* [PATCH v2 1/2] i386: introduce kvm_hv_evmcs_available()
2020-12-17 12:49 [PATCH v2 0/2] i386: simplify Hyper-V enlightenments enablement Vitaly Kuznetsov
@ 2020-12-17 12:49 ` Vitaly Kuznetsov
2020-12-17 12:49 ` [PATCH v2 2/2] i386: provide simple 'hyperv=on' option to x86 machine types Vitaly Kuznetsov
1 sibling, 0 replies; 3+ messages in thread
From: Vitaly Kuznetsov @ 2020-12-17 12:49 UTC (permalink / raw)
To: qemu-devel; +Cc: Paolo Bonzini, Marcelo Tosatti, Eduardo Habkost
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-stub.c | 5 +++++
target/i386/kvm.c | 8 ++++++++
target/i386/kvm_i386.h | 1 +
3 files changed, 14 insertions(+)
diff --git a/target/i386/kvm-stub.c b/target/i386/kvm-stub.c
index 92f49121b8fa..0a163ae207c5 100644
--- a/target/i386/kvm-stub.c
+++ b/target/i386/kvm-stub.c
@@ -39,3 +39,8 @@ bool kvm_hv_vpindex_settable(void)
{
return false;
}
+
+bool kvm_hv_evmcs_available(void)
+{
+ return false;
+}
diff --git a/target/i386/kvm.c b/target/i386/kvm.c
index bcfa4b03e077..96395d499729 100644
--- a/target/i386/kvm.c
+++ b/target/i386/kvm.c
@@ -95,6 +95,7 @@ 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;
@@ -192,6 +193,11 @@ 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);
@@ -2124,6 +2130,8 @@ 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_i386.h b/target/i386/kvm_i386.h
index dc725083891c..08968cfb33f1 100644
--- a/target/i386/kvm_i386.h
+++ b/target/i386/kvm_i386.h
@@ -47,6 +47,7 @@ bool kvm_has_x2apic_api(void);
bool kvm_has_waitpkg(void);
bool kvm_hv_vpindex_settable(void);
+bool kvm_hv_evmcs_available(void);
uint64_t kvm_swizzle_msi_ext_dest_id(uint64_t address);
--
2.29.2
^ permalink raw reply related [flat|nested] 3+ messages in thread* [PATCH v2 2/2] i386: provide simple 'hyperv=on' option to x86 machine types
2020-12-17 12:49 [PATCH v2 0/2] i386: simplify Hyper-V enlightenments enablement Vitaly Kuznetsov
2020-12-17 12:49 ` [PATCH v2 1/2] i386: introduce kvm_hv_evmcs_available() Vitaly Kuznetsov
@ 2020-12-17 12:49 ` Vitaly Kuznetsov
1 sibling, 0 replies; 3+ messages in thread
From: Vitaly Kuznetsov @ 2020-12-17 12:49 UTC (permalink / raw)
To: qemu-devel; +Cc: Paolo Bonzini, Marcelo Tosatti, Eduardo Habkost
Enabling Hyper-V emulation for a Windows VM is a tiring experience as it
requires listing all currently supported enlightenments ("hv_*" CPU
features) explicitly. We do have a 'hv_passthrough' mode enabling
everything but it can't be used in production as it prevents migration.
Introduce a simple 'hyperv=on' option for all x86 machine types enabling
all currently supported Hyper-V enlightenments. Later, when new
enlightenments get implemented, we will be adding them to newer machine
types only (by disabling them for legacy machine types) thus preserving
migration.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
---
docs/hyperv.txt | 8 ++++++++
hw/i386/x86.c | 42 ++++++++++++++++++++++++++++++++++++++++++
include/hw/i386/x86.h | 7 +++++++
3 files changed, 57 insertions(+)
diff --git a/docs/hyperv.txt b/docs/hyperv.txt
index 5df00da54fc4..1a76a07f8417 100644
--- a/docs/hyperv.txt
+++ b/docs/hyperv.txt
@@ -29,6 +29,14 @@ When any set of the Hyper-V enlightenments is enabled, QEMU changes hypervisor
identification (CPUID 0x40000000..0x4000000A) to Hyper-V. KVM identification
and features are kept in leaves 0x40000100..0x40000101.
+Hyper-V enlightenments can be enabled in bulk by specifying 'hyperv=on' to an
+x86 machine type:
+
+ qemu-system-x86_64 -machine q35,accel=kvm,kernel-irqchip=split,hyperv=on ...
+
+Note, new enlightenments are only added to the latest (in-develompent) machine
+type, older machine types keep the list of the supported features intact to
+safeguard migration.
3. Existing enlightenments
===========================
diff --git a/hw/i386/x86.c b/hw/i386/x86.c
index 49e1d419b2ce..7a8e0313aedb 100644
--- a/hw/i386/x86.c
+++ b/hw/i386/x86.c
@@ -418,6 +418,18 @@ void x86_cpu_pre_plug(HotplugHandler *hotplug_dev,
cs->cpu_index = idx;
numa_cpu_pre_plug(cpu_slot, dev, errp);
+
+ if (x86ms->hyperv_enabled) {
+ X86MachineClass *x86mc = X86_MACHINE_GET_CLASS(x86ms);
+ uint64_t hyperv_features = x86mc->default_hyperv_features;
+
+ /* Enlightened VMCS is only available on Intel/VMX */
+ if (!kvm_hv_evmcs_available()) {
+ hyperv_features &= ~BIT(HYPERV_FEAT_EVMCS);
+ }
+
+ cpu->hyperv_features |= hyperv_features;
+ }
}
CpuInstanceProperties
@@ -1199,6 +1211,20 @@ static void x86_machine_set_acpi(Object *obj, Visitor *v, const char *name,
visit_type_OnOffAuto(v, name, &x86ms->acpi, errp);
}
+static bool x86_machine_get_hyperv(Object *obj, Error **errp)
+{
+ X86MachineState *x86ms = X86_MACHINE(obj);
+
+ return x86ms->hyperv_enabled;
+}
+
+static void x86_machine_set_hyperv(Object *obj, bool value, Error **errp)
+{
+ X86MachineState *x86ms = X86_MACHINE(obj);
+
+ x86ms->hyperv_enabled = value;
+}
+
static void x86_machine_initfn(Object *obj)
{
X86MachineState *x86ms = X86_MACHINE(obj);
@@ -1222,6 +1248,16 @@ static void x86_machine_class_init(ObjectClass *oc, void *data)
x86mc->save_tsc_khz = true;
nc->nmi_monitor_handler = x86_nmi;
+ /* Hyper-V features enabled with 'hyperv=on' */
+ x86mc->default_hyperv_features = BIT(HYPERV_FEAT_RELAXED) |
+ BIT(HYPERV_FEAT_VAPIC) | BIT(HYPERV_FEAT_TIME) |
+ BIT(HYPERV_FEAT_CRASH) | BIT(HYPERV_FEAT_RESET) |
+ BIT(HYPERV_FEAT_VPINDEX) | BIT(HYPERV_FEAT_RUNTIME) |
+ BIT(HYPERV_FEAT_SYNIC) | BIT(HYPERV_FEAT_STIMER) |
+ BIT(HYPERV_FEAT_FREQUENCIES) | BIT(HYPERV_FEAT_REENLIGHTENMENT) |
+ BIT(HYPERV_FEAT_TLBFLUSH) | BIT(HYPERV_FEAT_EVMCS) |
+ BIT(HYPERV_FEAT_IPI) | BIT(HYPERV_FEAT_STIMER_DIRECT);
+
object_class_property_add(oc, X86_MACHINE_SMM, "OnOffAuto",
x86_machine_get_smm, x86_machine_set_smm,
NULL, NULL);
@@ -1233,6 +1269,12 @@ static void x86_machine_class_init(ObjectClass *oc, void *data)
NULL, NULL);
object_class_property_set_description(oc, X86_MACHINE_ACPI,
"Enable ACPI");
+
+ object_class_property_add_bool(oc, X86_MACHINE_HYPERV,
+ x86_machine_get_hyperv, x86_machine_set_hyperv);
+
+ object_class_property_set_description(oc, X86_MACHINE_HYPERV,
+ "Enable Hyper-V enlightenments");
}
static const TypeInfo x86_machine_info = {
diff --git a/include/hw/i386/x86.h b/include/hw/i386/x86.h
index 56080bd1fb14..c6e9c8500357 100644
--- a/include/hw/i386/x86.h
+++ b/include/hw/i386/x86.h
@@ -38,6 +38,9 @@ struct X86MachineClass {
bool save_tsc_khz;
/* Enables contiguous-apic-ID mode */
bool compat_apic_id_mode;
+
+ /* Hyper-V features enabled with 'hyperv=on' */
+ uint64_t default_hyperv_features;
};
struct X86MachineState {
@@ -72,10 +75,14 @@ struct X86MachineState {
* will be translated to MSI messages in the address space.
*/
AddressSpace *ioapic_as;
+
+ /* Hyper-V emulation */
+ bool hyperv_enabled;
};
#define X86_MACHINE_SMM "smm"
#define X86_MACHINE_ACPI "acpi"
+#define X86_MACHINE_HYPERV "hyperv"
#define TYPE_X86_MACHINE MACHINE_TYPE_NAME("x86")
OBJECT_DECLARE_TYPE(X86MachineState, X86MachineClass, X86_MACHINE)
--
2.29.2
^ permalink raw reply related [flat|nested] 3+ messages in thread