KVM: nSVM: use vmcb_save_area_cached in nested_vmcb_valid_sregs()

Now that struct vmcb_save_area_cached contains the required
vmcb fields values (done in nested_load_save_from_vmcb12()),
check them to see if they are correct in nested_vmcb_valid_sregs().

While at it, rename nested_vmcb_valid_sregs in nested_vmcb_check_save.
__nested_vmcb_check_save takes the additional @save parameter, so it
is helpful when we want to check a non-svm save state, like in
svm_set_nested_state. The reason for that is that save is the L1
state, not L2, so we check it without moving it to svm->nested.save.

Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Message-Id: <20211103140527.752797-5-eesposit@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index d6c7030e4ac0ab868bd8d7906bae0494a1974c8b..545d0ad19de4d93a600edaaa3b2010cdb8888ce2 100644 (file)
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -245,8 +245,8 @@ static bool nested_vmcb_check_controls(struct kvm_vcpu *vcpu,
 }
 
 /* Common checks that apply to both L1 and L2 state.  */
-static bool nested_vmcb_valid_sregs(struct kvm_vcpu *vcpu,
-                                   struct vmcb_save_area *save)
+static bool __nested_vmcb_check_save(struct kvm_vcpu *vcpu,
+                                    struct vmcb_save_area_cached *save)
 {
        /*
         * FIXME: these should be done after copying the fields,
@@ -286,6 +286,14 @@ static bool nested_vmcb_valid_sregs(struct kvm_vcpu *vcpu,
        return true;
 }
 
+static bool nested_vmcb_check_save(struct kvm_vcpu *vcpu)
+{
+       struct vcpu_svm *svm = to_svm(vcpu);
+       struct vmcb_save_area_cached *save = &svm->nested.save;
+
+       return __nested_vmcb_check_save(vcpu, save);
+}
+
 static
 void __nested_copy_vmcb_control_to_cache(struct vmcb_control_area *to,
                                         struct vmcb_control_area *from)
@@ -694,7 +702,7 @@ int nested_svm_vmrun(struct kvm_vcpu *vcpu)
        nested_copy_vmcb_control_to_cache(svm, &vmcb12->control);
        nested_copy_vmcb_save_to_cache(svm, &vmcb12->save);
 
-       if (!nested_vmcb_valid_sregs(vcpu, &vmcb12->save) ||
+       if (!nested_vmcb_check_save(vcpu) ||
            !nested_vmcb_check_controls(vcpu, &svm->nested.ctl)) {
                vmcb12->control.exit_code    = SVM_EXIT_ERR;
                vmcb12->control.exit_code_hi = 0;
@@ -1330,6 +1338,7 @@ static int svm_set_nested_state(struct kvm_vcpu *vcpu,
                &user_kvm_nested_state->data.svm[0];
        struct vmcb_control_area *ctl;
        struct vmcb_save_area *save;
+       struct vmcb_save_area_cached save_cached;
        unsigned long cr0;
        int ret;
 
@@ -1397,10 +1406,11 @@ static int svm_set_nested_state(struct kvm_vcpu *vcpu,
         * Validate host state saved from before VMRUN (see
         * nested_svm_check_permissions).
         */
+       __nested_copy_vmcb_save_to_cache(&save_cached, save);
        if (!(save->cr0 & X86_CR0_PG) ||
            !(save->cr0 & X86_CR0_PE) ||
            (save->rflags & X86_EFLAGS_VM) ||
-           !nested_vmcb_valid_sregs(vcpu, save))
+           !__nested_vmcb_check_save(vcpu, &save_cached))
                goto out_free;
 
        /*