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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v2 4/4] x86/microcode: Support builtin CPU microcode
Xen relies on boot modules to perform early microcode updates. This commit adds
another mode, namely "builtin" via the BUILTIN_UCODE config parameter. If set,
the Xen image itself will contain the microcode updates. Upon boot, Xen
inspects its image for microcode blobs and performs the update.
A Xen image with builtin microcode will, by default, attempt the microcode
update. Disabling the builtin microcode update can be done via the Xen command
line parameter 'ucode=no-builtin'. Moreover, the microcode provided via other
options (such as 'ucode=<integer>|scan' or 'ucode=<filename>' config when
booting via EFI) takes precedence over the builtin one.
Signed-off-by: Eslam Elnikety <elnikety@xxxxxxxxxx>
---
Changes in v2:
- Allow for ucode=<integer>|scan,{no-}builtin and detail the model. Reflect
those changes onto microcode.c and docs/misc/xen-command-line.pandoc
- Add documentation to the existing docs/admin-guide/microcode-loading.rst
- Build on Patches 1--3 to avoid xmalloc/memcpy for the builtin microcode
- Work configuration in order to specify the individual microcode blobs to use
for the builtin microcode, and rework the microcode/Makefile accordingly
---
docs/admin-guide/microcode-loading.rst | 31 +++++++++++++++
docs/misc/xen-command-line.pandoc | 10 ++++-
xen/arch/x86/Kconfig | 30 +++++++++++++++
xen/arch/x86/Makefile | 1 +
xen/arch/x86/microcode.c | 52 ++++++++++++++++++++++++++
xen/arch/x86/microcode/Makefile | 46 +++++++++++++++++++++++
xen/arch/x86/xen.lds.S | 12 ++++++
7 files changed, 180 insertions(+), 2 deletions(-)
create mode 100644 xen/arch/x86/microcode/Makefile
diff --git a/docs/admin-guide/microcode-loading.rst
b/docs/admin-guide/microcode-loading.rst
index e83cadd2c2..989e8d446b 100644
--- a/docs/admin-guide/microcode-loading.rst
+++ b/docs/admin-guide/microcode-loading.rst
@@ -104,6 +104,37 @@ The ``ucode=scan`` command line option will cause Xen to
search through all
modules to find any CPIO archives, and search the archive for the applicable
file. Xen will stop searching at the first match.
+Loading microcode built within the Xen image
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Xen can bundle microcode updates within its image. This support is conditional
+on the build configuration BUILTIN_UCODE being enabled. Builtin microcode is
+useful to ensure that, by default, a minimum microcode patch level will be
+applied to the underlying CPU.
+
+To use microcode updates available on the build system as builtin,
+use BUILTIN_UCODE_DIR to refer to the directory containing the firmware updates
+and specify the individual microcode patches via either BUILTIN_UCODE_AMD or
+BUILTIN_UCODE_INTEL for AMD microcode or INTEL microcode, respectively. For
+instance, the configuration below is suitable for a build system which has a
+``/lib/firmware/`` directory which, in turn, includes the individual microcode
+patches ``amd-ucode/microcode_amd_fam15h.bin``, ``intel-ucode/06-3a-09``, and
+``intel-ucode/06-2f-02``.
+
+ CONFIG_BUILTIN_UCODE=y
+ CONFIG_BUILTIN_UCODE_DIR="/lib/firmware/"
+ CONFIG_BUILTIN_UCODE_AMD="amd-ucode/microcode_amd_fam15h.bin"
+ CONFIG_BUILTIN_UCODE_INTEL="intel-ucode/06-3a-09 intel-ucode/06-2f-02"
+
+Alternatively, CONFIG_BUILTIN_UCODE_{AMD,INTEL} can directly point to the
+concatenation of the individual microcode blobs. For instance, assuming that
+``amd-ucode/AuthenticAMD.bin`` and ``intel-ucode/GenuineIntel.bin`` hold
+multiple microcode updates for AMD and INTEL, respectively, you may use the
+configuration below.
+
+ CONFIG_BUILTIN_UCODE_AMD="amd-ucode/AuthenticAMD.bin"
+ CONFIG_BUILTIN_UCODE_INTEL="intel-ucode/GenuineIntel.bin"
+
Run time microcode loading
--------------------------
diff --git a/docs/misc/xen-command-line.pandoc
b/docs/misc/xen-command-line.pandoc
index 40faf3bc3a..9cfc2df05a 100644
--- a/docs/misc/xen-command-line.pandoc
+++ b/docs/misc/xen-command-line.pandoc
@@ -2126,10 +2126,10 @@ logic applies:
active by default.
### ucode (x86)
-> `= List of [ <integer> | scan=<bool>, nmi=<bool> ]`
+> `= List of [ <integer> | scan=<bool>, builtin=<bool>, nmi=<bool> ]`
Applicability: x86
- Default: `nmi`
+ Default: `nmi` if BUILTIN_UCODE is not enabled, `builtin,nmi` otherwise
Controls for CPU microcode loading. For early loading, this parameter can
specify how and where to find the microcode update blob. For late loading,
@@ -2150,6 +2150,12 @@ microcode in the cpio name space must be:
- on Intel: kernel/x86/microcode/GenuineIntel.bin
- on AMD : kernel/x86/microcode/AuthenticAMD.bin
+'builtin' instructs the hypervisor to use the builtin microcode update. This
+option is available only if option BUILTIN_UCODE is enabled at build. The
+default value is `true`. If a microcode is provided via other options (such
+as 'integer', 'scan', or `ucode=<filename>` config when booting via EFI),
+the provided microcode takes precedence over the builtin one.
+
'nmi' determines late loading is performed in NMI handler or just in
stop_machine context. In NMI handler, even NMIs are blocked, which is
considered safer. The default value is `true`.
diff --git a/xen/arch/x86/Kconfig b/xen/arch/x86/Kconfig
index 02bb05f42e..9bc220925b 100644
--- a/xen/arch/x86/Kconfig
+++ b/xen/arch/x86/Kconfig
@@ -218,6 +218,36 @@ config MEM_SHARING
bool "Xen memory sharing support" if EXPERT = "y"
depends on HVM
+config BUILTIN_UCODE
+ bool "Support for Builtin Microcode"
+ ---help---
+ Include the CPU microcode update in the Xen image itself. With this
+ support, Xen can update the CPU microcode upon boot using the builtin
+ microcode, with no need for an additional microcode boot modules.
+
+ If unsure, say N.
+
+config BUILTIN_UCODE_DIR
+ string "Directory containing microcode updates"
+ default "/lib/firmware/"
+ depends on BUILTIN_UCODE
+ ---help---
+ The directory containing the microcode blobs.
+
+config BUILTIN_UCODE_AMD
+ string "AMD microcode updates"
+ default ""
+ depends on BUILTIN_UCODE
+ ---help---
+ AMD builtin microcode; space-sparated, relative to BUILTIN_UCODE_DIR.
+
+config BUILTIN_UCODE_INTEL
+ string "INTEL microcode updates"
+ default ""
+ depends on BUILTIN_UCODE
+ ---help---
+ INTEL builtin microcode; space-sparated, relative to
BUILTIN_UCODE_DIR.
+
endmenu
source "common/Kconfig"
diff --git a/xen/arch/x86/Makefile b/xen/arch/x86/Makefile
index 7da5a2631e..886691a377 100644
--- a/xen/arch/x86/Makefile
+++ b/xen/arch/x86/Makefile
@@ -3,6 +3,7 @@ subdir-y += cpu
subdir-y += genapic
subdir-$(CONFIG_GUEST) += guest
subdir-$(CONFIG_HVM) += hvm
+subdir-$(CONFIG_BUILTIN_UCODE) += microcode
subdir-y += mm
subdir-$(CONFIG_XENOPROF) += oprofile
subdir-$(CONFIG_PV) += pv
diff --git a/xen/arch/x86/microcode.c b/xen/arch/x86/microcode.c
index 4616fa9d2e..bcfbd31041 100644
--- a/xen/arch/x86/microcode.c
+++ b/xen/arch/x86/microcode.c
@@ -97,6 +97,14 @@ static struct ucode_mod_blob __initdata ucode_blob;
*/
static bool_t __initdata ucode_scan;
+#ifdef CONFIG_BUILTIN_UCODE
+/* builtin is the default when BUILTIN_UCODE is set */
+static bool __initdata ucode_builtin = true;
+
+extern const char __builtin_intel_ucode_start[], __builtin_intel_ucode_end[];
+extern const char __builtin_amd_ucode_start[], __builtin_amd_ucode_end[];
+#endif
+
/* By default, ucode loading is done in NMI handler */
static bool ucode_in_nmi = true;
@@ -122,6 +130,10 @@ static int __init parse_ucode_param(const char *s)
ucode_in_nmi = val;
else if ( (val = parse_boolean("scan", s, ss)) >= 0 )
ucode_scan = val;
+#ifdef CONFIG_BUILTIN_UCODE
+ else if ( (val = parse_boolean("builtin", s, ss)) >= 0 )
+ ucode_builtin = val;
+#endif
else
{
const char *q;
@@ -208,6 +220,40 @@ void __init microcode_grab_module(
ucode_mod = mod[ucode_mod_idx];
else if ( ucode_scan )
microcode_scan_module(module_map, mbi);
+
+#ifdef CONFIG_BUILTIN_UCODE
+ /*
+ * Do not use the builtin microcode if:
+ * (a) builtin has been explicitly turned off (e.g., ucode=no-builtin)
+ * (b) a microcode module has been specified or a scan is successful
+ */
+ if ( !ucode_builtin || ucode_mod.mod_end || ucode_blob.size )
+ {
+ ucode_builtin = false;
+ return;
+ }
+
+ /* Set ucode_start/_end to the proper blob */
+ if ( boot_cpu_data.x86_vendor == X86_VENDOR_AMD )
+ {
+ ucode_blob.size = __builtin_amd_ucode_end - __builtin_amd_ucode_start;
+ ucode_blob.data = __builtin_amd_ucode_start;
+ }
+ else if ( boot_cpu_data.x86_vendor == X86_VENDOR_INTEL )
+ {
+ ucode_blob.size = __builtin_intel_ucode_end -
+ __builtin_intel_ucode_start;
+ ucode_blob.data = __builtin_intel_ucode_start;
+ }
+ else
+ return;
+
+ if ( !ucode_blob.size )
+ {
+ printk("No builtin ucode for the CPU vendor.\n");
+ ucode_blob.data = NULL;
+ }
+#endif
}
const struct microcode_ops *microcode_ops;
@@ -701,7 +747,13 @@ static int __init microcode_init(void)
*/
if ( ucode_blob.size )
{
+#ifdef CONFIG_BUILTIN_UCODE
+ /* No need to destroy module mappings if builtin was used */
+ if ( !ucode_builtin )
+ bootstrap_map(NULL);
+#else
bootstrap_map(NULL);
+#endif
ucode_blob.size = 0;
ucode_blob.data = NULL;
}
diff --git a/xen/arch/x86/microcode/Makefile b/xen/arch/x86/microcode/Makefile
new file mode 100644
index 0000000000..c34d99903a
--- /dev/null
+++ b/xen/arch/x86/microcode/Makefile
@@ -0,0 +1,46 @@
+# Copyright (C) 2019 Amazon.com, Inc. or its affiliates.
+# Author: Eslam Elnikety <elnikety@xxxxxxxxxx>
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+
+# Remove quotes and excess spaces from configuration strings
+UCODE_DIR=$(strip $(subst $\",,$(CONFIG_BUILTIN_UCODE_DIR)))
+UCODE_AMD=$(strip $(subst $\",,$(CONFIG_BUILTIN_UCODE_AMD)))
+UCODE_INTEL=$(strip $(subst $\",,$(CONFIG_BUILTIN_UCODE_INTEL)))
+
+# AMD and INTEL microcode blobs. Use 'wildcard' to filter for existing blobs.
+amd-blobs := $(wildcard $(addprefix $(UCODE_DIR),$(UCODE_AMD)))
+intel-blobs := $(wildcard $(addprefix $(UCODE_DIR),$(UCODE_INTEL)))
+
+ifneq ($(amd-blobs),)
+obj-y += ucode_amd.o
+endif
+
+ifneq ($(intel-blobs),)
+obj-y += ucode_intel.o
+endif
+
+ifeq ($(amd-blobs)$(intel-blobs),)
+obj-y += ucode_dummy.o
+endif
+
+ucode_amd.o: Makefile $(amd-blobs)
+ cat $(amd-blobs) > $@.bin
+ $(OBJCOPY) -I binary -O elf64-x86-64 -B i386:x86-64 --rename-section
.data=.builtin_amd_ucode,alloc,load,readonly,data,contents $@.bin $@
+ rm -f $@.bin
+
+ucode_intel.o: Makefile $(intel-blobs)
+ cat $(intel-blobs) > $@.bin
+ $(OBJCOPY) -I binary -O elf64-x86-64 -B i386:x86-64 --rename-section
.data=.builtin_intel_ucode,alloc,load,readonly,data,contents $@.bin $@
+ rm -f $@.bin
+
+ucode_dummy.o: Makefile
+ $(CC) $(CFLAGS) -c -x c /dev/null -o $@;
diff --git a/xen/arch/x86/xen.lds.S b/xen/arch/x86/xen.lds.S
index 111edb5360..7a4c58c246 100644
--- a/xen/arch/x86/xen.lds.S
+++ b/xen/arch/x86/xen.lds.S
@@ -265,6 +265,18 @@ SECTIONS
*(SORT(.data.vpci.*))
__end_vpci_array = .;
#endif
+
+#if defined(CONFIG_BUILTIN_UCODE)
+ . = ALIGN(POINTER_ALIGN);
+ __builtin_amd_ucode_start = .;
+ *(.builtin_amd_ucode)
+ __builtin_amd_ucode_end = .;
+
+ . = ALIGN(POINTER_ALIGN);
+ __builtin_intel_ucode_start = .;
+ *(.builtin_intel_ucode)
+ __builtin_intel_ucode_end = .;
+#endif
} :text
. = ALIGN(SECTION_ALIGN);
--
2.17.1
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