Commit 1e44f3ab authored by Paolo Bonzini's avatar Paolo Bonzini
Browse files

target/i386: skip KVM_GET/SET_NESTED_STATE if VMX disabled, or for SVM 



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: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 79a197ab

target/i386/kvm.c

+8 −8
Original line number Diff line number Diff line
@@ -1711,15 +1711,15 @@ 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;

        }
@@ -3515,7 +3515,7 @@ 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;

    }
@@ -3529,7 +3529,7 @@ 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;

    }

target/i386/machine.c

+1 −20
Original line number Diff line number Diff line
@@ -1035,31 +1035,13 @@ 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)
@@ -1121,7 +1103,6 @@ static const VMStateDescription vmstate_kvm_nested_state = { 
    },

    .subsections = (const VMStateDescription*[]) {

        &vmstate_vmx_nested_state,

        &vmstate_svm_nested_state,

        NULL

    }

};