From a8a32dd460a1d838cfe97ec53a2eb76c018c5dbf Mon Sep 17 00:00:00 2001

From: Paolo Bonzini <pbonzini@redhat.com>

Date: Mon, 22 Jul 2019 18:22:19 +0100

Subject: [PATCH 38/39] target/i386: skip KVM_GET/SET_NESTED_STATE if VMX

 disabled, or for SVM

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

Message-id: <20190722182220.19374-18-pbonzini@redhat.com>

Patchwork-id: 89636

O-Subject: [RHEL-8.1.0 PATCH qemu-kvm v3 17/18] target/i386: skip KVM_GET/SET_NESTED_STATE if VMX disabled, or for SVM

Bugzilla: 1689269

RH-Acked-by: Peter Xu <zhexu@redhat.com>

RH-Acked-by: Laurent Vivier <lvivier@redhat.com>

RH-Acked-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

Do not allocate env->nested_state unless we later need to migrate the

nested virtualization state.

With this change, nested_state_needed() will return false if the

VMX flag is not included in the virtual machine.  KVM_GET/SET_NESTED_STATE

is also disabled for SVM which is safer (we know that at least the NPT

root and paging mode have to be saved/loaded), and thus the corresponding

subsection can go away as well.

Inspired by a patch from Liran Alon.

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

(cherry picked from commit 1e44f3ab71fb4291d266a264f7c207ae5c6d59b2)

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

---

 target/i386/kvm.c     | 16 ++++++++--------

 target/i386/machine.c | 21 +--------------------

 2 files changed, 9 insertions(+), 28 deletions(-)

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

index 0bd286e..8648f1f 100644

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

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

@@ -1220,15 +1220,15 @@ int kvm_arch_init_vcpu(CPUState *cs)

     max_nested_state_len = kvm_max_nested_state_length();

     if (max_nested_state_len > 0) {

         assert(max_nested_state_len >= offsetof(struct kvm_nested_state, data));

-        env->nested_state = g_malloc0(max_nested_state_len);

-        env->nested_state->size = max_nested_state_len;

-

-        if (IS_INTEL_CPU(env)) {

-            struct kvm_vmx_nested_state_hdr *vmx_hdr =

-                &env->nested_state->hdr.vmx;

+        if (cpu_has_vmx(env)) {

+            struct kvm_vmx_nested_state_hdr *vmx_hdr;

+            env->nested_state = g_malloc0(max_nested_state_len);

+            env->nested_state->size = max_nested_state_len;

             env->nested_state->format = KVM_STATE_NESTED_FORMAT_VMX;

+

+            vmx_hdr = &env->nested_state->hdr.vmx;

             vmx_hdr->vmxon_pa = -1ull;

             vmx_hdr->vmcs12_pa = -1ull;

         }

@@ -2966,7 +2966,7 @@ static int kvm_put_nested_state(X86CPU *cpu)

     CPUX86State *env = &cpu->env;

     int max_nested_state_len = kvm_max_nested_state_length();

-    if (max_nested_state_len <= 0) {

+    if (!env->nested_state) {

         return 0;

     }

@@ -2980,7 +2980,7 @@ static int kvm_get_nested_state(X86CPU *cpu)

     int max_nested_state_len = kvm_max_nested_state_length();

     int ret;

-    if (max_nested_state_len <= 0) {

+    if (!env->nested_state) {

         return 0;

     }

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

index 8d90d98..fa8d1cc 100644

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

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

@@ -1004,31 +1004,13 @@ static const VMStateDescription vmstate_vmx_nested_state = {

     }

 };

-static bool svm_nested_state_needed(void *opaque)

-{

-    struct kvm_nested_state *nested_state = opaque;

-

-    return (nested_state->format == KVM_STATE_NESTED_FORMAT_SVM);

-}

-

-static const VMStateDescription vmstate_svm_nested_state = {

-    .name = "cpu/kvm_nested_state/svm",

-    .version_id = 1,

-    .minimum_version_id = 1,

-    .needed = svm_nested_state_needed,

-    .fields = (VMStateField[]) {

-        VMSTATE_END_OF_LIST()

-    }

-};

-

 static bool nested_state_needed(void *opaque)

 {

     X86CPU *cpu = opaque;

     CPUX86State *env = &cpu->env;

     return (env->nested_state &&

-            (vmx_nested_state_needed(env->nested_state) ||

-             svm_nested_state_needed(env->nested_state)));

+            vmx_nested_state_needed(env->nested_state));

 }

 static int nested_state_post_load(void *opaque, int version_id)

@@ -1090,7 +1072,6 @@ static const VMStateDescription vmstate_kvm_nested_state = {

     },

     .subsections = (const VMStateDescription*[]) {

         &vmstate_vmx_nested_state,

-        &vmstate_svm_nested_state,

         NULL

     }

 };

-- 

1.8.3.1