i386: Hyper-V XMM fast hypercall input feature

Hyper-V specification allows to pass parameters for certain hypercalls using XMM registers ("XMM Fast Hypercall Input"). When the feature is in use, it allows for faster hypercalls processing as KVM can avoid reading guest's memory. KVM supports the feature since v5.14. Rename HV_HYPERCALL_{PARAMS_XMM_AVAILABLE -> XMM_INPUT_AVAILABLE} to comply with KVM. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Message-Id: <20220525115949.1294004-4-vkuznets@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
qemu · May 25, 2022 · 9411e8b · 9411e8b
1 parent 869840d
commit 9411e8b
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diff --git a/docs/hyperv.txt b/docs/hyperv.txt
@@ -249,6 +249,12 @@ Enlightened VMCS ('hv-evmcs') feature to also be enabled.
 
 Recommended: hv-evmcs (Intel)
 
+3.23. hv-xmm-input
+===================
+Hyper-V specification allows to pass parameters for certain hypercalls using XMM
+registers ("XMM Fast Hypercall Input"). When the feature is in use, it allows
+for faster hypercalls processing as KVM can avoid reading guest's memory.
+
 4. Supplementary features
 =========================
 

diff --git a/target/i386/cpu.c b/target/i386/cpu.c
@@ -6970,6 +6970,8 @@ static Property x86_cpu_properties[] = {
                       HYPERV_FEAT_AVIC, 0),
     DEFINE_PROP_BIT64("hv-emsr-bitmap", X86CPU, hyperv_features,
                       HYPERV_FEAT_MSR_BITMAP, 0),
+    DEFINE_PROP_BIT64("hv-xmm-input", X86CPU, hyperv_features,
+                      HYPERV_FEAT_XMM_INPUT, 0),
     DEFINE_PROP_ON_OFF_AUTO("hv-no-nonarch-coresharing", X86CPU,
                             hyperv_no_nonarch_cs, ON_OFF_AUTO_OFF),
     DEFINE_PROP_BIT64("hv-syndbg", X86CPU, hyperv_features,

diff --git a/target/i386/cpu.h b/target/i386/cpu.h
@@ -1107,6 +1107,7 @@ uint64_t x86_cpu_get_supported_feature_word(FeatureWord w,
 #define HYPERV_FEAT_AVIC                15
 #define HYPERV_FEAT_SYNDBG              16
 #define HYPERV_FEAT_MSR_BITMAP          17
+#define HYPERV_FEAT_XMM_INPUT           18
 
 #ifndef HYPERV_SPINLOCK_NEVER_NOTIFY
 #define HYPERV_SPINLOCK_NEVER_NOTIFY             0xFFFFFFFF

diff --git a/target/i386/kvm/hyperv-proto.h b/target/i386/kvm/hyperv-proto.h
@@ -54,7 +54,7 @@
 #define HV_GUEST_DEBUGGING_AVAILABLE            (1u << 1)
 #define HV_PERF_MONITOR_AVAILABLE               (1u << 2)
 #define HV_CPU_DYNAMIC_PARTITIONING_AVAILABLE   (1u << 3)
-#define HV_HYPERCALL_PARAMS_XMM_AVAILABLE       (1u << 4)
+#define HV_HYPERCALL_XMM_INPUT_AVAILABLE        (1u << 4)
 #define HV_GUEST_IDLE_STATE_AVAILABLE           (1u << 5)
 #define HV_FREQUENCY_MSRS_AVAILABLE             (1u << 8)
 #define HV_GUEST_CRASH_MSR_AVAILABLE            (1u << 10)

diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c
@@ -980,6 +980,13 @@ static struct {
              .bits = HV_NESTED_MSR_BITMAP}
         }
     },
+    [HYPERV_FEAT_XMM_INPUT] = {
+        .desc = "XMM fast hypercall input (hv-xmm-input)",
+        .flags = {
+            {.func = HV_CPUID_FEATURES, .reg = R_EDX,
+             .bits = HV_HYPERCALL_XMM_INPUT_AVAILABLE}
+        }
+    },
 };
 
 static struct kvm_cpuid2 *try_get_hv_cpuid(CPUState *cs, int max,