[PATCH v3 4/8] nSVM: use vmcb_save_area_cached in nested_vmcb_valid_sregs()

Emanuele Giuseppe Esposito
2021-10-11T14:37:47Z

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().

Since we are always checking for the nested struct, it is enough
to have only the vcpu as parameter.

Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
---
arch/x86/kvm/svm/nested.c | 19 ++++++++++++-------
1 file changed, 12 insertions(+), 7 deletions(-)

diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index f6030a202bc5..d07cd4b88acd 100644
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -230,9 +230,10 @@ 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_valid_sregs(struct kvm_vcpu *vcpu)
{
+ struct vcpu_svm *svm = to_svm(vcpu);
+ struct vmcb_save_area_cached *save = &svm->nested.save;
/*
* FIXME: these should be done after copying the fields,
* to avoid TOC/TOU races. For these save area checks
@@ -658,7 +659,7 @@ 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_valid_sregs(vcpu) ||
!nested_vmcb_check_controls(vcpu, &svm->nested.ctl)) {
vmcb12->control.exit_code = SVM_EXIT_ERR;
vmcb12->control.exit_code_hi = 0;
@@ -1355,11 +1356,12 @@ 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(svm, save);
if (!(save->cr0 & X86_CR0_PG) ||
!(save->cr0 & X86_CR0_PE) ||
(save->rflags & X86_EFLAGS_VM) ||
- !nested_vmcb_valid_sregs(vcpu, save))
- goto out_free;
+ !nested_vmcb_valid_sregs(vcpu))
+ goto out_free_save;

/*
* While the nested guest CR3 is already checked and set by
@@ -1371,7 +1373,7 @@ static int svm_set_nested_state(struct kvm_vcpu *vcpu,
ret = nested_svm_load_cr3(&svm->vcpu, vcpu->arch.cr3,
nested_npt_enabled(svm), false);
if (WARN_ON_ONCE(ret))
- goto out_free;
+ goto out_free_save;

/*
@@ -1395,12 +1397,15 @@ static int svm_set_nested_state(struct kvm_vcpu *vcpu,

svm_copy_vmrun_state(&svm->vmcb01.ptr->save, save);
nested_copy_vmcb_control_to_cache(svm, ctl);
- nested_copy_vmcb_save_to_cache(svm, save);

svm_switch_vmcb(svm, &svm->nested.vmcb02);
nested_vmcb02_prepare_control(svm);
kvm_make_request(KVM_REQ_GET_NESTED_STATE_PAGES, vcpu);
ret = 0;
+
+out_free_save:
+ memset(&svm->nested.save, 0, sizeof(struct vmcb_save_area_cached));
+
out_free:
kfree(save);
kfree(ctl);
--
2.27.0