From: Vitaly Kuznetsov <vkuznets@redhat.com>
To: qemu-devel@nongnu.org, Eduardo Habkost <ehabkost@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
Marcelo Tosatti <mtosatti@redhat.com>,
"Michael S. Tsirkin" <mst@redhat.com>,
Igor Mammedov <imammedo@redhat.com>
Subject: [PATCH v8 8/9] i386: Hyper-V SynIC requires POST_MESSAGES/SIGNAL_EVENTS privileges
Date: Tue, 8 Jun 2021 14:08:16 +0200 [thread overview]
Message-ID: <20210608120817.1325125-9-vkuznets@redhat.com> (raw)
In-Reply-To: <20210608120817.1325125-1-vkuznets@redhat.com>
When Hyper-V SynIC is enabled, we may need to allow Windows guests to make
hypercalls (POST_MESSAGES/SIGNAL_EVENTS). No issue is currently observed
because KVM is very permissive, allowing these hypercalls regarding of
guest visible CPUid bits.
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
---
target/i386/kvm/hyperv-proto.h | 6 ++++++
target/i386/kvm/kvm.c | 6 ++++++
2 files changed, 12 insertions(+)
diff --git a/target/i386/kvm/hyperv-proto.h b/target/i386/kvm/hyperv-proto.h
index e30d64b4ade4..5fbb385cc136 100644
--- a/target/i386/kvm/hyperv-proto.h
+++ b/target/i386/kvm/hyperv-proto.h
@@ -38,6 +38,12 @@
#define HV_ACCESS_FREQUENCY_MSRS (1u << 11)
#define HV_ACCESS_REENLIGHTENMENTS_CONTROL (1u << 13)
+/*
+ * HV_CPUID_FEATURES.EBX bits
+ */
+#define HV_POST_MESSAGES (1u << 4)
+#define HV_SIGNAL_EVENTS (1u << 5)
+
/*
* HV_CPUID_FEATURES.EDX bits
*/
diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c
index 33830117fa31..260c563d59a3 100644
--- a/target/i386/kvm/kvm.c
+++ b/target/i386/kvm/kvm.c
@@ -1343,6 +1343,12 @@ static int hyperv_fill_cpuids(CPUState *cs,
/* Unconditionally required with any Hyper-V enlightenment */
c->eax |= HV_HYPERCALL_AVAILABLE;
+ /* SynIC and Vmbus devices require messages/signals hypercalls */
+ if (hyperv_feat_enabled(cpu, HYPERV_FEAT_SYNIC) &&
+ !cpu->hyperv_synic_kvm_only) {
+ c->ebx |= HV_POST_MESSAGES | HV_SIGNAL_EVENTS;
+ }
+
/* Not exposed by KVM but needed to make CPU hotplug in Windows work */
c->edx |= HV_CPU_DYNAMIC_PARTITIONING_AVAILABLE;
--
2.31.1
next prev parent reply other threads:[~2021-06-08 12:20 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-08 12:08 [PATCH v8 0/9] i386: KVM: expand Hyper-V features early Vitaly Kuznetsov
2021-06-08 12:08 ` [PATCH v8 1/9] i386: avoid hardcoding '12' as 'hyperv_vendor_id' length Vitaly Kuznetsov
2021-06-08 12:12 ` Philippe Mathieu-Daudé
2021-06-08 12:08 ` [PATCH v8 2/9] i386: clarify 'hv-passthrough' behavior Vitaly Kuznetsov
2021-06-08 12:08 ` [PATCH v8 3/9] i386: hardcode supported eVMCS version to '1' Vitaly Kuznetsov
2021-06-08 12:52 ` Eduardo Habkost
2021-06-16 8:12 ` Vitaly Kuznetsov
2021-06-08 12:08 ` [PATCH v8 4/9] i386: make hyperv_expand_features() return bool Vitaly Kuznetsov
2021-06-08 12:08 ` [PATCH v8 5/9] i386: expand Hyper-V features during CPU feature expansion time Vitaly Kuznetsov
2021-06-08 12:08 ` [PATCH v8 6/9] i386: kill off hv_cpuid_check_and_set() Vitaly Kuznetsov
2021-06-08 12:08 ` [PATCH v8 7/9] i386: HV_HYPERCALL_AVAILABLE privilege bit is always needed Vitaly Kuznetsov
2021-06-08 12:08 ` Vitaly Kuznetsov [this message]
2021-06-08 12:08 ` [PATCH v8 9/9] qtest/hyperv: Introduce a simple hyper-v test Vitaly Kuznetsov
2021-06-08 12:52 ` Eduardo Habkost
2021-07-08 21:02 ` Eduardo Habkost
2021-07-09 8:22 ` Igor Mammedov
2021-07-16 12:12 ` Vitaly Kuznetsov
2021-07-19 13:56 ` Igor Mammedov
2021-07-07 14:00 ` [PATCH v8 0/9] i386: KVM: expand Hyper-V features early Eduardo Habkost
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