From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: Tue, 5 Apr 2022 05:31:10 +0000 (+0200)
Subject: 4.9-stable patches
X-Git-Tag: v5.17.2~35
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=6b4b4083f99f282dbe8f0f07b41662f3289e35da;p=thirdparty%2Fkernel%2Fstable-queue.git

4.9-stable patches

added patches:
	kvm-x86-forbid-vmm-to-set-synic-stimer-msrs-when-synic-wasn-t-activated.patch
---

diff --git a/queue-4.9/kvm-x86-forbid-vmm-to-set-synic-stimer-msrs-when-synic-wasn-t-activated.patch b/queue-4.9/kvm-x86-forbid-vmm-to-set-synic-stimer-msrs-when-synic-wasn-t-activated.patch
new file mode 100644
index 00000000000..b16d796527d
--- /dev/null
+++ b/queue-4.9/kvm-x86-forbid-vmm-to-set-synic-stimer-msrs-when-synic-wasn-t-activated.patch
@@ -0,0 +1,65 @@
+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: KVM: x86: Forbid VMM to set SYNIC/STIMER MSRs when SynIC wasn't activated
+
+From: Vitaly Kuznetsov <vkuznets@redhat.com>
+
+commit b1e34d325397a33d97d845e312d7cf2a8b646b44 upstream.
+
+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>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ arch/x86/kvm/hyperv.c |   15 +++++++++++++++
+ 1 file changed, 15 insertions(+)
+
+--- a/arch/x86/kvm/hyperv.c
++++ b/arch/x86/kvm/hyperv.c
+@@ -244,6 +244,9 @@ static int synic_set_msr(struct kvm_vcpu
+ 	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;
+@@ -504,6 +507,12 @@ static int stimer_start(struct kvm_vcpu_
+ static int stimer_set_config(struct kvm_vcpu_hv_stimer *stimer, u64 config,
+ 			     bool host)
+ {
++	struct kvm_vcpu *vcpu = stimer_to_vcpu(stimer);
++	struct kvm_vcpu_hv_synic *synic = vcpu_to_synic(vcpu);
++
++	if (!synic->active && (!host || config))
++		return 1;
++
+ 	trace_kvm_hv_stimer_set_config(stimer_to_vcpu(stimer)->vcpu_id,
+ 				       stimer->index, config, host);
+ 
+@@ -518,6 +527,12 @@ static int stimer_set_config(struct kvm_
+ static int stimer_set_count(struct kvm_vcpu_hv_stimer *stimer, u64 count,
+ 			    bool host)
+ {
++	struct kvm_vcpu *vcpu = stimer_to_vcpu(stimer);
++	struct kvm_vcpu_hv_synic *synic = vcpu_to_synic(vcpu);
++
++	if (!synic->active && (!host || count))
++		return 1;
++
+ 	trace_kvm_hv_stimer_set_count(stimer_to_vcpu(stimer)->vcpu_id,
+ 				      stimer->index, count, host);
+ 
diff --git a/queue-4.9/series b/queue-4.9/series
index 01575459ef8..0b3a45c058e 100644
--- a/queue-4.9/series
+++ b/queue-4.9/series
@@ -160,3 +160,4 @@ asoc-topology-allow-tlv-control-to-be-either-read-or-write.patch
 arm-dts-spear1340-update-serial-node-properties.patch
 arm-dts-spear13xx-update-spi-dma-properties.patch
 openvswitch-fixed-nd-target-mask-field-in-the-flow-dump.patch
+kvm-x86-forbid-vmm-to-set-synic-stimer-msrs-when-synic-wasn-t-activated.patch