.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Tim Deegan <tim@xen.org>
Acked-by: Jun Nakajima <jun.nakajima@intel.com>

xen/arch/x86/hvm/hvm.c

@@ -1619,8 +1619,6 @@ static void hvm_set_uc_mode(struct vcpu *v, bool_t is_in_uc_mode)
 {
     v->domain->arch.hvm_domain.is_in_uc_mode = is_in_uc_mode;
     shadow_blow_tables_per_domain(v->domain);
-    if ( hvm_funcs.set_uc_mode )
-        return hvm_funcs.set_uc_mode(v);
 }
 
 int hvm_mov_to_cr(unsigned int cr, unsigned int gpr)

xen/arch/x86/hvm/mtrr.c

@@ -696,9 +696,6 @@ uint8_t epte_get_entry_emt(struct domain *d, unsigned long gfn, mfn_t mfn,
     if ( !v->domain->arch.hvm_domain.params[HVM_PARAM_IDENT_PT] )
         return MTRR_TYPE_WRBACK;
 
-    if ( (v == current) && v->domain->arch.hvm_domain.is_in_uc_mode )
-        return MTRR_TYPE_UNCACHABLE;
-
     if ( !mfn_valid(mfn_x(mfn)) )
         return MTRR_TYPE_UNCACHABLE;
 

xen/arch/x86/hvm/vmx/vmx.c

@@ -1392,14 +1392,6 @@ static int vmx_event_pending(struct vcpu *v)
     return intr_info & INTR_INFO_VALID_MASK;
 }
 
-static void vmx_set_uc_mode(struct vcpu *v)
-{
-    if ( paging_mode_hap(v->domain) )
-        ept_change_entry_emt_with_range(
-            v->domain, 0, p2m_get_hostp2m(v->domain)->max_mapped_pfn);
-    hvm_asid_flush_vcpu(v);
-}
-
 static void vmx_set_info_guest(struct vcpu *v)
 {
     unsigned long intr_shadow;
@@ -1558,7 +1550,6 @@ static struct hvm_function_table __initdata vmx_function_table = {
     .msr_read_intercept   = vmx_msr_read_intercept,
     .msr_write_intercept  = vmx_msr_write_intercept,
     .invlpg_intercept     = vmx_invlpg_intercept,
-    .set_uc_mode          = vmx_set_uc_mode,
     .set_info_guest       = vmx_set_info_guest,
     .set_rdtsc_exiting    = vmx_set_rdtsc_exiting,
     .nhvm_vcpu_initialise = nvmx_vcpu_initialise,

xen/arch/x86/mm/p2m-ept.c

@@ -587,44 +587,6 @@ out:
     return mfn;
 }
 
-/* WARNING: Only caller doesn't care about PoD pages.  So this function will
- * always return 0 for PoD pages, not populate them.  If that becomes necessary,
- * pass a p2m_query_t type along to distinguish. */
-static ept_entry_t ept_get_entry_content(struct p2m_domain *p2m,
-    unsigned long gfn, int *level)
-{
-    ept_entry_t *table = map_domain_page(pagetable_get_pfn(p2m_get_pagetable(p2m)));
-    unsigned long gfn_remainder = gfn;
-    ept_entry_t *ept_entry;
-    ept_entry_t content = { .epte = 0 };
-    u32 index;
-    int i;
-    int ret=0;
-    struct ept_data *ept = &p2m->ept;
-
-    /* This pfn is higher than the highest the p2m map currently holds */
-    if ( gfn > p2m->max_mapped_pfn )
-        goto out;
-
-    for ( i = ept_get_wl(ept); i > 0; i-- )
-    {
-        ret = ept_next_level(p2m, 1, &table, &gfn_remainder, i);
-        if ( !ret || ret == GUEST_TABLE_POD_PAGE )
-            goto out;
-        else if ( ret == GUEST_TABLE_SUPER_PAGE )
-            break;
-    }
-
-    index = gfn_remainder >> (i * EPT_TABLE_ORDER);
-    ept_entry = table + index;
-    content = *ept_entry;
-    *level = i;
-
- out:
-    unmap_domain_page(table);
-    return content;
-}
-
 void ept_walk_table(struct domain *d, unsigned long gfn)
 {
     struct p2m_domain *p2m = p2m_get_hostp2m(d);
@@ -676,88 +638,6 @@ out:
     return;
 }
 
-/*
- * To test if the new emt type is the same with old,
- * return 1 to not to reset ept entry.
- */
-static int need_modify_ept_entry(struct p2m_domain *p2m, unsigned long gfn,
-                                 mfn_t mfn, uint8_t o_ipat, uint8_t o_emt,
-                                 p2m_type_t p2mt)
-{
-    uint8_t ipat;
-    uint8_t emt;
-    bool_t direct_mmio = (p2mt == p2m_mmio_direct);
-
-    emt = epte_get_entry_emt(p2m->domain, gfn, mfn, &ipat, direct_mmio);
-
-    if ( (emt == o_emt) && (ipat == o_ipat) )
-        return 0;
-
-    return 1;
-}
-
-void ept_change_entry_emt_with_range(struct domain *d,
-                                     unsigned long start_gfn,
-                                     unsigned long end_gfn)
-{
-    unsigned long gfn;
-    ept_entry_t e;
-    mfn_t mfn;
-    int order = 0;
-    struct p2m_domain *p2m = p2m_get_hostp2m(d);
-    int rc;
-
-    p2m_lock(p2m);
-    for ( gfn = start_gfn; gfn <= end_gfn; gfn++ )
-    {
-        int level = 0;
-        uint64_t trunk = 0;
-
-        e = ept_get_entry_content(p2m, gfn, &level);
-        if ( !is_epte_present(&e) || !p2m_has_emt(e.sa_p2mt) )
-            continue;
-
-        order = 0;
-        mfn = _mfn(e.mfn);
-
-        if ( is_epte_superpage(&e) )
-        {
-            while ( level )
-            {
-                trunk = (1UL << (level * EPT_TABLE_ORDER)) - 1;
-                if ( !(gfn & trunk) && (gfn + trunk <= end_gfn) )
-                {
-                    /* gfn assigned with 2M or 1G, and the end covers more than
-                     * the super page areas.
-                     * Set emt for super page.
-                     */
-                    order = level * EPT_TABLE_ORDER;
-                    if ( need_modify_ept_entry(p2m, gfn, mfn, 
-                          e.ipat, e.emt, e.sa_p2mt) )
-                    {
-                        rc = ept_set_entry(p2m, gfn, mfn, order,
-                                           e.sa_p2mt, e.access);
-                        ASSERT(rc);
-                    }
-                    gfn += trunk;
-                    break;
-                }
-                level--;
-             }
-        }
-        else /* gfn assigned with 4k */
-        {
-            if ( need_modify_ept_entry(p2m, gfn, mfn,
-                                       e.ipat, e.emt, e.sa_p2mt) )
-            {
-                rc = ept_set_entry(p2m, gfn, mfn, order, e.sa_p2mt, e.access);
-                ASSERT(rc);
-            }
-        }
-    }
-    p2m_unlock(p2m);
-}
-
 /*
  * Walk the whole p2m table, changing any entries of the old type
  * to the new type.  This is used in hardware-assisted paging to

xen/include/asm-x86/hvm/hvm.h

@@ -156,7 +156,6 @@ struct hvm_function_table {
     int (*msr_read_intercept)(unsigned int msr, uint64_t *msr_content);
     int (*msr_write_intercept)(unsigned int msr, uint64_t msr_content);
     void (*invlpg_intercept)(unsigned long vaddr);
-    void (*set_uc_mode)(struct vcpu *v);
     void (*set_info_guest)(struct vcpu *v);
     void (*set_rdtsc_exiting)(struct vcpu *v, bool_t);