[V11 PATCH 0/4] pvh dom0 patches...

[V11 PATCH 0/4] pvh dom0 patches...

[Mukesh Rathor]

Hi,

Inching even closer to the finish line, please find v11 of the pvh dom0
patches based on c/s: 9f2f129

git tree: git://oss.oracle.com/git/mrathor/xen.git  branch: dom0pvh-v11

Changed in v11 from v10:
  patch 1: none

  patch 2: none

  patch 3: 
      - add pvh fixmes in p2m.c
      - add ASSERT in atomic_write_ept_entry

  patch 4: none

thanks,
Mukesh

[V11 PATCH 1/4] pvh dom0: construct_dom0 changes

[Mukesh Rathor]

This patch changes construct_dom0() to boot in pvh mode:
  - Make sure dom0 elf supports pvh mode.
  - Call guest_physmap_add_page for pvh rather than simple p2m setting
  - Map all non-RAM regions 1:1 upto the end region in e820 or 4GB which
    ever is higher.
  - Allocate p2m, copying calculation from toolstack.
  - Allocate shared info page from the virtual space so that dom0 PT
    can be updated. Then update p2m for it with the actual mfn.
  - Since we build the page tables for pvh same as for pv, in
    pvh_fixup_page_tables_for_hap we replace the mfns with pfns.

Signed-off-by: Mukesh Rathor <mukesh.rathor@oracle.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
---
 xen/arch/x86/domain_build.c | 249 +++++++++++++++++++++++++++++++++++++++++---
 xen/arch/x86/mm/hap/hap.c   |  12 +++
 xen/include/asm-x86/hap.h   |   1 +
 3 files changed, 245 insertions(+), 17 deletions(-)

diff --git a/xen/arch/x86/domain_build.c b/xen/arch/x86/domain_build.c
index 1eccead..38ed9f6 100644
--- a/xen/arch/x86/domain_build.c
+++ b/xen/arch/x86/domain_build.c
@@ -35,6 +35,7 @@
 #include <asm/setup.h>
 #include <asm/bzimage.h> /* for bzimage_parse */
 #include <asm/io_apic.h>
+#include <asm/hap.h>
 
 #include <public/version.h>
 
@@ -307,6 +308,158 @@ static void __init process_dom0_ioports_disable(void)
     }
 }
 
+static __init void pvh_add_mem_mapping(struct domain *d, unsigned long gfn,
+                                       unsigned long mfn, unsigned long nr_mfns)
+{
+    unsigned long i;
+    int rc;
+
+    for ( i = 0; i < nr_mfns; i++ )
+        if ( (rc = set_mmio_p2m_entry(d, gfn + i, _mfn(mfn + i))) )
+            panic("pvh_add_mem_mapping: gfn:%lx mfn:%lx i:%ld rc:%d\n",
+                  gfn, mfn, i, rc);
+}
+
+/*
+ * Set the 1:1 map for all non-RAM regions for dom 0. Thus, dom0 will have
+ * the entire io region mapped in the EPT/NPT.
+ *
+ * pvh fixme: The following doesn't map MMIO ranges when they sit above the
+ *            highest E820 covered address.
+ */
+static __init void pvh_map_all_iomem(struct domain *d)
+{
+    unsigned long start_pfn, end_pfn, end = 0, start = 0;
+    const struct e820entry *entry;
+    unsigned int i, nump;
+
+    for ( i = 0, entry = e820.map; i < e820.nr_map; i++, entry++ )
+    {
+        end = entry->addr + entry->size;
+
+        if ( entry->type == E820_RAM || entry->type == E820_UNUSABLE ||
+             i == e820.nr_map - 1 )
+        {
+            start_pfn = PFN_DOWN(start);
+
+            /* Unused RAM areas are marked UNUSABLE, so skip them too */
+            if ( entry->type == E820_RAM || entry->type == E820_UNUSABLE )
+                end_pfn = PFN_UP(entry->addr);
+            else
+                end_pfn = PFN_UP(end);
+
+            if ( start_pfn < end_pfn )
+            {
+                nump = end_pfn - start_pfn;
+                /* Add pages to the mapping */
+                pvh_add_mem_mapping(d, start_pfn, start_pfn, nump);
+            }
+            start = end;
+        }
+    }
+
+    /*
+     * Some BIOSes may not report io space above ram that is less than 4GB. So
+     * we map any non-ram upto 4GB.
+     */
+    if ( end < GB(4) )
+    {
+        start_pfn = PFN_UP(end);
+        end_pfn = (GB(4)) >> PAGE_SHIFT;
+        nump = end_pfn - start_pfn;
+        pvh_add_mem_mapping(d, start_pfn, start_pfn, nump);
+    }
+}
+
+static __init void dom0_update_physmap(struct domain *d, unsigned long pfn,
+                                   unsigned long mfn, unsigned long vphysmap_s)
+{
+    if ( is_pvh_domain(d) )
+    {
+        int rc = guest_physmap_add_page(d, pfn, mfn, 0);
+        BUG_ON(rc);
+        return;
+    }
+    if ( !is_pv_32on64_domain(d) )
+        ((unsigned long *)vphysmap_s)[pfn] = mfn;
+    else
+        ((unsigned int *)vphysmap_s)[pfn] = mfn;
+
+    set_gpfn_from_mfn(mfn, pfn);
+}
+
+/* Replace mfns with pfns in dom0 page tables */
+static __init void pvh_fixup_page_tables_for_hap(struct vcpu *v,
+                                                 unsigned long v_start,
+                                                 unsigned long v_end)
+{
+    int i, j, k;
+    l4_pgentry_t *pl4e, *l4start;
+    l3_pgentry_t *pl3e;
+    l2_pgentry_t *pl2e;
+    l1_pgentry_t *pl1e;
+    unsigned long cr3_pfn;
+
+    ASSERT(paging_mode_enabled(v->domain));
+
+    l4start = map_domain_page(pagetable_get_pfn(v->arch.guest_table));
+
+    /* Clear entries prior to guest L4 start */
+    pl4e = l4start + l4_table_offset(v_start);
+    memset(l4start, 0, (unsigned long)pl4e - (unsigned long)l4start);
+
+    for ( ; pl4e <= l4start + l4_table_offset(v_end - 1); pl4e++ )
+    {
+        pl3e = map_l3t_from_l4e(*pl4e);
+        for ( i = 0; i < PAGE_SIZE / sizeof(*pl3e); i++, pl3e++ )
+        {
+            if ( !(l3e_get_flags(*pl3e) & _PAGE_PRESENT) )
+                continue;
+
+            pl2e = map_l2t_from_l3e(*pl3e);
+            for ( j = 0; j < PAGE_SIZE / sizeof(*pl2e); j++, pl2e++ )
+            {
+                if ( !(l2e_get_flags(*pl2e)  & _PAGE_PRESENT) )
+                    continue;
+
+                pl1e = map_l1t_from_l2e(*pl2e);
+                for ( k = 0; k < PAGE_SIZE / sizeof(*pl1e); k++, pl1e++ )
+                {
+                    if ( !(l1e_get_flags(*pl1e) & _PAGE_PRESENT) )
+                        continue;
+
+                    *pl1e = l1e_from_pfn(get_gpfn_from_mfn(l1e_get_pfn(*pl1e)),
+                                         l1e_get_flags(*pl1e));
+                }
+                unmap_domain_page(pl1e);
+                *pl2e = l2e_from_pfn(get_gpfn_from_mfn(l2e_get_pfn(*pl2e)),
+                                     l2e_get_flags(*pl2e));
+            }
+            unmap_domain_page(pl2e);
+            *pl3e = l3e_from_pfn(get_gpfn_from_mfn(l3e_get_pfn(*pl3e)),
+                                 l3e_get_flags(*pl3e));
+        }
+        unmap_domain_page(pl3e);
+        *pl4e = l4e_from_pfn(get_gpfn_from_mfn(l4e_get_pfn(*pl4e)),
+                             l4e_get_flags(*pl4e));
+    }
+
+    /* Clear entries post guest L4. */
+    if ( (unsigned long)pl4e & (PAGE_SIZE - 1) )
+        memset(pl4e, 0, PAGE_SIZE - ((unsigned long)pl4e & (PAGE_SIZE - 1)));
+
+    unmap_domain_page(l4start);
+
+    cr3_pfn = get_gpfn_from_mfn(paddr_to_pfn(v->arch.cr3));
+    v->arch.hvm_vcpu.guest_cr[3] = pfn_to_paddr(cr3_pfn);
+
+    /*
+     * Finally, we update the paging modes (hap_update_paging_modes). This will
+     * create monitor_table for us, update v->arch.cr3, and update vmcs.cr3.
+     */
+    paging_update_paging_modes(v);
+}
+
 static __init void mark_pv_pt_pages_rdonly(struct domain *d,
                                            l4_pgentry_t *l4start,
                                            unsigned long vpt_start,
@@ -516,6 +669,8 @@ int __init construct_dom0(
     l3_pgentry_t *l3tab = NULL, *l3start = NULL;
     l2_pgentry_t *l2tab = NULL, *l2start = NULL;
     l1_pgentry_t *l1tab = NULL, *l1start = NULL;
+    paddr_t shared_info_paddr = 0;
+    u32 save_pvh_pg_mode = 0;
 
     /*
      * This fully describes the memory layout of the initial domain. All 
@@ -593,12 +748,21 @@ int __init construct_dom0(
         goto out;
     }
 
-    if ( parms.elf_notes[XEN_ELFNOTE_SUPPORTED_FEATURES].type != XEN_ENT_NONE &&
-         !test_bit(XENFEAT_dom0, parms.f_supported) )
+    if ( parms.elf_notes[XEN_ELFNOTE_SUPPORTED_FEATURES].type != XEN_ENT_NONE )
     {
-        printk("Kernel does not support Dom0 operation\n");
-        rc = -EINVAL;
-        goto out;
+        if ( !test_bit(XENFEAT_dom0, parms.f_supported) )
+        {
+            printk("Kernel does not support Dom0 operation\n");
+            rc = -EINVAL;
+            goto out;
+        }
+        if ( is_pvh_domain(d) &&
+             !test_bit(XENFEAT_hvm_callback_vector, parms.f_supported) )
+        {
+            printk("Kernel does not support PVH mode\n");
+            rc = -EINVAL;
+            goto out;
+        }
     }
 
     if ( compat32 )
@@ -663,6 +827,13 @@ int __init construct_dom0(
     vstartinfo_end   = (vstartinfo_start +
                         sizeof(struct start_info) +
                         sizeof(struct dom0_vga_console_info));
+
+    if ( is_pvh_domain(d) )
+    {
+        shared_info_paddr = round_pgup(vstartinfo_end) - v_start;
+        vstartinfo_end   += PAGE_SIZE;
+    }
+
     vpt_start        = round_pgup(vstartinfo_end);
     for ( nr_pt_pages = 2; ; nr_pt_pages++ )
     {
@@ -903,6 +1074,13 @@ int __init construct_dom0(
         (void)alloc_vcpu(d, i, cpu);
     }
 
+    /*
+     * pvh: we temporarily disable d->arch.paging.mode so that we can build cr3
+     * needed to run on dom0's page tables.
+     */
+    save_pvh_pg_mode = d->arch.paging.mode;
+    d->arch.paging.mode = 0;
+
     /* Set up CR3 value for write_ptbase */
     if ( paging_mode_enabled(d) )
         paging_update_paging_modes(v);
@@ -969,6 +1147,22 @@ int __init construct_dom0(
                          nr_pages);
     }
 
+    if ( is_pvh_domain(d) )
+    {
+        unsigned long hap_pages, memkb = nr_pages * (PAGE_SIZE / 1024);
+
+        /* Copied from: libxl_get_required_shadow_memory() */
+        memkb = 4 * (256 * d->max_vcpus + 2 * (memkb / 1024));
+        hap_pages = ( (memkb + 1023) / 1024) << (20 - PAGE_SHIFT);
+        hap_set_alloc_for_pvh_dom0(d, hap_pages);
+    }
+
+    /*
+     * We enable paging mode again so guest_physmap_add_page will do the
+     * right thing for us.
+     */
+    d->arch.paging.mode = save_pvh_pg_mode;
+
     /* Write the phys->machine and machine->phys table entries. */
     for ( pfn = 0; pfn < count; pfn++ )
     {
@@ -985,11 +1179,7 @@ int __init construct_dom0(
         if ( pfn > REVERSE_START && (vinitrd_start || pfn < initrd_pfn) )
             mfn = alloc_epfn - (pfn - REVERSE_START);
 #endif
-        if ( !is_pv_32on64_domain(d) )
-            ((unsigned long *)vphysmap_start)[pfn] = mfn;
-        else
-            ((unsigned int *)vphysmap_start)[pfn] = mfn;
-        set_gpfn_from_mfn(mfn, pfn);
+        dom0_update_physmap(d, pfn, mfn, vphysmap_start);
         if (!(pfn & 0xfffff))
             process_pending_softirqs();
     }
@@ -1005,8 +1195,8 @@ int __init construct_dom0(
             if ( !page->u.inuse.type_info &&
                  !get_page_and_type(page, d, PGT_writable_page) )
                 BUG();
-            ((unsigned long *)vphysmap_start)[pfn] = mfn;
-            set_gpfn_from_mfn(mfn, pfn);
+
+            dom0_update_physmap(d, pfn, mfn, vphysmap_start);
             ++pfn;
             if (!(pfn & 0xfffff))
                 process_pending_softirqs();
@@ -1026,11 +1216,7 @@ int __init construct_dom0(
 #ifndef NDEBUG
 #define pfn (nr_pages - 1 - (pfn - (alloc_epfn - alloc_spfn)))
 #endif
-            if ( !is_pv_32on64_domain(d) )
-                ((unsigned long *)vphysmap_start)[pfn] = mfn;
-            else
-                ((unsigned int *)vphysmap_start)[pfn] = mfn;
-            set_gpfn_from_mfn(mfn, pfn);
+            dom0_update_physmap(d, pfn, mfn, vphysmap_start);
 #undef pfn
             page++; pfn++;
             if (!(pfn & 0xfffff))
@@ -1054,6 +1240,15 @@ int __init construct_dom0(
         si->console.dom0.info_size = sizeof(struct dom0_vga_console_info);
     }
 
+    /*
+     * PVH: We need to update si->shared_info while we are on dom0 page tables,
+     * but need to defer the p2m update until after we have fixed up the
+     * page tables for PVH so that the m2p for the si pte entry returns
+     * correct pfn.
+     */
+    if ( is_pvh_domain(d) )
+        si->shared_info = shared_info_paddr;
+
     if ( is_pv_32on64_domain(d) )
         xlat_start_info(si, XLAT_start_info_console_dom0);
 
@@ -1087,8 +1282,15 @@ int __init construct_dom0(
     regs->eflags = X86_EFLAGS_IF;
 
     if ( opt_dom0_shadow )
+    {
+        if ( is_pvh_domain(d) )
+        {
+            printk("Unsupported option dom0_shadow for PVH\n");
+            return -EINVAL;
+        }
         if ( paging_enable(d, PG_SH_enable) == 0 ) 
             paging_update_paging_modes(v);
+    }
 
     if ( supervisor_mode_kernel )
     {
@@ -1179,6 +1381,19 @@ int __init construct_dom0(
         printk(" Xen warning: dom0 kernel broken ELF: %s\n",
                elf_check_broken(&elf));
 
+    if ( is_pvh_domain(d) )
+    {
+        /* finally, fixup the page table, replacing mfns with pfns */
+        pvh_fixup_page_tables_for_hap(v, v_start, v_end);
+
+        /* the pt has correct pfn for si, now update the mfn in the p2m */
+        mfn = virt_to_mfn(d->shared_info);
+        pfn = shared_info_paddr >> PAGE_SHIFT;
+        dom0_update_physmap(d, pfn, mfn, 0);
+
+        pvh_map_all_iomem(d);
+    }
+
     if ( d->domain_id == hardware_domid )
         iommu_hwdom_init(d);
 
diff --git a/xen/arch/x86/mm/hap/hap.c b/xen/arch/x86/mm/hap/hap.c
index a7593e7..fbce461 100644
--- a/xen/arch/x86/mm/hap/hap.c
+++ b/xen/arch/x86/mm/hap/hap.c
@@ -587,6 +587,18 @@ int hap_domctl(struct domain *d, xen_domctl_shadow_op_t *sc,
     }
 }
 
+void __init hap_set_alloc_for_pvh_dom0(struct domain *d,
+                                       unsigned long hap_pages)
+{
+    int rc;
+
+    paging_lock(d);
+    rc = hap_set_allocation(d, hap_pages, NULL);
+    paging_unlock(d);
+
+    BUG_ON(rc);
+}
+
 static const struct paging_mode hap_paging_real_mode;
 static const struct paging_mode hap_paging_protected_mode;
 static const struct paging_mode hap_paging_pae_mode;
diff --git a/xen/include/asm-x86/hap.h b/xen/include/asm-x86/hap.h
index e03f983..5161927 100644
--- a/xen/include/asm-x86/hap.h
+++ b/xen/include/asm-x86/hap.h
@@ -63,6 +63,7 @@ int   hap_track_dirty_vram(struct domain *d,
                            XEN_GUEST_HANDLE_64(uint8) dirty_bitmap);
 
 extern const struct paging_mode *hap_paging_get_mode(struct vcpu *);
+void hap_set_alloc_for_pvh_dom0(struct domain *d, unsigned long num_pages);
 
 #endif /* XEN_HAP_H */
 
-- 
1.8.3.1

[V11 PATCH 2/4] pvh dom0: Add checks and restrictions for p2m_is_foreign

[Mukesh Rathor]

In this patch, we add some checks and restrictions in the relevant
p2m paths for p2m_is_foreign.

Signed-off-by: Mukesh Rathor <mukesh.rathor@oracle.com>
Acked-by: Tim Deegan <tim@xen.org>
---
 xen/arch/x86/mm/p2m-ept.c |  1 +
 xen/arch/x86/mm/p2m.c     | 12 +++++++++---
 2 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/xen/arch/x86/mm/p2m-ept.c b/xen/arch/x86/mm/p2m-ept.c
index 5d19965..7926bc4 100644
--- a/xen/arch/x86/mm/p2m-ept.c
+++ b/xen/arch/x86/mm/p2m-ept.c
@@ -777,6 +777,7 @@ static void ept_change_entry_type_global(struct p2m_domain *p2m,
 
     BUG_ON(p2m_is_grant(ot) || p2m_is_grant(nt));
     BUG_ON(p2m_is_mmio(ot) || p2m_is_mmio(nt));
+    BUG_ON(p2m_is_foreign(ot) || p2m_is_foreign(nt));
 
     ept_change_entry_type_page(_mfn(ept_get_asr(ept)),
                                ept_get_wl(ept), ot, nt);
diff --git a/xen/arch/x86/mm/p2m.c b/xen/arch/x86/mm/p2m.c
index 1d0528b..5923968 100644
--- a/xen/arch/x86/mm/p2m.c
+++ b/xen/arch/x86/mm/p2m.c
@@ -553,6 +553,10 @@ guest_physmap_add_entry(struct domain *d, unsigned long gfn,
         return 0;
     }
 
+    /* foreign pages are added thru p2m_add_foreign */
+    if ( p2m_is_foreign(t) )
+        return -EINVAL;
+
     p2m_lock(p2m);
 
     P2M_DEBUG("adding gfn=%#lx mfn=%#lx\n", gfn, mfn);
@@ -587,9 +591,9 @@ guest_physmap_add_entry(struct domain *d, unsigned long gfn,
             omfn = p2m->get_entry(p2m, gfn + i, &ot, &a, 0, NULL);
             ASSERT(!p2m_is_shared(ot));
         }
-        if ( p2m_is_grant(ot) )
+        if ( p2m_is_grant(ot) || p2m_is_foreign(ot) )
         {
-            /* Really shouldn't be unmapping grant maps this way */
+            /* Really shouldn't be unmapping grant/foreign maps this way */
             domain_crash(d);
             p2m_unlock(p2m);
             
@@ -691,6 +695,7 @@ p2m_type_t p2m_change_type(struct domain *d, unsigned long gfn,
     struct p2m_domain *p2m = p2m_get_hostp2m(d);
 
     BUG_ON(p2m_is_grant(ot) || p2m_is_grant(nt));
+    BUG_ON(p2m_is_foreign(ot) || p2m_is_foreign(nt));
 
     gfn_lock(p2m, gfn, 0);
 
@@ -715,6 +720,7 @@ void p2m_change_type_range(struct domain *d,
     struct p2m_domain *p2m = p2m_get_hostp2m(d);
 
     BUG_ON(p2m_is_grant(ot) || p2m_is_grant(nt));
+    BUG_ON(p2m_is_foreign(ot) || p2m_is_foreign(nt));
 
     p2m_lock(p2m);
     p2m->defer_nested_flush = 1;
@@ -765,7 +771,7 @@ static int set_typed_p2m_entry(struct domain *d, unsigned long gfn, mfn_t mfn,
 
     gfn_lock(p2m, gfn, 0);
     omfn = p2m->get_entry(p2m, gfn, &ot, &a, 0, NULL);
-    if ( p2m_is_grant(ot) )
+    if ( p2m_is_grant(ot) || p2m_is_foreign(ot) )
     {
         p2m_unlock(p2m);
         domain_crash(d);
-- 
1.8.3.1

[V11 PATCH 3/4] pvh dom0: Add and remove foreign pages

[Mukesh Rathor]

In this patch, a new function, p2m_add_foreign(), is added
to map pages from a foreign guest into dom0 for various purposes
like domU creation, running xentrace, etc... Such pages are
typed p2m_map_foreign.  Note, it is the nature of such pages
that a refcnt is held during their stay in the p2m. The
refcnt is added and released in the low level ept function
atomic_write_ept_entry. That macro is converted to a function to allow
for such refcounting, which only applies to leaf entries in the ept.

Also, get_pg_owner is changed to allow pvh to map foreign mappings,
and is made public to be used by p2m_add_foreign().

Signed-off-by: Mukesh Rathor <mukesh.rathor@oracle.com>
---
 xen/arch/x86/mm.c         |   9 ++--
 xen/arch/x86/mm/p2m-ept.c |  70 ++++++++++++++++++++------
 xen/arch/x86/mm/p2m-pt.c  |   7 +++
 xen/arch/x86/mm/p2m.c     | 122 +++++++++++++++++++++++++++++++++++++++++++---
 xen/include/asm-x86/mm.h  |   2 +
 xen/include/asm-x86/p2m.h |   7 +++
 6 files changed, 192 insertions(+), 25 deletions(-)

diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
index 1a8a5e0..8d12c30 100644
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -2795,7 +2795,7 @@ int new_guest_cr3(unsigned long mfn)
     return rc;
 }
 
-static struct domain *get_pg_owner(domid_t domid)
+struct domain *get_pg_owner(domid_t domid)
 {
     struct domain *pg_owner = NULL, *curr = current->domain;
 
@@ -2811,7 +2811,7 @@ static struct domain *get_pg_owner(domid_t domid)
         goto out;
     }
 
-    if ( unlikely(paging_mode_translate(curr)) )
+    if ( !is_pvh_domain(curr) && unlikely(paging_mode_translate(curr)) )
     {
         MEM_LOG("Cannot mix foreign mappings with translated domains");
         goto out;
@@ -2838,7 +2838,7 @@ static struct domain *get_pg_owner(domid_t domid)
     return pg_owner;
 }
 
-static void put_pg_owner(struct domain *pg_owner)
+void put_pg_owner(struct domain *pg_owner)
 {
     rcu_unlock_domain(pg_owner);
 }
@@ -4584,6 +4584,9 @@ int xenmem_add_to_physmap_one(
             page = mfn_to_page(mfn);
             break;
         }
+        case XENMAPSPACE_gmfn_foreign:
+            rc = p2m_add_foreign(d, idx, gpfn, foreign_domid);
+            return rc;
         default:
             break;
     }
diff --git a/xen/arch/x86/mm/p2m-ept.c b/xen/arch/x86/mm/p2m-ept.c
index 7926bc4..eb80118 100644
--- a/xen/arch/x86/mm/p2m-ept.c
+++ b/xen/arch/x86/mm/p2m-ept.c
@@ -36,8 +36,6 @@
 
 #define atomic_read_ept_entry(__pepte)                              \
     ( (ept_entry_t) { .epte = read_atomic(&(__pepte)->epte) } )
-#define atomic_write_ept_entry(__pepte, __epte)                     \
-    write_atomic(&(__pepte)->epte, (__epte).epte)
 
 #define is_epte_present(ept_entry)      ((ept_entry)->epte & 0x7)
 #define is_epte_superpage(ept_entry)    ((ept_entry)->sp)
@@ -46,6 +44,47 @@ static inline bool_t is_epte_valid(ept_entry_t *e)
     return (e->epte != 0 && e->sa_p2mt != p2m_invalid);
 }
 
+/* returns : 0 for success, -errno otherwise */
+static int atomic_write_ept_entry(ept_entry_t *entryptr, ept_entry_t new,
+                                  int level)
+{
+    bool_t same_mfn = (new.mfn == entryptr->mfn);
+    unsigned long oldmfn = INVALID_MFN;
+
+    if ( level )
+    {
+        ASSERT(!p2m_is_foreign(new.sa_p2mt));
+        write_atomic(&entryptr->epte, new.epte);
+        return 0;
+    }
+
+    if ( unlikely(p2m_is_foreign(new.sa_p2mt)) && !same_mfn )
+    {
+        struct domain *fdom;
+
+        if ( !mfn_valid(new.mfn) )
+            return -EINVAL;
+
+        fdom = page_get_owner(mfn_to_page(new.mfn));
+        if ( fdom == NULL )
+            return -ESRCH;
+
+        /* get refcount on the page */
+        if ( !get_page(mfn_to_page(new.mfn), fdom) )
+            return -EBUSY;
+    }
+
+    if ( unlikely(p2m_is_foreign(entryptr->sa_p2mt)) && !same_mfn )
+        oldmfn = entryptr->mfn;
+
+    write_atomic(&entryptr->epte, new.epte);
+
+    if ( unlikely(oldmfn != INVALID_MFN) )
+        put_page(mfn_to_page(oldmfn));
+
+    return 0;
+}
+
 static void ept_p2m_type_to_flags(ept_entry_t *entry, p2m_type_t type, p2m_access_t access)
 {
     /* First apply type permissions */
@@ -271,7 +310,7 @@ static int ept_next_level(struct p2m_domain *p2m, bool_t read_only,
     return GUEST_TABLE_NORMAL_PAGE;
 }
 
-static bool_t ept_invalidate_emt(mfn_t mfn)
+static bool_t ept_invalidate_emt(mfn_t mfn, int level)
 {
     ept_entry_t *epte = map_domain_page(mfn_x(mfn));
     unsigned int i;
@@ -286,7 +325,7 @@ static bool_t ept_invalidate_emt(mfn_t mfn)
             continue;
 
         e.emt = MTRR_NUM_TYPES;
-        atomic_write_ept_entry(&epte[i], e);
+        atomic_write_ept_entry(&epte[i], e, level);
         changed = 1;
     }
 
@@ -341,7 +380,7 @@ bool_t ept_handle_misconfig(uint64_t gpa)
                                                _mfn(e.mfn), 0, &ipat,
                                                e.sa_p2mt == p2m_mmio_direct);
                     e.ipat = ipat;
-                    atomic_write_ept_entry(&epte[i], e);
+                    atomic_write_ept_entry(&epte[i], e, level);
                 }
             }
             else
@@ -353,7 +392,7 @@ bool_t ept_handle_misconfig(uint64_t gpa)
                 {
                     if ( ept_split_super_page(p2m, &e, level, level - 1) )
                     {
-                        atomic_write_ept_entry(&epte[i], e);
+                        atomic_write_ept_entry(&epte[i], e, level);
                         unmap_domain_page(epte);
                         mfn = e.mfn;
                         continue;
@@ -364,7 +403,7 @@ bool_t ept_handle_misconfig(uint64_t gpa)
                 }
                 e.emt = emt;
                 e.ipat = ipat;
-                atomic_write_ept_entry(&epte[i], e);
+                atomic_write_ept_entry(&epte[i], e, level);
             }
 
             okay = 1;
@@ -374,10 +413,10 @@ bool_t ept_handle_misconfig(uint64_t gpa)
         if ( e.emt == MTRR_NUM_TYPES )
         {
             ASSERT(is_epte_present(&e));
-            ept_invalidate_emt(_mfn(e.mfn));
+            ept_invalidate_emt(_mfn(e.mfn), level);
             smp_wmb();
             e.emt = 0;
-            atomic_write_ept_entry(&epte[i], e);
+            atomic_write_ept_entry(&epte[i], e, level);
             unmap_domain_page(epte);
             okay = 1;
         }
@@ -444,6 +483,7 @@ ept_set_entry(struct p2m_domain *p2m, unsigned long gfn, mfn_t mfn,
     ASSERT((target == 2 && hvm_hap_has_1gb()) ||
            (target == 1 && hvm_hap_has_2mb()) ||
            (target == 0));
+    ASSERT(!p2m_is_foreign(p2mt) || target == 0);
 
     table = map_domain_page(pagetable_get_pfn(p2m_get_pagetable(p2m)));
 
@@ -507,7 +547,7 @@ ept_set_entry(struct p2m_domain *p2m, unsigned long gfn, mfn_t mfn,
 
         /* now install the newly split ept sub-tree */
         /* NB: please make sure domian is paused and no in-fly VT-d DMA. */
-        atomic_write_ept_entry(ept_entry, split_ept_entry);
+        atomic_write_ept_entry(ept_entry, split_ept_entry, i);
 
         /* then move to the level we want to make real changes */
         for ( ; i > target; i-- )
@@ -546,10 +586,10 @@ ept_set_entry(struct p2m_domain *p2m, unsigned long gfn, mfn_t mfn,
         ept_p2m_type_to_flags(&new_entry, p2mt, p2ma);
     }
 
-    atomic_write_ept_entry(ept_entry, new_entry);
+    rc = atomic_write_ept_entry(ept_entry, new_entry, i);
 
     /* Track the highest gfn for which we have ever had a valid mapping */
-    if ( p2mt != p2m_invalid &&
+    if ( rc == 0 && p2mt != p2m_invalid &&
          (gfn + (1UL << order) - 1 > p2m->max_mapped_pfn) )
         p2m->max_mapped_pfn = gfn + (1UL << order) - 1;
 
@@ -581,7 +621,7 @@ out:
        last thing we do, after the ept_sync_domain() and removal
        from the iommu tables, so as to avoid a potential
        use-after-free. */
-    if ( is_epte_present(&old_entry) )
+    if ( rc == 0 && is_epte_present(&old_entry) )
         ept_free_entry(p2m, &old_entry, target);
 
     return rc;
@@ -761,7 +801,7 @@ static void ept_change_entry_type_page(mfn_t ept_page_mfn, int ept_page_level,
 
             e.sa_p2mt = nt;
             ept_p2m_type_to_flags(&e, nt, e.access);
-            atomic_write_ept_entry(&epte[i], e);
+            atomic_write_ept_entry(&epte[i], e, ept_page_level);
         }
     }
 
@@ -792,7 +832,7 @@ static void ept_memory_type_changed(struct p2m_domain *p2m)
     if ( !mfn )
         return;
 
-    if ( ept_invalidate_emt(_mfn(mfn)) )
+    if ( ept_invalidate_emt(_mfn(mfn), ept_get_wl(&p2m->ept)) )
         ept_sync_domain(p2m);
 }
 
diff --git a/xen/arch/x86/mm/p2m-pt.c b/xen/arch/x86/mm/p2m-pt.c
index 56a1593..1bbf0fe 100644
--- a/xen/arch/x86/mm/p2m-pt.c
+++ b/xen/arch/x86/mm/p2m-pt.c
@@ -308,6 +308,13 @@ p2m_pt_set_entry(struct p2m_domain *p2m, unsigned long gfn, mfn_t mfn,
         __trace_var(TRC_MEM_SET_P2M_ENTRY, 0, sizeof(t), &t);
     }
 
+    if ( p2m_is_foreign(p2mt) )
+    {
+        /* pvh fixme: foreign types are only supported on ept at present */
+        gdprintk(XENLOG_WARNING, "Unimplemented foreign p2m type.\n");
+        return -EINVAL;
+    }
+
     table = map_domain_page(mfn_x(pagetable_get_mfn(p2m_get_pagetable(p2m))));
     rc = p2m_next_level(p2m, &table, &gfn_remainder, gfn,
                         L4_PAGETABLE_SHIFT - PAGE_SHIFT,
diff --git a/xen/arch/x86/mm/p2m.c b/xen/arch/x86/mm/p2m.c
index 5923968..b1e23b0 100644
--- a/xen/arch/x86/mm/p2m.c
+++ b/xen/arch/x86/mm/p2m.c
@@ -36,6 +36,7 @@
 #include <xen/event.h>
 #include <asm/hvm/nestedhvm.h>
 #include <asm/hvm/svm/amd-iommu-proto.h>
+#include <xsm/xsm.h>
 
 #include "mm-locks.h"
 
@@ -287,14 +288,20 @@ struct page_info *get_page_from_gfn_p2m(
         /* Fast path: look up and get out */
         p2m_read_lock(p2m);
         mfn = __get_gfn_type_access(p2m, gfn, t, a, 0, NULL, 0);
-        if ( (p2m_is_ram(*t) || p2m_is_grant(*t))
-             && mfn_valid(mfn)
+        if ( p2m_is_any_ram(*t) && mfn_valid(mfn)
              && !((q & P2M_UNSHARE) && p2m_is_shared(*t)) )
         {
             page = mfn_to_page(mfn);
-            if ( !get_page(page, d)
-                 /* Page could be shared */
-                 && !get_page(page, dom_cow) )
+            if ( p2m_is_foreign(*t) )
+            {
+                struct domain *fdom = page_get_owner_and_reference(page);
+                ASSERT(fdom != d);
+                if ( fdom == NULL )
+                    page = NULL;
+            }
+            else if ( !get_page(page, d)
+                      /* Page could be shared */
+                      && !get_page(page, dom_cow) )
                 page = NULL;
         }
         p2m_read_unlock(p2m);
@@ -444,6 +451,10 @@ int p2m_alloc_table(struct p2m_domain *p2m)
     return rc;
 }
 
+/*
+ * pvh fixme: when adding support for pvh non-hardware domains, this path must
+ * cleanup any foreign p2m types (release refcnts on them).
+ */
 void p2m_teardown(struct p2m_domain *p2m)
 /* Return all the p2m pages to Xen.
  * We know we don't have any extra mappings to these pages */
@@ -795,8 +806,8 @@ static int set_typed_p2m_entry(struct domain *d, unsigned long gfn, mfn_t mfn,
 }
 
 /* Set foreign mfn in the given guest's p2m table. */
-static int __attribute__((unused))
-set_foreign_p2m_entry(struct domain *d, unsigned long gfn, mfn_t mfn)
+static int set_foreign_p2m_entry(struct domain *d, unsigned long gfn,
+                                 mfn_t mfn)
 {
     return set_typed_p2m_entry(d, gfn, mfn, p2m_map_foreign);
 }
@@ -1757,6 +1768,103 @@ out_p2m_audit:
 #endif /* P2M_AUDIT */
 
 /*
+ * Add frame from foreign domain to target domain's physmap. Similar to
+ * XENMAPSPACE_gmfn but the frame is foreign being mapped into current,
+ * and is not removed from foreign domain.
+ *
+ * Usage: - libxl on pvh dom0 creating a guest and doing privcmd_ioctl_mmap.
+ *        - xentrace running on dom0 mapping xenheap pages. foreigndom would
+ *          be DOMID_XEN in such a case.
+ *        etc..
+ *
+ * Side Effect: the mfn for fgfn will be refcounted in lower level routines
+ *              so it is not lost while mapped here. The refcnt is released
+ *              via the XENMEM_remove_from_physmap path.
+ *
+ * Returns: 0 ==> success
+ */
+int p2m_add_foreign(struct domain *tdom, unsigned long fgfn,
+                    unsigned long gpfn, domid_t foreigndom)
+{
+    p2m_type_t p2mt, p2mt_prev;
+    unsigned long prev_mfn, mfn;
+    struct page_info *page;
+    int rc = -EINVAL;
+    struct domain *fdom = NULL;
+
+    ASSERT(tdom);
+    if ( foreigndom == DOMID_SELF || !is_pvh_domain(tdom) )
+        return -EINVAL;
+
+    /*
+     * pvh fixme: until support is added to p2m teardown code to cleanup any
+     * foreign entries, limit this to hardware domain only.
+     */
+    if ( !is_hardware_domain(tdom) )
+        return -EPERM;
+
+    fdom = get_pg_owner(foreigndom);
+    if ( fdom == NULL )
+        return -ESRCH;
+
+    if ( tdom == fdom )
+        goto out;
+
+    rc = xsm_map_gmfn_foreign(XSM_TARGET, tdom, fdom);
+    if ( rc )
+        goto out;
+
+    /*
+     * Take a refcnt on the mfn. NB: following supported for foreign mapping:
+     *     ram_rw | ram_logdirty | ram_ro | paging_out.
+     */
+    page = get_page_from_gfn(fdom, fgfn, &p2mt, P2M_ALLOC);
+    if ( !page ||
+         !p2m_is_ram(p2mt) || p2m_is_shared(p2mt) || p2m_is_hole(p2mt) )
+    {
+        if ( page )
+            put_page(page);
+        goto out;
+    }
+    mfn = mfn_x(page_to_mfn(page));
+
+    /* Remove previously mapped page if it is present. */
+    prev_mfn = mfn_x(get_gfn(tdom, gpfn, &p2mt_prev));
+    if ( mfn_valid(_mfn(prev_mfn)) )
+    {
+        if ( is_xen_heap_mfn(prev_mfn) )
+            /* Xen heap frames are simply unhooked from this phys slot */
+            guest_physmap_remove_page(tdom, gpfn, prev_mfn, 0);
+        else
+            /* Normal domain memory is freed, to avoid leaking memory. */
+            guest_remove_page(tdom, gpfn);
+    }
+    /*
+     * Create the new mapping. Can't use guest_physmap_add_page() because it
+     * will update the m2p table which will result in  mfn -> gpfn of dom0
+     * and not fgfn of domU.
+     */
+    rc = set_foreign_p2m_entry(tdom, gpfn, _mfn(mfn));
+    if ( rc )
+        gdprintk(XENLOG_WARNING, "set_foreign_p2m_entry failed. "
+                 "gpfn:%lx mfn:%lx fgfn:%lx td:%d fd:%d\n",
+                 gpfn, mfn, fgfn, tdom->domain_id, fdom->domain_id);
+
+    put_page(page);
+
+    /*
+     * This put_gfn for the above get_gfn for prev_mfn.  We must do this
+     * after set_foreign_p2m_entry so another cpu doesn't populate the gpfn
+     * before us.
+     */
+    put_gfn(tdom, gpfn);
+
+out:
+    if ( fdom )
+        put_pg_owner(fdom);
+    return rc;
+}
+/*
  * Local variables:
  * mode: C
  * c-file-style: "BSD"
diff --git a/xen/include/asm-x86/mm.h b/xen/include/asm-x86/mm.h
index 7059adc..6bf6e72 100644
--- a/xen/include/asm-x86/mm.h
+++ b/xen/include/asm-x86/mm.h
@@ -358,6 +358,8 @@ 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);
+struct domain *get_pg_owner(domid_t domid);
+void put_pg_owner(struct domain *pg_owner);
 
 static inline void put_page_and_type(struct page_info *page)
 {
diff --git a/xen/include/asm-x86/p2m.h b/xen/include/asm-x86/p2m.h
index 86847e9..72517d2 100644
--- a/xen/include/asm-x86/p2m.h
+++ b/xen/include/asm-x86/p2m.h
@@ -183,6 +183,10 @@ typedef unsigned int p2m_query_t;
 #define p2m_is_broken(_t)   (p2m_to_mask(_t) & P2M_BROKEN_TYPES)
 #define p2m_is_foreign(_t)  (p2m_to_mask(_t) & p2m_to_mask(p2m_map_foreign))
 
+#define p2m_is_any_ram(_t)  (p2m_to_mask(_t) &                   \
+                             (P2M_RAM_TYPES | P2M_GRANT_TYPES |  \
+                              p2m_to_mask(p2m_map_foreign)))
+
 /* Per-p2m-table state */
 struct p2m_domain {
     /* Lock that protects updates to the p2m */
@@ -515,6 +519,9 @@ void p2m_memory_type_changed(struct domain *d);
 int set_mmio_p2m_entry(struct domain *d, unsigned long gfn, mfn_t mfn);
 int clear_mmio_p2m_entry(struct domain *d, unsigned long gfn);
 
+/* Add foreign mapping to the guest's p2m table. */
+int p2m_add_foreign(struct domain *tdom, unsigned long fgfn,
+                    unsigned long gpfn, domid_t foreign_domid);
 
 /* 
  * Populate-on-demand
-- 
1.8.3.1

[V11 PATCH 4/4] dom0: add opt_dom0pvh to setup.c

[Mukesh Rathor]

Finally last patch in the series to enable creation of pvh dom0.
A pvh dom0 is created by adding dom0pvh to grub xen command line.

Signed-off-by: Mukesh Rathor <mukesh.rathor@oracle.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
 docs/misc/pvh-readme.txt            |  2 ++
 docs/misc/xen-command-line.markdown |  7 +++++++
 xen/arch/x86/setup.c                | 11 +++++++++--
 3 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/docs/misc/pvh-readme.txt b/docs/misc/pvh-readme.txt
index 9fea137..c5b3de4 100644
--- a/docs/misc/pvh-readme.txt
+++ b/docs/misc/pvh-readme.txt
@@ -37,6 +37,8 @@ supported. Phase I patches are broken into three parts:
    - tools changes for creating a PVH guest
    - boot of 64bit dom0 in PVH mode.
 
+To boot 64bit dom0 in PVH mode, add dom0pvh to grub xen command line.
+
 Following fixme's exist in the code:
   - arch/x86/time.c: support more tsc modes.
 
diff --git a/docs/misc/xen-command-line.markdown b/docs/misc/xen-command-line.markdown
index 7dc938b..d248c62 100644
--- a/docs/misc/xen-command-line.markdown
+++ b/docs/misc/xen-command-line.markdown
@@ -494,6 +494,13 @@ Practices](http://wiki.xen.org/wiki/Xen_Best_Practices#Xen_dom0_dedicated_memory
 
 Pin dom0 vcpus to their respective pcpus
 
+### dom0pvh
+> `= <boolean>`
+
+> Default: `false`
+
+Flag that makes a 64bit dom0 boot in PVH mode. No 32bit support at present.
+
 ### e820-mtrr-clip
 > `= <boolean>`
 
diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c
index 2e30701..373e236 100644
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -61,6 +61,10 @@ integer_param("maxcpus", max_cpus);
 static bool_t __initdata disable_smep;
 invbool_param("smep", disable_smep);
 
+/* Boot dom0 in pvh mode */
+static bool_t __initdata opt_dom0pvh;
+boolean_param("dom0pvh", opt_dom0pvh);
+
 /* **** Linux config option: propagated to domain0. */
 /* "acpi=off":    Sisables both ACPI table parsing and interpreter. */
 /* "acpi=force":  Override the disable blacklist.                   */
@@ -541,7 +545,7 @@ void __init noreturn __start_xen(unsigned long mbi_p)
 {
     char *memmap_type = NULL;
     char *cmdline, *kextra, *loader;
-    unsigned int initrdidx;
+    unsigned int initrdidx, domcr_flags = DOMCRF_s3_integrity;
     multiboot_info_t *mbi = __va(mbi_p);
     module_t *mod = (module_t *)__va(mbi->mods_addr);
     unsigned long nr_pages, raw_max_page, modules_headroom, *module_map;
@@ -1338,8 +1342,11 @@ void __init noreturn __start_xen(unsigned long mbi_p)
     if ( !tboot_protect_mem_regions() )
         panic("Could not protect TXT memory regions");
 
+    if ( opt_dom0pvh )
+        domcr_flags |= DOMCRF_pvh | DOMCRF_hap;
+
     /* Create initial domain 0. */
-    dom0 = domain_create(0, DOMCRF_s3_integrity, 0);
+    dom0 = domain_create(0, domcr_flags, 0);
     if ( IS_ERR(dom0) || (alloc_dom0_vcpu0(dom0) == NULL) )
         panic("Error creating domain 0");
 
-- 
1.8.3.1

Re: [V11 PATCH 3/4] pvh dom0: Add and remove foreign pages

[Jan Beulich]

>>> On 02.05.14 at 03:55, <mukesh.rathor@oracle.com> wrote:
> @@ -4584,6 +4584,9 @@ int xenmem_add_to_physmap_one(
>              page = mfn_to_page(mfn);
>              break;
>          }
> +        case XENMAPSPACE_gmfn_foreign:
> +            rc = p2m_add_foreign(d, idx, gpfn, foreign_domid);
> +            return rc;

Any reason not to simply "return p2m_add_foreign();"?

> +static int atomic_write_ept_entry(ept_entry_t *entryptr, ept_entry_t new,
> +                                  int level)
> +{
> +    bool_t same_mfn = (new.mfn == entryptr->mfn);
> +    unsigned long oldmfn = INVALID_MFN;
> +
> +    if ( level )
> +    {
> +        ASSERT(!p2m_is_foreign(new.sa_p2mt));
> +        write_atomic(&entryptr->epte, new.epte);
> +        return 0;
> +    }
> +
> +    if ( unlikely(p2m_is_foreign(new.sa_p2mt)) && !same_mfn )
> +    {
> +        struct domain *fdom;
> +
> +        if ( !mfn_valid(new.mfn) )
> +            return -EINVAL;
> +
> +        fdom = page_get_owner(mfn_to_page(new.mfn));
> +        if ( fdom == NULL )
> +            return -ESRCH;
> +
> +        /* get refcount on the page */
> +        if ( !get_page(mfn_to_page(new.mfn), fdom) )
> +            return -EBUSY;
> +    }
> +
> +    if ( unlikely(p2m_is_foreign(entryptr->sa_p2mt)) && !same_mfn )
> +        oldmfn = entryptr->mfn;

I'm afraid this "same_mfn" handling is correct only if sa_p2mt also
does not change.

> @@ -287,14 +288,20 @@ struct page_info *get_page_from_gfn_p2m(
>          /* Fast path: look up and get out */
>          p2m_read_lock(p2m);
>          mfn = __get_gfn_type_access(p2m, gfn, t, a, 0, NULL, 0);
> -        if ( (p2m_is_ram(*t) || p2m_is_grant(*t))
> -             && mfn_valid(mfn)
> +        if ( p2m_is_any_ram(*t) && mfn_valid(mfn)
>               && !((q & P2M_UNSHARE) && p2m_is_shared(*t)) )
>          {
>              page = mfn_to_page(mfn);
> -            if ( !get_page(page, d)
> -                 /* Page could be shared */
> -                 && !get_page(page, dom_cow) )
> +            if ( p2m_is_foreign(*t) )

I think here (and possible elsewhere) use of unlikely() is desirable.

> @@ -444,6 +451,10 @@ int p2m_alloc_table(struct p2m_domain *p2m)
>      return rc;
>  }
>  
> +/*
> + * pvh fixme: when adding support for pvh non-hardware domains, this path must
> + * cleanup any foreign p2m types (release refcnts on them).
> + */

And I wonder whether you shouldn't enforce this by disallowing non-
hardware domains to create foreign mappings.

> +int p2m_add_foreign(struct domain *tdom, unsigned long fgfn,
> +                    unsigned long gpfn, domid_t foreigndom)
> +{
> +    p2m_type_t p2mt, p2mt_prev;
> +    unsigned long prev_mfn, mfn;
> +    struct page_info *page;
> +    int rc = -EINVAL;
> +    struct domain *fdom = NULL;

Two pointless initializers.

Jan

Re: [V11 PATCH 3/4] pvh dom0: Add and remove foreign pages

[Mukesh Rathor]

On Mon, 05 May 2014 11:56:05 +0100
"Jan Beulich" <JBeulich@suse.com> wrote:

> >>> On 02.05.14 at 03:55, <mukesh.rathor@oracle.com> wrote:
> > @@ -4584,6 +4584,9 @@ int xenmem_add_to_physmap_one(
> >              page = mfn_to_page(mfn);
> >              break;
> >          }
> > +        case XENMAPSPACE_gmfn_foreign:
> > +            rc = p2m_add_foreign(d, idx, gpfn, foreign_domid);
> > +            return rc;
> 
> Any reason not to simply "return p2m_add_foreign();"?

Could, rc allows quick adding of printk for debugging. But, 
I will change it.

> > +static int atomic_write_ept_entry(ept_entry_t *entryptr,
> > ept_entry_t new,
> > +                                  int level)
> > +{
> > +    bool_t same_mfn = (new.mfn == entryptr->mfn);
> > +    unsigned long oldmfn = INVALID_MFN;
> > +
> > +    if ( level )
> > +    {
> > +        ASSERT(!p2m_is_foreign(new.sa_p2mt));
> > +        write_atomic(&entryptr->epte, new.epte);
> > +        return 0;
> > +    }
> > +
> > +    if ( unlikely(p2m_is_foreign(new.sa_p2mt)) && !same_mfn )
> > +    {
> > +        struct domain *fdom;
> > +
> > +        if ( !mfn_valid(new.mfn) )
> > +            return -EINVAL;
> > +
> > +        fdom = page_get_owner(mfn_to_page(new.mfn));
> > +        if ( fdom == NULL )
> > +            return -ESRCH;
> > +
> > +        /* get refcount on the page */
> > +        if ( !get_page(mfn_to_page(new.mfn), fdom) )
> > +            return -EBUSY;
> > +    }
> > +
> > +    if ( unlikely(p2m_is_foreign(entryptr->sa_p2mt)) && !same_mfn )
> > +        oldmfn = entryptr->mfn;
> 
> I'm afraid this "same_mfn" handling is correct only if sa_p2mt also
> does not change.

Yup, my bad. Will fix it, thanks.

> > @@ -287,14 +288,20 @@ struct page_info *get_page_from_gfn_p2m(
> >          /* Fast path: look up and get out */
> >          p2m_read_lock(p2m);
> >          mfn = __get_gfn_type_access(p2m, gfn, t, a, 0, NULL, 0);
> > -        if ( (p2m_is_ram(*t) || p2m_is_grant(*t))
> > -             && mfn_valid(mfn)
> > +        if ( p2m_is_any_ram(*t) && mfn_valid(mfn)
> >               && !((q & P2M_UNSHARE) && p2m_is_shared(*t)) )
> >          {
> >              page = mfn_to_page(mfn);
> > -            if ( !get_page(page, d)
> > -                 /* Page could be shared */
> > -                 && !get_page(page, dom_cow) )
> > +            if ( p2m_is_foreign(*t) )
> 
> I think here (and possible elsewhere) use of unlikely() is desirable.

Ok.

> > @@ -444,6 +451,10 @@ int p2m_alloc_table(struct p2m_domain *p2m)
> >      return rc;
> >  }
> >  
> > +/*
> > + * pvh fixme: when adding support for pvh non-hardware domains,
> > this path must
> > + * cleanup any foreign p2m types (release refcnts on them).
> > + */
> 
> And I wonder whether you shouldn't enforce this by disallowing non-
> hardware domains to create foreign mappings.

Hmm... Tim wanted the enforcement. That will ensure the cleanup is
implemented without falling thru the cracks.

thanks
Mukesh

Re: [V11 PATCH 3/4] pvh dom0: Add and remove foreign pages

[Jan Beulich]

>>> On 06.05.14 at 03:21, <mukesh.rathor@oracle.com> wrote:
> "Jan Beulich" <JBeulich@suse.com> wrote:
>> >>> On 02.05.14 at 03:55, <mukesh.rathor@oracle.com> wrote:
>> > @@ -444,6 +451,10 @@ int p2m_alloc_table(struct p2m_domain *p2m)
>> >      return rc;
>> >  }
>> >  
>> > +/*
>> > + * pvh fixme: when adding support for pvh non-hardware domains,
>> > this path must
>> > + * cleanup any foreign p2m types (release refcnts on them).
>> > + */
>> 
>> And I wonder whether you shouldn't enforce this by disallowing non-
>> hardware domains to create foreign mappings.
> 
> Hmm... Tim wanted the enforcement. That will ensure the cleanup is
> implemented without falling thru the cracks.

I'm confused - aren't you stating that Tim requested the same I did?
Or else, what "enforcement" are you referring to?

Jan

Re: [V11 PATCH 3/4] pvh dom0: Add and remove foreign pages

[Mukesh Rathor]

On Tue, 06 May 2014 08:51:24 +0100
"Jan Beulich" <JBeulich@suse.com> wrote:

> >>> On 06.05.14 at 03:21, <mukesh.rathor@oracle.com> wrote:
> > "Jan Beulich" <JBeulich@suse.com> wrote:
> >> >>> On 02.05.14 at 03:55, <mukesh.rathor@oracle.com> wrote:
> >> > @@ -444,6 +451,10 @@ int p2m_alloc_table(struct p2m_domain *p2m)
> >> >      return rc;
> >> >  }
> >> >  
> >> > +/*
> >> > + * pvh fixme: when adding support for pvh non-hardware domains,
> >> > this path must
> >> > + * cleanup any foreign p2m types (release refcnts on them).
> >> > + */
> >> 
> >> And I wonder whether you shouldn't enforce this by disallowing non-
> >> hardware domains to create foreign mappings.
> > 
> > Hmm... Tim wanted the enforcement. That will ensure the cleanup is
> > implemented without falling thru the cracks.
> 
> I'm confused - aren't you stating that Tim requested the same I did?
> Or else, what "enforcement" are you referring to?

Yes, Tim requested enforcement which I added in p2m_add_foreign():

+    /*
+     * pvh fixme: until support is added to p2m teardown code to cleanup any
+     * foreign entries, limit this to hardware domain only.
+     */
+    if ( !is_hardware_domain(tdom) )
+        return -EPERM;

Thus, non-hardware domains can't map foreign types. Not sure if there's
anything worth enforcing in p2m_teardown with above.

I'm not sure I understand what you think "I shouldn't enforce".

Mukesh

Re: [V11 PATCH 3/4] pvh dom0: Add and remove foreign pages

[Jan Beulich]

>>> On 07.05.14 at 03:12, <mukesh.rathor@oracle.com> wrote:
> On Tue, 06 May 2014 08:51:24 +0100
> "Jan Beulich" <JBeulich@suse.com> wrote:
> 
>> >>> On 06.05.14 at 03:21, <mukesh.rathor@oracle.com> wrote:
>> > "Jan Beulich" <JBeulich@suse.com> wrote:
>> >> >>> On 02.05.14 at 03:55, <mukesh.rathor@oracle.com> wrote:
>> >> > @@ -444,6 +451,10 @@ int p2m_alloc_table(struct p2m_domain *p2m)
>> >> >      return rc;
>> >> >  }
>> >> >  
>> >> > +/*
>> >> > + * pvh fixme: when adding support for pvh non-hardware domains,
>> >> > this path must
>> >> > + * cleanup any foreign p2m types (release refcnts on them).
>> >> > + */
>> >> 
>> >> And I wonder whether you shouldn't enforce this by disallowing non-
>> >> hardware domains to create foreign mappings.
>> > 
>> > Hmm... Tim wanted the enforcement. That will ensure the cleanup is
>> > implemented without falling thru the cracks.
>> 
>> I'm confused - aren't you stating that Tim requested the same I did?
>> Or else, what "enforcement" are you referring to?
> 
> Yes, Tim requested enforcement which I added in p2m_add_foreign():
> 
> +    /*
> +     * pvh fixme: until support is added to p2m teardown code to cleanup any
> +     * foreign entries, limit this to hardware domain only.
> +     */
> +    if ( !is_hardware_domain(tdom) )
> +        return -EPERM;
> 
> Thus, non-hardware domains can't map foreign types. Not sure if there's
> anything worth enforcing in p2m_teardown with above.

I must have overlooked this - this is exactly what I was after. Sorry
for the noise.

Jan

Re: [V11 PATCH 3/4] pvh dom0: Add and remove foreign pages

[Roger Pau Monné]

On 02/05/14 03:55, Mukesh Rathor wrote:
> +int p2m_add_foreign(struct domain *tdom, unsigned long fgfn,
> +                    unsigned long gpfn, domid_t foreigndom)
> +{
> +    p2m_type_t p2mt, p2mt_prev;
> +    unsigned long prev_mfn, mfn;
> +    struct page_info *page;
> +    int rc = -EINVAL;
> +    struct domain *fdom = NULL;
> +
> +    ASSERT(tdom);
> +    if ( foreigndom == DOMID_SELF || !is_pvh_domain(tdom) )
> +        return -EINVAL;
> +
> +    /*
> +     * pvh fixme: until support is added to p2m teardown code to cleanup any
> +     * foreign entries, limit this to hardware domain only.
> +     */
> +    if ( !is_hardware_domain(tdom) )
> +        return -EPERM;
> +
> +    fdom = get_pg_owner(foreigndom);
> +    if ( fdom == NULL )
> +        return -ESRCH;
> +
> +    if ( tdom == fdom )
> +        goto out;
> +
> +    rc = xsm_map_gmfn_foreign(XSM_TARGET, tdom, fdom);
> +    if ( rc )
> +        goto out;
> +
> +    /*
> +     * Take a refcnt on the mfn. NB: following supported for foreign mapping:
> +     *     ram_rw | ram_logdirty | ram_ro | paging_out.
> +     */
> +    page = get_page_from_gfn(fdom, fgfn, &p2mt, P2M_ALLOC);
> +    if ( !page ||
> +         !p2m_is_ram(p2mt) || p2m_is_shared(p2mt) || p2m_is_hole(p2mt) )
> +    {
> +        if ( page )
> +            put_page(page);

This is missing setting rc to an error value, something like the
following is needed:

rc = -EINVAL;

Roger.

> +        goto out;
> +    }
> +    mfn = mfn_x(page_to_mfn(page));
> +
> +    /* Remove previously mapped page if it is present. */
> +    prev_mfn = mfn_x(get_gfn(tdom, gpfn, &p2mt_prev));
> +    if ( mfn_valid(_mfn(prev_mfn)) )
> +    {
> +        if ( is_xen_heap_mfn(prev_mfn) )
> +            /* Xen heap frames are simply unhooked from this phys slot */
> +            guest_physmap_remove_page(tdom, gpfn, prev_mfn, 0);
> +        else
> +            /* Normal domain memory is freed, to avoid leaking memory. */
> +            guest_remove_page(tdom, gpfn);
> +    }
> +    /*
> +     * Create the new mapping. Can't use guest_physmap_add_page() because it
> +     * will update the m2p table which will result in  mfn -> gpfn of dom0
> +     * and not fgfn of domU.
> +     */
> +    rc = set_foreign_p2m_entry(tdom, gpfn, _mfn(mfn));
> +    if ( rc )
> +        gdprintk(XENLOG_WARNING, "set_foreign_p2m_entry failed. "
> +                 "gpfn:%lx mfn:%lx fgfn:%lx td:%d fd:%d\n",
> +                 gpfn, mfn, fgfn, tdom->domain_id, fdom->domain_id);
> +
> +    put_page(page);
> +
> +    /*
> +     * This put_gfn for the above get_gfn for prev_mfn.  We must do this
> +     * after set_foreign_p2m_entry so another cpu doesn't populate the gpfn
> +     * before us.
> +     */
> +    put_gfn(tdom, gpfn);
> +
> +out:
> +    if ( fdom )
> +        put_pg_owner(fdom);
> +    return rc;
> +}

Re: [V11 PATCH 1/4] pvh dom0: construct_dom0 changes

[Tim Deegan]

At 18:55 -0700 on 01 May (1398966904), Mukesh Rathor wrote:
> This patch changes construct_dom0() to boot in pvh mode:
>   - Make sure dom0 elf supports pvh mode.
>   - Call guest_physmap_add_page for pvh rather than simple p2m setting
>   - Map all non-RAM regions 1:1 upto the end region in e820 or 4GB which
>     ever is higher.
>   - Allocate p2m, copying calculation from toolstack.
>   - Allocate shared info page from the virtual space so that dom0 PT
>     can be updated. Then update p2m for it with the actual mfn.
>   - Since we build the page tables for pvh same as for pv, in
>     pvh_fixup_page_tables_for_hap we replace the mfns with pfns.
> 
> Signed-off-by: Mukesh Rathor <mukesh.rathor@oracle.com>
> Reviewed-by: Jan Beulich <jbeulich@suse.com>

For the x86/mm changes (even though I would have preferred that to be
a paging_* API rather than a hap_* one):

Acked-by: Tim Deegan <tim@xen.org>