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Re: [Xen-devel] [v3][PATCH 13/16] tools/libxl: detect and avoid conflicts with RDM
- To: "Tian, Kevin" <kevin.tian@xxxxxxxxx>, "jbeulich@xxxxxxxx" <jbeulich@xxxxxxxx>, "tim@xxxxxxx" <tim@xxxxxxx>, "andrew.cooper3@xxxxxxxxxx" <andrew.cooper3@xxxxxxxxxx>, "Zhang, Yang Z" <yang.z.zhang@xxxxxxxxx>, "wei.liu2@xxxxxxxxxx" <wei.liu2@xxxxxxxxxx>, "ian.campbell@xxxxxxxxxx" <ian.campbell@xxxxxxxxxx>, "Ian.Jackson@xxxxxxxxxxxxx" <Ian.Jackson@xxxxxxxxxxxxx>, "stefano.stabellini@xxxxxxxxxx" <stefano.stabellini@xxxxxxxxxx>
- From: "Chen, Tiejun" <tiejun.chen@xxxxxxxxx>
- Date: Fri, 12 Jun 2015 16:30:47 +0800
- Cc: "xen-devel@xxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxx>
- Delivery-date: Fri, 12 Jun 2015 08:31:07 +0000
- List-id: Xen developer discussion <xen-devel.lists.xen.org>
On 2015/6/11 18:19, Tian, Kevin wrote:
From: Chen, Tiejun
Sent: Thursday, June 11, 2015 9:15 AM
While building a VM, HVM domain builder provides struct hvm_info_table{}
to help hvmloader. Currently it includes two fields to construct guest
e820 table by hvmloader, low_mem_pgend and high_mem_pgend. So we should
check them to fix any conflict with RAM.
RMRR can reside in address space beyond 4G theoretically, but we never
see this in real world. So in order to avoid breaking highmem layout
we don't solve highmem conflict. Note this means highmem rmrr could still
be supported if no conflict.
But in the case of lowmem, RMRR probably scatter the whole RAM space.
Especially multiple RMRR entries would worsen this to lead a complicated
memory layout. And then its hard to extend hvm_info_table{} to work
hvmloader out. So here we're trying to figure out a simple solution to
avoid breaking existing layout. So when a conflict occurs,
#1. Above a predefined boundary (default 2G)
- move lowmem_end below reserved region to solve conflict;
#2. Below a predefined boundary (default 2G)
- Check strict/relaxed policy.
"strict" policy leads to fail libxl. Note when both policies
are specified on a given region, 'strict' is always preferred.
"relaxed" policy issue a warning message and also mask this entry
INVALID
to indicate we shouldn't expose this entry to hvmloader.
Note this predefined boundary can be changes with the parameter
"rdm_mem_boundary" in .cfg file.
Signed-off-by: Tiejun Chen <tiejun.chen@xxxxxxxxx>
Reviewed-by: Kevin Tian <kevint.tian@xxxxxxxxx>
One comment though. could you be consistent to use RDM in the code?
RMRR is just an example of RDM...
Sure.
Thanks
Tiejun
---
docs/man/xl.cfg.pod.5 | 21 ++++
tools/libxc/xc_hvm_build_x86.c | 5 +-
tools/libxl/libxl.h | 6 +
tools/libxl/libxl_create.c | 6 +-
tools/libxl/libxl_dm.c | 255
+++++++++++++++++++++++++++++++++++++++++
tools/libxl/libxl_dom.c | 11 +-
tools/libxl/libxl_internal.h | 11 +-
tools/libxl/libxl_types.idl | 8 ++
tools/libxl/xl_cmdimpl.c | 3 +
9 files changed, 322 insertions(+), 4 deletions(-)
diff --git a/docs/man/xl.cfg.pod.5 b/docs/man/xl.cfg.pod.5
index 638b350..6fd2370 100644
--- a/docs/man/xl.cfg.pod.5
+++ b/docs/man/xl.cfg.pod.5
@@ -767,6 +767,27 @@ to a given device, and "strict" is default here.
Note this would override global B<rdm> option.
+=item B<rdm_mem_boundary=MBYTES>
+
+Number of megabytes to set a boundary for checking rdm conflict.
+
+When RDM conflicts with RAM, RDM probably scatter the whole RAM space.
+Especially multiple RMRR entries would worsen this to lead a complicated
+memory layout. So here we're trying to figure out a simple solution to
+avoid breaking existing layout. So when a conflict occurs,
+
+ #1. Above a predefined boundary
+ - move lowmem_end below reserved region to solve conflict;
+
+ #2. Below a predefined boundary
+ - Check strict/relaxed policy.
+ "strict" policy leads to fail libxl. Note when both policies
+ are specified on a given region, 'strict' is always preferred.
+ "relaxed" policy issue a warning message and also mask this entry
INVALID
+ to indicate we shouldn't expose this entry to hvmloader.
+
+Here the default is 2G.
+
=back
=back
diff --git a/tools/libxc/xc_hvm_build_x86.c b/tools/libxc/xc_hvm_build_x86.c
index 0e98c84..5142578 100644
--- a/tools/libxc/xc_hvm_build_x86.c
+++ b/tools/libxc/xc_hvm_build_x86.c
@@ -21,6 +21,7 @@
#include <stdlib.h>
#include <unistd.h>
#include <zlib.h>
+#include <assert.h>
#include "xg_private.h"
#include "xc_private.h"
@@ -270,7 +271,7 @@ static int setup_guest(xc_interface *xch,
elf_parse_binary(&elf);
v_start = 0;
- v_end = args->mem_size;
+ v_end = args->lowmem_end;
if ( nr_pages > target_pages )
memflags |= XENMEMF_populate_on_demand;
@@ -754,6 +755,8 @@ int xc_hvm_build_target_mem(xc_interface *xch,
args.mem_size = (uint64_t)memsize << 20;
args.mem_target = (uint64_t)target << 20;
args.image_file_name = image_name;
+ if ( args.mmio_size == 0 )
+ args.mmio_size = HVM_BELOW_4G_MMIO_LENGTH;
return xc_hvm_build(xch, domid, &args);
}
diff --git a/tools/libxl/libxl.h b/tools/libxl/libxl.h
index 0a7913b..a6212fb 100644
--- a/tools/libxl/libxl.h
+++ b/tools/libxl/libxl.h
@@ -858,6 +858,12 @@ const char *libxl_defbool_to_string(libxl_defbool b);
#define LIBXL_TIMER_MODE_DEFAULT -1
#define LIBXL_MEMKB_DEFAULT ~0ULL
+/*
+ * We'd like to set a memory boundary to determine if we need to check
+ * any overlap with reserved device memory.
+ */
+#define LIBXL_RDM_MEM_BOUNDARY_MEMKB_DEFAULT (2048 * 1024)
+
#define LIBXL_MS_VM_GENID_LEN 16
typedef struct {
uint8_t bytes[LIBXL_MS_VM_GENID_LEN];
diff --git a/tools/libxl/libxl_create.c b/tools/libxl/libxl_create.c
index 6c8ec63..0438731 100644
--- a/tools/libxl/libxl_create.c
+++ b/tools/libxl/libxl_create.c
@@ -109,6 +109,10 @@ void libxl__rdm_setdefault(libxl__gc *gc,
libxl_domain_build_info
*b_info)
{
if (b_info->rdm.reserve == LIBXL_RDM_RESERVE_FLAG_INVALID)
b_info->rdm.reserve = LIBXL_RDM_RESERVE_FLAG_RELAXED;
+
+ if (b_info->rdm_mem_boundary_memkb == LIBXL_MEMKB_DEFAULT)
+ b_info->rdm_mem_boundary_memkb =
+ LIBXL_RDM_MEM_BOUNDARY_MEMKB_DEFAULT;
}
int libxl__domain_build_info_setdefault(libxl__gc *gc,
@@ -460,7 +464,7 @@ int libxl__domain_build(libxl__gc *gc,
switch (info->type) {
case LIBXL_DOMAIN_TYPE_HVM:
- ret = libxl__build_hvm(gc, domid, info, state);
+ ret = libxl__build_hvm(gc, domid, d_config, state);
if (ret)
goto out;
diff --git a/tools/libxl/libxl_dm.c b/tools/libxl/libxl_dm.c
index 33f9ce6..d908350 100644
--- a/tools/libxl/libxl_dm.c
+++ b/tools/libxl/libxl_dm.c
@@ -90,6 +90,261 @@ const char *libxl__domain_device_model(libxl__gc *gc,
return dm;
}
+static struct xen_reserved_device_memory
+*xc_device_get_rdm(libxl__gc *gc,
+ uint32_t flag,
+ uint16_t seg,
+ uint8_t bus,
+ uint8_t devfn,
+ unsigned int *nr_entries)
+{
+ struct xen_reserved_device_memory *xrdm;
+ int rc;
+
+ rc = xc_reserved_device_memory_map(CTX->xch, flag, seg, bus, devfn,
+ NULL, nr_entries);
+ assert(rc <= 0);
+ /* "0" means we have no any rdm entry. */
+ if (!rc)
+ goto out;
+
+ if (errno == ENOBUFS) {
+ xrdm = malloc(*nr_entries * sizeof(xen_reserved_device_memory_t));
+ if (!xrdm) {
+ LOG(ERROR, "Could not allocate RDM buffer!\n");
+ goto out;
+ }
+ rc = xc_reserved_device_memory_map(CTX->xch, flag, seg, bus, devfn,
+ xrdm, nr_entries);
+ if (rc) {
+ LOG(ERROR, "Could not get reserved device memory maps.\n");
+ *nr_entries = 0;
+ free(xrdm);
+ xrdm = NULL;
+ }
+ } else
+ LOG(ERROR, "Could not get reserved device memory maps.\n");
+
+ out:
+ return xrdm;
+}
+
+/*
+ * Check whether there exists rdm hole in the specified memory range.
+ * Returns true if exists, else returns false.
+ */
+static bool overlaps_rdm(uint64_t start, uint64_t memsize,
+ uint64_t rdm_start, uint64_t rdm_size)
+{
+ return (start + memsize > rdm_start) && (start < rdm_start + rdm_size);
+}
+
+/*
+ * Check reported RDM regions and handle potential gfn conflicts according
+ * to user preferred policy.
+ *
+ * RMRR can reside in address space beyond 4G theoretically, but we never
+ * see this in real world. So in order to avoid breaking highmem layout
+ * we don't solve highmem conflict. Note this means highmem rmrr could still
+ * be supported if no conflict.
+ *
+ * But in the case of lowmem, RMRR probably scatter the whole RAM space.
+ * Especially multiple RMRR entries would worsen this to lead a complicated
+ * memory layout. And then its hard to extend hvm_info_table{} to work
+ * hvmloader out. So here we're trying to figure out a simple solution to
+ * avoid breaking existing layout. So when a conflict occurs,
+ *
+ * #1. Above a predefined boundary (default 2G)
+ * - Move lowmem_end below reserved region to solve conflict;
+ *
+ * #2. Below a predefined boundary (default 2G)
+ * - Check strict/relaxed policy.
+ * "strict" policy leads to fail libxl. Note when both policies
+ * are specified on a given region, 'strict' is always preferred.
+ * "relaxed" policy issue a warning message and also mask this entry
+ * INVALID to indicate we shouldn't expose this entry to hvmloader.
+ */
+int libxl__domain_device_construct_rdm(libxl__gc *gc,
+ libxl_domain_config *d_config,
+ uint64_t rdm_mem_boundary,
+ struct xc_hvm_build_args *args)
+{
+ int i, j, conflict;
+ struct xen_reserved_device_memory *xrdm = NULL;
+ uint32_t type = d_config->b_info.rdm.type;
+ uint16_t seg;
+ uint8_t bus, devfn;
+ uint64_t rdm_start, rdm_size;
+ uint64_t highmem_end = args->highmem_end ? args->highmem_end : (1ull<<32);
+
+ /* Might not expose rdm. */
+ if (type == LIBXL_RDM_RESERVE_TYPE_NONE && !d_config->num_pcidevs)
+ return 0;
+
+ /* Query all RDM entries in this platform */
+ if (type == LIBXL_RDM_RESERVE_TYPE_HOST) {
+ unsigned int nr_entries;
+
+ /* Collect all rdm info if exist. */
+ xrdm = xc_device_get_rdm(gc, PCI_DEV_RDM_ALL,
+ 0, 0, 0, &nr_entries);
+ if (!nr_entries)
+ return 0;
+
+ assert(xrdm);
+
+ d_config->num_rdms = nr_entries;
+ d_config->rdms = libxl__realloc(NOGC, d_config->rdms,
+ d_config->num_rdms * sizeof(libxl_device_rdm));
+
+ for (i = 0; i < d_config->num_rdms; i++) {
+ d_config->rdms[i].start =
+ (uint64_t)xrdm[i].start_pfn << XC_PAGE_SHIFT;
+ d_config->rdms[i].size =
+ (uint64_t)xrdm[i].nr_pages << XC_PAGE_SHIFT;
+ d_config->rdms[i].flag = d_config->b_info.rdm.reserve;
+ }
+
+ free(xrdm);
+ } else
+ d_config->num_rdms = 0;
+
+ /* Query RDM entries per-device */
+ for (i = 0; i < d_config->num_pcidevs; i++) {
+ unsigned int nr_entries;
+ bool new = true;
+
+ seg = d_config->pcidevs[i].domain;
+ bus = d_config->pcidevs[i].bus;
+ devfn = PCI_DEVFN(d_config->pcidevs[i].dev, d_config->pcidevs[i].func);
+ nr_entries = 0;
+ xrdm = xc_device_get_rdm(gc, ~PCI_DEV_RDM_ALL,
+ seg, bus, devfn, &nr_entries);
+ /* No RDM to associated with this device. */
+ if (!nr_entries)
+ continue;
+
+ assert(xrdm);
+
+ /*
+ * Need to check whether this entry is already saved in the array.
+ * This could come from two cases:
+ *
+ * - user may configure to get all RMRRs in this platform, which
+ * is already queried before this point
+ * - or two assigned devices may share one RMRR entry
+ *
+ * different policies may be configured on the same RMRR due to above
+ * two cases. We choose a simple policy to always favor stricter policy
+ */
+ for (j = 0; j < d_config->num_rdms; j++) {
+ if (d_config->rdms[j].start ==
+ (uint64_t)xrdm[0].start_pfn << XC_PAGE_SHIFT)
+ {
+ if (d_config->rdms[j].flag != LIBXL_RDM_RESERVE_FLAG_STRICT)
+ d_config->rdms[j].flag = d_config->pcidevs[i].rdm_reserve;
+ new = false;
+ break;
+ }
+ }
+
+ if (new) {
+ d_config->num_rdms++;
+ d_config->rdms = libxl__realloc(NOGC, d_config->rdms,
+ d_config->num_rdms * sizeof(libxl_device_rdm));
+
+ d_config->rdms[d_config->num_rdms - 1].start =
+ (uint64_t)xrdm[0].start_pfn << XC_PAGE_SHIFT;
+ d_config->rdms[d_config->num_rdms - 1].size =
+ (uint64_t)xrdm[0].nr_pages << XC_PAGE_SHIFT;
+ d_config->rdms[d_config->num_rdms - 1].flag =
+ d_config->pcidevs[i].rdm_reserve;
+ }
+ free(xrdm);
+ }
+
+ /*
+ * Next step is to check and avoid potential conflict between RDM entries
+ * and guest RAM. To avoid intrusive impact to existing memory layout
+ * {lowmem, mmio, highmem} which is passed around various function blocks,
+ * below conflicts are not handled which are rare and handling them would
+ * lead to a more scattered layout:
+ * - RMRR in highmem area (>4G)
+ * - RMRR lower than a defined memory boundary (e.g. 2G)
+ * Otherwise for conflicts between boundary and 4G, we'll simply move
lowmem
+ * end below reserved region to solve conflict.
+ *
+ * If a conflict is detected on a given RMRR entry, an error will be
+ * returned if 'strict' policy is specified. Instead, if 'relaxed' policy
+ * specified, this conflict is treated just as a warning, but we mark this
+ * RMRR entry as INVALID to indicate that this entry shouldn't be exposed
+ * to hvmloader.
+ *
+ * Firstly we should check the case of rdm < 4G because we may need to
+ * expand highmem_end.
+ */
+ for (i = 0; i < d_config->num_rdms; i++) {
+ rdm_start = d_config->rdms[i].start;
+ rdm_size = d_config->rdms[i].size;
+ conflict = overlaps_rdm(0, args->lowmem_end, rdm_start, rdm_size);
+
+ if (!conflict)
+ continue;
+
+ /* Just check if RDM > our memory boundary. */
+ if (rdm_start > rdm_mem_boundary) {
+ /*
+ * We will move downwards lowmem_end so we have to expand
+ * highmem_end.
+ */
+ highmem_end += (args->lowmem_end - rdm_start);
+ /* Now move downwards lowmem_end. */
+ args->lowmem_end = rdm_start;
+ }
+ }
+
+ /* Sync highmem_end. */
+ args->highmem_end = highmem_end;
+
+ /*
+ * Finally we can take same policy to check lowmem(< 2G) and
+ * highmem adjusted above.
+ */
+ for (i = 0; i < d_config->num_rdms; i++) {
+ rdm_start = d_config->rdms[i].start;
+ rdm_size = d_config->rdms[i].size;
+ /* Does this entry conflict with lowmem? */
+ conflict = overlaps_rdm(0, args->lowmem_end,
+ rdm_start, rdm_size);
+ /* Does this entry conflict with highmem? */
+ conflict |= overlaps_rdm((1ULL<<32),
+ args->highmem_end - (1ULL<<32),
+ rdm_start, rdm_size);
+
+ if (!conflict)
+ continue;
+
+ if(d_config->rdms[i].flag == LIBXL_RDM_RESERVE_FLAG_STRICT) {
+ LOG(ERROR, "RDM conflict at 0x%lx.\n", d_config->rdms[i].start);
+ goto out;
+ } else {
+ LOG(WARN, "Ignoring RDM conflict at 0x%lx.\n",
+ d_config->rdms[i].start);
+
+ /*
+ * Then mask this INVALID to indicate we shouldn't expose this
+ * to hvmloader.
+ */
+ d_config->rdms[i].flag = LIBXL_RDM_RESERVE_FLAG_INVALID;
+ }
+ }
+
+ return 0;
+
+ out:
+ return ERROR_FAIL;
+}
+
const libxl_vnc_info *libxl__dm_vnc(const libxl_domain_config *guest_config)
{
const libxl_vnc_info *vnc = NULL;
diff --git a/tools/libxl/libxl_dom.c b/tools/libxl/libxl_dom.c
index 867172a..1777b32 100644
--- a/tools/libxl/libxl_dom.c
+++ b/tools/libxl/libxl_dom.c
@@ -914,13 +914,14 @@ out:
}
int libxl__build_hvm(libxl__gc *gc, uint32_t domid,
- libxl_domain_build_info *info,
+ libxl_domain_config *d_config,
libxl__domain_build_state *state)
{
libxl_ctx *ctx = libxl__gc_owner(gc);
struct xc_hvm_build_args args = {};
int ret, rc = ERROR_FAIL;
uint64_t mmio_start, lowmem_end, highmem_end;
+ libxl_domain_build_info *const info = &d_config->b_info;
memset(&args, 0, sizeof(struct xc_hvm_build_args));
/* The params from the configuration file are in Mb, which are then
@@ -958,6 +959,14 @@ int libxl__build_hvm(libxl__gc *gc, uint32_t domid,
args.highmem_end = highmem_end;
args.mmio_start = mmio_start;
+ ret = libxl__domain_device_construct_rdm(gc, d_config,
+ info->rdm_mem_boundary_memkb*1024,
+ &args);
+ if (ret) {
+ LOG(ERROR, "checking reserved device memory failed");
+ goto out;
+ }
+
if (info->num_vnuma_nodes != 0) {
int i;
diff --git a/tools/libxl/libxl_internal.h b/tools/libxl/libxl_internal.h
index e9ac886..52f3831 100644
--- a/tools/libxl/libxl_internal.h
+++ b/tools/libxl/libxl_internal.h
@@ -1011,7 +1011,7 @@ _hidden int libxl__build_post(libxl__gc *gc, uint32_t
domid,
_hidden int libxl__build_pv(libxl__gc *gc, uint32_t domid,
libxl_domain_build_info *info, libxl__domain_build_state *state);
_hidden int libxl__build_hvm(libxl__gc *gc, uint32_t domid,
- libxl_domain_build_info *info,
+ libxl_domain_config *d_config,
libxl__domain_build_state *state);
_hidden int libxl__qemu_traditional_cmd(libxl__gc *gc, uint32_t domid,
@@ -1519,6 +1519,15 @@ _hidden int libxl__need_xenpv_qemu(libxl__gc *gc,
int nr_channels, libxl_device_channel *channels);
/*
+ * This function will fix reserved device memory conflict
+ * according to user's configuration.
+ */
+_hidden int libxl__domain_device_construct_rdm(libxl__gc *gc,
+ libxl_domain_config *d_config,
+ uint64_t rdm_mem_guard,
+ struct xc_hvm_build_args *args);
+
+/*
* This function will cause the whole libxl process to hang
* if the device model does not respond. It is deprecated.
*
diff --git a/tools/libxl/libxl_types.idl b/tools/libxl/libxl_types.idl
index 4dfcaf7..b4282a0 100644
--- a/tools/libxl/libxl_types.idl
+++ b/tools/libxl/libxl_types.idl
@@ -395,6 +395,7 @@ libxl_domain_build_info = Struct("domain_build_info",[
("target_memkb", MemKB),
("video_memkb", MemKB),
("shadow_memkb", MemKB),
+ ("rdm_mem_boundary_memkb", MemKB),
("rtc_timeoffset", uint32),
("exec_ssidref", uint32),
("exec_ssid_label", string),
@@ -559,6 +560,12 @@ libxl_device_pci = Struct("device_pci", [
("rdm_reserve", libxl_rdm_reserve_flag),
])
+libxl_device_rdm = Struct("device_rdm", [
+ ("start", uint64),
+ ("size", uint64),
+ ("flag", libxl_rdm_reserve_flag),
+ ])
+
libxl_device_dtdev = Struct("device_dtdev", [
("path", string),
])
@@ -589,6 +596,7 @@ libxl_domain_config = Struct("domain_config", [
("disks", Array(libxl_device_disk, "num_disks")),
("nics", Array(libxl_device_nic, "num_nics")),
("pcidevs", Array(libxl_device_pci, "num_pcidevs")),
+ ("rdms", Array(libxl_device_rdm, "num_rdms")),
("dtdevs", Array(libxl_device_dtdev, "num_dtdevs")),
("vfbs", Array(libxl_device_vfb, "num_vfbs")),
("vkbs", Array(libxl_device_vkb, "num_vkbs")),
diff --git a/tools/libxl/xl_cmdimpl.c b/tools/libxl/xl_cmdimpl.c
index 4364ba4..85d74fd 100644
--- a/tools/libxl/xl_cmdimpl.c
+++ b/tools/libxl/xl_cmdimpl.c
@@ -1374,6 +1374,9 @@ static void parse_config_data(const char *config_source,
if (!xlu_cfg_get_long (config, "videoram", &l, 0))
b_info->video_memkb = l * 1024;
+ if (!xlu_cfg_get_long (config, "rdm_mem_boundary", &l, 0))
+ b_info->rdm_mem_boundary_memkb = l * 1024;
+
if (!xlu_cfg_get_long(config, "max_event_channels", &l, 0))
b_info->event_channels = l;
--
1.9.1
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