From d72e41f9a16360eb23e9d943fa7e33291c5fcd87 Mon Sep 17 00:00:00 2001

From: Paolo Bonzini <pbonzini@redhat.com>

Date: Mon, 17 Feb 2020 16:23:18 -0500

Subject: [PATCH 03/12] target/i386: kvm: initialize feature MSRs very early

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

Message-id: <20200217162323.2572-2-pbonzini@redhat.com>

Patchwork-id: 93896

O-Subject: [RHEL7.9 qemu-kvm-rhev PATCH 1/6] target/i386: kvm: initialize feature MSRs very early

Bugzilla: 1791653

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

RH-Acked-by: Philippe Mathieu-Daudé <philmd@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)

[RHEL7: no MSR_IA32_CORE_CAPABILITY]

Signed-off-by: Jon Maloy <jmaloy.redhat.com>

---

 target/i386/kvm.c      | 55 +++++++++++++++++++++++++++---------------

 target/i386/kvm_i386.h |  1 +

 2 files changed, 36 insertions(+), 20 deletions(-)

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

index a6e5a87cf5..d8a4dbfde3 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),

@@ -1175,6 +1177,8 @@ int kvm_arch_init_vcpu(CPUState *cs)

         has_msr_tsc_aux = false;

     }

+    kvm_init_msrs(cpu);

+

     return 0;

  fail:

@@ -1797,11 +1801,40 @@ static int kvm_put_msr_feature_control(X86CPU *cpu)

     return 0;

 }

+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]);

+    }

+

+    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);

@@ -1856,12 +1889,6 @@ 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]);

-    }

-

     /*

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

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

@@ -2040,19 +2067,7 @@ 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 1de9876cd9..856044750e 100644

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

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

@@ -69,4 +69,5 @@ void kvm_put_apicbase(X86CPU *cpu, uint64_t value);

 bool kvm_enable_x2apic(void);

 bool kvm_has_x2apic_api(void);

+

 #endif

-- 

2.18.2