libxc: introduce xc_map_domain_meminfo (and xc_unmap_domain_meminfo)

And use it in xc_exchange_page(). This is basically because the
following change need something really similar to the set of
steps that are here abstracted in these two functions.

Despite of the change in the interface and in the signature of
some functions, this is pure code motion. No functional changes
involved.

Signed-off-by: Dario Faggioli <dario.faggioli@citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>

1 files changed, 127 insertions, 0 deletions

diff --git a/tools/libxc/xc_domain.c b/tools/libxc/xc_domain.c
index 3210e34a73..81316d3c7f 100644
--- a/tools/libxc/xc_domain.c
+++ b/tools/libxc/xc_domain.c
@@ -21,6 +21,8 @@
  */
 
 #include "xc_private.h"
+#include "xc_core.h"
+#include "xg_private.h"
 #include "xg_save_restore.h"
 #include <xen/memory.h>
 #include <xen/hvm/hvm_op.h>
@@ -1477,6 +1479,131 @@ int xc_domain_bind_pt_isa_irq(
                                   PT_IRQ_TYPE_ISA, 0, 0, 0, machine_irq));
 }
 
+int xc_unmap_domain_meminfo(xc_interface *xch, struct xc_domain_meminfo *minfo)
+{
+    struct domain_info_context _di = { .guest_width = minfo->guest_width };
+    struct domain_info_context *dinfo = &_di;
+
+    free(minfo->pfn_type);
+    if ( minfo->p2m_table )
+        munmap(minfo->p2m_table, P2M_FLL_ENTRIES * PAGE_SIZE);
+    minfo->p2m_table = NULL;
+
+    return 0;
+}
+
+int xc_map_domain_meminfo(xc_interface *xch, int domid,
+                          struct xc_domain_meminfo *minfo)
+{
+    struct domain_info_context _di;
+    struct domain_info_context *dinfo = &_di;
+
+    xc_dominfo_t info;
+    shared_info_any_t *live_shinfo;
+    xen_capabilities_info_t xen_caps = "";
+    int i;
+
+    /* Only be initialized once */
+    if ( minfo->pfn_type || minfo->p2m_table )
+    {
+        errno = EINVAL;
+        return -1;
+    }
+
+    if ( xc_domain_getinfo(xch, domid, 1, &info) != 1 )
+    {
+        PERROR("Could not get domain info");
+        return -1;
+    }
+
+    if ( xc_domain_get_guest_width(xch, domid, &minfo->guest_width) )
+    {
+        PERROR("Could not get domain address size");
+        return -1;
+    }
+    _di.guest_width = minfo->guest_width;
+
+    /* Get page table levels (see get_platform_info() in xg_save_restore.h */
+    if ( xc_version(xch, XENVER_capabilities, &xen_caps) )
+    {
+        PERROR("Could not get Xen capabilities (for page table levels)");
+        return -1;
+    }
+    if ( strstr(xen_caps, "xen-3.0-x86_64") )
+        /* Depends on whether it's a compat 32-on-64 guest */
+        minfo->pt_levels = ( (minfo->guest_width == 8) ? 4 : 3 );
+    else if ( strstr(xen_caps, "xen-3.0-x86_32p") )
+        minfo->pt_levels = 3;
+    else if ( strstr(xen_caps, "xen-3.0-x86_32") )
+        minfo->pt_levels = 2;
+    else
+    {
+        errno = EFAULT;
+        return -1;
+    }
+
+    /* We need the shared info page for mapping the P2M */
+    live_shinfo = xc_map_foreign_range(xch, domid, PAGE_SIZE, PROT_READ,
+                                       info.shared_info_frame);
+    if ( !live_shinfo )
+    {
+        PERROR("Could not map the shared info frame (MFN 0x%lx)",
+               info.shared_info_frame);
+        return -1;
+    }
+
+    if ( xc_core_arch_map_p2m_writable(xch, minfo->guest_width, &info,
+                                       live_shinfo, &minfo->p2m_table,
+                                       &minfo->p2m_size) )
+    {
+        PERROR("Could not map the P2M table");
+        munmap(live_shinfo, PAGE_SIZE);
+        return -1;
+    }
+    munmap(live_shinfo, PAGE_SIZE);
+    _di.p2m_size = minfo->p2m_size;
+
+    /* Make space and prepare for getting the PFN types */
+    minfo->pfn_type = calloc(sizeof(*minfo->pfn_type), minfo->p2m_size);
+    if ( !minfo->pfn_type )
+    {
+        PERROR("Could not allocate memory for the PFN types");
+        goto failed;
+    }
+    for ( i = 0; i < minfo->p2m_size; i++ )
+        minfo->pfn_type[i] = pfn_to_mfn(i, minfo->p2m_table,
+                                        minfo->guest_width);
+
+    /* Retrieve PFN types in batches */
+    for ( i = 0; i < minfo->p2m_size ; i+=1024 )
+    {
+        int count = ((minfo->p2m_size - i ) > 1024 ) ?
+                        1024: (minfo->p2m_size - i);
+
+        if ( xc_get_pfn_type_batch(xch, domid, count, minfo->pfn_type + i) )
+        {
+            PERROR("Could not get %d-eth batch of PFN types", (i+1)/1024);
+            goto failed;
+        }
+    }
+
+    return 0;
+
+failed:
+    if ( minfo->pfn_type )
+    {
+        free(minfo->pfn_type);
+        minfo->pfn_type = NULL;
+    }
+    if ( minfo->p2m_table )
+    {
+        munmap(minfo->p2m_table, P2M_FLL_ENTRIES * PAGE_SIZE);
+        minfo->p2m_table = NULL;
+    }
+
+    return -1;
+}
+
 int xc_domain_memory_mapping(
     xc_interface *xch,
     uint32_t domid,