[PATCH v5 4/7] nSVM: use vmcb_save_area_cached in nested_vmcb_valid_sregs()

Emanuele Giuseppe Esposito
2021-11-03T14:06:35Z

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 just check it.

Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
---
arch/x86/kvm/svm/nested.c | 18 ++++++++++++++----
1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index 162b338a6c74..64fb43234e06 100644
--- 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;

/*
--
2.27.0