This bug seems not to be a problem, and may reflect an issue with
NetBSD. Even though the decode of the features1 register does not
include MONITOR/MWAIT, that capability is separately reported on a
separate line, further down (apologies in advance for any confusing
line-wrap):
# cpuctl identify 0
cpu0: highest basic info 000d
cpu0: highest hypervisor info 4001
cpu0: highest extended info 8008
cpu0: Running on hypervisor: QEMU(TCG)
cpu0: "Intel Core Processor (Broadwell)"
cpu0: Intel Core M-5xxx, 5th gen Core (Broadwell) (686-class), 3198.24 MHz
cpu0: family 0x6 model 0x3d stepping 0x2 (id 0x306d2)
cpu0: features 0x78bfbfd
cpu0: features 0x78bfbfd
cpu0: features1 0xced82203
cpu0: features1 0xced82203
cpu0: features2 0x28100800
cpu0: features3 0x21
cpu0: features5 0x180389
cpu0: xsave features 0x7
cpu0: xsave instructions 0x1
cpu0: xsave area size: current 832, maximum 832, xgetbv enabled
cpu0: enabled xsave 0x7
cpu0: I-cache 32KB 64B/line 8-way, D-cache 32KB 64B/line 8-way
cpu0: L2 cache 4MB 64B/line 16-way
cpu0: L3 cache 16MB 64B/line 16-way
cpu0: Initial APIC ID 0
cpu0: Cluster/Package ID 0
cpu0: Core ID 0
cpu0: SMT ID 0
cpu0: MONITOR/MWAIT extensions 0x3
cpu0: monitor-line size 0
cpu0: DSPM-eax 0x4
cpu0: SEF highest subleaf
cpu0: Power Management features: 0
cpu0: microcode version 0x0, platform ID 0
#
On Fri, 22 May 2020, Thomas Huth wrote:
> Can you still reproduce this issue with the latest version of QEMU?
> Looking at
> https://git.qemu.org/?p=qemu.git;a=commitdiff;h=0723cc8a5558c94388 for
> example, it might have been fixed since QEMU v4.2...
>
> ** Changed in: qemu
> Status: New => Incomplete
>
> --
> You received this bug notification because you are subscribed to the bug
> report.
> https://bugs.launchpad.net/bugs/1693667
>
> Title:
> -cpu haswell / broadwell have no MONITOR in features1
>
> Status in QEMU:
> Incomplete
>
> Bug description:
> In qemu 2.9.0 if you run
>
> qemu-system-x86_64 -cpu Broadwell (or Haswell)
>
> then the CPU features1 flag include the SSE3 bit, but do NOT include
> the MONITOR/MWAIT bit. This is so even when the host includes the
> features.
>
>
> Additionally, running qemu in this manner results in several error messages:
>
> warning: TCG doesn't support requested feature: CPUID.01H:ECX.fma [bit 12]
> warning: TCG doesn't support requested feature: CPUID.01H:ECX.pcid [bit 17]
> warning: TCG doesn't support requested feature: CPUID.01H:ECX.x2apic [bit 21]
> warning: TCG doesn't support requested feature: CPUID.01H:ECX.tsc-deadline
> [bit 24]
> warning: TCG doesn't support requested feature: CPUID.01H:ECX.avx [bit 28]
> warning: TCG doesn't support requested feature: CPUID.01H:ECX.f16c [bit 29]
> warning: TCG doesn't support requested feature: CPUID.01H:ECX.rdrand [bit 30]
> warning: TCG doesn't support requested feature: CPUID.07H:EBX.hle [bit 4]
> warning: TCG doesn't support requested feature: CPUID.07H:EBX.avx2 [bit 5]
> warning: TCG doesn't support requested feature: CPUID.07H:EBX.invpcid [bit
> 10]
> warning: TCG doesn't support requested feature: CPUID.07H:EBX.rtm [bit 11]
> warning: TCG doesn't support requested feature: CPUID.07H:EBX.rdseed [bit 18]
> warning: TCG doesn't support requested feature:
> CPUID.8001H:ECX.3dnowprefetch
>
>
> (Among possible other uses, the lack of the MONITOR feature bit causes
> NetBSD to fall-back on a
> check-and-pause loop while an application CPU is waiting to be told to
> proceed by the boot CPU.)
>
> To manage notifications about this bug go to:
> https://bugs.launchpad.net/qemu/+bug/1693667/+subscriptions
>
> !DSPAM:5ec76256254551748016490!
>
>
++--+---+
| Paul Goyette | PGP Key fingerprint: | E-mail addresses: |
| (Retired) | FA29 0E3B 35AF E8AE 6651 | p...@whooppee.com |
| Software Developer | 0786 F758 55DE 53BA 7731 | pgoye...@netbsd.org |
++--+---+
--
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
https://bugs.launchpad.net/bugs/1693667
Title:
-cpu haswell / broadwell have no MONITOR in features1
Status in QEMU:
Incomplete
Bug description:
In qemu 2.9.0 if you run
qemu-system-x86_64 -cpu Broadwell (or Haswell)
then the CPU features1 flag include the SSE3 bit, but do NOT include
the MONITOR/MWAIT bit. This is so even when the host includes the
features.
Additionally, running qemu in this manner results in several error messages:
warning: TCG doesn't support requested feature: CPUID.01H:ECX.fma [bit 12]
warning: TCG doesn't support requested feature: CPUID.01H:ECX.pcid [bit 17]
warning: TCG doesn't support requested feature: CPUID.01H:ECX.x2apic [bit 21]
warning: TCG doesn't support requested feature: CPUID.01H:ECX.tsc-deadline
[bit 24]
warning: TCG doesn't support requested feature: