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| author | Sean Christopherson <sean.j.christopherson@intel.com> | 2020-04-16 03:07:39 +0300 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2020-04-21 16:13:09 +0300 |
| commit | b8d295f96b6c9745d7eebee622690e0e835c63af (patch) | |
| tree | 1ea185121d41d5ec121422bf758397870f05b554 /arch/x86/kvm/vmx/nested.c | |
| parent | c36b71503a2268206ebeda6697094ffb4e7e94c2 (diff) | |
| download | linux-b8d295f96b6c9745d7eebee622690e0e835c63af.tar.xz | |
KVM: nVMX: Remove non-functional "support" for CR3 target values
Remove all references to cr3_target_value[0-3] and replace the fields
in vmcs12 with "dead_space" to preserve the vmcs12 layout. KVM doesn't
support emulating CR3-target values, despite a variety of code that
implies otherwise, as KVM unconditionally reports '0' for the number of
supported CR3-target values.
This technically fixes a bug where KVM would incorrectly allow VMREAD
and VMWRITE to nonexistent fields, i.e. cr3_target_value[0-3]. Per
Intel's SDM, the number of supported CR3-target values reported in
VMX_MISC also enumerates the existence of the associated VMCS fields:
If a future implementation supports more than 4 CR3-target values, they
will be encoded consecutively following the 4 encodings given here.
Alternatively, the "bug" could be fixed by actually advertisting support
for 4 CR3-target values, but that'd likely just enable kvm-unit-tests
given that no one has complained about lack of support for going on ten
years, e.g. KVM, Xen and HyperV don't use CR3-target values.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200416000739.9012-1-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/vmx/nested.c')
| -rw-r--r-- | arch/x86/kvm/vmx/nested.c | 17 |
1 files changed, 0 insertions, 17 deletions
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index 78744c6e4a04..f228339cd0a0 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -1785,10 +1785,6 @@ static int copy_enlightened_to_vmcs12(struct vcpu_vmx *vmx) * vmcs12->vm_exit_msr_store_addr = evmcs->vm_exit_msr_store_addr; * vmcs12->vm_exit_msr_load_addr = evmcs->vm_exit_msr_load_addr; * vmcs12->vm_entry_msr_load_addr = evmcs->vm_entry_msr_load_addr; - * vmcs12->cr3_target_value0 = evmcs->cr3_target_value0; - * vmcs12->cr3_target_value1 = evmcs->cr3_target_value1; - * vmcs12->cr3_target_value2 = evmcs->cr3_target_value2; - * vmcs12->cr3_target_value3 = evmcs->cr3_target_value3; * vmcs12->page_fault_error_code_mask = * evmcs->page_fault_error_code_mask; * vmcs12->page_fault_error_code_match = @@ -1862,10 +1858,6 @@ static int copy_vmcs12_to_enlightened(struct vcpu_vmx *vmx) * evmcs->vm_exit_msr_store_addr = vmcs12->vm_exit_msr_store_addr; * evmcs->vm_exit_msr_load_addr = vmcs12->vm_exit_msr_load_addr; * evmcs->vm_entry_msr_load_addr = vmcs12->vm_entry_msr_load_addr; - * evmcs->cr3_target_value0 = vmcs12->cr3_target_value0; - * evmcs->cr3_target_value1 = vmcs12->cr3_target_value1; - * evmcs->cr3_target_value2 = vmcs12->cr3_target_value2; - * evmcs->cr3_target_value3 = vmcs12->cr3_target_value3; * evmcs->tpr_threshold = vmcs12->tpr_threshold; * evmcs->virtual_processor_id = vmcs12->virtual_processor_id; * evmcs->exception_bitmap = vmcs12->exception_bitmap; @@ -5541,15 +5533,6 @@ static bool nested_vmx_exit_handled_cr(struct kvm_vcpu *vcpu, return true; break; case 3: - if ((vmcs12->cr3_target_count >= 1 && - vmcs12->cr3_target_value0 == val) || - (vmcs12->cr3_target_count >= 2 && - vmcs12->cr3_target_value1 == val) || - (vmcs12->cr3_target_count >= 3 && - vmcs12->cr3_target_value2 == val) || - (vmcs12->cr3_target_count >= 4 && - vmcs12->cr3_target_value3 == val)) - return false; if (nested_cpu_has(vmcs12, CPU_BASED_CR3_LOAD_EXITING)) return true; break; |