From c4660f9a4e2ffde711294ee7c5959f17735fd863 Mon Sep 17 00:00:00 2001

From: Paolo Bonzini <pbonzini@redhat.com>

Date: Thu, 6 Feb 2020 23:51:16 +0000

Subject: [PATCH 2/2] target/i386: kvm: initialize feature MSRs very early

RH-Author: Paolo Bonzini <pbonzini@redhat.com>

Message-id: <20200206235116.19421-2-pbonzini@redhat.com>

Patchwork-id: 93733

O-Subject: [PATCH 1/1] target/i386: kvm: initialize feature MSRs very early

Bugzilla: 1790308

RH-Acked-by: Vitaly Kuznetsov <vkuznets@redhat.com>

RH-Acked-by: Laszlo Ersek <lersek@redhat.com>

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

Some read-only MSRs affect the behavior of ioctls such as

KVM_SET_NESTED_STATE.  We can initialize them once and for all

right after the CPU is realized, since they will never be modified

by the guest.

Reported-by: Qingua Cheng <qcheng@redhat.com>

Cc: qemu-stable@nongnu.org

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

Message-Id: <1579544504-3616-2-git-send-email-pbonzini@redhat.com>

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

(cherry picked from commit 420ae1fc51c99abfd03b1c590f55617edd2a2bed)

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

Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com>

---

 target/i386/kvm.c      | 81 ++++++++++++++++++++++++++++++--------------------

 target/i386/kvm_i386.h |  1 +

 2 files changed, 49 insertions(+), 33 deletions(-)

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

index 92eda8d..e43bcd3 100644

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

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

@@ -65,6 +65,8 @@

  * 255 kvm_msr_entry structs */

 #define MSR_BUF_SIZE 4096

+static void kvm_init_msrs(X86CPU *cpu);

+

 const KVMCapabilityInfo kvm_arch_required_capabilities[] = {

     KVM_CAP_INFO(SET_TSS_ADDR),

     KVM_CAP_INFO(EXT_CPUID),

@@ -1296,6 +1298,8 @@ int kvm_arch_init_vcpu(CPUState *cs)

         has_msr_tsc_aux = false;

     }

+    kvm_init_msrs(cpu);

+

     return 0;

  fail:

@@ -2099,11 +2103,53 @@ static void kvm_msr_entry_add_vmx(X86CPU *cpu, FeatureWordArray f)

                       VMCS12_MAX_FIELD_INDEX << 1);

 }

+static int kvm_buf_set_msrs(X86CPU *cpu)

+{

+    int ret = kvm_vcpu_ioctl(CPU(cpu), KVM_SET_MSRS, cpu->kvm_msr_buf);

+    if (ret < 0) {

+        return ret;

+    }

+

+    if (ret < cpu->kvm_msr_buf->nmsrs) {

+        struct kvm_msr_entry *e = &cpu->kvm_msr_buf->entries[ret];

+        error_report("error: failed to set MSR 0x%" PRIx32 " to 0x%" PRIx64,

+                     (uint32_t)e->index, (uint64_t)e->data);

+    }

+

+    assert(ret == cpu->kvm_msr_buf->nmsrs);

+    return 0;

+}

+

+static void kvm_init_msrs(X86CPU *cpu)

+{

+    CPUX86State *env = &cpu->env;

+

+    kvm_msr_buf_reset(cpu);

+    if (has_msr_arch_capabs) {

+        kvm_msr_entry_add(cpu, MSR_IA32_ARCH_CAPABILITIES,

+                          env->features[FEAT_ARCH_CAPABILITIES]);

+    }

+

+    if (has_msr_core_capabs) {

+        kvm_msr_entry_add(cpu, MSR_IA32_CORE_CAPABILITY,

+                          env->features[FEAT_CORE_CAPABILITY]);

+    }

+

+    /*

+     * Older kernels do not include VMX MSRs in KVM_GET_MSR_INDEX_LIST, but

+     * all kernels with MSR features should have them.

+     */

+    if (kvm_feature_msrs && cpu_has_vmx(env)) {

+        kvm_msr_entry_add_vmx(cpu, env->features);

+    }

+

+    assert(kvm_buf_set_msrs(cpu) == 0);

+}

+

 static int kvm_put_msrs(X86CPU *cpu, int level)

 {

     CPUX86State *env = &cpu->env;

     int i;

-    int ret;

     kvm_msr_buf_reset(cpu);

@@ -2161,17 +2207,6 @@ static int kvm_put_msrs(X86CPU *cpu, int level)

     }

 #endif

-    /* If host supports feature MSR, write down. */

-    if (has_msr_arch_capabs) {

-        kvm_msr_entry_add(cpu, MSR_IA32_ARCH_CAPABILITIES,

-                          env->features[FEAT_ARCH_CAPABILITIES]);

-    }

-

-    if (has_msr_core_capabs) {

-        kvm_msr_entry_add(cpu, MSR_IA32_CORE_CAPABILITY,

-                          env->features[FEAT_CORE_CAPABILITY]);

-    }

-

     /*

      * The following MSRs have side effects on the guest or are too heavy

      * for normal writeback. Limit them to reset or full state updates.

@@ -2331,14 +2366,6 @@ static int kvm_put_msrs(X86CPU *cpu, int level)

         /* Note: MSR_IA32_FEATURE_CONTROL is written separately, see

          *       kvm_put_msr_feature_control. */

-

-        /*

-         * Older kernels do not include VMX MSRs in KVM_GET_MSR_INDEX_LIST, but

-         * all kernels with MSR features should have them.

-         */

-        if (kvm_feature_msrs && cpu_has_vmx(env)) {

-            kvm_msr_entry_add_vmx(cpu, env->features);

-        }

     }

     if (env->mcg_cap) {

@@ -2354,19 +2381,7 @@ static int kvm_put_msrs(X86CPU *cpu, int level)

         }

     }

-    ret = kvm_vcpu_ioctl(CPU(cpu), KVM_SET_MSRS, cpu->kvm_msr_buf);

-    if (ret < 0) {

-        return ret;

-    }

-

-    if (ret < cpu->kvm_msr_buf->nmsrs) {

-        struct kvm_msr_entry *e = &cpu->kvm_msr_buf->entries[ret];

-        error_report("error: failed to set MSR 0x%" PRIx32 " to 0x%" PRIx64,

-                     (uint32_t)e->index, (uint64_t)e->data);

-    }

-

-    assert(ret == cpu->kvm_msr_buf->nmsrs);

-    return 0;

+    return kvm_buf_set_msrs(cpu);

 }

diff --git a/target/i386/kvm_i386.h b/target/i386/kvm_i386.h

index df9bbf3..5748337 100644

--- a/target/i386/kvm_i386.h

+++ b/target/i386/kvm_i386.h

@@ -70,4 +70,5 @@ void kvm_put_apicbase(X86CPU *cpu, uint64_t value);

 bool kvm_enable_x2apic(void);

 bool kvm_has_x2apic_api(void);

+

 #endif

-- 

1.8.3.1