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KVM: nVMX: properly handle errors in nested_vmx_handle_enlightened_vmptrld()

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nested_vmx_handle_enlightened_vmptrld() fails in two cases:
- when we fail to kvm_vcpu_map() the supplied GPA
- when revision_id is incorrect.
Genuine Hyper-V raises #UD in the former case (at least with *some*
incorrect GPAs) and does VMfailInvalid() in the later. KVM doesn't do
anything so L1 just gets stuck retrying the same faulty VMLAUNCH.

nested_vmx_handle_enlightened_vmptrld() has two call sites:
nested_vmx_run() and nested_get_vmcs12_pages(). The former needs to queue
do much: the failure there happens after migration when L2 was running (and
L1 did something weird like wrote to VP assist page from a different vCPU),
just kill L1 with KVM_EXIT_INTERNAL_ERROR.

Reported-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
[Squash kbuild autopatch. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Vitaly Kuznetsov 2020-03-09 16:52:13 +01:00 committed by Paolo Bonzini
parent e942dbf8c5
commit b6a0653ae2
2 changed files with 36 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
arch/x86/kvm/vmx/evmcs.h
View File

@ -198,6 +198,13 @@ static inline void evmcs_sanitize_exec_ctrls(struct vmcs_config *vmcs_conf) {}
static inline void evmcs_touch_msr_bitmap(void) {}
#endif /* IS_ENABLED(CONFIG_HYPERV) */
enum nested_evmptrld_status {
EVMPTRLD_DISABLED,
EVMPTRLD_SUCCEEDED,
EVMPTRLD_VMFAIL,
EVMPTRLD_ERROR,
};
bool nested_enlightened_vmentry(struct kvm_vcpu *vcpu, u64 *evmcs_gpa);
uint16_t nested_get_evmcs_version(struct kvm_vcpu *vcpu);
int nested_enable_evmcs(struct kvm_vcpu *vcpu,

39
arch/x86/kvm/vmx/nested.c
View File

@ -1909,18 +1909,18 @@ static int copy_vmcs12_to_enlightened(struct vcpu_vmx *vmx)
* This is an equivalent of the nested hypervisor executing the vmptrld
* instruction.
*/
static int nested_vmx_handle_enlightened_vmptrld(struct kvm_vcpu *vcpu,
bool from_launch)
static enum nested_evmptrld_status nested_vmx_handle_enlightened_vmptrld(
struct kvm_vcpu *vcpu, bool from_launch)
{
struct vcpu_vmx *vmx = to_vmx(vcpu);
bool evmcs_gpa_changed = false;
u64 evmcs_gpa;
if (likely(!vmx->nested.enlightened_vmcs_enabled))
return 1;
return EVMPTRLD_DISABLED;
if (!nested_enlightened_vmentry(vcpu, &evmcs_gpa))
return 1;
return EVMPTRLD_DISABLED;
if (unlikely(!vmx->nested.hv_evmcs ||
evmcs_gpa != vmx->nested.hv_evmcs_vmptr)) {
@ -1931,7 +1931,7 @@ static int nested_vmx_handle_enlightened_vmptrld(struct kvm_vcpu *vcpu,
if (kvm_vcpu_map(vcpu, gpa_to_gfn(evmcs_gpa),
&vmx->nested.hv_evmcs_map))
return 0;
return EVMPTRLD_ERROR;
vmx->nested.hv_evmcs = vmx->nested.hv_evmcs_map.hva;
@ -1960,7 +1960,7 @@ static int nested_vmx_handle_enlightened_vmptrld(struct kvm_vcpu *vcpu,
if ((vmx->nested.hv_evmcs->revision_id != KVM_EVMCS_VERSION) &&
(vmx->nested.hv_evmcs->revision_id != VMCS12_REVISION)) {
nested_release_evmcs(vcpu);
return 0;
return EVMPTRLD_VMFAIL;
}
vmx->nested.dirty_vmcs12 = true;
@ -1989,7 +1989,7 @@ static int nested_vmx_handle_enlightened_vmptrld(struct kvm_vcpu *vcpu,
vmx->nested.hv_evmcs->hv_clean_fields &=
~HV_VMX_ENLIGHTENED_CLEAN_FIELD_ALL;
return 1;
return EVMPTRLD_SUCCEEDED;
}
void nested_sync_vmcs12_to_shadow(struct kvm_vcpu *vcpu)
@ -3059,8 +3059,21 @@ static bool nested_get_vmcs12_pages(struct kvm_vcpu *vcpu)
* L2 was running), map it here to make sure vmcs12 changes are
* properly reflected.
*/
if (vmx->nested.enlightened_vmcs_enabled && !vmx->nested.hv_evmcs)
nested_vmx_handle_enlightened_vmptrld(vcpu, false);
if (vmx->nested.enlightened_vmcs_enabled && !vmx->nested.hv_evmcs) {
enum nested_evmptrld_status evmptrld_status =
nested_vmx_handle_enlightened_vmptrld(vcpu, false);
if (evmptrld_status == EVMPTRLD_VMFAIL ||
evmptrld_status == EVMPTRLD_ERROR) {
pr_debug_ratelimited("%s: enlightened vmptrld failed\n",
__func__);
vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
vcpu->run->internal.suberror =
KVM_INTERNAL_ERROR_EMULATION;
vcpu->run->internal.ndata = 0;
return false;
}
}
if (nested_cpu_has2(vmcs12, SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES)) {
/*
@ -3325,12 +3338,18 @@ static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch)
enum nvmx_vmentry_status status;
struct vcpu_vmx *vmx = to_vmx(vcpu);
u32 interrupt_shadow = vmx_get_interrupt_shadow(vcpu);
enum nested_evmptrld_status evmptrld_status;
if (!nested_vmx_check_permission(vcpu))
return 1;
if (!nested_vmx_handle_enlightened_vmptrld(vcpu, launch))
evmptrld_status = nested_vmx_handle_enlightened_vmptrld(vcpu, launch);
if (evmptrld_status == EVMPTRLD_ERROR) {
kvm_queue_exception(vcpu, UD_VECTOR);
return 1;
} else if (evmptrld_status == EVMPTRLD_VMFAIL) {
return nested_vmx_failInvalid(vcpu);
}
if (!vmx->nested.hv_evmcs && vmx->nested.current_vmptr == -1ull)
return nested_vmx_failInvalid(vcpu);