Synic default SCONTROL MSR needs to be enabled
Subsystems (4)
cover Synic default SCONTROL MSR needs to be enabled
Based on an analysis of the HyperV firmwares (Gen1 and Gen2) it seems like the SCONTROL is not being set to the ENABLED state as like we have thought.
Also from a test done by Vitaly Kuznetsov, running a nested HyperV it was concluded that the first access to the SCONTROL MSR with a read resulted with the value of 0x1, aka HV_SYNIC_CONTROL_ENABLE.
It's important to note that this diverges from the value states in the HyperV TLFS of 0.
Jon Doron (1):
x86/kvm/hyper-v: Synic default SCONTROL MSR needs to be enabled
arch/x86/kvm/hyperv.c | 1 + 1 file changed, 1 insertion(+)
Signature · 1 line
2.24.1
PATCH 1/1 x86/kvm/hyper-v: Synic default SCONTROL MSR needs to be enabled
Based on an analysis of the HyperV firmwares (Gen1 and Gen2) it seems like the SCONTROL is not being set to the ENABLED state as like we have thought.
Also from a test done by Vitaly Kuznetsov, running a nested HyperV it was concluded that the first access to the SCONTROL MSR with a read resulted with the value of 0x1, aka HV_SYNIC_CONTROL_ENABLE.
It's important to note that this diverges from the value states in the HyperV TLFS of 0.
--- arch/x86/kvm/hyperv.c | 1 + 1 file changed, 1 insertion(+)
arch/x86/kvm/hyperv.c +1 -0
@@ -900,6 +900,7 @@ int kvm_hv_activate_synic(struct kvm_vcpu *vcpu, bool dont_zero_synic_pages)kvm_request_apicv_update (vcpu->kvm, false,APICV_INHIBIT_REASON_HYPERV ); synic->active = true; synic->dont_zero_synic_pages = dont_zero_synic_pages; + synic->control =HV_SYNIC_CONTROL_ENABLE ;return 0 ; }
Signature · 1 line
2.24.1
Re: [PATCH v1 1/1] x86/kvm/hyper-v: Synic default SCONTROL MSR needs to be enabled
Quoted 22 lines · Jon Doron
Based on an analysis of the HyperV firmwares (Gen1 and Gen2) it seems like the SCONTROL is not being set to the ENABLED state as like we have thought.
Also from a test done by Vitaly Kuznetsov, running a nested HyperV it was concluded that the first access to the SCONTROL MSR with a read resulted with the value of
0x1, akaHV_SYNIC_CONTROL_ENABLE.It's important to note that this diverges from the value states in the HyperV TLFS of 0.
Signed-off-by Jon Doron <[email protected]>--- arch/x86/kvm/hyperv.c | 1 + 1 file changed, 1 insertion(+)arch/x86/kvm/hyperv.c +0
-0
arch/x86/kvm/hyperv.c int kvm_hv_activate_synic(struct kvm_vcpu *vcpu, bool dont_zero_synic_pages) · line 906
Quoted 7 lines
arch/x86/kvm/hyperv.c +1
-0@@ -900,6 +900,7 @@ int kvm_hv_activate_synic(struct kvm_vcpu *vcpu, bool dont_zero_synic_pages)kvm_request_apicv_update (vcpu->kvm, false,APICV_INHIBIT_REASON_HYPERV ); synic->active = true; synic->dont_zero_synic_pages = dont_zero_synic_pages; + synic->control =HV_SYNIC_CONTROL_ENABLE ;return 0 ; }
Applied, thanks!
Paolo
Ping, can this patch please be queued to 5.9?
Thanks,
-- Jon.
Quoted 21 lines · Jon Doron
Based on an analysis of the HyperV firmwares (Gen1 and Gen2) it seems like the SCONTROL is not being set to the ENABLED state as like we have thought.
Also from a test done by Vitaly Kuznetsov, running a nested HyperV it was concluded that the first access to the SCONTROL MSR with a read resulted with the value of
0x1, akaHV_SYNIC_CONTROL_ENABLE.It's important to note that this diverges from the value states in the HyperV TLFS of 0.
Jon Doron (1):
x86/kvm/hyper-v: Synic default SCONTROL MSR needs to be enabledarch/x86/kvm/hyperv.c | 1 + 1 file changed, 1 insertion(+)--
2.24.1