# HG changeset patch
# Parent a81f4c7b4e393f0e2cd855e86cf3bfb1a8308ee0
libxl: Add support for passing in the machine's E820 for PCI passthrough
The code that populates E820 is unconditionally triggered by the guest
configuration having "pci=['<BDF>,..']", being a PV guest, and if
b_info->u.pv.machine_e820 is set.
The code do_domain_create calls the libxl__e820_alloc when
it notices that the guest is PV, has at least one PCI devices, and has
the machine_e820 flag set.
libxl__e820_alloc calls the xc_get_machine_memory_map to retrieve the systems
E820. Then the E820 is sanitized to weed out E820 entries below 16MB, and as
well remove any E820_RAM or E820_UNUSED regions as the guest does not need to
know about them. The guest only needs the E820_ACPI, E820_NVS, E820_RESERVED to
get an idea of where the PCI I/O space is. Mostly.. The Linux kernel assumes
that any
gap in the E820 is considered PCI I/O space which means that if we pass
in the guest 2GB, and the E820_ACPI, and its friend start at 3GB, the
gap between 2GB and 3GB will be considered as PCI I/O space. To guard against
that we also create an E820_UNUSABLE between the region of 'target_kb'
(called ram_end in the code) up to the first E820_[ACPI,NVS,RESERVED] region.
Lastly, the xc_domain_set_memory_map is called to install the new E820.
When tested with another PV guest (NetBSD 5.1) the modified E820 gave
it no trouble. The code has also been tested with older "classic" Xen Linux
and with the newer "pvops" with success (SLES11, RHEL5, Ubuntu Lucid,
Debian Squeeze, 2.6.37, 2.6.38, 2.6.39).
Memory that is slack or for balloon (so 'maxmem' in guest configuration)
is put behind the machine E820. Which in most cases is after the 4GB.
The reason for doing the fetching of the E820 using the hypercall in
the toolstack (instead of the guest doing it) is that when a guest
would do a hypercall to 'XENMEM_machine_memory_map' it would
retrieve an E820 with I/O range caps added in. Meaning that the
region after 4GB up to end of possible memory would be marked as unusable
and the kernel would not have any space to allocate a balloon
region.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
diff -r a81f4c7b4e39 tools/libxl/libxl.idl
--- a/tools/libxl/libxl.idl Tue Apr 12 14:46:05 2011 -0400
+++ b/tools/libxl/libxl.idl Tue Apr 12 16:29:17 2011 -0400
@@ -118,6 +118,7 @@ libxl_domain_build_info = Struct("domain
("cmdline", string),
("ramdisk", libxl_file_reference),
("features", string, True),
+ ("machine_e820", bool, False, "Use
machine's E820 for PCI passthrough."),
])),
])),
],
diff -r a81f4c7b4e39 tools/libxl/libxl_create.c
--- a/tools/libxl/libxl_create.c Tue Apr 12 14:46:05 2011 -0400
+++ b/tools/libxl/libxl_create.c Tue Apr 12 16:29:17 2011 -0400
@@ -516,6 +516,14 @@ static int do_domain_create(libxl__gc *g
for (i = 0; i < d_config->num_pcidevs; i++)
libxl__device_pci_add(gc, domid, &d_config->pcidevs[i], 1);
+ if (!d_config->c_info.hvm && d_config->b_info.u.pv.machine_e820) {
+ int rc = 0;
+ rc = libxl__e820_alloc(ctx, domid, d_config);
+ if (rc)
+ LIBXL__LOG(ctx, LIBXL__LOG_WARNING,
+ "Failed while collecting E820 with: %d (errno:%d)\n",
+ rc, errno);
+ }
if ( cb && (d_config->c_info.hvm || d_config->b_info.u.pv.bootloader )) {
if ( (*cb)(ctx, domid, priv) )
goto error_out;
diff -r a81f4c7b4e39 tools/libxl/libxl_internal.h
--- a/tools/libxl/libxl_internal.h Tue Apr 12 14:46:05 2011 -0400
+++ b/tools/libxl/libxl_internal.h Tue Apr 12 16:29:17 2011 -0400
@@ -344,4 +344,5 @@ _hidden int libxl__error_set(libxl__gc *
_hidden int libxl__file_reference_map(libxl_file_reference *f);
_hidden int libxl__file_reference_unmap(libxl_file_reference *f);
+_hidden int libxl__e820_alloc(libxl_ctx *ctx, uint32_t domid,
libxl_domain_config *d_config);
#endif
diff -r a81f4c7b4e39 tools/libxl/libxl_pci.c
--- a/tools/libxl/libxl_pci.c Tue Apr 12 14:46:05 2011 -0400
+++ b/tools/libxl/libxl_pci.c Tue Apr 12 16:29:17 2011 -0400
@@ -1047,3 +1047,157 @@ int libxl_device_pci_shutdown(libxl_ctx
free(pcidevs);
return 0;
}
+
+static int e820_sanitize(libxl_ctx *ctx, 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 ERROR_INVAL;
+
+ nr = *nr_entries;
+ if (!nr)
+ return ERROR_INVAL;
+
+ if (nr > E820MAX)
+ return ERROR_NOMEM;
+
+ /* Weed out anything under 16MB */
+ 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
+ * undersired 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 ++;
+
+ LIBXL__LOG(ctx, LIBXL__LOG_DEBUG, "Memory: %ldkB End of RAM: 0x%lx (PFN) "
\
+ "Delta: %ldkB, PCI start: %ldkB (0x%lx PFN), Balloon %ldkB\n",
+ map_limitkb, ram_end >> 12, delta_kb, start_kb ,start >> 12,
+ balloon_kb);
+
+ /* Check if there is a region between ram_end and start. */
+ if (start > ram_end) {
+ /* .. 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_. */
+ 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 == E820_UNUSABLE) ||
+ (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;
+
+ for (i = 0; i < nr; i++) {
+ LIBXL__LOG(ctx, LIBXL__LOG_DEBUG, ":%s\t[%lx -> %lx]",
+ e820[i].type == E820_RAM ? "RAM " :
+ (e820[i].type == E820_RESERVED ? "RSV " :
+ e820[i].type == E820_ACPI ? "ACPI" :
+ (e820[i].type == E820_NVS ? "NVS " :
+ (e820[i].type == E820_UNUSABLE ? "UNU " : "----"))),
+ e820[i].addr >> 12,
+ (e820[i].addr + e820[i].size) >> 12);
+ }
+
+ /* Done: copy the sanitized version. */
+ *nr_entries = nr;
+ memcpy(src, e820, nr * sizeof(struct e820entry));
+ return 0;
+}
+
+
+int libxl__e820_alloc(libxl_ctx *ctx, uint32_t domid, libxl_domain_config
*d_config)
+{
+ int rc;
+ uint32_t nr;
+ struct e820entry map[E820MAX];
+ libxl_domain_build_info *b_info;
+
+ if (d_config == NULL || d_config->c_info.hvm)
+ return ERROR_INVAL;
+
+ b_info = &d_config->b_info;
+ if (!b_info->u.pv.machine_e820)
+ return ERROR_INVAL;
+
+ rc = xc_get_machine_memory_map(ctx->xch, map, E820MAX);
+ if (rc < 0) {
+ errno = rc;
+ return ERROR_FAIL;
+ }
+ nr = rc;
+ rc = e820_sanitize(ctx, map, &nr, b_info->target_memkb,
+ (b_info->max_memkb - b_info->target_memkb) +
+ b_info->u.pv.slack_memkb);
+ if (rc)
+ return ERROR_FAIL;
+
+ rc = xc_domain_set_memory_map(ctx->xch, domid, map, nr);
+
+ if (rc < 0) {
+ errno = rc;
+ return ERROR_FAIL;
+ }
+ return 0;
+}
diff -r a81f4c7b4e39 tools/libxl/xl_cmdimpl.c
--- a/tools/libxl/xl_cmdimpl.c Tue Apr 12 14:46:05 2011 -0400
+++ b/tools/libxl/xl_cmdimpl.c Tue Apr 12 16:29:17 2011 -0400
@@ -373,6 +373,7 @@ static void printf_info(int domid,
printf("\t\t\t(kernel %s)\n", b_info->kernel.path);
printf("\t\t\t(cmdline %s)\n", b_info->u.pv.cmdline);
printf("\t\t\t(ramdisk %s)\n", b_info->u.pv.ramdisk.path);
+ printf("\t\t\t(machine_e820 %d)\n", b_info->u.pv.machine_e820);
printf("\t\t)\n");
}
printf("\t)\n");
@@ -984,6 +985,8 @@ skip_vfb:
if (!libxl_device_pci_parse_bdf(ctx, pcidev, buf))
d_config->num_pcidevs++;
}
+ if (d_config->num_pcidevs && !c_info->hvm)
+ b_info->u.pv.machine_e820 = true;
}
switch (xlu_cfg_get_list(config, "cpuid", &cpuids, 0, 1)) {
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