概述
我在 Debian buster 上运行 Xen 服务器。最新内核、最新 BIOS 版本、传统启动。
启动到 Xen 服务器时仅显示 8 GB 可用 RAM，同时识别出已连接的 16 GB RAM。
在没有 Xen 的情况下启动到 Debian 显示所有 16 GB 的 RAM 都是空闲的。
我的问题：知道我可以做什么来强制 Xen 使用全部 16 GB 吗？
xl dmesg例如，我可以看到由于某些不匹配而使用 32 位寻址而不是 64 位寻址时出现错误。我可以强制 ACPI 使用 64 位吗？
日志
来自 Xen
引导到 Xen 时ACPI: 32/64X FACS address mismatch in FADT - da7ed080/0000000000000000, using 32仅显示并使用 16 GB 可用 RAM 中的 8 GB。
user@server:~/ free -m
free -m
total used free shared buff/cache available
Mem: 7387 379 6635 9 373 6841
Swap: 16291 0 16291
user@server:~/ dmidecode -t17
# dmidecode 3.2
Getting SMBIOS data from sysfs.
SMBIOS 2.7 present.
Handle 0x0041, DMI type 17, 34 bytes
Memory Device
Array Handle: 0x0040
Error Information Handle: Not Provided
Total Width: 64 bits
Data Width: 64 bits
Size: 4096 MB
Form Factor: DIMM
Set: None
Locator: DIMM3
Bank Locator: Not Specified
Type: DDR3
Type Detail: Synchronous
Speed: 1600 MT/s
Manufacturer: Samsung
Serial Number: 03B0650F7097
Asset Tag: 02151000
Part Number: M378B5173QH0-CK0
Rank: 1
Configured Memory Speed: 1333 MT/s
Handle 0x0043, DMI type 17, 34 bytes
Memory Device
Array Handle: 0x0040
Error Information Handle: Not Provided
Total Width: 64 bits
Data Width: 64 bits
Size: 4096 MB
Form Factor: DIMM
Set: None
Locator: DIMM1
Bank Locator: Not Specified
Type: DDR3
Type Detail: Synchronous
Speed: 1333 MT/s
Manufacturer: Kingston
Serial Number: 05009D00801C
Asset Tag: 07194900
Part Number: 99U5402-034.A00LF
Rank: 1
Configured Memory Speed: 1333 MT/s
Handle 0x0045, DMI type 17, 34 bytes
Memory Device
Array Handle: 0x0040
Error Information Handle: Not Provided
Total Width: 64 bits
Data Width: 64 bits
Size: 4096 MB
Form Factor: DIMM
Set: None
Locator: DIMM4
Bank Locator: Not Specified
Type: DDR3
Type Detail: Synchronous
Speed: 1600 MT/s
Manufacturer: Samsung
Serial Number: 0330650F7097
Asset Tag: 02151000
Part Number: M378B5173QH0-CK0
Rank: 1
Configured Memory Speed: 1333 MT/s
Handle 0x0047, DMI type 17, 34 bytes
Memory Device
Array Handle: 0x0040
Error Information Handle: Not Provided
Total Width: 64 bits
Data Width: 64 bits
Size: 4096 MB
Form Factor: DIMM
Set: None
Locator: DIMM2
Bank Locator: Not Specified
Type: DDR3
Type Detail: Synchronous
Speed: 1333 MT/s
Manufacturer: Kingston
Serial Number: 0500A4008015
Asset Tag: 07194900
Part Number: 99U5402-034.A00LF
Rank: 1
Configured Memory Speed: 1333 MT/s
user@server:~/ xl dmesg
(XEN) parameter "placeholder" unknown!
(XEN) Xen version 4.11.4-pre (Debian 4.11.3+24-g14b62ab3e5-1~deb10u1) ([email protected]) (gcc (Debian 8.3.0-6) 8.3.0) debug=n Wed Jan 8 20:16:51 UTC 2020
(XEN) Bootloader: GRUB 2.02+dfsg1-20
(XEN) Command line: placeholder
(XEN) Xen image load base address: 0xdb000000
(XEN) Video information:
(XEN) VGA is text mode 80x25, font 8x16
(XEN) VBE/DDC methods: V2; EDID transfer time: 1 seconds
(XEN) Disc information:
(XEN) Found 1 MBR signatures
(XEN) Found 3 EDD information structures
(XEN) Xen-e820 RAM map:
(XEN) 0000000000000000 - 000000000009d800 (usable)
(XEN) 000000000009d800 - 00000000000a0000 (reserved)
(XEN) 00000000000e0000 - 0000000000100000 (reserved)
(XEN) 0000000000100000 - 00000000d0ad5000 (usable)
(XEN) 00000000d0ad5000 - 00000000d0adc000 (ACPI NVS)
(XEN) 00000000d0adc000 - 00000000d0f18000 (usable)
(XEN) 00000000d0f18000 - 00000000d13af000 (reserved)
(XEN) 00000000d13af000 - 00000000d7eeb000 (usable)
(XEN) 00000000d7eeb000 - 00000000d8000000 (reserved)
(XEN) 00000000d8000000 - 00000000d8760000 (usable)
(XEN) 00000000d8760000 - 00000000d8800000 (reserved)
(XEN) 00000000d8800000 - 00000000d8fae000 (usable)
(XEN) 00000000d8fae000 - 00000000d9000000 (ACPI data)
(XEN) 00000000d9000000 - 00000000da71c000 (usable)
(XEN) 00000000da71c000 - 00000000da800000 (ACPI NVS)
(XEN) 00000000da800000 - 00000000dbe11000 (usable)
(XEN) 00000000dbe11000 - 00000000dc000000 (reserved)
(XEN) 00000000dd000000 - 00000000df200000 (reserved)
(XEN) 00000000f8000000 - 00000000fc000000 (reserved)
(XEN) 00000000fec00000 - 00000000fec01000 (reserved)
(XEN) 00000000fed00000 - 00000000fed04000 (reserved)
(XEN) 00000000fed1c000 - 00000000fed20000 (reserved)
(XEN) 00000000fee00000 - 00000000fee01000 (reserved)
(XEN) 00000000ff000000 - 0000000100000000 (reserved)
(XEN) 0000000100000000 - 000000041ee00000 (usable)
(XEN) ACPI: RSDP 000F0490, 0024 (r2 DELL )
(XEN) ACPI: XSDT D8FED098, 00AC (r1 DELL CBX3 1072009 AMI 10013)
(XEN) ACPI: FACP D8FF8B50, 010C (r5 DELL CBX3 1072009 AMI 10013)
(XEN) ACPI: DSDT D8FED1D0, B97E (r2 DELL CBX3 14 INTL 20091112)
(XEN) ACPI: FACS DA7ED080, 0040
(XEN) ACPI: APIC D8FF8C60, 0092 (r3 DELL CBX3 1072009 AMI 10013)
(XEN) ACPI: FPDT D8FF8CF8, 0044 (r1 DELL CBX3 1072009 AMI 10013)
(XEN) ACPI: SLIC D8FF8D40, 0176 (r3 DELL CBX3 1072009 MSFT 10013)
(XEN) ACPI: LPIT D8FF8EB8, 005C (r1 DELL CBX3 0 AMI. 5)
(XEN) ACPI: SSDT D8FF8F18, 0539 (r1 PmRef Cpu0Ist 3000 INTL 20120711)
(XEN) ACPI: SSDT D8FF9458, 0AD8 (r1 PmRef CpuPm 3000 INTL 20120711)
(XEN) ACPI: SSDT D8FF9F30, 01C7 (r1 PmRef LakeTiny 3000 INTL 20120711)
(XEN) ACPI: HPET D8FFA0F8, 0038 (r1 DELL CBX3 1072009 AMI. 5)
(XEN) ACPI: SSDT D8FFA130, 036D (r1 SataRe SataTabl 1000 INTL 20120711)
(XEN) ACPI: MCFG D8FFA4A0, 003C (r1 DELL CBX3 1072009 MSFT 97)
(XEN) ACPI: SSDT D8FFA4E0, 34D6 (r1 SaSsdt SaSsdt 3000 INTL 20091112)
(XEN) ACPI: ASF! D8FFD9B8, 00A5 (r32 INTEL HCG 1 TFSM F4240)
(XEN) ACPI: SSDT D8FFDA60, 0587 (r1 AMITCG PROC 1 INTL 20120711)
(XEN) ACPI: MSDM D8FFDFE8, 0055 (r3 DELL CBX3 6222004 AMI 10013)
(XEN) ACPI: DMAR D8FFE040, 00B8 (r1 INTEL HSW 1 INTL 1)
(XEN) ACPI: TCPA D8FFE0F8, 0032 (r2 APTIO4 NAPAASF 1 MSFT 1000013)
(XEN) System RAM: 16292MB (16683156kB)
(XEN) Domain heap initialised
(XEN) ACPI: 32/64X FACS address mismatch in FADT - da7ed080/0000000000000000, using 32
(XEN) IOAPIC[0]: apic_id 8, version 32, address 0xfec00000, GSI 0-23
(XEN) Enabling APIC mode: Flat. Using 1 I/O APICs
(XEN) Switched to APIC driver x2apic_cluster
(XEN) xstate: size: 0x340 and states: 0x7
user@server:~/ xl info
host : server
release : 4.19.0-8-amd64
version : #1 SMP Debian 4.19.98-1 (2020-01-26)
machine : x86_64
nr_cpus : 8
max_cpu_id : 7
nr_nodes : 1
cores_per_socket : 4
threads_per_core : 2
cpu_mhz : 3591.702
hw_caps : bfebfbff:77faf3ff:2c100800:00000021:00000001:000027ab:00000000:00000100
virt_caps : hvm hvm_directio
total_memory : 16292
free_memory : 8278
sharing_freed_memory : 0
sharing_used_memory : 0
outstanding_claims : 0
free_cpus : 0
xen_major : 4
xen_minor : 11
xen_extra : .4-pre
xen_version : 4.11.4-pre
xen_caps : xen-3.0-x86_64 xen-3.0-x86_32p hvm-3.0-x86_32 hvm-3.0-x86_32p hvm-3.0-x86_64
xen_scheduler : credit
xen_pagesize : 4096
platform_params : virt_start=0xffff800000000000
xen_changeset :
xen_commandline : placeholder
cc_compiler : gcc (Debian 8.3.0-6) 8.3.0
cc_compile_by : pkg-xen-devel
cc_compile_domain : lists.alioth.debian.org
cc_compile_date : Wed Jan 8 20:16:51 UTC 2020
build_id : b6822aa1d8f867753b92985e5cb0e806e520a08c
xend_config_format : 4
来自 Debian Buster（不带 Xen）
在没有 Xen 的情况下启动到 Debian buster 会产生完整的 16 GB，一切都很好。
user@server:~/ free -m
total used free shared buff/cache available
Mem: 15950 388 15310 8 251 15292
Swap: 16291 0 16291
user@server:~/ dmidecode -t17
# dmidecode 3.2
Getting SMBIOS data from sysfs.
SMBIOS 2.7 present.
Handle 0x0041, DMI type 17, 34 bytes
Memory Device
Array Handle: 0x0040
Error Information Handle: Not Provided
Total Width: 64 bits
Data Width: 64 bits
Size: 4096 MB
Form Factor: DIMM
Set: None
Locator: DIMM3
Bank Locator: Not Specified
Type: DDR3
Type Detail: Synchronous
Speed: 1600 MT/s
Manufacturer: Samsung
Serial Number: 03B0650F7097
Asset Tag: 02151000
Part Number: M378B5173QH0-CK0
Rank: 1
Configured Memory Speed: 1333 MT/s
Handle 0x0043, DMI type 17, 34 bytes
Memory Device
Array Handle: 0x0040
Error Information Handle: Not Provided
Total Width: 64 bits
Data Width: 64 bits
Size: 4096 MB
Form Factor: DIMM
Set: None
Locator: DIMM1
Bank Locator: Not Specified
Type: DDR3
Type Detail: Synchronous
Speed: 1333 MT/s
Manufacturer: Kingston
Serial Number: 05009D00801C
Asset Tag: 07194900
Part Number: 99U5402-034.A00LF
Rank: 1
Configured Memory Speed: 1333 MT/s
Handle 0x0045, DMI type 17, 34 bytes
Memory Device
Array Handle: 0x0040
Error Information Handle: Not Provided
Total Width: 64 bits
Data Width: 64 bits
Size: 4096 MB
Form Factor: DIMM
Set: None
Locator: DIMM4
Bank Locator: Not Specified
Type: DDR3
Type Detail: Synchronous
Speed: 1600 MT/s
Manufacturer: Samsung
Serial Number: 0330650F7097
Asset Tag: 02151000
Part Number: M378B5173QH0-CK0
Rank: 1
Configured Memory Speed: 1333 MT/s
Handle 0x0047, DMI type 17, 34 bytes
Memory Device
Array Handle: 0x0040
Error Information Handle: Not Provided
Total Width: 64 bits
Data Width: 64 bits
Size: 4096 MB
Form Factor: DIMM
Set: None
Locator: DIMM2
Bank Locator: Not Specified
Type: DDR3
Type Detail: Synchronous
Speed: 1333 MT/s
Manufacturer: Kingston
Serial Number: 0500A4008015
Asset Tag: 07194900
Part Number: 99U5402-034.A00LF
Rank: 1
Configured Memory Speed: 1333 MT/s
答案1
total_memory : 16292
free_memory : 8278
inxl info的输出显示 Xen 正在使用所有可用内存，但不是以您期望的方式：它看到了所有 16GiB，但还剩下 8GiB 多一点未分配。因此，您的 dom0 看到的内存不到 8GiB，其余的可供 domU 使用。
如果你想为 dom0 分配更多内存，你需要编辑您的引导加载程序配置。
（32/64X 错误消息并不意味着系统正在切换到 32 位寻址；它意味着 ACPI 表中存在地址不匹配，并且内核正在使用有效地址，即此处的 32 位地址。这只会影响它如何找到特定的 ACPI 表。）