[PULL 15/17] i386: Hyper-V Support extended GVA ranges for TLB flush hypercalls

[Paolo Bonzini <pbonzini@redhat.com>]

From: Vitaly Kuznetsov <vkuznets@redhat.com>

KVM kind of supported "extended GVA ranges" (up to 4095 additional GFNs
per hypercall) since the implementation of Hyper-V PV TLB flush feature
(Linux-4.18) as regardless of the request, full TLB flush was always
performed. "Extended GVA ranges for TLB flush hypercalls" feature bit
wasn't exposed then. Now, as KVM gains support for fine-grained TLB
flush handling, exposing this feature starts making sense.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20220525115949.1294004-5-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 docs/hyperv.txt                | 7 +++++++
 target/i386/cpu.h              | 1 +
 target/i386/kvm/hyperv-proto.h | 1 +
 target/i386/cpu.c              | 2 ++
 target/i386/kvm/kvm.c          | 8 ++++++++
 5 files changed, 19 insertions(+)

diff --git a/docs/hyperv.txt b/docs/hyperv.txt
index af1b10c0b3..4b132b1c94 100644
--- a/docs/hyperv.txt
+++ b/docs/hyperv.txt
@@ -255,6 +255,13 @@ 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.
 
+3.24. hv-tlbflush-ext
+=====================
+Allow for extended GVA ranges to be passed to Hyper-V TLB flush hypercalls
+(HvFlushVirtualAddressList/HvFlushVirtualAddressListEx).
+
+Requires: hv-tlbflush
+
 4. Supplementary features
 =========================
 
diff --git a/target/i386/cpu.h b/target/i386/cpu.h
index 37e9553584..5ff48257e5 100644
--- a/target/i386/cpu.h
+++ b/target/i386/cpu.h
@@ -1108,6 +1108,7 @@ uint64_t x86_cpu_get_supported_feature_word(FeatureWord w,
 #define HYPERV_FEAT_SYNDBG              16
 #define HYPERV_FEAT_MSR_BITMAP          17
 #define HYPERV_FEAT_XMM_INPUT           18
+#define HYPERV_FEAT_TLBFLUSH_EXT        19
 
 #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
index f5f16474fa..c7854ed6d3 100644
--- a/target/i386/kvm/hyperv-proto.h
+++ b/target/i386/kvm/hyperv-proto.h
@@ -59,6 +59,7 @@
 #define HV_FREQUENCY_MSRS_AVAILABLE             (1u << 8)
 #define HV_GUEST_CRASH_MSR_AVAILABLE            (1u << 10)
 #define HV_FEATURE_DEBUG_MSRS_AVAILABLE         (1u << 11)
+#define HV_EXT_GVA_RANGES_FLUSH_AVAILABLE       (1u << 14)
 #define HV_STIMER_DIRECT_MODE_AVAILABLE         (1u << 19)
 
 /*
diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index 63cec0ea68..3429a4e455 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -6972,6 +6972,8 @@ static Property x86_cpu_properties[] = {
                       HYPERV_FEAT_MSR_BITMAP, 0),
     DEFINE_PROP_BIT64("hv-xmm-input", X86CPU, hyperv_features,
                       HYPERV_FEAT_XMM_INPUT, 0),
+    DEFINE_PROP_BIT64("hv-tlbflush-ext", X86CPU, hyperv_features,
+                      HYPERV_FEAT_TLBFLUSH_EXT, 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/kvm/kvm.c b/target/i386/kvm/kvm.c
index 7e6f934eda..a11c8e88f6 100644
--- a/target/i386/kvm/kvm.c
+++ b/target/i386/kvm/kvm.c
@@ -987,6 +987,14 @@ static struct {
              .bits = HV_HYPERCALL_XMM_INPUT_AVAILABLE}
         }
     },
+    [HYPERV_FEAT_TLBFLUSH_EXT] = {
+        .desc = "Extended gva ranges for TLB flush hypercalls (hv-tlbflush-ext)",
+        .flags = {
+            {.func = HV_CPUID_FEATURES, .reg = R_EDX,
+             .bits = HV_EXT_GVA_RANGES_FLUSH_AVAILABLE}
+        },
+        .dependencies = BIT(HYPERV_FEAT_TLBFLUSH)
+    },
 };
 
 static struct kvm_cpuid2 *try_get_hv_cpuid(CPUState *cs, int max,
-- 
2.36.1