* FAILED: patch "[PATCH] KVM: x86: Forbid VMM to set SYNIC/STIMER MSRs when SynIC" failed to apply to 4.9-stable tree
@ 2022-04-03 6:39 gregkh
0 siblings, 0 replies; only message in thread
From: gregkh @ 2022-04-03 6:39 UTC (permalink / raw)
To: vkuznets, pbonzini; +Cc: stable
The patch below does not apply to the 4.9-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From b1e34d325397a33d97d845e312d7cf2a8b646b44 Mon Sep 17 00:00:00 2001
From: Vitaly Kuznetsov <vkuznets@redhat.com>
Date: Fri, 25 Mar 2022 14:21:40 +0100
Subject: [PATCH] KVM: x86: Forbid VMM to set SYNIC/STIMER MSRs when SynIC
wasn't activated
Setting non-zero values to SYNIC/STIMER MSRs activates certain features,
this should not happen when KVM_CAP_HYPERV_SYNIC{,2} was not activated.
Note, it would've been better to forbid writing anything to SYNIC/STIMER
MSRs, including zeroes, however, at least QEMU tries clearing
HV_X64_MSR_STIMER0_CONFIG without SynIC. HV_X64_MSR_EOM MSR is somewhat
'special' as writing zero there triggers an action, this also should not
happen when SynIC wasn't activated.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20220325132140.25650-4-vkuznets@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index f715b5a2b0e4..4177c17a26bf 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -239,7 +239,7 @@ static int synic_set_msr(struct kvm_vcpu_hv_synic *synic,
struct kvm_vcpu *vcpu = hv_synic_to_vcpu(synic);
int ret;
- if (!synic->active && !host)
+ if (!synic->active && (!host || data))
return 1;
trace_kvm_hv_synic_set_msr(vcpu->vcpu_id, msr, data, host);
@@ -285,6 +285,9 @@ static int synic_set_msr(struct kvm_vcpu_hv_synic *synic,
case HV_X64_MSR_EOM: {
int i;
+ if (!synic->active)
+ break;
+
for (i = 0; i < ARRAY_SIZE(synic->sint); i++)
kvm_hv_notify_acked_sint(vcpu, i);
break;
@@ -664,7 +667,7 @@ static int stimer_set_config(struct kvm_vcpu_hv_stimer *stimer, u64 config,
struct kvm_vcpu_hv *hv_vcpu = to_hv_vcpu(vcpu);
struct kvm_vcpu_hv_synic *synic = to_hv_synic(vcpu);
- if (!synic->active && !host)
+ if (!synic->active && (!host || config))
return 1;
if (unlikely(!host && hv_vcpu->enforce_cpuid && new_config.direct_mode &&
@@ -693,7 +696,7 @@ static int stimer_set_count(struct kvm_vcpu_hv_stimer *stimer, u64 count,
struct kvm_vcpu *vcpu = hv_stimer_to_vcpu(stimer);
struct kvm_vcpu_hv_synic *synic = to_hv_synic(vcpu);
- if (!synic->active && !host)
+ if (!synic->active && (!host || count))
return 1;
trace_kvm_hv_stimer_set_count(hv_stimer_to_vcpu(stimer)->vcpu_id,
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2022-04-03 6:39 FAILED: patch "[PATCH] KVM: x86: Forbid VMM to set SYNIC/STIMER MSRs when SynIC" failed to apply to 4.9-stable tree gregkh
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