> On 25 Nov 2018, at 19:47, Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote:
>
> On 08/11/18 10:51, Liran Alon wrote:
>> From: Leonid Shatz <leonid.shatz@xxxxxxxxxx>
>>
>> Since commit e79f245ddec1 ("X86/KVM: Properly update 'tsc_offset' to
>> represent the running guest"), vcpu->arch.tsc_offset meaning was
>> changed to always reflect the tsc_offset value set on active VMCS.
>> Regardless if vCPU is currently running L1 or L2.
>>
>> However, above mentioned commit failed to also change
>> kvm_vcpu_write_tsc_offset() to set vcpu->arch.tsc_offset correctly.
>> This is because vmx_write_tsc_offset() could set the tsc_offset value
>> in active VMCS to given offset parameter *plus vmcs12->tsc_offset*.
>> However, kvm_vcpu_write_tsc_offset() just sets vcpu->arch.tsc_offset
>> to given offset parameter. Without taking into account the possible
>> addition of vmcs12->tsc_offset. (Same is true for SVM case).
>>
>> Fix this issue by changing kvm_x86_ops->write_tsc_offset() to return
>> actually set tsc_offset in active VMCS and modify
>> kvm_vcpu_write_tsc_offset() to set returned value in
>> vcpu->arch.tsc_offset.
>> In addition, rename write_tsc_offset() argument to clearly indicate
>> it specifies a L1 TSC offset.
>>
>> Fixes: e79f245ddec1 ("X86/KVM: Properly update 'tsc_offset' to represent the running guest")
>>
>> Reviewed-by: Liran Alon <liran.alon@xxxxxxxxxx>
>> Reviewed-by: Mihai Carabas <mihai.carabas@xxxxxxxxxx>
>> Reviewed-by: Krish Sadhukhan <krish.sadhukhan@xxxxxxxxxx>
>> Signed-off-by: Leonid Shatz <leonid.shatz@xxxxxxxxxx>
>
> I queued v1, and will send a replacement for patch 2 of this miniseries.
>
> Paoo
Paolo, I think this commit should go to the stable tree as it fixes a regression issue.
-Liran
