[PATCH 5 of 6] xend/xc: Implement a domain_set_e820_hole function to be used by python code

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

# HG changeset patch
# User Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
# Date 1332610898 14400
# Node ID 95eda76084314aa8a5cfd4b5e83969823492deda
# Parent  d42921da3931026ecf5da7c0e5bb86074e77cf71
xend/xc: Implement a domain_set_e820_hole function to be used by python code

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

diff -r d42921da3931 -r 95eda7608431 tools/python/xen/lowlevel/xc/xc.c
--- a/tools/python/xen/lowlevel/xc/xc.c	Sat Mar 24 13:41:38 2012 -0400
+++ b/tools/python/xen/lowlevel/xc/xc.c	Sat Mar 24 13:41:38 2012 -0400
@@ -16,6 +16,7 @@
 #include <sys/mman.h>
 #include <netdb.h>
 #include <arpa/inet.h>
+#include <stdio.h>
 
 #include "xenctrl.h"
 #include <xen/elfnote.h>
@@ -1697,6 +1698,243 @@ static PyObject *pyxc_domain_set_memmap_
     return zero;
 }
 
+#ifdef PRIu64
+static const char *e820_names(int type)
+{
+    switch (type) {
+        case E820_RAM: return "RAM";
+        case E820_RESERVED: return "Reserved";
+        case E820_ACPI: return "ACPI";
+        case E820_NVS: return "ACPI NVS";
+        case E820_UNUSABLE: return "Unusable";
+        default: break;
+    }
+    return "Unknown";
+}
+#endif
+static int e820_sanitize(struct e820entry src[],
+                         uint32_t *nr_entries,
+                         unsigned long map_limitkb,
+                         unsigned long balloon_kb)
+{
+    uint64_t delta_kb = 0, start = 0, start_kb = 0, last = 0, ram_end;
+    uint32_t i, idx = 0, nr;
+    struct e820entry e820[E820MAX];
+
+    if (!src || !map_limitkb || !balloon_kb || !nr_entries)
+        return -EINVAL;
+
+    nr = *nr_entries;
+    if (!nr)
+        return -EINVAL;
+
+    if (nr > E820MAX)
+        return -EINVAL;
+
+    /* Weed out anything under 1MB */
+    for (i = 0; i < nr; i++) {
+        if (src[i].addr > 0x100000)
+            continue;
+
+        src[i].type = 0;
+        src[i].size = 0;
+        src[i].addr = -1ULL;
+    }
+
+    /* Find the lowest and highest entry in E820, skipping over
+     * undesired entries. */
+    start = -1ULL;
+    last = 0;
+    for (i = 0; i < nr; i++) {
+        if ((src[i].type == E820_RAM) ||
+            (src[i].type == E820_UNUSABLE) ||
+            (src[i].type == 0))
+		continue;
+
+        start = src[i].addr < start ? src[i].addr : start;
+        last = src[i].addr + src[i].size > last ?
+               src[i].addr + src[i].size > last : last;
+    }
+    if (start > 1024)
+        start_kb = start >> 10;
+
+    /* Add the memory RAM region for the guest */
+    e820[idx].addr = 0;
+    e820[idx].size = (uint64_t)map_limitkb << 10;
+    e820[idx].type = E820_RAM;
+
+    /* .. and trim if neccessary */
+    if (start_kb && map_limitkb > start_kb) {
+        delta_kb = map_limitkb - start_kb;
+        if (delta_kb)
+            e820[idx].size -= (uint64_t)(delta_kb << 10);
+    }
+    /* Note: We don't touch balloon_kb here. Will add it at the end. */
+    ram_end = e820[idx].addr + e820[idx].size;
+    idx ++;
+#ifdef PRIu64
+    printf("Memory: %"PRIu64"kB End of RAM: " \
+               "0x%"PRIx64" (PFN) Delta: %"PRIu64"kB, PCI start: %"PRIu64"kB " \
+               "(0x%"PRIx64" PFN), Balloon %"PRIu64"kB\n", (uint64_t)map_limitkb,
+               ram_end >> 12, delta_kb, start_kb ,start >> 12,
+               (uint64_t)balloon_kb);
+#endif
+
+    /* This whole code below is to guard against if the Intel IGD is passed into
+     * the guest. If we don't pass in IGD, this whole code can be ignored.
+     *
+     * The reason for this code is that Intel boxes fill their E820 with
+     * E820_RAM amongst E820_RESERVED and we can't just ditch those E820_RAM.
+     * That is b/c any "gaps" in the E820 is considered PCI I/O space by
+     * Linux and it would be utilized by the Intel IGD as I/O space while
+     * in reality it was an RAM region.
+     *
+     * What this means is that we have to walk the E820 and for any region
+     * that is RAM and below 4GB and above ram_end, needs to change its type
+     * to E820_UNUSED. We also need to move some of the E820_RAM regions if
+     * the overlap with ram_end. */
+    for (i = 0; i < nr; i++) {
+	uint64_t end = src[i].addr + src[i].size;
+
+	/* We don't care about E820_UNUSABLE, but we need to
+         * change the type to zero b/c the loop after this
+         * sticks E820_UNUSABLE on the guest's E820 but ignores
+         * the ones with type zero. */
+        if ((src[i].type == E820_UNUSABLE) ||
+	    /* Any region that is within the "RAM region" can
+             * be safely ditched. */
+            (end < ram_end)) {
+                src[i].type = 0;
+                continue;
+        }
+
+        /* Look only at RAM regions. */
+	if (src[i].type != E820_RAM)
+            continue;
+
+        /* We only care about RAM regions below 4GB. */
+        if (src[i].addr >= (1ULL<<32))
+            continue;
+
+	/* E820_RAM overlaps with our RAM region. Move it */
+	if (src[i].addr < ram_end) {
+            uint64_t delta;
+
+            src[i].type = E820_UNUSABLE;
+            delta = ram_end - src[i].addr;
+            /* The end < ram_end should weed this out */
+            if (src[i].size - delta < 0)
+                src[i].type = 0;
+            else {
+                src[i].size -= delta;
+                src[i].addr = ram_end;
+            }
+            if (src[i].addr + src[i].size != end) {
+                /* We messed up somewhere */
+                src[i].type = 0;
+#ifdef PRIu64
+                printf( "Computed E820 wrongly. Continuing on.");
+#endif
+            }
+        }
+        /* Lastly, convert the RAM to UNSUABLE. Look in the Linux kernel
+           at git commit 2f14ddc3a7146ea4cd5a3d1ecd993f85f2e4f948
+            "xen/setup: Inhibit resource API from using System RAM E820
+           gaps as PCI mem gaps" for full explanation. */
+        if (end > ram_end)
+            src[i].type = E820_UNUSABLE;
+    }
+
+    /* Check if there is a region between ram_end and start. */
+    if (start > ram_end) {
+        int add_unusable = 1;
+        for (i = 0; i < nr && add_unusable; i++) {
+            if (src[i].type != E820_UNUSABLE)
+                continue;
+            if (ram_end != src[i].addr)
+                continue;
+            if (start != src[i].addr + src[i].size) {
+                /* there is one, adjust it */
+                src[i].size = start - src[i].addr;
+            }
+            add_unusable = 0;
+        }
+        /* .. and if not present, add it in. This is to guard against
+           the Linux guest assuming that the gap between the end of
+           RAM region and the start of the E820_[ACPI,NVS,RESERVED]
+           is PCI I/O space. Which it certainly is _not_. */
+        if (add_unusable) {
+            e820[idx].type = E820_UNUSABLE;
+            e820[idx].addr = ram_end;
+            e820[idx].size = start - ram_end;
+            idx++;
+        }
+    }
+    /* Almost done: copy them over, ignoring the undesireable ones */
+    for (i = 0; i < nr; i++) {
+        if ((src[i].type == E820_RAM) ||
+	    (src[i].type == 0))
+	    continue;
+
+        e820[idx].type = src[i].type;
+        e820[idx].addr = src[i].addr;
+        e820[idx].size = src[i].size;
+        idx++;
+    }
+    /* At this point we have the mapped RAM + E820 entries from src. */
+    if (balloon_kb) {
+        /* and if we truncated the RAM region, then add it to the end. */
+        e820[idx].type = E820_RAM;
+        e820[idx].addr = (uint64_t)(1ULL << 32) > last ?
+                         (uint64_t)(1ULL << 32) : last;
+        /* also add the balloon memory to the end. */
+        e820[idx].size = (uint64_t)(delta_kb << 10) +
+                         (uint64_t)(balloon_kb << 10);
+        idx++;
+
+    }
+    nr = idx;
+#ifdef PRIu64
+    for (i = 0; i < nr; i++) {
+      printf(":\t[%"PRIx64" -> %"PRIx64"] %s",
+                 e820[i].addr >> 12, (e820[i].addr + e820[i].size) >> 12,
+                 e820_names(e820[i].type));
+    }
+#endif
+    /* Done: copy the sanitized version. */
+    *nr_entries = nr;
+    memcpy(src, e820, nr * sizeof(struct e820entry));
+    return 0;
+}
+
+static PyObject *pyxc_domain_set_e820_hole(XcObject *self, PyObject *args)
+{
+    uint32_t dom, nr;
+    unsigned int target_kb;
+    unsigned int balloon_kb;
+    int rc;
+    struct e820entry map[E820MAX];
+
+    if ( !PyArg_ParseTuple(args, "iii", &dom, &target_kb, &balloon_kb) )
+        return NULL;
+
+    rc = xc_get_machine_memory_map(self->xc_handle, map, E820MAX);
+	if (rc < 0)
+        return pyxc_error_to_exception(self->xc_handle);
+
+	nr = rc;
+	rc = e820_sanitize(map, &nr, target_kb, balloon_kb);
+	if (rc)
+        return pyxc_error_to_exception(self->xc_handle);
+
+	rc = xc_domain_set_memory_map(self->xc_handle, dom, map, nr);
+	if (rc < 0)
+        return pyxc_error_to_exception(self->xc_handle);
+
+    Py_INCREF(zero);
+    return zero;
+}
+
 static PyObject *pyxc_domain_ioport_permission(XcObject *self,
                                                PyObject *args,
                                                PyObject *kwds)
@@ -2701,6 +2939,15 @@ static PyMethodDef pyxc_methods[] = {
       " map_limitkb [int]: .\n"
       "Returns: [int] 0 on success; -1 on error.\n" },
 
+    { "domain_set_e820_hole", 
+      (PyCFunction)pyxc_domain_set_e820_hole, 
+      METH_VARARGS, "\n"
+      "Set a domain's E820 memory map\n"
+      " dom [int]: Identifier of domain.\n"
+      " target_memkb [int]: .\n"
+      " balloon_kb [int]: .\n"
+      "Returns: [int] 0 on success; -1 on error.\n" },
+
 #ifdef __ia64__
     { "nvram_init",
       (PyCFunction)pyxc_nvram_init,