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Re: [Xen-devel] [PATCH v5 1/1] Add mmio_hole_size
On 09/11/2014 12:20 PM, Don Slutz wrote:
If you add enough PCI devices then all mmio may not fit below 4G
which may not be the layout the user wanted. This allows you to
increase the below 4G address space that PCI devices can use and
therefore in more cases not have any mmio that is above 4G.
There are real PCI cards that do not support mmio over 4G, so if you
want to emulate them precisely, you may also need to increase the
space below 4G for them. There are drivers for these cards that also
do not work if they have their mmio space mapped above 4G.
This allows growing the MMIO hole to the size needed.
This may help with using pci passthru and HVM.
Signed-off-by: Don Slutz <dslutz@xxxxxxxxxxx>
---
v5:
Add LIBXL_HAVE_BUILDINFO_HVM_MMIO_HOLE_SIZE.
v4:
s/pci_hole_min_size/mmio_hole_size/
s/HVM_BELOW_4G_RAM_END/HVM_BELOW_4G_MMIO_START/
Add ignore to hvmloader message
Adjust commit message
Dropped min; stopped mmio_hole_size changing in hvmloader
docs/man/xl.cfg.pod.5 | 12 +++++++
tools/firmware/hvmloader/config.h | 1 -
tools/firmware/hvmloader/pci.c | 71 +++++++++++++++++++++++++++------------
tools/libxc/xc_hvm_build_x86.c | 30 +++++++++++++++--
tools/libxc/xenguest.h | 11 ++++++
tools/libxl/libxl.h | 5 +++
tools/libxl/libxl_create.c | 29 ++++++++++++----
tools/libxl/libxl_dm.c | 24 +++++++++++--
tools/libxl/libxl_dom.c | 3 +-
tools/libxl/libxl_types.idl | 1 +
tools/libxl/xl_cmdimpl.c | 13 +++++++
11 files changed, 166 insertions(+), 34 deletions(-)
diff --git a/docs/man/xl.cfg.pod.5 b/docs/man/xl.cfg.pod.5
index 517ae2f..45f7857 100644
--- a/docs/man/xl.cfg.pod.5
+++ b/docs/man/xl.cfg.pod.5
@@ -1111,6 +1111,18 @@ wallclock (i.e., real) time.
=back
+=head3 Memory layout
+
+=over 4
+
+=item B<mmio_hole_size=BYTES>
+
+Specifies the size the MMIO hole below 4GiB will be. Only valid for
+device_model_version = "qemu-xen". Note: this requires QEMU 2.1.0
+or later.
Can you add text describing restrictions on hole size? Not smaller than
256MB, I think.
+
+=back
+
=head3 Support for Paravirtualisation of HVM Guests
The following options allow Paravirtualised features (such as devices)
diff --git a/tools/firmware/hvmloader/config.h
b/tools/firmware/hvmloader/config.h
index 80bea46..b838cf9 100644
--- a/tools/firmware/hvmloader/config.h
+++ b/tools/firmware/hvmloader/config.h
@@ -53,7 +53,6 @@ extern struct bios_config ovmf_config;
#define PCI_ISA_IRQ_MASK 0x0c20U /* ISA IRQs 5,10,11 are PCI connected */
/* MMIO hole: Hardcoded defaults, which can be dynamically expanded. */
-#define PCI_MEM_START 0xf0000000
#define PCI_MEM_END 0xfc000000
extern unsigned long pci_mem_start, pci_mem_end;
diff --git a/tools/firmware/hvmloader/pci.c b/tools/firmware/hvmloader/pci.c
index 3712988..e5cd2e3 100644
--- a/tools/firmware/hvmloader/pci.c
+++ b/tools/firmware/hvmloader/pci.c
@@ -28,9 +28,10 @@
#include <xen/memory.h>
#include <xen/hvm/ioreq.h>
#include <xen/hvm/hvm_xs_strings.h>
+#include <xen/hvm/e820.h>
#include <stdbool.h>
-unsigned long pci_mem_start = PCI_MEM_START;
+unsigned long pci_mem_start = HVM_BELOW_4G_MMIO_START;
unsigned long pci_mem_end = PCI_MEM_END;
uint64_t pci_hi_mem_start = 0, pci_hi_mem_end = 0;
@@ -59,6 +60,7 @@ void pci_setup(void)
uint64_t bar_sz;
} *bars = (struct bars *)scratch_start;
unsigned int i, nr_bars = 0;
+ uint64_t mmio_hole_size = 0;
const char *s;
/*
@@ -86,6 +88,10 @@ void pci_setup(void)
printf("Relocating guest memory for lowmem MMIO space %s\n",
allow_memory_relocate?"enabled":"disabled");
+ s = xenstore_read("platform/mmio_hole_size", NULL);
+ if ( s )
+ mmio_hole_size = strtoll(s, NULL, 0);
+
/* Program PCI-ISA bridge with appropriate link routes. */
isa_irq = 0;
for ( link = 0; link < 4; link++ )
@@ -237,26 +243,49 @@ void pci_setup(void)
pci_writew(devfn, PCI_COMMAND, cmd);
}
- /*
- * At the moment qemu-xen can't deal with relocated memory regions.
- * It's too close to the release to make a proper fix; for now,
- * only allow the MMIO hole to grow large enough to move guest memory
- * if we're running qemu-traditional. Items that don't fit will be
- * relocated into the 64-bit address space.
- *
- * This loop now does the following:
- * - If allow_memory_relocate, increase the MMIO hole until it's
- * big enough, or until it's 2GiB
- * - If !allow_memory_relocate, increase the MMIO hole until it's
- * big enough, or until it's 2GiB, or until it overlaps guest
- * memory
- */
- while ( (mmio_total > (pci_mem_end - pci_mem_start))
- && ((pci_mem_start << 1) != 0)
- && (allow_memory_relocate
- || (((pci_mem_start << 1) >> PAGE_SHIFT)
- >= hvm_info->low_mem_pgend)) )
- pci_mem_start <<= 1;
+ if ( mmio_hole_size )
+ {
+ uint64_t max_ram_below_4g = (1ULL << 32) - mmio_hole_size;
+
+ if ( max_ram_below_4g > HVM_BELOW_4G_MMIO_START )
+ {
+ printf("max_ram_below_4g=0x"PRIllx
+ " too big for mmio_hole_size=0x"PRIllx
+ " has been ignored.\n",
+ PRIllx_arg(max_ram_below_4g),
+ PRIllx_arg(mmio_hole_size));
+ }
Do you need to check whether the hole is too large?
Here and in the toolstack.
+ else
+ {
+ pci_mem_start = max_ram_below_4g;
+ printf("pci_mem_start=0x%lx (was 0x%x) for mmio_hole_size=%lu\n",
+ pci_mem_start, HVM_BELOW_4G_MMIO_START,
+ (long)mmio_hole_size);
+ }
+ }
+ else
+ {
+ /*
+ * At the moment qemu-xen can't deal with relocated memory regions.
+ * It's too close to the release to make a proper fix; for now,
+ * only allow the MMIO hole to grow large enough to move guest memory
+ * if we're running qemu-traditional. Items that don't fit will be
+ * relocated into the 64-bit address space.
+ *
+ * This loop now does the following:
+ * - If allow_memory_relocate, increase the MMIO hole until it's
+ * big enough, or until it's 2GiB
+ * - If !allow_memory_relocate, increase the MMIO hole until it's
+ * big enough, or until it's 2GiB, or until it overlaps guest
+ * memory
+ */
+ while ( (mmio_total > (pci_mem_end - pci_mem_start))
+ && ((pci_mem_start << 1) != 0)
+ && (allow_memory_relocate
+ || (((pci_mem_start << 1) >> PAGE_SHIFT)
+ >= hvm_info->low_mem_pgend)) )
+ pci_mem_start <<= 1;
+ }
if ( mmio_total > (pci_mem_end - pci_mem_start) )
{
diff --git a/tools/libxc/xc_hvm_build_x86.c b/tools/libxc/xc_hvm_build_x86.c
index c81a25b..94da7fa 100644
--- a/tools/libxc/xc_hvm_build_x86.c
+++ b/tools/libxc/xc_hvm_build_x86.c
@@ -628,14 +628,40 @@ int xc_hvm_build_target_mem(xc_interface *xch,
int target,
const char *image_name)
{
+ return xc_hvm_build_target_mem_with_hole(xch, domid, memsize, target,
+ image_name, 0);
+}
+
+int xc_hvm_build_with_hole(xc_interface *xch, uint32_t domid,
+ struct xc_hvm_build_args *args,
+ uint64_t mmio_hole_size)
+{
+ if (mmio_hole_size)
+ {
+ uint64_t max_ram_below_4g = (1ULL << 32) - mmio_hole_size;
+
+ if (max_ram_below_4g < HVM_BELOW_4G_MMIO_START)
"<=", to be consistent with the check in
libxl__domain_create_info_setdefault ().
+ {
+ args->mmio_size = mmio_hole_size;
+ }
+ }
+ return xc_hvm_build(xch, domid, args);
+}
+
+int xc_hvm_build_target_mem_with_hole(xc_interface *xch,
+ uint32_t domid,
+ int memsize,
+ int target,
+ const char *image_name,
+ uint64_t mmio_hole_size)
+{
struct xc_hvm_build_args args = {};
memset(&args, 0, sizeof(struct xc_hvm_build_args));
args.mem_size = (uint64_t)memsize << 20;
args.mem_target = (uint64_t)target << 20;
args.image_file_name = image_name;
-
- return xc_hvm_build(xch, domid, &args);
+ return xc_hvm_build_with_hole(xch, domid, &args, mmio_hole_size);
}
/*
diff --git a/tools/libxc/xenguest.h b/tools/libxc/xenguest.h
index 40bbac8..d35f38d 100644
--- a/tools/libxc/xenguest.h
+++ b/tools/libxc/xenguest.h
@@ -244,12 +244,23 @@ struct xc_hvm_build_args {
int xc_hvm_build(xc_interface *xch, uint32_t domid,
struct xc_hvm_build_args *hvm_args);
+int xc_hvm_build_with_hole(xc_interface *xch, uint32_t domid,
+ struct xc_hvm_build_args *args,
+ uint64_t mmio_hole_size);
+
int xc_hvm_build_target_mem(xc_interface *xch,
uint32_t domid,
int memsize,
int target,
const char *image_name);
+int xc_hvm_build_target_mem_with_hole(xc_interface *xch,
+ uint32_t domid,
+ int memsize,
+ int target,
+ const char *image_name,
+ uint64_t mmio_hole_size);
+
/*
* Sets *lockfd to -1.
* Has deallocated everything even on error.
diff --git a/tools/libxl/libxl.h b/tools/libxl/libxl.h
index dab3a67..e43d2d2 100644
--- a/tools/libxl/libxl.h
+++ b/tools/libxl/libxl.h
@@ -138,6 +138,11 @@
#define LIBXL_HAVE_BUILDINFO_IOMEM_START_GFN 1
/*
+ * libxl_domain_build_info has the u.hvm.mmio_hole_size field.
+ */
+#define LIBXL_HAVE_BUILDINFO_HVM_MMIO_HOLE_SIZE 1
+
+/*
* libxl ABI compatibility
*
* The only guarantee which libxl makes regarding ABI compatibility
diff --git a/tools/libxl/libxl_create.c b/tools/libxl/libxl_create.c
index b36c719..7383053 100644
--- a/tools/libxl/libxl_create.c
+++ b/tools/libxl/libxl_create.c
@@ -23,6 +23,7 @@
#include <xc_dom.h>
#include <xenguest.h>
#include <xen/hvm/hvm_info_table.h>
+#include <xen/hvm/e820.h>
int libxl__domain_create_info_setdefault(libxl__gc *gc,
libxl_domain_create_info *c_info)
@@ -428,13 +429,26 @@ int libxl__domain_build(libxl__gc *gc,
vments[4] = "start_time";
vments[5] = libxl__sprintf(gc, "%lu.%02d",
start_time.tv_sec,(int)start_time.tv_usec/10000);
- localents = libxl__calloc(gc, 7, sizeof(char *));
- localents[0] = "platform/acpi";
- localents[1] = libxl_defbool_val(info->u.hvm.acpi) ? "1" : "0";
- localents[2] = "platform/acpi_s3";
- localents[3] = libxl_defbool_val(info->u.hvm.acpi_s3) ? "1" : "0";
- localents[4] = "platform/acpi_s4";
- localents[5] = libxl_defbool_val(info->u.hvm.acpi_s4) ? "1" : "0";
+ localents = libxl__calloc(gc, 9, sizeof(char *));
+ i = 0;
+ localents[i++] = "platform/acpi";
+ localents[i++] = libxl_defbool_val(info->u.hvm.acpi) ? "1" : "0";
+ localents[i++] = "platform/acpi_s3";
+ localents[i++] = libxl_defbool_val(info->u.hvm.acpi_s3) ? "1" : "0";
+ localents[i++] = "platform/acpi_s4";
+ localents[i++] = libxl_defbool_val(info->u.hvm.acpi_s4) ? "1" : "0";
+ if (info->u.hvm.mmio_hole_size) {
+ uint64_t max_ram_below_4g =
+ (1ULL << 32) - info->u.hvm.mmio_hole_size;
+
+ if (max_ram_below_4g <= HVM_BELOW_4G_MMIO_START) {
You seem to be making various checks on hole size in multiple places ---
here, in libxl__build_device_model_args_new() and in
parse_config_data(). (And, to some degree, in xc_hvm_build_with_hole()).
Are they all necessary?
-boris
+ localents[i++] = "platform/mmio_hole_size";
+ localents[i++] =
+ libxl__sprintf(gc, "%"PRIu64,
+ info->u.hvm.mmio_hole_size);
+ }
+ }
+ assert(i < 9);
break;
case LIBXL_DOMAIN_TYPE_PV:
@@ -460,6 +474,7 @@ int libxl__domain_build(libxl__gc *gc,
vments[i++] = "image/cmdline";
vments[i++] = (char *) state->pv_cmdline;
}
+ assert(i < 11);
break;
default:
diff --git a/tools/libxl/libxl_dm.c b/tools/libxl/libxl_dm.c
index 103cbca..099a960 100644
--- a/tools/libxl/libxl_dm.c
+++ b/tools/libxl/libxl_dm.c
@@ -18,6 +18,7 @@
#include "libxl_osdeps.h" /* must come before any other headers */
#include "libxl_internal.h"
+#include <xen/hvm/e820.h>
static const char *libxl_tapif_script(libxl__gc *gc)
{
@@ -415,6 +416,7 @@ static char ** libxl__build_device_model_args_new(libxl__gc
*gc,
const libxl_vnc_info *vnc = libxl__dm_vnc(guest_config);
const libxl_sdl_info *sdl = dm_sdl(guest_config);
const char *keymap = dm_keymap(guest_config);
+ char *machinearg;
flexarray_t *dm_args;
int i;
uint64_t ram_size;
@@ -696,10 +698,28 @@ static char **
libxl__build_device_model_args_new(libxl__gc *gc,
/* Switching here to the machine "pc" which does not add
* the xen-platform device instead of the default "xenfv" machine.
*/
- flexarray_append(dm_args, "pc,accel=xen");
+ machinearg = libxl__sprintf(gc, "pc,accel=xen");
} else {
- flexarray_append(dm_args, "xenfv");
+ machinearg = libxl__sprintf(gc, "xenfv");
}
+ if (b_info->u.hvm.mmio_hole_size) {
+ uint64_t max_ram_below_4g = (1ULL << 32) -
+ b_info->u.hvm.mmio_hole_size;
+
+ if (max_ram_below_4g > HVM_BELOW_4G_MMIO_START) {
+ LIBXL__LOG(ctx, LIBXL__LOG_WARNING,
+ "max-ram-below-4g=%"PRIu64
+ " (mmio_hole_size=%"PRIu64
+ ") too big > %u ignored.\n",
+ max_ram_below_4g,
+ b_info->u.hvm.mmio_hole_size,
+ HVM_BELOW_4G_MMIO_START);
+ } else {
+ machinearg = libxl__sprintf(gc, "%s,max-ram-below-4g=%"PRIu64,
+ machinearg, max_ram_below_4g);
+ }
+ }
+ flexarray_append(dm_args, machinearg);
for (i = 0; b_info->extra_hvm && b_info->extra_hvm[i] != NULL; i++)
flexarray_append(dm_args, b_info->extra_hvm[i]);
break;
diff --git a/tools/libxl/libxl_dom.c b/tools/libxl/libxl_dom.c
index 0dfdb08..a3a56f5 100644
--- a/tools/libxl/libxl_dom.c
+++ b/tools/libxl/libxl_dom.c
@@ -728,7 +728,8 @@ int libxl__build_hvm(libxl__gc *gc, uint32_t domid,
goto out;
}
- ret = xc_hvm_build(ctx->xch, domid, &args);
+ ret = xc_hvm_build_with_hole(ctx->xch, domid, &args,
+ info->u.hvm.mmio_hole_size);
if (ret) {
LOGEV(ERROR, ret, "hvm building failed");
goto out;
diff --git a/tools/libxl/libxl_types.idl b/tools/libxl/libxl_types.idl
index f1fcbc3..c912b18 100644
--- a/tools/libxl/libxl_types.idl
+++ b/tools/libxl/libxl_types.idl
@@ -378,6 +378,7 @@ libxl_domain_build_info = Struct("domain_build_info",[
("timeoffset", string),
("hpet", libxl_defbool),
("vpt_align", libxl_defbool),
+ ("mmio_hole_size", UInt(64, init_val
= 0)),
("timer_mode", libxl_timer_mode),
("nested_hvm", libxl_defbool),
("smbios_firmware", string),
diff --git a/tools/libxl/xl_cmdimpl.c b/tools/libxl/xl_cmdimpl.c
index 8a38077..6c74fa9 100644
--- a/tools/libxl/xl_cmdimpl.c
+++ b/tools/libxl/xl_cmdimpl.c
@@ -34,6 +34,7 @@
#include <ctype.h>
#include <inttypes.h>
#include <limits.h>
+#include <xen/hvm/e820.h>
#include "libxl.h"
#include "libxl_utils.h"
@@ -1036,6 +1037,18 @@ static void parse_config_data(const char *config_source,
xlu_cfg_get_defbool(config, "hpet", &b_info->u.hvm.hpet, 0);
xlu_cfg_get_defbool(config, "vpt_align", &b_info->u.hvm.vpt_align, 0);
+ if (!xlu_cfg_get_long(config, "mmio_hole_size", &l, 0)) {
+ b_info->u.hvm.mmio_hole_size = (uint64_t) l;
+ if (b_info->u.hvm.mmio_hole_size < HVM_BELOW_4G_MMIO_LENGTH ||
+ b_info->u.hvm.mmio_hole_size > HVM_BELOW_4G_MMIO_START) {
+ fprintf(stderr, "ERROR: invalid value 0x%"PRIx64" (%"PRIu64
+ ") for \"mmio_hole_size\"\n",
+ b_info->u.hvm.mmio_hole_size,
+ b_info->u.hvm.mmio_hole_size);
+ exit (1);
+ }
+ }
+
if (!xlu_cfg_get_long(config, "timer_mode", &l, 1)) {
const char *s = libxl_timer_mode_to_string(l);
fprintf(stderr, "WARNING: specifying \"timer_mode\" as an integer is
deprecated. "
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