From eb0fc0ae2750a0462698d6d21ebb56a4249539f9 Mon Sep 17 00:00:00 2001

From: Paolo Bonzini <pbonzini@redhat.com>

Date: Mon, 17 Feb 2020 16:23:11 +0000

Subject: [PATCH 1/9] target/i386: kvm: initialize feature MSRs very early

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

Message-id: <20200217162316.2464-2-pbonzini@redhat.com>

Patchwork-id: 93899

O-Subject: [RHEL-AV-8.2.0 qemu-kvm PATCH 1/6] target/i386: kvm: initialize feature MSRs very early

Bugzilla: 1791648

RH-Acked-by: Philippe Mathieu-Daudé <philmd@redhat.com>

RH-Acked-by: Maxim Levitsky <mlevitsk@redhat.com>

RH-Acked-by: Dr. David Alan Gilbert <dgilbert@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: 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 86d9a1f..f41605b 100644

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

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

@@ -67,6 +67,8 @@

  * 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),

@@ -1842,6 +1844,8 @@ int kvm_arch_init_vcpu(CPUState *cs)

         has_msr_tsc_aux = false;

     }

+    kvm_init_msrs(cpu);

+

     r = hyperv_init_vcpu(cpu);

     if (r) {

         goto fail;

@@ -2660,11 +2664,53 @@ 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);

@@ -2722,17 +2768,6 @@ 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.

@@ -2910,14 +2945,6 @@ 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) {

@@ -2933,19 +2960,7 @@ 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 06fe06b..d98c6f6 100644

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

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

@@ -66,4 +66,5 @@ bool kvm_enable_x2apic(void);

 bool kvm_has_x2apic_api(void);

 bool kvm_hv_vpindex_settable(void);

+

 #endif

-- 

1.8.3.1