On 05/01/2018 11:12 AM, speck for Konrad Rzeszutek Wilk wrote:
> On Tue, May 01, 2018 at 05:24:20PM +0200, speck for Thomas Gleixner wrote:
>> Changes vs. V8:
>>
>> Addressed review feed back and added Linus variant of
>> alternative_write_msr().
>>
>>  - Use EINVAL in the prctl
>>
>>  - Fix the sbb typos
>>
>>  - Make AMD default to prctl as well (Borislav)
>>
>>  - Add the not affected CPU types (Tim)
>>
>> I've updated the git repository as well
>>
>>   ssh://git@cvs.ou.linutronix.de/linux/speck/linux master (forced update)
>>
>> There are also two stable backport branches now:
>>
>>   ssh://git@cvs.ou.linutronix.de/linux/speck/linux linux-4.16.y
>>
>>   ssh://git@cvs.ou.linutronix.de/linux/speck/linux linux-4.14.y
>>
>>
>> Delta patch against V8 below. Git bundle against 4.17-rc3 follows in
>> separate mail.
> 
> On my Skylake box this does what is expected:
> 
> 4
> RHEL-64 <root@instance-20180426-1449:/home/opc> dmesg | grep -i spec
> [    0.000000] Command line: BOOT_IMAGE=/boot/vmlinuz-4.17.0-rc3-v9+ root=UUID=533fa2dd-5b2f-4964-aa99-5ab349614dcd ro crashkernel=auto LANG=en_US.UTF-8 transparent_hugepage=never console=tty0 console=ttyS0,9600 rd.luks=0 rd.lvm=0 rd.md=0 rd.dm=0 netroot=iscsi:169.254.0.2:::1:iqn.2015-02.oracle.boot:uefi iscsi_param=node.session.timeo.replacement_timeout=6000 net.ifnames=1 nvme_core.shutdown_timeout=10 ipmi_si.tryacpi=0 ipmi_si.trydmi=0 ipmi_si.trydefaults=0 network-config=e2NvbmZpZzogZGlzYWJsZWR9Cg== spec_store_bypass_disable=on
> [    0.000000] please specify mtrr_gran_size/mtrr_chunk_size
> [    0.000000] Kernel command line: BOOT_IMAGE=/boot/vmlinuz-4.17.0-rc3-v9+ root=UUID=533fa2dd-5b2f-4964-aa99-5ab349614dcd ro crashkernel=auto LANG=en_US.UTF-8 transparent_hugepage=never console=tty0 console=ttyS0,9600 rd.luks=0 rd.lvm=0 rd.md=0 rd.dm=0 netroot=iscsi:169.254.0.2:::1:iqn.2015-02.oracle.boot:uefi iscsi_param=node.session.timeo.replacement_timeout=6000 net.ifnames=1 nvme_core.shutdown_timeout=10 ipmi_si.tryacpi=0 ipmi_si.trydmi=0 ipmi_si.trydefaults=0 network-config=e2NvbmZpZzogZGlzYWJsZWR9Cg== spec_store_bypass_disable=on
> [    0.145004] Spectre V2 : Mitigation: Full generic retpoline
> [    0.146001] Spectre V2 : Spectre v2 mitigation: Filling RSB on context switch
> [    0.147000] Spectre V2 : Spectre v2 mitigation: Enabling Indirect Branch Prediction Barrier
> [    0.148000] Spectre V2 : Enabling Restricted Speculation for firmware calls
> [    0.149004] Speculative Store Bypass: Mitigation: Speculative Store Bypass disabled
> RHEL-64 <root@instance-20180426-1449:/home/opc> rdmsr 0x48 --all | uniq
> 4
> 
> And I don't see the weird issue that Tim reported?
> 
> 

Did a trace_printk and IBRS feature was not set when my system check it in 

void x86_setup_ap_spec_ctrl(void)
{
        if (boot_cpu_has(X86_FEATURE_IBRS))
                x86_set_spec_ctrl(x86_spec_ctrl_base & ~x86_spec_ctrl_mask);


I checked cpuid and the IBRS feature bit was there.
I will do some more digging to find out why X86_FEATURE_IBRS is not set
by kernel on my system.  Konrad, you said someone else already reported
the IBRS issue and was that root caused?

Tim