main/xen: fix xsa45 and xsa58 (CVE-2013-1918,CVE-2013-1432)

ref #2123

3 files changed, 1271 insertions, 1 deletions

diff --git a/main/xen/APKBUILD b/main/xen/APKBUILD
index a4dc8ed9ab..a2b82db3eb 100644
--- a/main/xen/APKBUILD
+++ b/main/xen/APKBUILD
@@ -3,7 +3,7 @@
 # Maintainer: William Pitcock <nenolod@dereferenced.org>
 pkgname=xen
 pkgver=4.2.2
-pkgrel=5
+pkgrel=6
 pkgdesc="Xen hypervisor"
 url="http://www.xen.org/"
 arch="x86 x86_64"
@@ -24,6 +24,7 @@ source="http://bits.xensource.com/oss-xen/release/$pkgver/$pkgname-$pkgver.tar.g
 	xsa41.patch
 	xsa41b.patch
 	xsa41c.patch
+	xsa45-4.2.patch
 	xsa48-4.2.patch
 	xsa52-4.2-unstable.patch
 	xsa53-4.2.patch
@@ -31,6 +32,7 @@ source="http://bits.xensource.com/oss-xen/release/$pkgver/$pkgname-$pkgver.tar.g
 	xsa55.patch
 	xsa56.patch
 	xsa57.patch
+	xsa58-4.2.patch
 
 	fix-pod2man-choking.patch
 
@@ -154,6 +156,7 @@ md5sums="f7362b19401a47826f2d8fd603a1782a  xen-4.2.2.tar.gz
 8ad8942000b8a4be4917599cad9209cf  xsa41.patch
 ed7d0399c6ca6aeee479da5d8f807fe0  xsa41b.patch
 2f3dd7bdc59d104370066d6582725575  xsa41c.patch
+9265540493f41f7d40c48d0886ec5823  xsa45-4.2.patch
 b3e3a57d189a4f86c9766eaf3b5207f4  xsa48-4.2.patch
 83a9cdd035bcd18bf035434a1ba08c38  xsa52-4.2-unstable.patch
 03a1a4ebc470ee7e638e04db2701a4f7  xsa53-4.2.patch
@@ -161,6 +164,7 @@ a8393d1ec6b886ea72ffe624a04ee10a  xsa54.patch
 42cd104f2a33d67938a63a6372cff573  xsa55.patch
 e70b9128ffc2175cea314a533a7d8457  xsa56.patch
 7475158130474ee062a4eb878259af61  xsa57.patch
+7de2cd11c10d6a554f3c81e0688c38b7  xsa58-4.2.patch
 c1d1a415415b0192e5dae9032962bf61  fix-pod2man-choking.patch
 95d8af17bf844d41a015ff32aae51ba1  xenstored.initd
 b017ccdd5e1c27bbf1513e3569d4ff07  xenstored.confd
@@ -181,6 +185,7 @@ a0c225d716d343fe041b63e3940900c5b3573ed3bcfc5b7c2d52ea2861c3fc28  docs-Fix-gener
 93452beba88a8da8e89b8bfa743074a358ba1d9052151c608e21c4d62f8c4867  xsa41.patch
 896a07f57310c9bea9bc2a305166cf796282c381cb7839be49105b1726a860b5  xsa41b.patch
 683dd96a0a8899f794070c8c09643dfeeb39f92da531955cba961b45f6075914  xsa41c.patch
+f3c8c75cc6f55409139b1928017d1e432e5e64b6fac2083395f4723353e1c775  xsa45-4.2.patch
 dc23077028584e71a08dd0dc9e81552c76744a5ce9d39df5958a95ae9cf3107b  xsa48-4.2.patch
 5b8582185bf90386729e81db1f7780c69a891b074a87d9a619a90d6f639bea13  xsa52-4.2-unstable.patch
 785f7612bd229f7501f4e98e4760f307d90c64305ee14707d262b77f05fa683d  xsa53-4.2.patch
@@ -188,6 +193,7 @@ dc23077028584e71a08dd0dc9e81552c76744a5ce9d39df5958a95ae9cf3107b  xsa48-4.2.patc
 ac3ebaf3ec37e28ba08e23d63626d7aaccf0a3f282dd0af9c24cc4df3fd8fae0  xsa55.patch
 a691c5f5332a42c0d38ddb4dc037eb902f01ba31033b64c47d02909a8de0257d  xsa56.patch
 b6a5106848541972519cc529859d9ff3083c79367276c7031560fa4ce6f9f770  xsa57.patch
+194d6610fc38b767d643e5d58a1268f45921fb35e309b47aca6a388b861311c2  xsa58-4.2.patch
 b4e7d43364a06b2cb04527db3e9567524bc489fef475709fd8493ebf1e62406d  fix-pod2man-choking.patch
 81d335946c81311c86e2f2112b773a568a5a530c0db9802b2fe559e71bb8b381  xenstored.initd
 ea9171e71ab3d33061979bcf3bb737156192aa4b0be4d1234438ced75b6fdef3  xenstored.confd
@@ -208,6 +214,7 @@ sha512sums="4943b18016ed8c2b194a3b55e6655b3b734b39ffb8cb7ee0a0580f2f4460a1d0e92e
 94672a4d37db4e370370157cac9507ee1a75832f4be779fba148c1faa0b18f26ed57126eee6256ccd5d218463325a730266b53139554f4865adedb7659154c16  xsa41.patch
 bda9105793f2327e1317991762120d0668af0e964076b18c9fdbfd509984b2e88d85df95702c46b2e00d5350e8113f6aa7b34b19064d19abbeb4d43f0c431d38  xsa41b.patch
 36b60478660ff7748328f5ab9adff13286eee1a1bad06e42fdf7e6aafe105103988525725aacd660cf5b2a184a9e2d6b3818655203c1fa07e07dcebdf23f35d9  xsa41c.patch
+a57b4c8be76a938d51e51ffb39f0781389ebef320f359b0ae9af4a93af970d37dde50a304d4864a75b7fb32861a4745b9da5fa6acce0f2a688b11b13ab43fb4e  xsa45-4.2.patch
 31dd8c62d41cc0a01a79d9b24a5b793f5e2058230808d9c5364c6ff3477ab02f3258f1bbd761d97dc1b97ee120b41524b999eaac77f33b606496fc324b5fa2e4  xsa48-4.2.patch
 b64a965fab8534958e453c493211ed3a6555aafb90d18f6d56a45b41d3086a0029aee85b6b6eb93b0d861d5fdc0ef10fc32e9b4f83593b37c43922d838085dd8  xsa52-4.2-unstable.patch
 9b08924e563e79d2b308c1521da520c0579b334b61ac99a5593eabdb96dbda2da898b542cc47bda6d663c68343216d9d29c04853b6d1b6ecdde964b0cbb3f7ab  xsa53-4.2.patch
@@ -215,6 +222,7 @@ c9010be637d4f96ef03c880e1ef28228f762c5980108380a105bd190b631a882c8dff81e9421246d
 b4f43095163146a29ae258575bb03bd45f5a315d3cca7434a0b88c18eb1b6e1cf17ef13b4ac428a08797271a3dbc756d3f705a990991c8d2fc96f0f272c3665a  xsa55.patch
 26a1c2cc92ddd4c1ab6712b0e41a0135d0e76a7fe3a14b651fb0235e352e5a24077414371acccb93058b7ce4d882b667386811170ba74570c53165837bcd983d  xsa56.patch
 5ccc1654d9f0270485495f9fc913e41663ddbda602ffe049e0a9c3247c6246690b7ec4165482f96921c5253a2a5205ca384048339996e611c07ab60a6a75cf6a  xsa57.patch
+60813c01f6bb909da8748919df4d0ffa923baf4b7b55287e0bec3389fb83020158225182e112941c9e126b4df57e7b8724f2a69d0c1fa9ce3b37c0bdf1a49da4  xsa58-4.2.patch
 ffb1113fcec0853b690c177655c7d1136388efdebf0d7f625b80481b98eadd3e9ef461442ced53e11acf0e347800a2b0a41e18b05065b5d04bffdd8a4e127cec  fix-pod2man-choking.patch
 792b062e8a16a2efd3cb4662d379d1500527f2a7ca9228d7831c2bd34f3b9141df949153ea05463a7758c3e3dd9a4182492ad5505fa38e298ecf8c99db77b4ee  xenstored.initd
 100cf4112f401f45c1e4e885a5074698c484b40521262f6268fad286498e95f4c51e746f0e94eb43a590bb8e813a397bb53801ccacebec9541020799d8d70514  xenstored.confd
diff --git a/main/xen/xsa45-4.2.patch b/main/xen/xsa45-4.2.patch
new file mode 100644
index 0000000000..dfdfdea64b
--- /dev/null
+++ b/main/xen/xsa45-4.2.patch
@@ -0,0 +1,1133 @@
+diff --git a/xen/arch/x86/domain.c b/xen/arch/x86/domain.c
+index 26a7f12..b97ac6d 100644
+--- a/xen/arch/x86/domain.c
++++ b/xen/arch/x86/domain.c
+@@ -73,8 +73,6 @@ void (*dead_idle) (void) __read_mostly = default_dead_idle;
+ static void paravirt_ctxt_switch_from(struct vcpu *v);
+ static void paravirt_ctxt_switch_to(struct vcpu *v);
+ 
+-static void vcpu_destroy_pagetables(struct vcpu *v);
+-
+ static void default_idle(void)
+ {
+     local_irq_disable();
+@@ -860,6 +858,9 @@ int arch_set_info_guest(
+ 
+     if ( !v->is_initialised )
+     {
++        if ( !compat && !(flags & VGCF_in_kernel) && !c.nat->ctrlreg[1] )
++            return -EINVAL;
++
+         v->arch.pv_vcpu.ldt_base = c(ldt_base);
+         v->arch.pv_vcpu.ldt_ents = c(ldt_ents);
+     }
+@@ -957,24 +958,44 @@ int arch_set_info_guest(
+     if ( rc != 0 )
+         return rc;
+ 
++    set_bit(_VPF_in_reset, &v->pause_flags);
++
+     if ( !compat )
+-    {
+         cr3_gfn = xen_cr3_to_pfn(c.nat->ctrlreg[3]);
+-        cr3_page = get_page_from_gfn(d, cr3_gfn, NULL, P2M_ALLOC);
+-
+-        if ( !cr3_page )
+-        {
+-            destroy_gdt(v);
+-            return -EINVAL;
+-        }
+-        if ( !paging_mode_refcounts(d)
+-             && !get_page_type(cr3_page, PGT_base_page_table) )
+-        {
+-            put_page(cr3_page);
+-            destroy_gdt(v);
+-            return -EINVAL;
+-        }
++#ifdef CONFIG_COMPAT
++    else
++        cr3_gfn = compat_cr3_to_pfn(c.cmp->ctrlreg[3]);
++#endif
++    cr3_page = get_page_from_gfn(d, cr3_gfn, NULL, P2M_ALLOC);
+ 
++    if ( !cr3_page )
++        rc = -EINVAL;
++    else if ( paging_mode_refcounts(d) )
++        /* nothing */;
++    else if ( cr3_page == v->arch.old_guest_table )
++    {
++        v->arch.old_guest_table = NULL;
++        put_page(cr3_page);
++    }
++    else
++    {
++        /*
++         * Since v->arch.guest_table{,_user} are both NULL, this effectively
++         * is just a call to put_old_guest_table().
++         */
++        if ( !compat )
++            rc = vcpu_destroy_pagetables(v);
++        if ( !rc )
++            rc = get_page_type_preemptible(cr3_page,
++                                           !compat ? PGT_root_page_table
++                                                   : PGT_l3_page_table);
++        if ( rc == -EINTR )
++            rc = -EAGAIN;
++    }
++    if ( rc )
++        /* handled below */;
++    else if ( !compat )
++    {
+         v->arch.guest_table = pagetable_from_page(cr3_page);
+ #ifdef __x86_64__
+         if ( c.nat->ctrlreg[1] )
+@@ -982,56 +1003,44 @@ int arch_set_info_guest(
+             cr3_gfn = xen_cr3_to_pfn(c.nat->ctrlreg[1]);
+             cr3_page = get_page_from_gfn(d, cr3_gfn, NULL, P2M_ALLOC);
+ 
+-            if ( !cr3_page ||
+-                 (!paging_mode_refcounts(d)
+-                  && !get_page_type(cr3_page, PGT_base_page_table)) )
++            if ( !cr3_page )
++                rc = -EINVAL;
++            else if ( !paging_mode_refcounts(d) )
+             {
+-                if (cr3_page)
+-                    put_page(cr3_page);
+-                cr3_page = pagetable_get_page(v->arch.guest_table);
+-                v->arch.guest_table = pagetable_null();
+-                if ( paging_mode_refcounts(d) )
+-                    put_page(cr3_page);
+-                else
+-                    put_page_and_type(cr3_page);
+-                destroy_gdt(v);
+-                return -EINVAL;
++                rc = get_page_type_preemptible(cr3_page, PGT_root_page_table);
++                switch ( rc )
++                {
++                case -EINTR:
++                    rc = -EAGAIN;
++                case -EAGAIN:
++                    v->arch.old_guest_table =
++                        pagetable_get_page(v->arch.guest_table);
++                    v->arch.guest_table = pagetable_null();
++                    break;
++                }
+             }
+-
+-            v->arch.guest_table_user = pagetable_from_page(cr3_page);
+-        }
+-        else if ( !(flags & VGCF_in_kernel) )
+-        {
+-            destroy_gdt(v);
+-            return -EINVAL;
++            if ( !rc )
++               v->arch.guest_table_user = pagetable_from_page(cr3_page);
+         }
+     }
+     else
+     {
+         l4_pgentry_t *l4tab;
+ 
+-        cr3_gfn = compat_cr3_to_pfn(c.cmp->ctrlreg[3]);
+-        cr3_page = get_page_from_gfn(d, cr3_gfn, NULL, P2M_ALLOC);
+-
+-        if ( !cr3_page)
+-        {
+-            destroy_gdt(v);
+-            return -EINVAL;
+-        }
+-
+-        if (!paging_mode_refcounts(d)
+-            && !get_page_type(cr3_page, PGT_l3_page_table) )
+-        {
+-            put_page(cr3_page);
+-            destroy_gdt(v);
+-            return -EINVAL;
+-        }
+-
+         l4tab = __va(pagetable_get_paddr(v->arch.guest_table));
+         *l4tab = l4e_from_pfn(page_to_mfn(cr3_page),
+             _PAGE_PRESENT|_PAGE_RW|_PAGE_USER|_PAGE_ACCESSED);
+ #endif
+     }
++    if ( rc )
++    {
++        if ( cr3_page )
++            put_page(cr3_page);
++        destroy_gdt(v);
++        return rc;
++    }
++
++    clear_bit(_VPF_in_reset, &v->pause_flags);
+ 
+     if ( v->vcpu_id == 0 )
+         update_domain_wallclock_time(d);
+@@ -1053,17 +1062,16 @@ int arch_set_info_guest(
+ #undef c
+ }
+ 
+-void arch_vcpu_reset(struct vcpu *v)
++int arch_vcpu_reset(struct vcpu *v)
+ {
+     if ( !is_hvm_vcpu(v) )
+     {
+         destroy_gdt(v);
+-        vcpu_destroy_pagetables(v);
+-    }
+-    else
+-    {
+-        vcpu_end_shutdown_deferral(v);
++        return vcpu_destroy_pagetables(v);
+     }
++
++    vcpu_end_shutdown_deferral(v);
++    return 0;
+ }
+ 
+ /* 
+@@ -2069,63 +2077,6 @@ static int relinquish_memory(
+     return ret;
+ }
+ 
+-static void vcpu_destroy_pagetables(struct vcpu *v)
+-{
+-    struct domain *d = v->domain;
+-    unsigned long pfn;
+-
+-#ifdef __x86_64__
+-    if ( is_pv_32on64_vcpu(v) )
+-    {
+-        pfn = l4e_get_pfn(*(l4_pgentry_t *)
+-                          __va(pagetable_get_paddr(v->arch.guest_table)));
+-
+-        if ( pfn != 0 )
+-        {
+-            if ( paging_mode_refcounts(d) )
+-                put_page(mfn_to_page(pfn));
+-            else
+-                put_page_and_type(mfn_to_page(pfn));
+-        }
+-
+-        l4e_write(
+-            (l4_pgentry_t *)__va(pagetable_get_paddr(v->arch.guest_table)),
+-            l4e_empty());
+-
+-        v->arch.cr3 = 0;
+-        return;
+-    }
+-#endif
+-
+-    pfn = pagetable_get_pfn(v->arch.guest_table);
+-    if ( pfn != 0 )
+-    {
+-        if ( paging_mode_refcounts(d) )
+-            put_page(mfn_to_page(pfn));
+-        else
+-            put_page_and_type(mfn_to_page(pfn));
+-        v->arch.guest_table = pagetable_null();
+-    }
+-
+-#ifdef __x86_64__
+-    /* Drop ref to guest_table_user (from MMUEXT_NEW_USER_BASEPTR) */
+-    pfn = pagetable_get_pfn(v->arch.guest_table_user);
+-    if ( pfn != 0 )
+-    {
+-        if ( !is_pv_32bit_vcpu(v) )
+-        {
+-            if ( paging_mode_refcounts(d) )
+-                put_page(mfn_to_page(pfn));
+-            else
+-                put_page_and_type(mfn_to_page(pfn));
+-        }
+-        v->arch.guest_table_user = pagetable_null();
+-    }
+-#endif
+-
+-    v->arch.cr3 = 0;
+-}
+-
+ int domain_relinquish_resources(struct domain *d)
+ {
+     int ret;
+@@ -2143,7 +2094,11 @@ int domain_relinquish_resources(struct domain *d)
+ 
+         /* Drop the in-use references to page-table bases. */
+         for_each_vcpu ( d, v )
+-            vcpu_destroy_pagetables(v);
++        {
++            ret = vcpu_destroy_pagetables(v);
++            if ( ret )
++                return ret;
++        }
+ 
+         if ( !is_hvm_domain(d) )
+         {
+diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
+index 3d471a5..efacc98 100644
+--- a/xen/arch/x86/hvm/hvm.c
++++ b/xen/arch/x86/hvm/hvm.c
+@@ -3509,8 +3509,11 @@ static void hvm_s3_suspend(struct domain *d)
+ 
+     for_each_vcpu ( d, v )
+     {
++        int rc;
++
+         vlapic_reset(vcpu_vlapic(v));
+-        vcpu_reset(v);
++        rc = vcpu_reset(v);
++        ASSERT(!rc);
+     }
+ 
+     vpic_reset(d);
+diff --git a/xen/arch/x86/hvm/vlapic.c b/xen/arch/x86/hvm/vlapic.c
+index 52d111b..7778342 100644
+--- a/xen/arch/x86/hvm/vlapic.c
++++ b/xen/arch/x86/hvm/vlapic.c
+@@ -252,10 +252,13 @@ static void vlapic_init_sipi_action(unsigned long _vcpu)
+     {
+     case APIC_DM_INIT: {
+         bool_t fpu_initialised;
++        int rc;
++
+         domain_lock(target->domain);
+         /* Reset necessary VCPU state. This does not include FPU state. */
+         fpu_initialised = target->fpu_initialised;
+-        vcpu_reset(target);
++        rc = vcpu_reset(target);
++        ASSERT(!rc);
+         target->fpu_initialised = fpu_initialised;
+         vlapic_reset(vcpu_vlapic(target));
+         domain_unlock(target->domain);
+diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
+index 8444610..055f307 100644
+--- a/xen/arch/x86/mm.c
++++ b/xen/arch/x86/mm.c
+@@ -1241,7 +1241,16 @@ static int put_page_from_l3e(l3_pgentry_t l3e, unsigned long pfn,
+ #endif
+ 
+     if ( unlikely(partial > 0) )
++    {
++        ASSERT(preemptible >= 0);
+         return __put_page_type(l3e_get_page(l3e), preemptible);
++    }
++
++    if ( preemptible < 0 )
++    {
++        current->arch.old_guest_table = l3e_get_page(l3e);
++        return 0;
++    }
+ 
+     return put_page_and_type_preemptible(l3e_get_page(l3e), preemptible);
+ }
+@@ -1254,7 +1263,17 @@ static int put_page_from_l4e(l4_pgentry_t l4e, unsigned long pfn,
+          (l4e_get_pfn(l4e) != pfn) )
+     {
+         if ( unlikely(partial > 0) )
++        {
++            ASSERT(preemptible >= 0);
+             return __put_page_type(l4e_get_page(l4e), preemptible);
++        }
++
++        if ( preemptible < 0 )
++        {
++            current->arch.old_guest_table = l4e_get_page(l4e);
++            return 0;
++        }
++
+         return put_page_and_type_preemptible(l4e_get_page(l4e), preemptible);
+     }
+     return 1;
+@@ -1549,12 +1568,17 @@ static int alloc_l3_table(struct page_info *page, int preemptible)
+     if ( rc < 0 && rc != -EAGAIN && rc != -EINTR )
+     {
+         MEM_LOG("Failure in alloc_l3_table: entry %d", i);
++        if ( i )
++        {
++            page->nr_validated_ptes = i;
++            page->partial_pte = 0;
++            current->arch.old_guest_table = page;
++        }
+         while ( i-- > 0 )
+         {
+             if ( !is_guest_l3_slot(i) )
+                 continue;
+             unadjust_guest_l3e(pl3e[i], d);
+-            put_page_from_l3e(pl3e[i], pfn, 0, 0);
+         }
+     }
+ 
+@@ -1584,22 +1608,24 @@ static int alloc_l4_table(struct page_info *page, int preemptible)
+             page->nr_validated_ptes = i;
+             page->partial_pte = partial ?: 1;
+         }
+-        else if ( rc == -EINTR )
++        else if ( rc < 0 )
+         {
++            if ( rc != -EINTR )
++                MEM_LOG("Failure in alloc_l4_table: entry %d", i);
+             if ( i )
+             {
+                 page->nr_validated_ptes = i;
+                 page->partial_pte = 0;
+-                rc = -EAGAIN;
++                if ( rc == -EINTR )
++                    rc = -EAGAIN;
++                else
++                {
++                    if ( current->arch.old_guest_table )
++                        page->nr_validated_ptes++;
++                    current->arch.old_guest_table = page;
++                }
+             }
+         }
+-        else if ( rc < 0 )
+-        {
+-            MEM_LOG("Failure in alloc_l4_table: entry %d", i);
+-            while ( i-- > 0 )
+-                if ( is_guest_l4_slot(d, i) )
+-                    put_page_from_l4e(pl4e[i], pfn, 0, 0);
+-        }
+         if ( rc < 0 )
+             return rc;
+ 
+@@ -2047,7 +2073,7 @@ static int mod_l3_entry(l3_pgentry_t *pl3e,
+         pae_flush_pgd(pfn, pgentry_ptr_to_slot(pl3e), nl3e);
+     }
+ 
+-    put_page_from_l3e(ol3e, pfn, 0, 0);
++    put_page_from_l3e(ol3e, pfn, 0, -preemptible);
+     return rc;
+ }
+ 
+@@ -2110,7 +2136,7 @@ static int mod_l4_entry(l4_pgentry_t *pl4e,
+         return -EFAULT;
+     }
+ 
+-    put_page_from_l4e(ol4e, pfn, 0, 0);
++    put_page_from_l4e(ol4e, pfn, 0, -preemptible);
+     return rc;
+ }
+ 
+@@ -2268,7 +2294,15 @@ static int alloc_page_type(struct page_info *page, unsigned long type,
+                 PRtype_info ": caf=%08lx taf=%" PRtype_info,
+                 page_to_mfn(page), get_gpfn_from_mfn(page_to_mfn(page)),
+                 type, page->count_info, page->u.inuse.type_info);
+-        page->u.inuse.type_info = 0;
++        if ( page != current->arch.old_guest_table )
++            page->u.inuse.type_info = 0;
++        else
++        {
++            ASSERT((page->u.inuse.type_info &
++                    (PGT_count_mask | PGT_validated)) == 1);
++            get_page_light(page);
++            page->u.inuse.type_info |= PGT_partial;
++        }
+     }
+     else
+     {
+@@ -2808,49 +2842,150 @@ static void put_superpage(unsigned long mfn)
+ 
+ #endif
+ 
++static int put_old_guest_table(struct vcpu *v)
++{
++    int rc;
++
++    if ( !v->arch.old_guest_table )
++        return 0;
++
++    switch ( rc = put_page_and_type_preemptible(v->arch.old_guest_table, 1) )
++    {
++    case -EINTR:
++    case -EAGAIN:
++        return -EAGAIN;
++    }
++
++    v->arch.old_guest_table = NULL;
++
++    return rc;
++}
++
++int vcpu_destroy_pagetables(struct vcpu *v)
++{
++    unsigned long mfn = pagetable_get_pfn(v->arch.guest_table);
++    struct page_info *page;
++    int rc = put_old_guest_table(v);
++
++    if ( rc )
++        return rc;
++
++#ifdef __x86_64__
++    if ( is_pv_32on64_vcpu(v) )
++        mfn = l4e_get_pfn(*(l4_pgentry_t *)mfn_to_virt(mfn));
++#endif
++
++    if ( mfn )
++    {
++        page = mfn_to_page(mfn);
++        if ( paging_mode_refcounts(v->domain) )
++            put_page(page);
++        else
++            rc = put_page_and_type_preemptible(page, 1);
++    }
++
++#ifdef __x86_64__
++    if ( is_pv_32on64_vcpu(v) )
++    {
++        if ( !rc )
++            l4e_write(
++                (l4_pgentry_t *)__va(pagetable_get_paddr(v->arch.guest_table)),
++                l4e_empty());
++    }
++    else
++#endif
++    if ( !rc )
++    {
++        v->arch.guest_table = pagetable_null();
++
++#ifdef __x86_64__
++        /* Drop ref to guest_table_user (from MMUEXT_NEW_USER_BASEPTR) */
++        mfn = pagetable_get_pfn(v->arch.guest_table_user);
++        if ( mfn )
++        {
++            page = mfn_to_page(mfn);
++            if ( paging_mode_refcounts(v->domain) )
++                put_page(page);
++            else
++                rc = put_page_and_type_preemptible(page, 1);
++        }
++        if ( !rc )
++            v->arch.guest_table_user = pagetable_null();
++#endif
++    }
++
++    v->arch.cr3 = 0;
++
++    return rc;
++}
+ 
+ int new_guest_cr3(unsigned long mfn)
+ {
+     struct vcpu *curr = current;
+     struct domain *d = curr->domain;
+-    int okay;
++    int rc;
+     unsigned long old_base_mfn;
+ 
+ #ifdef __x86_64__
+     if ( is_pv_32on64_domain(d) )
+     {
+-        okay = paging_mode_refcounts(d)
+-            ? 0 /* Old code was broken, but what should it be? */
+-            : mod_l4_entry(
++        rc = paging_mode_refcounts(d)
++             ? -EINVAL /* Old code was broken, but what should it be? */
++             : mod_l4_entry(
+                     __va(pagetable_get_paddr(curr->arch.guest_table)),
+                     l4e_from_pfn(
+                         mfn,
+                         (_PAGE_PRESENT|_PAGE_RW|_PAGE_USER|_PAGE_ACCESSED)),
+-                    pagetable_get_pfn(curr->arch.guest_table), 0, 0, curr) == 0;
+-        if ( unlikely(!okay) )
++                    pagetable_get_pfn(curr->arch.guest_table), 0, 1, curr);
++        switch ( rc )
+         {
++        case 0:
++            break;
++        case -EINTR:
++        case -EAGAIN:
++            return -EAGAIN;
++        default:
+             MEM_LOG("Error while installing new compat baseptr %lx", mfn);
+-            return 0;
++            return rc;
+         }
+ 
+         invalidate_shadow_ldt(curr, 0);
+         write_ptbase(curr);
+ 
+-        return 1;
++        return 0;
+     }
+ #endif
+-    okay = paging_mode_refcounts(d)
+-        ? get_page_from_pagenr(mfn, d)
+-        : !get_page_and_type_from_pagenr(mfn, PGT_root_page_table, d, 0, 0);
+-    if ( unlikely(!okay) )
++    rc = put_old_guest_table(curr);
++    if ( unlikely(rc) )
++        return rc;
++
++    old_base_mfn = pagetable_get_pfn(curr->arch.guest_table);
++    /*
++     * This is particularly important when getting restarted after the
++     * previous attempt got preempted in the put-old-MFN phase.
++     */
++    if ( old_base_mfn == mfn )
+     {
+-        MEM_LOG("Error while installing new baseptr %lx", mfn);
++        write_ptbase(curr);
+         return 0;
+     }
+ 
+-    invalidate_shadow_ldt(curr, 0);
++    rc = paging_mode_refcounts(d)
++         ? (get_page_from_pagenr(mfn, d) ? 0 : -EINVAL)
++         : get_page_and_type_from_pagenr(mfn, PGT_root_page_table, d, 0, 1);
++    switch ( rc )
++    {
++    case 0:
++        break;
++    case -EINTR:
++    case -EAGAIN:
++        return -EAGAIN;
++    default:
++        MEM_LOG("Error while installing new baseptr %lx", mfn);
++        return rc;
++    }
+ 
+-    old_base_mfn = pagetable_get_pfn(curr->arch.guest_table);
++    invalidate_shadow_ldt(curr, 0);
+ 
+     curr->arch.guest_table = pagetable_from_pfn(mfn);
+     update_cr3(curr);
+@@ -2859,13 +2994,25 @@ int new_guest_cr3(unsigned long mfn)
+ 
+     if ( likely(old_base_mfn != 0) )
+     {
++        struct page_info *page = mfn_to_page(old_base_mfn);
++
+         if ( paging_mode_refcounts(d) )
+-            put_page(mfn_to_page(old_base_mfn));
++            put_page(page);
+         else
+-            put_page_and_type(mfn_to_page(old_base_mfn));
++            switch ( rc = put_page_and_type_preemptible(page, 1) )
++            {
++            case -EINTR:
++                rc = -EAGAIN;
++            case -EAGAIN:
++                curr->arch.old_guest_table = page;
++                break;
++            default:
++                BUG_ON(rc);
++                break;
++            }
+     }
+ 
+-    return 1;
++    return rc;
+ }
+ 
+ static struct domain *get_pg_owner(domid_t domid)
+@@ -2994,12 +3141,29 @@ long do_mmuext_op(
+     unsigned int foreigndom)
+ {
+     struct mmuext_op op;
+-    int rc = 0, i = 0, okay;
+     unsigned long type;
+-    unsigned int done = 0;
++    unsigned int i = 0, done = 0;
+     struct vcpu *curr = current;
+     struct domain *d = curr->domain;
+     struct domain *pg_owner;
++    int okay, rc = put_old_guest_table(curr);
++
++    if ( unlikely(rc) )
++    {
++        if ( likely(rc == -EAGAIN) )
++            rc = hypercall_create_continuation(
++                     __HYPERVISOR_mmuext_op, "hihi", uops, count, pdone,
++                     foreigndom);
++        return rc;
++    }
++
++    if ( unlikely(count == MMU_UPDATE_PREEMPTED) &&
++         likely(guest_handle_is_null(uops)) )
++    {
++        /* See the curr->arch.old_guest_table related
++         * hypercall_create_continuation() below. */
++        return (int)foreigndom;
++    }
+ 
+     if ( unlikely(count & MMU_UPDATE_PREEMPTED) )
+     {
+@@ -3024,7 +3188,7 @@ long do_mmuext_op(
+ 
+     for ( i = 0; i < count; i++ )
+     {
+-        if ( hypercall_preempt_check() )
++        if ( curr->arch.old_guest_table || hypercall_preempt_check() )
+         {
+             rc = -EAGAIN;
+             break;
+@@ -3088,21 +3252,17 @@ long do_mmuext_op(
+             }
+ 
+             if ( (rc = xsm_memory_pin_page(d, pg_owner, page)) != 0 )
+-            {
+-                put_page_and_type(page);
+                 okay = 0;
+-                break;
+-            }
+-
+-            if ( unlikely(test_and_set_bit(_PGT_pinned,
+-                                           &page->u.inuse.type_info)) )
++            else if ( unlikely(test_and_set_bit(_PGT_pinned,
++                                                &page->u.inuse.type_info)) )
+             {
+                 MEM_LOG("Mfn %lx already pinned", page_to_mfn(page));
+-                put_page_and_type(page);
+                 okay = 0;
+-                break;
+             }
+ 
++            if ( unlikely(!okay) )
++                goto pin_drop;
++
+             /* A page is dirtied when its pin status is set. */
+             paging_mark_dirty(pg_owner, page_to_mfn(page));
+ 
+@@ -3116,7 +3276,13 @@ long do_mmuext_op(
+                                                &page->u.inuse.type_info));
+                 spin_unlock(&pg_owner->page_alloc_lock);
+                 if ( drop_ref )
+-                    put_page_and_type(page);
++                {
++        pin_drop:
++                    if ( type == PGT_l1_page_table )
++                        put_page_and_type(page);
++                    else
++                        curr->arch.old_guest_table = page;
++                }
+             }
+ 
+             break;
+@@ -3144,7 +3310,17 @@ long do_mmuext_op(
+                 break;
+             }
+ 
+-            put_page_and_type(page);
++            switch ( rc = put_page_and_type_preemptible(page, 1) )
++            {
++            case -EINTR:
++            case -EAGAIN:
++                curr->arch.old_guest_table = page;
++                rc = 0;
++                break;
++            default:
++                BUG_ON(rc);
++                break;
++            }
+             put_page(page);
+ 
+             /* A page is dirtied when its pin status is cleared. */
+@@ -3154,8 +3330,13 @@ long do_mmuext_op(
+         }
+ 
+         case MMUEXT_NEW_BASEPTR:
+-            okay = (!paging_mode_translate(d)
+-                    && new_guest_cr3(op.arg1.mfn));
++            if ( paging_mode_translate(d) )
++                okay = 0;
++            else
++            {
++                rc = new_guest_cr3(op.arg1.mfn);
++                okay = !rc;
++            }
+             break;
+ 
+         
+@@ -3169,29 +3350,56 @@ long do_mmuext_op(
+                 break;
+             }
+ 
++            old_mfn = pagetable_get_pfn(curr->arch.guest_table_user);
++            /*
++             * This is particularly important when getting restarted after the
++             * previous attempt got preempted in the put-old-MFN phase.
++             */
++            if ( old_mfn == op.arg1.mfn )
++                break;
++
+             if ( op.arg1.mfn != 0 )
+             {
+                 if ( paging_mode_refcounts(d) )
+                     okay = get_page_from_pagenr(op.arg1.mfn, d);
+                 else
+-                    okay = !get_page_and_type_from_pagenr(
+-                        op.arg1.mfn, PGT_root_page_table, d, 0, 0);
++                {
++                    rc = get_page_and_type_from_pagenr(
++                        op.arg1.mfn, PGT_root_page_table, d, 0, 1);
++                    okay = !rc;
++                }
+                 if ( unlikely(!okay) )
+                 {
+-                    MEM_LOG("Error while installing new mfn %lx", op.arg1.mfn);
++                    if ( rc == -EINTR )
++                        rc = -EAGAIN;
++                    else if ( rc != -EAGAIN )
++                        MEM_LOG("Error while installing new mfn %lx",
++                                op.arg1.mfn);
+                     break;
+                 }
+             }
+ 
+-            old_mfn = pagetable_get_pfn(curr->arch.guest_table_user);
+             curr->arch.guest_table_user = pagetable_from_pfn(op.arg1.mfn);
+ 
+             if ( old_mfn != 0 )
+             {
++                struct page_info *page = mfn_to_page(old_mfn);
++
+                 if ( paging_mode_refcounts(d) )
+-                    put_page(mfn_to_page(old_mfn));
++                    put_page(page);
+                 else
+-                    put_page_and_type(mfn_to_page(old_mfn));
++                    switch ( rc = put_page_and_type_preemptible(page, 1) )
++                    {
++                    case -EINTR:
++                        rc = -EAGAIN;
++                    case -EAGAIN:
++                        curr->arch.old_guest_table = page;
++                        okay = 0;
++                        break;
++                    default:
++                        BUG_ON(rc);
++                        break;
++                    }
+             }
+ 
+             break;
+@@ -3433,9 +3641,27 @@ long do_mmuext_op(
+     }
+ 
+     if ( rc == -EAGAIN )
++    {
++        ASSERT(i < count);
+         rc = hypercall_create_continuation(
+             __HYPERVISOR_mmuext_op, "hihi",
+             uops, (count - i) | MMU_UPDATE_PREEMPTED, pdone, foreigndom);
++    }
++    else if ( curr->arch.old_guest_table )
++    {
++        XEN_GUEST_HANDLE(void) null;
++
++        ASSERT(rc || i == count);
++        set_xen_guest_handle(null, NULL);
++        /*
++         * In order to have a way to communicate the final return value to
++         * our continuation, we pass this in place of "foreigndom", building
++         * on the fact that this argument isn't needed anymore.
++         */
++        rc = hypercall_create_continuation(
++                __HYPERVISOR_mmuext_op, "hihi", null,
++                MMU_UPDATE_PREEMPTED, null, rc);
++    }
+ 
+     put_pg_owner(pg_owner);
+ 
+@@ -3462,11 +3688,28 @@ long do_mmu_update(
+     void *va;
+     unsigned long gpfn, gmfn, mfn;
+     struct page_info *page;
+-    int rc = 0, i = 0;
+-    unsigned int cmd, done = 0, pt_dom;
+-    struct vcpu *v = current;
++    unsigned int cmd, i = 0, done = 0, pt_dom;
++    struct vcpu *curr = current, *v = curr;
+     struct domain *d = v->domain, *pt_owner = d, *pg_owner;
+     struct domain_mmap_cache mapcache;
++    int rc = put_old_guest_table(curr);
++
++    if ( unlikely(rc) )
++    {
++        if ( likely(rc == -EAGAIN) )
++            rc = hypercall_create_continuation(
++                     __HYPERVISOR_mmu_update, "hihi", ureqs, count, pdone,
++                     foreigndom);
++        return rc;
++    }
++
++    if ( unlikely(count == MMU_UPDATE_PREEMPTED) &&
++         likely(guest_handle_is_null(ureqs)) )
++    {
++        /* See the curr->arch.old_guest_table related
++         * hypercall_create_continuation() below. */
++        return (int)foreigndom;
++    }
+ 
+     if ( unlikely(count & MMU_UPDATE_PREEMPTED) )
+     {
+@@ -3515,7 +3758,7 @@ long do_mmu_update(
+ 
+     for ( i = 0; i < count; i++ )
+     {
+-        if ( hypercall_preempt_check() )
++        if ( curr->arch.old_guest_table || hypercall_preempt_check() )
+         {
+             rc = -EAGAIN;
+             break;
+@@ -3696,9 +3939,27 @@ long do_mmu_update(
+     }
+ 
+     if ( rc == -EAGAIN )
++    {
++        ASSERT(i < count);
+         rc = hypercall_create_continuation(
+             __HYPERVISOR_mmu_update, "hihi",
+             ureqs, (count - i) | MMU_UPDATE_PREEMPTED, pdone, foreigndom);
++    }
++    else if ( curr->arch.old_guest_table )
++    {
++        XEN_GUEST_HANDLE(void) null;
++
++        ASSERT(rc || i == count);
++        set_xen_guest_handle(null, NULL);
++        /*
++         * In order to have a way to communicate the final return value to
++         * our continuation, we pass this in place of "foreigndom", building
++         * on the fact that this argument isn't needed anymore.
++         */
++        rc = hypercall_create_continuation(
++                __HYPERVISOR_mmu_update, "hihi", null,
++                MMU_UPDATE_PREEMPTED, null, rc);
++    }
+ 
+     put_pg_owner(pg_owner);
+ 
+diff --git a/xen/arch/x86/traps.c b/xen/arch/x86/traps.c
+index 692281a..eada470 100644
+--- a/xen/arch/x86/traps.c
++++ b/xen/arch/x86/traps.c
+@@ -2407,12 +2407,23 @@ static int emulate_privileged_op(struct cpu_user_regs *regs)
+ #endif
+             }
+             page = get_page_from_gfn(v->domain, gfn, NULL, P2M_ALLOC);
+-            rc = page ? new_guest_cr3(page_to_mfn(page)) : 0;
+             if ( page )
++            {
++                rc = new_guest_cr3(page_to_mfn(page));
+                 put_page(page);
++            }
++            else
++                rc = -EINVAL;
+             domain_unlock(v->domain);
+-            if ( rc == 0 ) /* not okay */
++            switch ( rc )
++            {
++            case 0:
++                break;
++            case -EAGAIN: /* retry after preemption */
++                goto skip;
++            default:      /* not okay */
+                 goto fail;
++            }
+             break;
+         }
+ 
+diff --git a/xen/arch/x86/x86_64/compat/mm.c b/xen/arch/x86/x86_64/compat/mm.c
+index fb7baca..ef7822b 100644
+--- a/xen/arch/x86/x86_64/compat/mm.c
++++ b/xen/arch/x86/x86_64/compat/mm.c
+@@ -268,6 +268,13 @@ int compat_mmuext_op(XEN_GUEST_HANDLE(mmuext_op_compat_t) cmp_uops,
+     int rc = 0;
+     XEN_GUEST_HANDLE(mmuext_op_t) nat_ops;
+ 
++    if ( unlikely(count == MMU_UPDATE_PREEMPTED) &&
++         likely(guest_handle_is_null(cmp_uops)) )
++    {
++        set_xen_guest_handle(nat_ops, NULL);
++        return do_mmuext_op(nat_ops, count, pdone, foreigndom);
++    }
++
+     preempt_mask = count & MMU_UPDATE_PREEMPTED;
+     count ^= preempt_mask;
+ 
+@@ -365,17 +372,23 @@ int compat_mmuext_op(XEN_GUEST_HANDLE(mmuext_op_compat_t) cmp_uops,
+                                     : mcs->call.args[1];
+                 unsigned int left = arg1 & ~MMU_UPDATE_PREEMPTED;
+ 
+-                BUG_ON(left == arg1);
++                BUG_ON(left == arg1 && left != i);
+                 BUG_ON(left > count);
+                 guest_handle_add_offset(nat_ops, i - left);
+                 guest_handle_subtract_offset(cmp_uops, left);
+                 left = 1;
+-                BUG_ON(!hypercall_xlat_continuation(&left, 0x01, nat_ops, cmp_uops));
+-                BUG_ON(left != arg1);
+-                if (!test_bit(_MCSF_in_multicall, &mcs->flags))
+-                    regs->_ecx += count - i;
++                if ( arg1 != MMU_UPDATE_PREEMPTED )
++                {
++                    BUG_ON(!hypercall_xlat_continuation(&left, 0x01, nat_ops,
++                                                        cmp_uops));
++                    if ( !test_bit(_MCSF_in_multicall, &mcs->flags) )
++                        regs->_ecx += count - i;
++                    else
++                        mcs->compat_call.args[1] += count - i;
++                }
+                 else
+-                    mcs->compat_call.args[1] += count - i;
++                    BUG_ON(hypercall_xlat_continuation(&left, 0));
++                BUG_ON(left != arg1);
+             }
+             else
+                 BUG_ON(err > 0);
+diff --git a/xen/common/compat/domain.c b/xen/common/compat/domain.c
+index 40a0287..9ddaa38 100644
+--- a/xen/common/compat/domain.c
++++ b/xen/common/compat/domain.c
+@@ -50,6 +50,10 @@ int compat_vcpu_op(int cmd, int vcpuid, XEN_GUEST_HANDLE(void) arg)
+         rc = v->is_initialised ? -EEXIST : arch_set_info_guest(v, cmp_ctxt);
+         domain_unlock(d);
+ 
++        if ( rc == -EAGAIN )
++            rc = hypercall_create_continuation(__HYPERVISOR_vcpu_op, "iih",
++                                               cmd, vcpuid, arg);
++
+         xfree(cmp_ctxt);
+         break;
+     }
+diff --git a/xen/common/domain.c b/xen/common/domain.c
+index c09fb73..89ab922 100644
+--- a/xen/common/domain.c
++++ b/xen/common/domain.c
+@@ -779,14 +779,18 @@ void domain_unpause_by_systemcontroller(struct domain *d)
+         domain_unpause(d);
+ }
+ 
+-void vcpu_reset(struct vcpu *v)
++int vcpu_reset(struct vcpu *v)
+ {
+     struct domain *d = v->domain;
++    int rc;
+ 
+     vcpu_pause(v);
+     domain_lock(d);
+ 
+-    arch_vcpu_reset(v);
++    set_bit(_VPF_in_reset, &v->pause_flags);
++    rc = arch_vcpu_reset(v);
++    if ( rc )
++        goto out_unlock;
+ 
+     set_bit(_VPF_down, &v->pause_flags);
+ 
+@@ -802,9 +806,13 @@ void vcpu_reset(struct vcpu *v)
+ #endif
+     cpumask_clear(v->cpu_affinity_tmp);
+     clear_bit(_VPF_blocked, &v->pause_flags);
++    clear_bit(_VPF_in_reset, &v->pause_flags);
+ 
++ out_unlock:
+     domain_unlock(v->domain);
+     vcpu_unpause(v);
++
++    return rc;
+ }
+ 
+ 
+@@ -841,6 +849,11 @@ long do_vcpu_op(int cmd, int vcpuid, XEN_GUEST_HANDLE(void) arg)
+         domain_unlock(d);
+ 
+         free_vcpu_guest_context(ctxt);
++
++        if ( rc == -EAGAIN )
++            rc = hypercall_create_continuation(__HYPERVISOR_vcpu_op, "iih",
++                                               cmd, vcpuid, arg);
++
+         break;
+ 
+     case VCPUOP_up: {
+diff --git a/xen/common/domctl.c b/xen/common/domctl.c
+index cbc8146..b3bfb38 100644
+--- a/xen/common/domctl.c
++++ b/xen/common/domctl.c
+@@ -307,8 +307,10 @@ long do_domctl(XEN_GUEST_HANDLE(xen_domctl_t) u_domctl)
+ 
+         if ( guest_handle_is_null(op->u.vcpucontext.ctxt) )
+         {
+-            vcpu_reset(v);
+-            ret = 0;
++            ret = vcpu_reset(v);
++            if ( ret == -EAGAIN )
++                ret = hypercall_create_continuation(
++                          __HYPERVISOR_domctl, "h", u_domctl);
+             goto svc_out;
+         }
+ 
+@@ -337,6 +339,10 @@ long do_domctl(XEN_GUEST_HANDLE(xen_domctl_t) u_domctl)
+             domain_pause(d);
+             ret = arch_set_info_guest(v, c);
+             domain_unpause(d);
++
++            if ( ret == -EAGAIN )
++                ret = hypercall_create_continuation(
++                          __HYPERVISOR_domctl, "h", u_domctl);
+         }
+ 
+     svc_out:
+diff --git a/xen/include/asm-x86/domain.h b/xen/include/asm-x86/domain.h
+index aecee68..898f63a 100644
+--- a/xen/include/asm-x86/domain.h
++++ b/xen/include/asm-x86/domain.h
+@@ -464,6 +464,7 @@ struct arch_vcpu
+     pagetable_t guest_table_user;       /* (MFN) x86/64 user-space pagetable */
+ #endif
+     pagetable_t guest_table;            /* (MFN) guest notion of cr3 */
++    struct page_info *old_guest_table;  /* partially destructed pagetable */
+     /* guest_table holds a ref to the page, and also a type-count unless
+      * shadow refcounts are in use */
+     pagetable_t shadow_table[4];        /* (MFN) shadow(s) of guest */
+diff --git a/xen/include/asm-x86/mm.h b/xen/include/asm-x86/mm.h
+index ba92568..82cdde6 100644
+--- a/xen/include/asm-x86/mm.h
++++ b/xen/include/asm-x86/mm.h
+@@ -605,6 +605,7 @@ void audit_domains(void);
+ int new_guest_cr3(unsigned long pfn);
+ void make_cr3(struct vcpu *v, unsigned long mfn);
+ void update_cr3(struct vcpu *v);
++int vcpu_destroy_pagetables(struct vcpu *);
+ void propagate_page_fault(unsigned long addr, u16 error_code);
+ void *do_page_walk(struct vcpu *v, unsigned long addr);
+ 
+diff --git a/xen/include/xen/domain.h b/xen/include/xen/domain.h
+index d4ac50f..504a70f 100644
+--- a/xen/include/xen/domain.h
++++ b/xen/include/xen/domain.h
+@@ -13,7 +13,7 @@ typedef union {
+ struct vcpu *alloc_vcpu(
+     struct domain *d, unsigned int vcpu_id, unsigned int cpu_id);
+ struct vcpu *alloc_dom0_vcpu0(void);
+-void vcpu_reset(struct vcpu *v);
++int vcpu_reset(struct vcpu *);
+ 
+ struct xen_domctl_getdomaininfo;
+ void getdomaininfo(struct domain *d, struct xen_domctl_getdomaininfo *info);
+@@ -67,7 +67,7 @@ void arch_dump_vcpu_info(struct vcpu *v);
+ 
+ void arch_dump_domain_info(struct domain *d);
+ 
+-void arch_vcpu_reset(struct vcpu *v);
++int arch_vcpu_reset(struct vcpu *);
+ 
+ extern spinlock_t vcpu_alloc_lock;
+ bool_t domctl_lock_acquire(void);
+diff --git a/xen/include/xen/sched.h b/xen/include/xen/sched.h
+index b619269..b0715cb 100644
+--- a/xen/include/xen/sched.h
++++ b/xen/include/xen/sched.h
+@@ -644,6 +644,9 @@ static inline struct domain *next_domain_in_cpupool(
+  /* VCPU is blocked due to missing mem_sharing ring. */
+ #define _VPF_mem_sharing     6
+ #define VPF_mem_sharing      (1UL<<_VPF_mem_sharing)
++ /* VCPU is being reset. */
++#define _VPF_in_reset        7
++#define VPF_in_reset         (1UL<<_VPF_in_reset)
+ 
+ static inline int vcpu_runnable(struct vcpu *v)
+ {
diff --git a/main/xen/xsa58-4.2.patch b/main/xen/xsa58-4.2.patch
new file mode 100644
index 0000000000..1ea3aaa97d
--- /dev/null
+++ b/main/xen/xsa58-4.2.patch
@@ -0,0 +1,129 @@
+x86: fix page refcount handling in page table pin error path
+
+In the original patch 7 of the series addressing XSA-45 I mistakenly
+took the addition of the call to get_page_light() in alloc_page_type()
+to cover two decrements that would happen: One for the PGT_partial bit
+that is getting set along with the call, and the other for the page
+reference the caller hold (and would be dropping on its error path).
+But of course the additional page reference is tied to the PGT_partial
+bit, and hence any caller of a function that may leave
+->arch.old_guest_table non-NULL for error cleanup purposes has to make
+sure a respective page reference gets retained.
+
+Similar issues were then also spotted elsewhere: In effect all callers
+of get_page_type_preemptible() need to deal with errors in similar
+ways. To make sure error handling can work this way without leaking
+page references, a respective assertion gets added to that function.
+
+This is CVE-2013-1432 / XSA-58.
+
+Reported-by: Andrew Cooper <andrew.cooper3@citrix.com>
+Signed-off-by: Jan Beulich <jbeulich@suse.com>
+Tested-by: Andrew Cooper <andrew.cooper3@citrix.com>
+Reviewed-by: Tim Deegan <tim@xen.org>
+
+--- a/xen/arch/x86/domain.c
++++ b/xen/arch/x86/domain.c
+@@ -941,6 +941,10 @@ int arch_set_info_guest(
+     if ( v->vcpu_id == 0 )
+         d->vm_assist = c(vm_assist);
+ 
++    rc = put_old_guest_table(current);
++    if ( rc )
++        return rc;
++
+     if ( !compat )
+         rc = (int)set_gdt(v, c.nat->gdt_frames, c.nat->gdt_ents);
+ #ifdef CONFIG_COMPAT
+@@ -980,18 +984,24 @@ int arch_set_info_guest(
+     }
+     else
+     {
+-        /*
+-         * Since v->arch.guest_table{,_user} are both NULL, this effectively
+-         * is just a call to put_old_guest_table().
+-         */
+         if ( !compat )
+-            rc = vcpu_destroy_pagetables(v);
++            rc = put_old_guest_table(v);
+         if ( !rc )
+             rc = get_page_type_preemptible(cr3_page,
+                                            !compat ? PGT_root_page_table
+                                                    : PGT_l3_page_table);
+-        if ( rc == -EINTR )
++        switch ( rc )
++        {
++        case -EINTR:
+             rc = -EAGAIN;
++        case -EAGAIN:
++        case 0:
++            break;
++        default:
++            if ( cr3_page == current->arch.old_guest_table )
++                cr3_page = NULL;
++            break;
++        }
+     }
+     if ( rc )
+         /* handled below */;
+@@ -1018,6 +1028,11 @@ int arch_set_info_guest(
+                         pagetable_get_page(v->arch.guest_table);
+                     v->arch.guest_table = pagetable_null();
+                     break;
++                default:
++                    if ( cr3_page == current->arch.old_guest_table )
++                        cr3_page = NULL;
++                case 0:
++                    break;
+                 }
+             }
+             if ( !rc )
+--- a/xen/arch/x86/mm.c
++++ b/xen/arch/x86/mm.c
+@@ -718,7 +718,8 @@ static int get_page_and_type_from_pagenr
+           get_page_type_preemptible(page, type) :
+           (get_page_type(page, type) ? 0 : -EINVAL));
+ 
+-    if ( unlikely(rc) && partial >= 0 )
++    if ( unlikely(rc) && partial >= 0 &&
++         (!preemptible || page != current->arch.old_guest_table) )
+         put_page(page);
+ 
+     return rc;
+@@ -2638,6 +2639,7 @@ int put_page_type_preemptible(struct pag
+ 
+ int get_page_type_preemptible(struct page_info *page, unsigned long type)
+ {
++    ASSERT(!current->arch.old_guest_table);
+     return __get_page_type(page, type, 1);
+ }
+ 
+@@ -2848,7 +2850,7 @@ static void put_superpage(unsigned long 
+ 
+ #endif
+ 
+-static int put_old_guest_table(struct vcpu *v)
++int put_old_guest_table(struct vcpu *v)
+ {
+     int rc;
+ 
+@@ -3253,7 +3255,8 @@ long do_mmuext_op(
+                     rc = -EAGAIN;
+                 else if ( rc != -EAGAIN )
+                     MEM_LOG("Error while pinning mfn %lx", page_to_mfn(page));
+-                put_page(page);
++                if ( page != curr->arch.old_guest_table )
++                    put_page(page);
+                 break;
+             }
+ 
+--- a/xen/include/asm-x86/mm.h
++++ b/xen/include/asm-x86/mm.h
+@@ -374,6 +374,7 @@ void put_page_type(struct page_info *pag
+ int  get_page_type(struct page_info *page, unsigned long type);
+ int  put_page_type_preemptible(struct page_info *page);
+ int  get_page_type_preemptible(struct page_info *page, unsigned long type);
++int  put_old_guest_table(struct vcpu *);
+ int  get_page_from_l1e(
+     l1_pgentry_t l1e, struct domain *l1e_owner, struct domain *pg_owner);
+ void put_page_from_l1e(l1_pgentry_t l1e, struct domain *l1e_owner);