From ebfeb40743756dfa7087b43ce4e9afe3e85f9710 Mon Sep 17 00:00:00 2001

From: Marcelo Tosatti <mtosatti@redhat.com>

Date: Wed, 28 Aug 2019 01:00:55 +0200

Subject: [PATCH 1/4] kvm: i386: halt poll control MSR support

RH-Author: Marcelo Tosatti <mtosatti@redhat.com>

Message-id: <20190828010051.GA30252@amt.cnet>

Patchwork-id: 90171

O-Subject: [RHEL-7.8 qemu-kvm PATCH] kvm: i386: halt poll control MSR support

Bugzilla: 1734502

RH-Acked-by: Eduardo Habkost <ehabkost@redhat.com>

RH-Acked-by: Igor Mammedov <imammedo@redhat.com>

RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>

This is the qemu part of the haltpoll driver: allows migrating

the MSR which the guest uses to disable host side polling.

Add support for halt poll control MSR: save/restore, migration

and new feature name.

The purpose of this MSR is to allow the guest to disable

host halt poll.

(cherry picked from commit d645e1328726b38b3c79525eb57842ce29c1df7c)

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

Message-Id: <20190603230408.GA7938@amt.cnet>

[Do not enable by default, as pointed out by Mark Kanda. - Paolo]

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>

---

 linux-headers/asm-x86/kvm_para.h |  2 ++

 target/i386/cpu.c                |  4 +++-

 target/i386/cpu.h                |  1 +

 target/i386/kvm.c                | 15 +++++++++++++++

 target/i386/machine.c            | 20 ++++++++++++++++++++

 5 files changed, 41 insertions(+), 1 deletion(-)

diff --git a/linux-headers/asm-x86/kvm_para.h b/linux-headers/asm-x86/kvm_para.h

index 4c58184..38ab00d 100644

--- a/linux-headers/asm-x86/kvm_para.h

+++ b/linux-headers/asm-x86/kvm_para.h

@@ -27,6 +27,7 @@

 #define KVM_FEATURE_PV_UNHALT		7

 #define KVM_FEATURE_PV_TLB_FLUSH	9

 #define KVM_FEATURE_ASYNC_PF_VMEXIT	10

+#define KVM_FEATURE_POLL_CONTROL	12

 /* The last 8 bits are used to indicate how to interpret the flags field

  * in pvclock structure. If no bits are set, all flags are ignored.

@@ -43,6 +44,7 @@

 #define MSR_KVM_ASYNC_PF_EN 0x4b564d02

 #define MSR_KVM_STEAL_TIME  0x4b564d03

 #define MSR_KVM_PV_EOI_EN      0x4b564d04

+#define MSR_KVM_POLL_CONTROL	0x4b564d05

 struct kvm_steal_time {

 	__u64 steal;

diff --git a/target/i386/cpu.c b/target/i386/cpu.c

index 1f2f286..928e53c 100644

--- a/target/i386/cpu.c

+++ b/target/i386/cpu.c

@@ -903,7 +903,7 @@ static FeatureWordInfo feature_word_info[FEATURE_WORDS] = {

             "kvmclock", "kvm-nopiodelay", "kvm-mmu", "kvmclock",

             "kvm-asyncpf", "kvm-steal-time", "kvm-pv-eoi", "kvm-pv-unhalt",

             NULL, "kvm-pv-tlb-flush", NULL, NULL,

-            NULL, NULL, NULL, NULL,

+            "kvm-poll-control", NULL, NULL, NULL,

             NULL, NULL, NULL, NULL,

             NULL, NULL, NULL, NULL,

             "kvmclock-stable-bit", NULL, NULL, NULL,

@@ -5342,6 +5342,8 @@ static void x86_cpu_initfn(Object *obj)

     object_property_add_alias(obj, "kvm_steal_time", obj, "kvm-steal-time", &error_abort);

     object_property_add_alias(obj, "kvm_pv_eoi", obj, "kvm-pv-eoi", &error_abort);

     object_property_add_alias(obj, "kvm_pv_unhalt", obj, "kvm-pv-unhalt", &error_abort);

+    object_property_add_alias(obj, "kvm_poll_control", obj, "kvm-poll-control",

+                              &error_abort);

     object_property_add_alias(obj, "svm_lock", obj, "svm-lock", &error_abort);

     object_property_add_alias(obj, "nrip_save", obj, "nrip-save", &error_abort);

     object_property_add_alias(obj, "tsc_scale", obj, "tsc-scale", &error_abort);

diff --git a/target/i386/cpu.h b/target/i386/cpu.h

index 8ab313e..095e695 100644

--- a/target/i386/cpu.h

+++ b/target/i386/cpu.h

@@ -1233,6 +1233,7 @@ typedef struct CPUX86State {

     uint64_t steal_time_msr;

     uint64_t async_pf_en_msr;

     uint64_t pv_eoi_en_msr;

+    uint64_t poll_control_msr;

     /* Partition-wide HV MSRs, will be updated only on the first vcpu */

     uint64_t msr_hv_hypercall;

diff --git a/target/i386/kvm.c b/target/i386/kvm.c

index 7afad93..72901e1 100644

--- a/target/i386/kvm.c

+++ b/target/i386/kvm.c

@@ -1199,6 +1199,9 @@ void kvm_arch_reset_vcpu(X86CPU *cpu)

             env->msr_hv_synic_sint[i] = HV_SINT_MASKED;

         }

     }

+

+    /* enabled by default */

+    env->poll_control_msr = 1;

 }

 void kvm_arch_do_init_vcpu(X86CPU *cpu)

@@ -1869,6 +1872,11 @@ static int kvm_put_msrs(X86CPU *cpu, int level)

         if (env->features[FEAT_KVM] & (1 << KVM_FEATURE_STEAL_TIME)) {

             kvm_msr_entry_add(cpu, MSR_KVM_STEAL_TIME, env->steal_time_msr);

         }

+

+        if (env->features[FEAT_KVM] & (1 << KVM_FEATURE_POLL_CONTROL)) {

+            kvm_msr_entry_add(cpu, MSR_KVM_POLL_CONTROL, env->poll_control_msr);

+        }

+

         if (has_architectural_pmu_version > 0) {

             if (has_architectural_pmu_version > 1) {

                 /* Stop the counter.  */

@@ -2241,6 +2249,9 @@ static int kvm_get_msrs(X86CPU *cpu)

     if (env->features[FEAT_KVM] & (1 << KVM_FEATURE_STEAL_TIME)) {

         kvm_msr_entry_add(cpu, MSR_KVM_STEAL_TIME, 0);

     }

+    if (env->features[FEAT_KVM] & (1 << KVM_FEATURE_POLL_CONTROL)) {

+        kvm_msr_entry_add(cpu, MSR_KVM_POLL_CONTROL, 1);

+    }

     if (has_architectural_pmu_version > 0) {

         if (has_architectural_pmu_version > 1) {

             kvm_msr_entry_add(cpu, MSR_CORE_PERF_FIXED_CTR_CTRL, 0);

@@ -2470,6 +2481,10 @@ static int kvm_get_msrs(X86CPU *cpu)

         case MSR_KVM_STEAL_TIME:

             env->steal_time_msr = msrs[i].data;

             break;

+        case MSR_KVM_POLL_CONTROL: {

+            env->poll_control_msr = msrs[i].data;

+            break;

+        }

         case MSR_CORE_PERF_FIXED_CTR_CTRL:

             env->msr_fixed_ctr_ctrl = msrs[i].data;

             break;

diff --git a/target/i386/machine.c b/target/i386/machine.c

index 9e7256a..52b1eae 100644

--- a/target/i386/machine.c

+++ b/target/i386/machine.c

@@ -325,6 +325,14 @@ static bool steal_time_msr_needed(void *opaque)

     return cpu->env.steal_time_msr != 0;

 }

+/* Poll control MSR enabled by default */

+static bool poll_control_msr_needed(void *opaque)

+{

+    X86CPU *cpu = opaque;

+

+    return cpu->env.poll_control_msr != 1;

+}

+

 static const VMStateDescription vmstate_steal_time_msr = {

     .name = "cpu/steal_time_msr",

     .version_id = 1,

@@ -358,6 +366,17 @@ static const VMStateDescription vmstate_pv_eoi_msr = {

     }

 };

+static const VMStateDescription vmstate_poll_control_msr = {

+    .name = "cpu/poll_control_msr",

+    .version_id = 1,

+    .minimum_version_id = 1,

+    .needed = poll_control_msr_needed,

+    .fields = (VMStateField[]) {

+        VMSTATE_UINT64(env.poll_control_msr, X86CPU),

+        VMSTATE_END_OF_LIST()

+    }

+};

+

 static bool fpop_ip_dp_needed(void *opaque)

 {

     X86CPU *cpu = opaque;

@@ -1033,6 +1052,7 @@ VMStateDescription vmstate_x86_cpu = {

         &vmstate_async_pf_msr,

         &vmstate_pv_eoi_msr,

         &vmstate_steal_time_msr,

+        &vmstate_poll_control_msr,

         &vmstate_fpop_ip_dp,

         &vmstate_msr_tsc_adjust,

         &vmstate_msr_tscdeadline,

-- 

1.8.3.1