linux-kernel - [BISECTED] KVM error with 5.0-rc

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Message-ID: <c8d44a6a-bdb6-6b8c-4a50-1d152a3964f8@skogtun.org>
Date:   Mon, 14 Jan 2019 18:04:27 +0100
From:   Harald Arnesen <harald@...gtun.org>
To:     Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Cc:     Sean Christopherson <sean.j.christopherson@...el.com>,
        Paolo Bonzini <pbonzini@...hat.com>
Subject: [BISECTED] KVM error with 5.0-rc

Qemu with KVM acceleration fails with kernel 5.0-rc1 and 5.0-rc2.
It works fine with 4.20.


$ qemu-system-x86_64 --enable-kvm
KVM: entry failed, hardware error 0x7
EAX=00000000 EBX=00000000 ECX=00000000 EDX=00000663
ESI=00000000 EDI=00000000 EBP=00000000 ESP=00000000
EIP=0000fff0 EFL=00000002 [-------] CPL=0 II=0 A20=1 SMM=0 HLT=0
ES =0000 00000000 0000ffff 00009300
CS =f000 ffff0000 0000ffff 00009b00
SS =0000 00000000 0000ffff 00009300
DS =0000 00000000 0000ffff 00009300
FS =0000 00000000 0000ffff 00009300
GS =0000 00000000 0000ffff 00009300
LDT=0000 00000000 0000ffff 00008200
TR =0000 00000000 0000ffff 00008b00
GDT=     00000000 0000ffff
IDT=     00000000 0000ffff
CR0=60000010 CR2=00000000 CR3=00000000 CR4=00000000
DR0=0000000000000000 DR1=0000000000000000 DR2=0000000000000000
DR3=0000000000000000
DR6=00000000ffff0ff0 DR7=0000000000000400
EFER=0000000000000000
Code=00 66 89 d8 66 e8 6f 9f ff ff 66 83 c4 0c 66 5b 66 5e 66 c3 <ea> 5b
e0 00 f0 30 36 2f 32 33 2f 39 39 00 fc 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00


Tried with a home-compiled qemu
$ qemu-system-x86_64 -version
QEMU emulator version 3.1.50 (v3.1.0-724-ge53f7796fb-dirty)

and the one from Devuan ASCII
$ /usr/bin/qemu-system-x86_64 -version
QEMU emulator version 2.8.1(Debian 1:2.8+dfsg-6+deb9u5)

same result with both.

Home-compiled gcc
$ gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/opt/gcc/libexec/gcc/x86_64-pc-linux-gnu/8.2.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: ../gcc-8.2.0/configure --prefix=/opt/gcc
--enable-multiarch --with-tune=core2 --with-arch=core2
--enable-__cxa_atexit
--enable-languages=ada,c,c++,fortran,go,jit,lto,objc,obj-c++
--enable-targets=all --enable-default-pie --disable-nls --enable-host-shared
Thread model: posix
gcc version 8.2.0 (GCC)

Bisecting gives:

c73da3fcab43357feb68cac227194b13e998a8db is the first bad commit
commit c73da3fcab43357feb68cac227194b13e998a8db
Author: Sean Christopherson <sean.j.christopherson@...el.com>
Date:   Mon Dec 3 13:53:00 2018 -0800

    KVM: VMX: Properly handle dynamic VM Entry/Exit controls

    EFER and PERF_GLOBAL_CTRL MSRs have dedicated VM Entry/Exit controls
    that KVM dynamically toggles based on whether or not the guest's value
    for each MSRs differs from the host.  Handle the dynamic behavior by
    adding a helper that clears the dynamic bits so the bits aren't set
    when initializing the VMCS field outside of the dynamic toggling flow.
    This makes the handling consistent with similar behavior for other
    controls, e.g. pin, exec and sec_exec.  More importantly, it eliminates
    two global bools that are stealthily modified by setup_vmcs_config.

    Opportunistically clean up a comment and print related to errata for
    IA32_PERF_GLOBAL_CTRL.

    Signed-off-by: Sean Christopherson <sean.j.christopherson@...el.com>
    Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>


Attached: config file, /proc/cpuinfo.
--
Hilsen Harald

View attachment "config-5.0.0-rc2" of type "text/plain" (120394 bytes)

View attachment "cpuinfo.txt" of type "text/plain" (3804 bytes)