[PATCH v4 19/21] i386: introduce kvm_hv_evmcs_available()

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>,
	Igor Mammedov <imammedo@redhat.com>
Subject: [PATCH v4 19/21] i386: introduce kvm_hv_evmcs_available()
Date: Wed, 10 Feb 2021 17:40:31 +0100	[thread overview]
Message-ID: <20210210164033.607612-20-vkuznets@redhat.com> (raw)
In-Reply-To: <20210210164033.607612-1-vkuznets@redhat.com>

Enlightened VMCS feature is hardware specific, it is only supported on
Intel CPUs. Introduce a simple kvm_hv_evmcs_available() helper, it will
be used to filter out 'hv_evmcs' when 'hyperv=on' option is added to
X86MachineClass.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
---
 target/i386/kvm/kvm-stub.c | 5 +++++
 target/i386/kvm/kvm.c      | 8 ++++++++
 target/i386/kvm/kvm_i386.h | 1 +
 3 files changed, 14 insertions(+)

diff --git a/target/i386/kvm/kvm-stub.c b/target/i386/kvm/kvm-stub.c
index 7f175faa3abd..4e486f41a60a 100644
--- a/target/i386/kvm/kvm-stub.c
+++ b/target/i386/kvm/kvm-stub.c
@@ -44,3 +44,8 @@ void kvm_hyperv_expand_features(X86CPU *cpu, Error **errp)
 {
     return;
 }
+
+bool kvm_hv_evmcs_available(void)
+{
+    return false;
+}
diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c
index 480908b2463a..6c26b2091d4a 100644
--- a/target/i386/kvm/kvm.c
+++ b/target/i386/kvm/kvm.c
@@ -96,6 +96,7 @@ static bool has_msr_hv_crash;
 static bool has_msr_hv_reset;
 static bool has_msr_hv_vpindex;
 static bool hv_vpindex_settable;
+static bool hv_evmcs_available;
 static bool has_msr_hv_runtime;
 static bool has_msr_hv_synic;
 static bool has_msr_hv_stimer;
@@ -195,6 +196,11 @@ bool kvm_hv_vpindex_settable(void)
     return hv_vpindex_settable;
 }
 
+bool kvm_hv_evmcs_available(void)
+{
+    return hv_evmcs_available;
+}
+
 static int kvm_get_tsc(CPUState *cs)
 {
     X86CPU *cpu = X86_CPU(cs);
@@ -2235,6 +2241,8 @@ int kvm_arch_init(MachineState *ms, KVMState *s)
     has_pit_state2 = kvm_check_extension(s, KVM_CAP_PIT_STATE2);
 
     hv_vpindex_settable = kvm_check_extension(s, KVM_CAP_HYPERV_VP_INDEX);
+    hv_evmcs_available =
+        kvm_check_extension(s, KVM_CAP_HYPERV_ENLIGHTENED_VMCS);
 
     has_exception_payload = kvm_check_extension(s, KVM_CAP_EXCEPTION_PAYLOAD);
     if (has_exception_payload) {
diff --git a/target/i386/kvm/kvm_i386.h b/target/i386/kvm/kvm_i386.h
index f1176491051d..0fa00511be27 100644
--- a/target/i386/kvm/kvm_i386.h
+++ b/target/i386/kvm/kvm_i386.h
@@ -48,6 +48,7 @@ bool kvm_has_waitpkg(void);
 
 bool kvm_hv_vpindex_settable(void);
 void kvm_hyperv_expand_features(X86CPU *cpu, Error **errp);
+bool kvm_hv_evmcs_available(void);
 
 uint64_t kvm_swizzle_msi_ext_dest_id(uint64_t address);
 
-- 
2.29.2


